HYDROSTATICKS; 
 
 O R, 
 
 The Weight, Force , and Preffure of 
 
 FLUID BODIES, 
 
 Made evident by Thyfical % and 
 Senftble Experiments, 
 
 TOGETHER 
 
 VVithfome Mifccllany Obferyati* 
 uns , the Jail whereof is a (hort 
 Hiflory of Coal, and of alhthe 
 
 Common , and Proper Accidents thereof; 
 a Subject never treated of before. 
 
To my very Honourable, and Noble I, o $.d, 
 
 R O B E R T 
 
 VISCOUNT of OXFUIRD, 
 
 LORD MACRGILL of COUSLAND. «» 
 
 My Noble Lord, , ' 
 
 He firft application I make, is 
 forpWo^that I have adventu¬ 
 red to prefix your nameto the 
 Frontifyiceoi thisW orkywhich 
 in it fclf,. cannot he thought 
 worthy of your Trufi andFroU’ffm ; there be¬ 
 ing no proportion between the greatnefs of 
 you r Merit ,and ib mean an Oblation ; fave what 
 flows from the Noblenefs of the SnbjeH, and 
 the fincerity of his refpeds whoprefents it* 
 It is truly a part of FHlofofby , that was 
 
' The Epftle Dedicatory, 
 
 never much Cultivated, but of late, ex* 
 cept in a more abftrad and fubril way, which 
 did render it lefs ufeful ; but is now more 
 improven by fenfible Manifeftationr of the So* 
 veraign Miftrifs of Arts, Nature her felf. 
 There are indeed ("my Lord) many excellent 
 Sciences , which do merit the favour of your 
 Lordfhips ftudies, and by which your Noble 
 Accomplishments might be more improven ; 
 yeti am bold to affirm, you cannot apply your 
 Noble Mind to any pair of PbiJofo/by, where 
 you will find more Pleafure, with lefs Pains- 
 more evidence of Reafon, with lefs Difficulty. 
 
 The famous Gregorio Leti, was fo much an 
 admirer of your Venues , that he fheltered urn 
 der your P atrocity, his Vita Di SiHo quintoPon- 
 tefece Romano . And if you were able to pro- 
 ted an envyed/tatoin Italy ,much more may 
 I exped full fecurity from your Name in 
 Scotland , where your intereft and relations are 
 fo confiderable. And if he, who only look'd up u 
 on your Vertuom Mind, while it was but blof- 
 foming, was fo much.perfwaded.to judge none 
 
 more 
 
The Epifile dedicatory. 
 more fit to Receive, Proted, and Claim his 
 Labours, much more I, who have feen the ac¬ 
 complishment of your Virtues at home . I 
 have likewife very much confidence of your 
 Noble and Candid Difpofition to" admit this 
 into your Favour , and aflfurance of your Af- 
 fedion and Skill, to Love it, and Underftand 
 it ; both which are cenfpicuous, the firft in 
 your encouragement to all Learning , the other 
 in your Capacity and Underftanding to com¬ 
 prehend , whatever you encourage. 
 
 Though (my Lord) I have been much 
 emboldened to offer this Dedication to your 
 Lordftiip, upon the account of your own He- 
 roic\Vertues , yet l mu ft not pafs over in fi- 
 lence, a moft fpecial Motive, which to me Shall 
 be the laft, fparing to expreft all the great 
 Caufes oblieging me fo to do } and that is, the 
 Memory of your Worthy and neareft Re¬ 
 lations , who are, my Lord your Father , Grand¬ 
 father , and Great-Grand-father , not only me¬ 
 morable for their Vertne and Learning, and 
 peculiar Endowments, whereby they were 
 
The Efiftle Dedicatory , 
 
 thought worthy to ferve, their King and Conn* 
 trey, in Council, and Honourable Courts ofjnfm 
 for thefe many years, but for the Dignity and 
 Antiquity of their famous Anceflours. How old 
 your Lordfhips Name is, Buchanan teftifies in 
 the clofe of the Second Boofy of his Hijlory , who 
 Writeth thus, Certe Gildus letmefl in Scotia No . 
 men, ut veins Mac%gildornm,feve MacJ\gi!lorum 
 gens indicat: e cuj vs goffer is bonefa adhuc in Sco¬ 
 tia d? Anglia flint familu. That is, Surely 
 Gild is an ancient Name in Scotland, as mtnefs 
 the old Family of Mackgilds, or Mackgills: 
 of ivhofe Pc ferity there are yet in Scotland and 
 England many Families of good account. And 
 as aninftanceof this, ihe fame Author tells 
 us of the Great Thane o/Galloway, Mac\gil - 
 him Gallovidk longb Potentifsimum , in the life of 
 MacJfeth , who by this Vfurger was put to 
 death for his adherence to his Prince , from 
 whom your Lordfnip, and your worthy Pro¬ 
 genitors are Lineally defcended, and of whom 
 'Buchanan meant iiKhe foregoing paflage/ince 
 your Predcceffors flouriflit in lus time ■ your 
 
7 he Epiflle Dedicatory. 
 
 CjreatMrand'Father having then been His 
 Maje/lies Advocat, his Brother Lord Regifler . 
 
 Having now ( m y Noble Lord) laid be¬ 
 fore you fo many confiderable Motive$,which 
 I humbly defire may prevail, 1 cannot but 
 make my next Application for Acceptance, and 
 ferioufly intreat this/fV^may be received into 
 the Tuition of your Favour, and get a full 
 Trot eft ion from the Cenforious, and being en- 
 lightned with the fplendor ofyour J\(me ,and 
 receiving the imprefsion of your ^Authority 
 upon it, may fafely pafs thorow the World, 
 for which fingular Favour, I lhall fervent* 
 ly wifh to your Self and Noble Family, 
 all Profperity, andHappinefs, and (hall think 
 my fdf very happy under the Character of, 
 
 Edinburgh $[zyio] 
 {the day ofyour Lo. 
 
 My Noble Lord, 
 Your Lo. mofi humble and 
 
 rity) 1672. 
 
 GEO RGE SINCLAR; 
 
 io 
 
TO THE 
 
 READER. 
 
 Courteous Reader, 
 
 Shall not detain thee in the entry with a long Preface, 
 but give a jhort account of vohat is needful to be known , 
 of the Caufe, Occafion, and Matter of the following 
 Treatije. After the publication of my laft Piece, about 
 the W eight and Preflure of the Air, I found it need¬ 
 ful to treat of the PrefiTure of the Water, bicaufe of the near relation 
 between the two: the operations , and effects of both depending almofi 
 upon the fame Principles and Cmfes.Andtbat there are many things , 
 which cannot throughly be under food, of the Pteffure of the Air, 
 without the knowledge of the PreflTure of the Water : therefore to 
 make the firfl the more evident , 1 have fpoken of the fecond: the 
 effects and operations of Hydroftatical Experiments , being more 
 confpicuous andfenfible , then the effects and operations of the otl ^ t 
 
 The Occafion was feme [pare time I had now and then, for making 
 fome Trials.- part whereof are publifhed here ; the re(l being rather 
 fome productions of Reafov, attentively exercifed on that Subject » 
 which notwithstanding may be called Experiments, though never 
 actually tried , nor haply can be^ becaufe of fome accidental impe¬ 
 diments: yet [uppoftng they were, I make it evident , thatfuch and 
 fuch Phenomena would follow^ whencefnany neceffary concluftons are 
 inferred. 
 
 As for thefubjeCt matter , there are frfl, moe then thirty Theo- . 
 reins order to the Preflure 0/Fluid Bodies, as Air, Water, and 
 Mercury, which in effect are nothing elfe , but fo many concluftons 
 rationally deduced from various and diverfe cffeCts of Aeroftatical, 
 Hydroftatical, and Hydrargyroftatical Experiments, which for the 
 mfi part, I have tried my [elf 
 
 There are next twenty Experiments briefly deferibed , by their own 
 ! 1 diflin # 
 
To the Reader. i 
 
 afithcl Schematifms their Phenomena, according to the Lam of 
 the Hydroftaticks arc fal vcd,and [everal new concltifms inferred. A \ 
 
 propofal is likewife made of a mo> : convenient Engine for Diving, j 
 Here, [everal difficulties are propofed, and anfwered, and all the oh- ' 
 vims Phenomena of Diving explicated.lfthe Lead which finks the 
 Ark, be judged too weighty and big, which may render it not fo 
 tractable, and likewife hinder the Ark from going jo near to the 
 ground, as is deferable, and in [owe meafure fop the fight, (which 
 troubles are (ifnppo(t) incident to tbeBtUalfo) it may be reduced 
 to a far lefs weight , and quantity, and the overplus being made 
 (quart and thin pieces, may line the mouth of the Ark without, be¬ 
 tween P SL &r ‘d L -’A according to the Figure 2.5, or may be put to, 
 or taken away at pleasure. The Bell may have likewife in fiead of 
 this troublefome Foot-board, a weighty Ring of Lead, or two, to go 
 round about the orifice without jn form of a Girth, or Belt, which may 
 flip off and on at pleafure, and will as conveniently fink it, as if it 
 'hada weight appended : the Foot-board then may be of any form, 
 quantity, or weight you pleafe. 
 
 There are thirdly feme Mifcellany Obfervations, the defignof 
 which is only Philofophical. Some of them are Experiments made 
 with the Air-pump, which I have adventured to infert here, even 
 though the Noble Mr. Boyl hath given an account of many. But be- 
 cav.fi the Engine was offered to me by the Laird oi Salton, a Gentle" 
 man of a choife Spirit, l could not, but in obedience to bis commands 
 make tif ? of it, andfhew him the Produtf. There are alfo two or three 
 o’jfe; vat ions in the clo ft , as that of the Primum vivens in Ani¬ 
 mals : of the Aliment,and growth of plants:^ of the motion of the 
 Aliment in Trees. To all which is added a jhort Hiftory oiCoa \,which 
 l hope will be acceptable to feme this fo needful a fubj eel,never hein? 
 treated of before by any. in it, mention is made of things common fo 
 Coal in general,as Dipps, Rifings, and Streeks. Next, ofG aes, or 
 Dykes, which prove fo troublefome Jometimes to the working of Coal. 
 Thirdly, of Damps, and Wild-fire. Next , a method is taught for 
 trying of Grounds,where never any Coal was dt[coveredbefore. And 
 iafriy. the manner how Levels, or Conduits under-ground\ ought to 
 b carried on, for draining the Coal, and freeing it of Water, 
 
 When 
 
To the Reader, 
 
 Wbenthis Boob was fir ft committed to the Prefs, I fent an intima¬ 
 tion thereof to (ome of my friends,for their encouragment to it , 4 
 Brattice now common, And commendable, which hath not wanted a 
 \ considerable juccefs, os witnefsthe refpett of many worthy per fens, to 
 ‘ whom I am oblidged. Bat there is a Generation , that rather, than 
 1 they will encourage any new Invention, fet them]elves by all means to 
 1 detratt from it,and the Authors of it: fo grieved are they, that 
 ; 0U ght of this hind fhouldfall into the hands of any , hut their own. 
 And therefore. if the Author fhallgive hut the title ofNzwto his In- 
 l vtntion, though never foidejervedly, they fly prefently in his throat, 
 
 | like fo many Wild-Catts, fludying either to Ridicule^/'/ work alto- 
 ? gether. a trade that ufually, the per (on of weakefl abilities, andmofl 
 ; empty heads, are better at, than learned men, like thoje Schollars,who 
 being nimble inputting tricks,and impoflures upon their Condifciples, 
 were dolts, as to their Leffon , or elfefall upon it with fuch {nailing, 
 
 \ and carping, as dtfeover, neither ingenuity , nor ingenioufnefs, but a 
 Iforeficknefs, called Envy. 
 
 In the Intimation, I affrmed, that the Vottrine concerning the 
 Weight, and Preflure of the Water was New. This one word,like 
 a (fark of Fire falling accidentally among Powder, hath been the occa- 
 ' f on offo much debate. Their ground is, hecaufe they look upon the' 
 
 \ Hydroftaticks, as a Science long ago perfefted, feing Archimedes 
 *2000 years ago hath demon fir at the Water to have a Preflure, and 
 1 fame ’others ft nee, as Stevinus. They affrm hkewife, that all the - 
 ’ Theorems^^ExperimentSj^r^ here,are either deductable from 
 Archimedes, and Stevinus, or are the fame with theirs, if theft 
 
 ■ Gentlemen had fufp ended their judgment^ till this Book had been pub- 
 lifhed, I fuffett they would not have ffoteen fo confidently. For Ar- 
 ichimedes his propofit ions, they are hut few, and proven ( as Mr Boyl 
 \faith ) by no very eafie demonftrations, which have more of Geo¬ 
 metrical fubcilicy, than ufefulnefs in them. But theft,which are here 
 .propo fed, are not only ufeful, but evidently evicted by reafon, and fen- 
 
 I Mbit Experiments, even to the meanefl capacities. And though 
 I (me of mine,may ( perhaps ) co-incide with jome of his, which to me 
 pf but accidental, yet our way ofprocedmris toco Coelo different. 
 His way is more Speculative;^# is morePafticalHii demonstrations 
 1 q a_ an 
 
To the Reader, | 
 
 ^Geometrical .• theft are Phyfical. His propofitions dre but for 
 the life of a few theft art for the ufe of all. His art not illufirated, J 
 and confirmed by Hydroftatical Experiments." thefeare, ' f, 
 
 Stevinus a late Writer keeps that fame method. Tet I judge it 
 eafie t$ let fee, even in the entry , how little cogent fome of his demon - 
 firations are, without derogating from fuch a Learned (JMav, He 
 hath indeed fome Pragmatical Examples ( as he calls them) foril- ■, 
 hfirating fome of his Geometrical Propofitions , anent the PrefTure 
 of the Water 5 but I leave them to be confiaeredby the judicious and 
 under fiar ding. Again, in this Method , 1 am yet as much different 
 from ethers, who have written lately, as fromtheje I have been ffe ak¬ 
 in g of ,. For, I not only treat of the Prttt'wtcfthe Water, but takes : 
 in with it, the P; eft'ure of the Air joy ntly ; ft nee to explicat fuffici- ) 
 t fitly the Phenomena of the Hydroftaticks , without it, it is impof- If 
 fible. And yet fader, I not only count erpoift hdwith Water, but ■ 
 Air with Mercury ,and Water with Mercury,^ which means feveral | 
 myflerjes, andfecretsin this Art, are difeovered. f 
 
 There are feveral Inventions found cut of late in the Hydrofh- 1 
 ticks, whofe e~ ents and efi els, cannot be clearly deduced from the 
 grounds of Archimedes, and Stevinus, who had not. that clear difeo- 
 %ery 'for ought we know) of the PrefTure of the Air, that fome now 
 have, without which, theft efeels can never be fuffciently explain - . 
 ed. And who doubts, but others afterwards, may make farder difeo- 
 v. tries, and profit the world yet more , with their Inventions, then any 
 have yet dme.Is then the Hydroftaticks,a Science long ago perfect¬ 
 ed? To this Pedantick Conceit, I mufl again oppofe the judgment 
 of Mr. Boyl, who faith moreover, that the ufefulnefs of this part of 
 Philoiophv hath been fcarce known any farder than by name, even 
 lq the generality of learned men. 
 
 But let us fuppofe,that the notion of the PrefTure of theWnctfisof 
 an i Id date, events eld as the Flood (for Noah furelyhew, that the 
 Prefliire of the Water, wouldfufiain the Ark) and (giving, hut 
 not granting) that Archimedes 2000 years age hath written all the 
 Principles of the Hydroftaticks, doth this hinder any man now,fiom 
 deducing new Conclufions from thefe old Principles i But then 
 it hereto fuch things for neither inthisgner in my lafi piece, are my. 
 
To the Reader. 
 
 Adverfaries able to trace me. ’Tis like thepurpojes maid have been 
 (o much the better , if l hid followed other mens foot dtp: and it is 
 like they might have been fo much the worfe, I doubt not, but I have 
 lighted upon other mens thoughts in fome things: and others writ- 
 ting on this fame [nhjcB , who perhaps are my Antipodes , may fad 
 uponmine, cJWj Antagonifts<i/)fr7#, they are able to deduce all my 
 Theorems, and the events ofall my Experiments/™/*; the grounds of 
 Archimedes and Scevinus, if they take not their word again, / 
 hop they will do it \ for now l put them to it. And though they jhould, 
 
 (which I am not afraid they (had do in ha(le ) yet they mufi prove 
 next,that thefe Theorems and Conclufions, fo deduced, are not new, 
 which all their Logick will not prove, But what if we do more , (fay 
 they) even overthrow many of all your Aerofhtical .WHydioftacical 
 Experiments,/^ this,and in your laft Peice? I give you liberty,and for 
 your hire , a Guiny for each Theorem, or Experment, you are able 
 toranfack, in either of the two Bocks, though they come near to an 
 hundred. But, ye mufl oblige your [elves ( my Matte: s) to do it with 
 Reafon, laying a fide your Sophiftry and C anina eloquentia. And 
 this 1 offer. Reader , that I may reduce them, to a better humour, and 
 encourage them to leave of flyting, and only uje reafon. Neither 
 mu (l tiny belike the Wafp, that only lights upon the fore place. But 
 if they love to kindle ary more fire, they will find me proofagainft it, 
 if it burn them , it fall not heat me. Neverthelefs , if they love to 
 juik under deck, like Green-horns, having no courage in themfelves , 
 or confidence in their caufe, they mufl excufc me, if at laft , 1 write 
 their names upon a Ticket, and bring them above deck. This is all 
 
 I have to fay, at prefent (Reader) and 1 bid thee farewell. 
 
 ERRATA. 
 
 Pag. 21. lin. 8. for weight read benfil. Pag. 18$. ltn. 44. for E H, F.H. 
 
 Pag.135.lin.14, for yoo.rtad 5000. Pag. 307.lm 46 . read promoting. Pag.313. 
 lin.2i,rMdrcfle&ion.lM. lin.25. read claborarint.Pag^ry.lio.J.rMd&magiii. 
 
 Note, that in placing the Figures, the 12, that (hould have the fourth place in 
 die third Plate, hath the firti place in the fourth. 
 
 Contents 
 
Contents of the Exp e r i m e n t s. 
 
 T He firft, fecond, and third 
 Experiment,touching the 
 rifing and filling down or Water 
 in Tubs of different fizes. 
 
 37-4i. 44. 
 The fourth :s a Hf dr0flatted 
 Ext>cri?ncnt,ihz\v.ng the Reafon 
 why the Mercurid Cylinder rifts, 
 and falls, in the Torricellitn Ex- 
 ferment, as it is carried up, or 
 down thorow the^/r./uf,46.50 
 The fifth, flawing the reafon, 
 why the Mercurid Cylinder rifes 
 and falls in the Barofcope , as the 
 Pipe is reclined and ereded.p.51 
 The fixth, touching the ftt- 
 (penflon of Liquors in Pipes, either 
 clots or open above, not only of 
 Water by Water, but of Wa¬ 
 ter by Air. fg. 55 j£fr. 
 
 The feventh, touching the 
 Cattfe of the fufpenflon, and keep¬ 
 ing up of Water in Weather-glaf- 
 fir. peg. 5$>. 
 
 The eighth, touching thefea- 
 fon, why a Stone weighs lefs in 
 Water than in Air. pag. 71, &c. 
 The ninth, touching the rea¬ 
 fon, why under 2 Water 34 foot 
 deep ; the bight of the Mercury in 
 the Barofcope , is 58 inches. 
 
 ■ fag. 77. &c. 
 The tenth, touching the rea¬ 
 
 fon , wny a man gripping with 
 his fingers the Torricellian Tub, 
 feems to find the weight of the 
 Liquor within, and yet finds it 
 not. pag.8z,&c. 
 
 The eleventh, touching the 
 counterpoifing of Mercury in 
 Glafs-pipes under-water, by the 
 help of a Ballance above, addu¬ 
 ced to prove that a heavy Body 
 weighs as much in Water, as in 
 Air. fag. 86, 
 
 The difficulty anfwered, 
 ftg.Zj.&c. 
 The twelfth, touching the 
 reafon, why a Cylinder of Brajs, 
 may be fufpended by a Surface of 
 Water, before it touch the bot* 
 tom, that’s 100 foot deep, 
 
 pag. 101. &c t 
 The thirteenth is, touching 
 two plain heavy Bodies fufpen¬ 
 ded under a Water 34 foot deep. 
 
 Pag . i op 
 
 Doclor Mores Argument a- 
 gainft the Preffure of the Air,an¬ 
 fwered. pag, iiy 
 
 The fourteenth, touching the 
 counterpoifing of Mercury with 
 Water : of Mercury with Air and 
 Wafer whence fome notable 
 Phenomena appear, pag. 120. &c. 
 The fifteenth,touching an Ex- 
 r periment 
 
The Contents ', 
 
 periment tried in a Water 72 The eighteenth,touching the 
 foot deep. fag. 1 2 7. &*. Diving-Ark, fag, 153. &e. 
 The fifteenth , touching the The nineteenth,touching a Si- 
 
 reafon, why the different wide- fhon made to work under Water 
 nefs of Tubs, makes no alterati- with Mercury , by the Prepare 
 on in the hight df the Liquors thereof, as a Siphon operats with 
 fufpended in them. fag. 133. Water , by the Prepare of the 
 The feventeenth, a notable Air, f. 180. 
 
 trial for proving, the Preffure of The laft is for demonftrating 
 the Water, fag, 137.&c> theprecifeand juft mightoHay 
 Mr, Boyls Experiment infuffi- Pillar of Atr i Water , or Mercury. 
 dent, . fag,1^6. 
 
 Contents of the Mi s c e 1 lany Observations. 
 observation 1 . Anent the kil- ing out the true South and North 
 ling of Animals in Coal-Jinks, by Points. . f. 212. 
 
 the power oi Damfs and ill Air, obferv, S. Touching the rea- 
 fag. 197. fon, why a dead body ofamn, or 
 Obferv. 2. Touching the po- &?^,rifetk from the ground of a 
 fition of Jupiter ^ with the Stars Water, after it hath lien there 
 of Gemini, Novemb.iq, 1669, three or four dayes. fA 16.. 
 
 f.101, obferv, 9. Is a fecond Expe- 
 obferv. 3. For knowing the riment made in a coal-fink , for 
 motion of the Sun , or Moon , in knowing the power of Damfs 
 Jeconds of time. ibid, and III-Air, 217. 
 
 obferv. 4. Touching an Ex- Obferv. 10, An account of Ex¬ 
 periment made on the top of percents tried with the Air - 
 Cheviot. f. 207, pumf. 
 
 obferv, 5. Touching the oval- obferv. II. An Experiment 
 Figure oi the at- nis fetting, made, forknowing the reafon, 
 f. 20 9, why a round heavy Body, as a 
 obferv. 6, Touching a confh Bullet of Irqn, falls not off a plain 
 derable Thunder , with great Body, under motion, but lies 
 Lightnings , in Eafl-Lothian, in dead, 7.224. 
 
 July 1670. p 210. obferv. 12. Shewing the reafon 
 
 obferv, 7, A method for find; why a ftone demitted from the 
 
 ton 
 
ihe Contents, 
 
 top of a Ships-Maft under Sail, derful force of the Air. p,z$ o, 
 falls direftly upon the place it obferv, 19. Touching Come 
 hangover. p, 226. propofals of new Engines for 
 
 _ obferv. 13, Touching the War. 
 hight of the Mercurf in the Bars- obferv, 20, Touching a fad trial 
 fcope,obCerred by D.Beal.p.zzS, one Mr. Campbsl fuffered in his 
 Obferv, 14. Touching the va- Family for many dayes from the 
 melon of the Magnetick Needle Devil, />, 238. 
 
 here. />. 228. Obferv, a 1. Touching a large 1 
 
 Obferv. i). Touching the Ele- Horn cut off a Womans head j 
 vation or the Foie here, £.228, lately. p, 24$, 1 
 
 obferv. 16. A fecond method obferv, 22. Touching the Prd 
 for finding the Meridian, p.219, mum vivens in Animals, ibid. 
 
 obferv. 17. Touching a confi- obferv. 23. Touching the Aid . 
 derable lhowre of Hail, with mentanigromhof plants f.zyz, 
 Thunder, and Rain, ibid. And touching the motion of 
 obferv. 18. Touching a curi- the aliment inTrees. p. 254, 
 ous Experiment made lately in obferv. 24. Touching a Hifio- 
 Germany, for ihewing the won- ry of Coal. fn •/>, 258. 
 
 In Au&orem & Opus Encomiast icon, 
 
 7T? Iherk expanfi. vitrei Mark Ancitalanton, 
 ,/H.Peroifdos, Eisfin, Fluidarumritevidentes, 
 Inger.iopatefaUa tm, Magnalia rerm, 
 
 Laudarknt alacres Galli, Belgique fagaces. 
 
 Asgrederk nmc ArieNova , trutinare profundi 
 Cortora , fubmerfas quondam producere Gazas, 
 
 ‘Iollere demerfu ingentia. pondera Cupis. 
 
 Gufracidum in Cryptis ortum Fofribus atrox, 
 
 Submijfo in Fundos Aura rensvante F labello, 
 
 Tropulfare doces, Lithanthracumque Cavernt 
 §>y.ek feveantur Aquk > quo tend ant, unde oriantv.r, 
 
 Or dine quo circum Saxorumflrata recumbant. 
 
 Qu'odbene czpijiiNatura cun&a foventk 
 M unera folertiperge Wuflrare Mathefi. 
 
 GEORGIUS HEPBURNUS, M. D. 
 a Monacbagro. 
 
 READER, 
 
To the Reader, 
 
 Reader, 
 
 T Hac thou mayeft know,by one word more,how ufe- 
 iul this part of Pbilofophy is, and how tartrom bein' 
 1 Set face long ago perfelted, take but this following 
 fal, lately, fince my Book came to a dole,communicated 
 to me by a Friend \ which, by his allowance, I have pub- 
 lifliedjrefei ving theAnfwer to himfeli,the Author thereof. 
 
 Brother, 
 
 B r what you have publtfhed in your Ars Nova & Magna, 
 and this Book, I have been led to this Invention, to 
 beget within the Bowels of the Sea , a Power, or Force , which 
 with great frfety^and eafe, (hull bring up the great eft weight , 
 that can bf funk therein: ad data qurecunque pondera de- 
 merfa, in Maris vifeeribus Potentiamproducere, quas mo- 
 do fecuro, & facili, e tundo cujufvis altitudinis ad fum- 
 mum, ipfa evehat- ldrew a Letter one night, jhewing the 
 way how this might be done , which I communicated to you, 
 
 ; that it might have been Printed with pur Book.* but after 
 fecond thoughts, I judged it more meet to keep it up for a, 
 time , and that it (houfd be fet forth by way 0/Propofal only 
 'at the frf^by 
 
 0< m> ft on, ' Youi; Brother, 
 
 May 20 , i6yz, Mr, tf ohn Sinclar, 
 
 j This Mew Invention , though HydrbftaticaJ, is truly 
 1 Mechanical, there being here a Pondus and a Potentia, whofe 
 [operations depends qpon Mechanical Principles. But in 
 I q q q feveral 
 
C] I 
 
 feyerai refpe&s it is far more admirable, than the moft part 
 of the-Mechanical Engines, which are look’d upon as far- 
 pendious, Many things, almoft incredible, are reported of $ 
 Archimedes, which he admirably brought about, by his p 
 Mechanical Powers •, but I am confident, that by this In- I: 
 vention i as great a weight may be lifted, if not greater, fi 
 as the Power of any Mechanical Faculty can be able to il; 
 move. I know, the greatefl conceivable weight, may 
 be demonftrat, to be moved by the ieaft conceivable f 
 Power, as the Earth, by the force of a mans band. But I* 
 how is itpoffible to contrive Artificially, an Engine for.. ' 
 thatpurpofe, which will do that by Art, which the de- : 
 monftration makes evident by reafon t It was thought a 1 
 great enterprize, when Pope Sixtus the fifth, rranfported ; 
 an Obdisk ,which had been long fince dedicated to theme- j 
 mory of fulius Ctfar , from the left fide of the Vatican, to ; 
 a more eminent place, roo foot difhrrt- ? but to raife a , 
 Ship of icoo.Tun intirely, nay, a weight ico times • 
 greater, is finely a far greater enterprize. This inven- 
 lion is fo much the more admirable, that not only by it, ■ 
 any fuppofed weight may be lifted, but from any deepnefs, : 
 Though this ( perhaps) cannot be done Mechanically, 
 becaufe of fome Phjfical, or Moral impediment, yet accot- ■ 
 ding to the Laws of the Hjdrcflaticks it can be demon- 
 ftrat, and made evident by reafon. And if this be, then . 
 finely, when the Weight Is determine, as the burdens of 
 all Ships are, and the deepnefs known to be within fo ma¬ 
 ny fathoms, this Invention cannot but be fuccefsful, • 
 Though the j,bength of Mechanical Inventions, may be 
 multiplied,beyond the bounds of our Imagination, where¬ 
 by the greateftmay be moved, by the Ieaft, 
 Power • yet the Wifdom of God, hath thought it fit, fo to 
 confine that knowledge, that it cannot teach; how both 
 
 of 
 
I ] 
 
 of them,can move with the (ante pirttxfsmi fpcat. FoC] 
 il that were, the very toks:of Nature beovettuM- 
 ed, Therefore, itis'obfetvable, that when a great weigh 
 is ’moved by a (mall Power, the motion df the one, is a. 
 much Q.owei than the motion of the other,,, a$ the Weight 
 of the one, exceeds the Force of the other, If/ttwerepofe 
 Able Mechanically to move the Barth with the Force of a 
 mans hand, the motion thereof would be as much flower, 
 than the motion of the hand, as the Wejgk'ohk&the, ex¬ 
 ceeds the Force of the other, which is a great difadvantage. 
 And as t\\e Weight ed Power do thus differ,. asto fm/rwe fc 
 and flownefs in motion", fo alfo, as-to Space. ' For, by h<Av 
 much the Power is in it felf lefs, than theffo/g/^by fo much 
 will the bounds or "Space, the Weight moves thorow,be lefs 
 than the S/we,the Power goes thorow. If itwerepoflible 
 (keeping the lame infbnce)to move thef^.with araans 
 hand, the S/we thorow which’ it paflech, would differ as 
 much from the Space the hand goes thofow, as the one ex¬ 
 ceeds the other ; which is another difadvantage. 
 
 It may be thought, that if this Invention depend Dpon 
 Mechanical Principles, It maybe obnoxious to thefe abater 
 ments.I anfwer^though there be in.ita.pWw/nd'a Poten¬ 
 tial Weighted a P^wer,this moving the Other, yet it will 
 : evidently appear from Experience, that the motion ofthe 
 one,is as fwift as the motion of the other, and that the one 
 moves as much space andfeoUnds in the fame.time., as the 
 other,which is a great advantage.- In this, it excells all the 
 Mechanical Powers , and Faculties, haVe ever yet been 
 invented and p: aftifed. If any think,, that fuch adevice 
 cannot be effe&uat, without a confiderabld expencei I an- 
 fvver, the expence is fo fmall, thatl am afhamed to mention 
 it. The'method and manner of doing this, is moft eafle 
 likewife, Neither ought this to be a ground,why any man 
 
fhould.contemn it; fince the moft ufeful Inventions ordi- i; 
 rarily are performed.with the greateft facility, . F 
 
 As it commends this part of Philofophy to all ingenious p 
 Spirits, as moft pleafant, and moft profitable, fo it gives f 
 a check to the ignorant, who look upon it as« Science long : 
 agofcrf.c&ed,~ . 
 
 In praife of the Author, and his Work, 
 
 i. 
 
 T if jHilfl Infant-Art no further Aid pretend 
 
 V V Then to fat notions, and i hare drfire 5 
 
 What by [mad toyl we now do comprehend, 
 
 Our Predeceffors only did admire, 
 
 t. 
 
 New fruitful Reafon, arm'd with powerful Art, 
 Uncovers Nature to each knowing eye : 
 
 Our Authors the World doth here impart 
 What was before efttem'd a my fiery, 
 
 3 . 
 
 The various motions of that Element, 
 
 Whofe liquid form gives birth to much debate 5. 
 
 By demon({ration he doth reprefent , 
 
 Unfolding th' intrigues of that fubtil ft ate. 
 
 4. 
 
 The Waters Courje,andSour[e , from whence they flow, 
 By him to th'Jenftfockarly are diflay'd'- 
 
 Their current Weight, and Miafure now we know, 
 
 'Tis no morefecret, hut an open Trade, 
 
 W. C. 
 
 HYDRO- 
 
THEOREMS, 
 
 Containing Tome ufeful Principles in or¬ 
 der to that excellent Dodrine, anent 
 
 the wonderful Weighty Force , and Prefjnre of 
 the Water in its own Element. 
 
 THEOREM I- 
 
 In all Fluids, befides the fir ft and vifihle Horizontal fur- 
 face, there are many me imaginary, yet real. 
 
 Figure i. 
 
 [OR thebetter undemanding the 
 following Experiments, it is 
 needful to premit the fubfe- 
 quentTheorems ; the firft where¬ 
 of is, that in all Fluid bodies, 
 fuch asAi?,Water,andMercury, 
 or any other liquid, there is be¬ 
 fides the fiift and vifible furface, 
 innumerable moe imaginary,un¬ 
 der that firft, yet real, as may 
 be' feen from the following Schema.tifm, which reprefents 
 a Veflel full of Water, where befides the firft furface 
 
 A AB 
 
i %i>o;oft atic3t Upeatem s, 
 
 ABC D, there is a fecond EFGH, and a third IK L M, 
 and fo downward, till yon come to the bottom. This 
 holds true, not only in Water, but in Air alfo, or in any 
 other Fluid body whatfoever. I call the under-furfaces 
 imaginary, not becaufe they are not real 5 for true and real 
 effe&s are performed by them-,, but becaufe they are not 
 actually diftinguifhed amongflthemfelves, but only by the 
 Intel led. 
 
 THEOREM II* 
 
 In all Fluids , as it is needful to conceive Horizontal 
 Plains , [o it is needful to conceive Perpendicular 
 Pillars putting the(e Plains at right Angles, 
 
 Figure i. 
 
 T His Propofition is likewife needful for undemanding 
 the following Dodrine, anent the Preffiire of the 
 Water: for in it, as in all Fluids, though there be not 
 Columes or Pillars a&ually divided, reaching from the 
 top to the bottom, yet there are innumerable imaginary 
 which do as really produce effeds by their preflfure, as if 
 they were a&ually diflinguitlred, Thefe imaginary Pillars 
 are reprefented in the nrft Schematifm, one whereof is 
 AEIN O P Q^, the other B F K R. T, and fo forth. 
 
 T H tO REM III- 
 
 There is a tmfcld Ballance^ one Natural, 
 another Artificial, 
 
 B Y the Artificial Balance, Iunderftand that which the 
 Mechanicks call Libra , which Merchants commonly 
 ife, By the Natural Uliana (which for diftindions caufe 
 ■".' ' If© 
 
t?pBio ftat(cal Hko?ci iis. 3 
 
 Ifonomitiat) I mean, v.g, a Siphon , or crooked Pipe, 
 wherein water naturally afcends or defeends, as high or low 
 in the one Leg, as in the other, ftill keeping an evennefs, 
 or iikenefs of weight. 
 
 THEOREM IV- 
 
 Fluid bodies count erpoije one another in the Ballance of 
 Nature, according to their Altitude only, 
 
 T His Theorem will appear afterwards m oft evident, 1 
 while we pals through the feveral Experiments $ and 
 it is of fpecial ufe for explicating fundry difficulties that 
 commonly occur in the Hydro(laticks, The meaning of it 
 is fliortly this .• while two Cylinders of Water are in the 
 oppofite Scales of the Natural Ballance, they do not coun- 
 terpoife one another according te their thicknefs; for 
 though the one Pillar ol Water be ten times thicker, then 
 the other, and confequently heavier, yet is it not able to 
 prefs up the other, that’s more, flender, aqdfo lighter, 
 beyond its own hight: and therefore they weigh only ac¬ 
 cording to their Altitudes . 
 
 THEOREM V- 
 In all Fluids there is a Pnffure, 
 Figure 1. 
 
 T His is true not only of the Elements of Air,and Wa¬ 
 ter, while they are out of their own place ( as they 
 fpeak) but while they are in it. For Air and Water, be¬ 
 ing naturally indued with weight, the fecond foot cannot 
 As be 
 
4 ^tyoftattcai gfleo?emg, _ 
 
 be under the firft, unlefsit fuftain it: if this be, it muft 
 neceffarily be preft with its burden. So this Water being 
 naturally a heavy body^the foot I cannot be under E, un- 
 lefs it fuftain it, and be preft with the burden of it; the 
 foot N,being burdened with them both. From this Pref- 
 fure, which is in Air, arifetha certain fort of force, and 
 power, which may be called Benfif by vertue whereof, a 
 little quantity of Air,can expand and fpread out it felf,to a 
 very large quantity, and may by extrinfick force be redu¬ 
 ced to that fmall quantity again. Though this expanfive 
 faculty be evident in Air, yet it is fcarcely difcernable in 
 Water, unlefs it be in very deep parts, near the bottom, 
 where the Preffiire is great. This Preilure is not of the 
 fame Degree in all the parts, but is increafed and augmen¬ 
 ted, according to the deepnefs of the Air,and Waterfor 
 •the Ah upon the tops of Mountains, and high places, is 
 thought to be of a lefs Preffure, then in Valleys: and Wa¬ 
 ter is of a lefs Preffiire, ten or twelve foot from the top, 
 then twenty or thirty, So is the Water N, under a far 
 lefs Preilure, then the Water, P or Q. 
 
 THEOREM VI- 
 
 The preffure of Fluids is on every Me, 
 
 Figure i. 
 
 T He meaning «, that Air and Water preffeth not on¬ 
 ly downward,but upward,not to the right hand only* 
 but to the left alfo,and every way.So the foot of water K, 
 sot only preffeth down the foot- R, but preffeth up the 
 foot F, yea preffeth the foot I, ana the foot L, with the 
 fame weight, An^ the feft imaginary furface, .is as much 
 
 preft 
 
foi>D?ofta t<cal £t)eo;ems. $ 
 
 preft up, by the water IK L M, as it is preft down by the 
 water EFGH. Upon this account it is, that when a 
 ' Sphere,or Glob is fufpended in themidle of Water,or Air, 
 £ all the points of their furfaces are uniformly preft. After 
 f this manner, are our bodies preft with the invironing Air, 
 and the man that dives, with the ambient and invironing 
 Water, 
 
 THEOREM VII- 
 
 All the farts of a Fluid in the fame Horizontal Line , 
 are equally preft. 
 
 Figure i, 
 
 T He meaning is, that the foot I, is no more preft, 
 then the foot K: neither is the foot L, more bur¬ 
 dened, then the foot M. Thereafonis, becaufe each of 
 thefe feet, fuftains the fame weight: for E F G H are. all 
 of them, of the fame burdentherefore all the parts of a 
 Fluid in the fame Horizontal Turf ace, are pi eft moft equal¬ 
 ly. T his holds true in Air, and Mercury, or in any other 
 Liquid alfo. 
 
 theorem VIII- 
 
 The Preffure of Fluids feemtohe according to 
 
 Arithmetical Progreflion. ! 
 
 Figure i, 
 
 / T'He meaning is, that if the firft foot of Water, have 
 I J_ one Degree of PrefTure in it, the fecond muft have 
 only two, and the third muft’have only three,and fo forth; 
 
 which* 
 
6 §pD*oftattcai XHeojems* 
 
 which appears from the Schematifm .• for the firft foot 
 having one Degree of weight, and the fecond foot I, hav¬ 
 ing oi'lts felf as much, and fuftaining E, it muft have two 
 Degrees, and no more. So the foot N, fuftaining two 
 Degrees of preflure from I and E , muft have the weight 
 only of three Degrees, 0 of four, P of five. It’s evident 
 alfo from Experience, for while by the Preflure of Water, 
 Mercury is fufpended in a glafs tub, we findthat as the 
 fi.-ft fourteen inches of Water, faftains one inch of Mercu¬ 
 ry, to the fecond fourteen inches fuftains but two, and the 
 third, but three. But if the preflure were according to 
 Geometrical f regression, the third foot of Water ought to 
 fuftain four inches of Mercury, the fourth, eight; the fifth, 
 fixteen, &c, which is contrary to Experience. 
 
 THEOREM IX- 
 
 In all Fluids there is a twofold weight, one Senfible, 
 the other Infallible, 
 
 T He firft is common to all heavy bodies, which we 
 find in Water, while we lift a Veffel full of it from 
 the ground. The Irfenfible weight of Water, and Air, 
 or of any other Fluid, can. fcarcely be difeerned by the 
 lenfes, though it be as real, as the former, becaufe the 
 Preflure is uniform. By vertue of the fecond, bodies na¬ 
 turally lighter than Water, are driven from the bottom to 
 the top, as Cork . So, a man falling into a deep Water, 
 goesprefentiy to the bottom, and inftantly comes up again. 
 Here is a natural effect, which cannot want a natural caufe* 
 2nd this can be nothing elfe, but the Prefliire of the Wa¬ 
 ter, by vertue whereof he comes up, and yet he finds no¬ 
 thing 
 
%)>BjOft atlcal Xj)co?tms, _7 
 
 : tiling driving him up, or pulling him up. Therefore, 
 
 : there is in all Fluid bodies, an Infenftblt weight, as there 
 ' is one Senfible ; feing the man that (perhaps) weighs fe- 
 venteen Stone, is driven up fifteen or fixteen fathom by 
 ' ] t> And it muft be very confiderable, and exceed the 
 weight of the man, feing it is able to overcome fuch a 
 weight. So are vapours and fmoke driven upward by the 
 Jnjenfble weight oi the Air, and by that fame weight, do 
 the Clouds fwim above us. 
 
 THEOREM X- 
 
 The Irifenftble weight of Fluids, is only found by [enfe , 
 when the Prefjure is not uniform. 
 
 F Or undemanding of this Propofition, I muftfuppofc 
 fomethings that are poffible, but not pratticable. 
 Put the cafe then, while a man opens his hand, the Air 
 below were removed, he would fcarce be able to fuftain 
 the weight of the Air, that refts upon the Palm above : 
 or if the Air above were annihilated, he would not be able 
 to bear down the weight that prefleth upward. Or, while 
 a Diver is in the bottom of the Sea, if it were poffible to 
 free any one part of his body from the PrefTure of the Wa¬ 
 ter, fuppofe his right arm, I doubt not, but the blood 
 would fpring out in abundance froni'his finger-ends .* for 
 the arm being free, and the other parts extreamly preft, 
 the blood of neceflity muft be driven from the fhoulder 
 downward, with force, which cannot be without confi¬ 
 derable pain. It is evident alfo, from the application of 
 theC uftin-glafs, which being duely applied to a mans 
 skin, caufeth the Air to prefs unequally, the parts with- 
 
s ppmo gancai I 
 
 oat, being morepreft, than the parts , within, in which 
 cafe the unequal Preffure caufeth the pain, and fo is found f 
 byfenle, 
 
 THEOREM XI- 
 
 A Cylinder of Water,or of any other Fluid body , lojeth of its : 
 weight, according to its rtclinatm from a Perpendi- 
 calar pofttion , towards an Horizontal or 
 leztllfcituaticn, 
 
 F Or undemanding of this, confider that while a 
 Pipe full of Water ftands perpendicular, the lowed i 
 footfuftains the whole weight of the Water above it:; 
 but no fooner you begin to recline the Pipe from that Po- i 
 fition, but afToon the Preffure upon the loweft footgrows L 
 Iefs ^ So that if the lowed foot, in a perpendicular pofi- 
 tiou , fuflained the burden of ten feet, it cannot fuflain 
 above five or fix, when it is half reclined. A certain evi¬ 
 dence whereof is this, the more a Cyilnderof Water is 
 reclined towards the Horizon,or Level,it takes the (hotter 
 Cylinder of Water to counterpoife it, as is evident in Sh 
 phoas. For, though the one Leg, be fixceen inches long, 
 and the other but fix 5 yet a Cylinder of Water fix inches 
 long, will counterpoife a Cylinder of fixteen. But this 
 cannot be , unlefs an alteration be made in the Preffure. 
 For, how is it poffible, that a Cylinder of Water can 
 fometimes be in aquilibrio with a leffer, and fometimes 
 with a greater weight, unlefs the Weight, and. Preffure of 
 it, be fometimes more, and fometimes lefs i When I fay 
 a Cylinder of Water lofeth of its weight by reclinationii 
 it is to be underflood only of the Infenftble Weight:, for 1 
 
^ptyoftaeical C&eojems* 9 
 
 the SmfibleWeight unchangeable, feing. it is alwayesa 
 Pillar of fo many inches, or feet. Now the true reafon, 
 , v/hy the PrefTure upon the loweft foot grows lefs, is this ; 
 
 ; the more the Pipe is reclined, the more weight of the 
 i Cylinder refts upon the fides of the Pipe within • by 
 i which means,the loweft foot is eafed of the burthen , and 
 is altogether eafed,when oncethe Pipe lyes Horizontal. 
 
 THEOREM XII. 
 
 All motion in Fluids, is from the unequal Preffurc 
 of the Horizontal furface. 
 
 Figure i, 
 
 F Or undemanding this,I muft diftinguilh a twofold mo¬ 
 tion in Fluids $ one common , another proper, by ver- 
 tue of the firft, they incline, as all other heavy bodies, to 
 |be at the center of the Earth. It is evident in the motion 
 fof Rivers, which defeend from the higher places to the val¬ 
 leys , even by vertue of that tendency they have to be at 
 <the center. By vertue of the fecond, they inclineto move 
 jeveryway; not only downward, but upward, hither and 
 Jthither, This fort of mot ion is peculiar, and proper only 
 fto Fluids; and it is that which is fpoken of in this Theo- 
 irern. I fay then, that all motion in Fluids, is from the un- 
 «equal Preifure of the Horizontal farface. For put the cafe 
 A, were more preft then B,e.g. with’afk>ne,tnen furely as 
 •the part Adefcends, the other part Bwillafccnd, andfo 
 f will C and D rife higher too. $uppofe next, the part A 
 * were fred of the Preffureof the Air, then furely in the 
 : fame inftant of time, wouldthe part A afeend, and the 
 I parts B C D defeend, As thisPropofition is true in order 
 B to 
 
io DpDfQttatical £ljcojems, 
 
 to the firft-and vifible furface A B CD, foitis true in or¬ 
 der to the imaginary furface I K'L M 5 for put the cafe the 
 fpace I, -were filled with a body naturally heavier then 
 Water, as lead or ftone, then behoved that partof thefur- 
 fkce to yeeld, it being more preft, then the part of the fame 
 forface-K, Or if the fpace K were filled with a body natu. 
 rally lighter then water, as Cork, then ought the wa« 
 terRto afeend, it being lefs preft, then the water N or S. 
 
 THEOREM XIII- 
 
 A bodynaturally heavier then Water, defuncts-, and 
 a body.naturally lighter, afeends . 
 
 Figure i. 
 
 F Or undemanding of this, let us fuppofe the quadrat 
 fpace E, to be filled with a piece of Lead or-Iron. I ' 
 fay then it muft.godown to I; and the reafon is, becaufe 
 the quadrat foot of Water I, is morepreffed then the 
 quadrat foot of Water K„ To iliuftrat this, let us fup¬ 
 pofe that each quadrat foot of this Water weighs a pound, 
 and that the heavy body exifting in E, weighs two 
 pound. If this be, the foot of Water I, muft yeeld, fee¬ 
 ing it is more preft then K : upon the fame account muft 
 the Water N yeeld, and give way to the Stone, feeing 
 it is more preft then R, For according to the twelfth 
 Theorem, There cannot he unequal Pre fure upon a furface, 
 unlejs motion follow.' 
 
 For underftanding thefecond part, let us fuppofe the 
 fpace R, to be filled with a piece of Cork, thatisfpe- 
 cifically or naturally lighter then Water. I fay then, it 
 muft afeend to the top B ; and the reafon is, becaule the 
 quadrat foot of Water, K, is more preft: upward, then the 
 
 quadrat 
 
^o^Hamai^Qeoiem0; u 
 
 quadrat foot ofWatet I," or L is: but this cannot beun 
 Fluid bodies, unlefs motion follow thereupon. I fay, it 
 is more preft up, becaufe R being lighter then N', or Si 
 itmuft-prefs with greater force upon K, then S can do 
 upon L, or N upon I. It isffilh toberemembred, 
 That Fluids preffetk with as much ftrcngth upward^ asdofttt' 
 mrd, according'tothefixth Theorem*, and that an Ho¬ 
 rizontal furface doth as really fuffer unequal Preffure fronf 
 below, as from above. 
 
 THEOREM XIV- 
 
 Bodies naturally lighter then Water, [mm nftn 
 the furface and tof^ 
 
 Figure i. 
 
 T He reafon of this Propofition molt be taken from 
 the nature of an equiptndium^ or equal weight. For 
 without doubt, there is a counter-ballance between the 
 Preffure of the Water, . and the weight of the body that 
 fwims. To make this probable, let us fuppofe there were 
 a piece of Timber in form of a Cube, fix inches thick eve-' 
 ry way, without weight. In this cafe, the iinder-furface 
 of that tour-fquar’d body, being .applied to the furface of 
 the Water A, would ly dofs'upon it, as one plain Table 
 lyes upon the.face of another, without any preffure; and 
 it being void Of weight, the part of the furface A 1 , would 
 be no more burdened, then the next part B adjacent; 
 whence no motion would follow. Here is no cquipndium, 
 or counter-ballance. 
 
 Secondly, let tis fuppofe the faid body to acquire two 
 ounces ot weight, then it follows, that it muff fifbfide, 
 and fink two inches below the furface A‘ JB C D, 'and that 
 5 2 fo 
 
n ftptyoftatical XJjeojemsu 
 
 fo far, till it come by vertue of its new acquired weighr, to 
 aconnter-ballancewith the Preflure of rhe Water. Which 
 PrefTure is nothing elfe, but as much force or weight, as is 
 equivalent to the weight of Water, that is thruft out of 
 its own place, by the fubfiding and finking of that body, 
 two inches. 
 
 Thirdly, let us fuppofe the fame body to acquire other 
 two ounces of weight, then muff it fubfide other two 
 inches. Laftly, let us fuppofe that it acquires fix ounces 
 of weight, then it follows that the whole body finks, fo 
 far, I mean, till its upmoft furface be in an Horizontal line 
 with the furface of the Water A B C D. Here it fwims 
 alio, becaufe the weight of it becomes juft the weight of 
 fo much Water, as it hath put out of its own place. I fay, 
 itmuftfwim, becaufe if the Water I, was able to fuftain 
 the Water E, which is put from its own place, furely it 
 muftbe able to fuftain that body alfo, that did thruft it 
 from its own place, feing both are of the fame weight, 
 namely fix ounces, la this cafe , the body immerged, 
 and the water wherein it is drowned, become of the fame 
 weight ft ec ifcally , feing bulk for bulk is of the fame 
 weight. To make this body ftecifcaEy, or naturally hea¬ 
 vier then Water, and confequently to fink to the bot¬ 
 tom, nothing is required, .but to fuppofe that it acquires 
 one ounce more of weight •, which done,it prefently goes 
 down, I, being more burdened then K. Note by the 
 way, a twofold weight in heavy bodies, one individual , 
 the other ftecifck , and that two bodies agreeing in in¬ 
 dividual weight,may differ in (fecifick weight. So a pound 
 of Lead, and a pound of Cork, agree individually be¬ 
 came they are both x 6. ounces: but they differ ftecificalft^ 
 becaufe the one is naturally heavier then the other, 
 
 THEO- 
 
$pb;oQatfcal Xtjeojtms. 
 
 THEOREM XV- 
 
 No Body that fiots above Water , even though its upper 
 fttrface be level with the [urfaee of the Water, can ever 
 be made to fwim between the top and the bottom . 
 Figure i. 
 
 F Or clearing this Propofition, let us fuppofe F to be a 
 four-fquare piece of Timber, of the fame fierifick and 
 natural weight with Water,and confequently its upper fur- 
 face to be level with the furfaCe of the Water A B C D. I 
 fay then, if it be preft down to R, it fhall arife thence, and 
 never reft till it be where it was, namely in F. Thereafon 
 feems to be this,becaufe the four-fquar’d body ofWater R, 
 is really heavier, then the four-fquar’d piece of Timber F. 
 II this be true, it follows of neceflity, that it muft afcend: 
 for if theTimber exifting inR,be lighter then the Water R, 
 the Water T muft be lefs preft, then the Water O, or the 
 Water V 5 whence ( according to the twelfth Theorem) 
 ■motion muft follow. Again,if the Timber R,exifting in the 
 Water R, be lighter then the fame Water is, -then muft 
 the Water K, be more preft up then the Water I, or L ; 
 whence yet, according to the fame Theorem, motion mufi 
 follow. If it be faid, that the Timber Fj is; of the fame 
 weight with the Water R, becaufe, it being equal in 
 weight with the Water F, which-ithaththruft out of its 
 own place, it muft alfo be equal in weight to the Water R, 
 feeing F and R being of the fame dimenfions, are of the 
 fame weight. There is no way to anfwer this difficulty,- 
 unlefs I fay the lour-fquar’d body of water R, is really and 
 truly heavier then the four-fquat’d body ofWater F. The 
 
 , reafon 
 
14 ^ptyoftatfcai £t)eojems* 
 
 reafon Teems to be, becaufe the Water R, isunderagrea- 
 ter PrefTure, then the Water F; and by vertue of this 
 greater PrefTure, there are really mot parts of Water in it, 
 then in F •, therefore it muft be heavier. Even as there are 
 far moe parts of Air,in one cubick foot near the Earth, then 
 infix or feven near th e Atmjphere. Hence it is, that 
 a pint of Water taken from the bottom of the Sea, fourty 
 fathom deep, willbe.heavier, Imeaninaballance, then a 
 pint taken from the furface. Take notice, that when the 
 vefTelis once full at the bottom, the orifice muft be clofely 
 flopped, till it come to the top : otherwife the parts that 
 are compreffed at the bottom, namely by the weight of 
 the Tuperiour parts, relaxes themfelves, before they come 
 to the top. 
 
 THEOREM XVI- 
 It is not impossible for a body to be ftijp ended between 
 the Mace and the bottom. 
 
 Figure i. 
 
 F Or undemanding this, fuppofe F to be a four-fquare 
 piece of Timber, which though it will not reft but at 
 the furface, A B C D, yet may be made to go down of its 
 own accord, and reft at T, namely, by making it To 
 much heavier, as the Water T is heavier then the Water 
 F. To know this difference,which is not very practicable * 
 the Cube of Water T,muft be brought from its own place^ 
 under the fame degree of PrefTure it hath, and put into the 
 Scale of a Ballance, and weighed with the Cube of Water 
 F, put into the other Scale. Now if the Water T, be 
 half an ounce heavier, then the Water F, then to make 
 the Timber. F hingin T, it mnft be made half an ounce 
 heavier. There feems to bereafon for it alfo ; for if a 
 
 Cube 
 
UpBjoltatM Xtieojcms. 15 
 
 Cube of Timber refting in the fpace T, be juft the-weight 
 of the Water T> the imaginary fiuface 0 T V, is no mote 
 preft, then if T were Water, and fo it cannot go .down¬ 
 ward : neither can it go,upward, ;feihg ;the'underpin of 
 the Water R, is no more preft up by the Tinker 5E, then 
 if the fpace T were filled with Water, If it be faid, accor¬ 
 ding to this reafoning, a Stone may be fufpended in a deep 
 Water, between the top and the bottom, which is abfurd. 
 Ianfwer, fuch a thing may happen ina very deep Water: 
 'For put the cafe aCu’oe of Lead twelve inches,, every way, 
 were to go down twelve thoufand fathom it is probable, 
 it would be fufpended before it came to the ground. For 
 coming to an imaginary furface far down, where the Pref- 
 fure is great, a Cube of Water twelve inches thick there, 
 may be as heavy (even fyecijically ) as the 1 Gubfe bfLeid 
 is, though the Lead be ten times heavier 'flecifieallf, then 
 any foot of Water at the top. If Water fuffercom- 
 preffion of parts, by the fuper-iour burden v it is more then 
 probable, that 'the fecond foot of Water burdened with 
 the.firft,’ hatfomoe parts in it, then are in the firft, and the 
 third moe, then in the fecond, and fo forth • and confe- 
 quently, that the fecond is heavier, then the firft, and the 
 third heavier, then the fecond. Now, if this be, why 
 may not that foot of Water, that hath fixty thoufand 
 foot above it, by vertae of this burden, be fo compreft, 
 that in it may be as many parts, as may counter-ballance a 
 Cube of Lead twelve inches every way t "If then,that /W- 
 ginary furface, that is fixty thoufand footdeep, be able to 
 Tuftain the faid foot of VVater,. which perhaps weighs 
 twenty pound, why may it not likewife (attain the Lead, 
 that is both of the fame dimenfions with it, and weight? 
 
 Hence 
 
Hence it is, that the Clouds do fwim m the Air by ver- 
 tue of a counter-ballance: And we fee,which confirms this 
 Do&rine that the thinned and lighted arealwayes far- 
 theft up / and the chicked and blacked, are alwayes far- 
 thed down. 
 
 THEOREM XVII- 
 
 The loner the farts of a Fluid are, they are the heavier» 
 though all of them, he of equal quantity and dmenftons. 
 Figure i. 
 
 T His follows from the former, which may appear a 
 Paradox, yet it feems to be true .• for though the 
 Water O at the bottom, be of the fame dimenfions with 
 the Water E at the top, yet it is really heavier, which 
 happens (aslfaid)fromthefuperiour Pretfure. It is dear 
 alfo from this, namely the Cube of Timber E, which 
 fwims upon the furface, being thrud down to Q^, comes 
 up to the top again, which could not be, unlefs the Wa¬ 
 ter Q, were heavier then the Water E. I fuppofe the Wa¬ 
 ter E, and the Timber E, to be exa&ly of the fame ffcci- 
 fck weisht, and confequently the furface of the Timber, 
 to Iy Horizontal with BCD. Now the reafon, why the 
 Timber afcends from <Tto E, is no other then this, name¬ 
 ly that the one Water is heavier then the other * for the 
 under part of the Water P, being more pred up with the 
 Timber exiding in Q, then with the Water Q it felf, it 
 mud yeeld and give way to theafcent: for if the Cube of 
 Timber exiding in Q,were as heavy as the Water (Tic felf, 
 it would no more prefs upon .P.,Qt endeavour, to be .up, then 
 the Water Qdoes, 
 
 T HEO- 
 
$pd;oftdticai Ctjcozems* 17 
 
 THEOREM XVIII. 
 
 A heavy body weighs left in Water, then in Air ', 
 
 Figure i, 
 
 T His is eafily proven from experience for after you 
 have weighed a ftonein the Air, and finds it two 
 pound, and an half, take it, and fufpend it by a threed knit 
 to the fcale of a ballance=, and let it down into the Water, 
 and you (hall find it half a pound lighter. The queftion 
 then is, why doth it lofe half a pound of its weight? I 
 anfwer, the ftonebecomes half a pound lighter, becaufe 
 the furface of Water on which it rcfts,fuflains halfa pound 
 of it: For put the cafe a flone were retting in R,thac weigh¬ 
 ed two pound and an half in the Air, it behoved to weigh 
 but two pound in this Water-? becaufe the Water T fu* 
 ftains halfa pound of it. For if this Water T be able to 
 Mam the Water R, that weighs half a pound, it muft 
 be alfo able to Main halfa pound ofthe ftonc, feing half 
 a pound of ftone is no heavier, then half a pound of W ater. 
 Note, that when a heavy body is weighed in Water, it be¬ 
 comes fo much lighter exa&ly,asis the weight ofthe Wa¬ 
 ter it thruftsoutofits own place. 
 
 THEOREM XIX- 
 
 A heavy body weighs lejs nigh the bottom ofthe Wfc 
 ter , then nigh the top thereof. 
 
 Figure i. 
 
 F iOr clearing thispropofition, I muft fuppofe from the 
 17. Theorem, that the lower the parts of Water 
 C be, 
 
is tjpojoftatfcal Ztywms, 
 
 be, they are the heavier, though all of them be of equal di- 
 meafions. If thea the loweft foot Q be heavier, that is, 
 have moe parts in it, then the foot N, it of neceffity fol¬ 
 lows, that a ftone fufpended in Q^, muft be lighter then 
 while it is fufpended in N or I. Becaufe, ifa ftone be 
 lighter in Water then in Air, as is faid.even by as much, as 
 is the weight of the bulk of Water, that the bulk of the 
 ftone expells, then furely it muff be lighter in the one,then 
 in the other place; becaufe fufpended in it expells 
 moe parts of Water, then while it is fufpended in N or I. 
 For example, let us fuppofe the Water N, to weigh eight 
 ounces, and the Water Q. to weigh nine, then muft the 
 ftone fufpended in Q,, weigh Ids by an ounce, then 
 fufpended in N, feeing as much is deduced from the weight 
 of the ftone, as is the weight of the Water.it expells: but 
 fo it is, that it thrufts nine ounces of Water out of its own 
 place in Q^, and but eight in N or I; therefore it muft 
 be one ounce lighter in the one place, then in the other. 
 This maybe tried, with a nice, and accurat ballance, which 
 will bring us to the knowledge of this, namely how much 
 the foot of Water Qjs heavier, then the Water NorO, 
 
 THEOREM XX- 
 
 One fart of a Fluid, cannot be under comprefsion , 
 unless all the farts next adjacent , be under 
 the fame degree of Prefure . 
 
 Figure i,. 
 
 T His propofition may be proven by many inftances: 
 
 tor when the Air of a Wind-gun, is reduced to lefs 
 quantity by the Rammer, all the parts are moft exadtly of 
 the tame So is it in a Bladder full of wind. It’s 
 
true, not only in order to this artificial Preffure, but bor¬ 
 der to the natural PrefTure, and Benfil of the Air likewife. 
 For the Air within a parlour, hath all its parts, under the 
 fame degree of natural compreflion : fo is it with the parts 
 of the Air, that are without, and immediatlyUnder the 
 weight of the Atmofahtre. Its evident alfo in the parts of 
 Water: for the foot of Water R, cannot be under Pref- 
 fure,unlef$ the Water S, and N, be under the fame de¬ 
 gree of it, T hough this be true of Fluids,while all the parts 
 lye in the fame Horizontal furface, yet tofpeak ftri&ly 1 , it 
 will not hold true of the parts fcitu'ated under divers fur- 
 faces ; for without queftion, the foot of Water T, muft 
 be under four degrees of PrefTure, if the Water R, bo 
 under three. And if the Air in the lowefl: ftory of a build¬ 
 ing, be under fix degrees of Xenftl , the Air in the higfreft 
 Rory muft be under five. If a man would diftinguilh Mt~ 
 uphyfically , and fubtilly, he will find a difference of this 
 hind, not only between the firft,and fecond fathom of Air, 
 neareft to the Earth,but between the firft, and fecond foot; 
 yea, between the fiift arid fecond inch,and lefs; rhuch more 
 'in Water, as to fenfe. However it be, yet the theo¬ 
 rem holds true 5 for we find no difference fenfible, be¬ 
 tween the compreflion of Air in this room; and the com¬ 
 preflion of Air in the next room above it, no not with the 
 Bdrofcope) or Torricellian Experiment, that adeems fuefi 
 differences accurately. I judge it likewife to "be true, in 
 order-to the next adjacent parts obEluids of different kinds; 
 for while a furface of Mercury, is burdened with a Pillar of 
 Water, or a furface of Water, with a Pillar of Air,, what¬ 
 ever degree of weight and PrefTure, is in the loweft parts 
 of thefe Pillars, the fame is communicated entirely, to the 
 furfaces, that fuftains them. So then, thefe is as much 
 C i force 
 
20 
 
 $pfi?oaattcal£i)eo?tins. 
 
 force and power, in the furface of-any Water, as there is 
 Weight and PrefTure, in the loweft foot of any Pillar of 
 Air, thatreftsupon it: otherwife, the furface of Water 
 would never be able to fuppdrt the faid Pillar .• for a fur* 
 face ot fix degrees of force, can never be able to Main a,. 
 aPillar of Air,. of eight, or ten degrees of weight. 
 
 THEOREM XXI- 
 
 Tht Pnffurc of Fluids , may he os much inthe leaf- 
 party as in the rvbele .. 
 
 Figure i; 
 
 T His Theorem-may feem hard, yet it can be made ma- 
 nifeft, by many inftances: for albeit the quantity 
 of Air, that fills a Parlour, be little in refpeft of the whole 
 
 Element, yetfurely, there is as much PrefTure in it, as in 
 the whole; becaufe Experience fhews, that the Mercurial 
 Cylinder in the Barofcope , will be as well Mained in a 
 Chamber, as without, and under the whole Atmojf.here 
 dire&Iy-,. which could not be, unlefs the fmall portion of 
 Air, that’s in this Parlour, had as much PrefTure in it, as 
 in the whole Element. Befides this, it will be found in a 
 far kfs quantity : for though the Barofcope were inclofed, 
 and imprifoned foclofs, within a fmall Vefiel, that the 
 Air within, could have no communion with the Air with¬ 
 out, yet the PrefTure of that very fmall quantity, will 
 Main 29. inches of Mercury, and this will come to pafs,i 
 even though the whole Element of Air were annihilated; 
 This Propofitionis likewife evident in order to the Pref- 
 fdre of the Water: for put the cafe, the Barofcope , whofef 
 Mereurial.Cylinden's 29Jnches, by the Preflure of the 
 
 Aft; 
 
i^Dfottatical IClitditmg. it 
 
 Air •, were fent down to the bottom of a Sea 34. foot deep, 
 within a Veflel, as a Hogs-head, and there exa&Iy in- 
 clofed, that the VVater within, could have no commerce, 
 with the Water without, yet as well, after this/hutting 
 up, as before, other 29. inches would be fuftained, by the 
 Preflure of this imprifotied Water, which proves evident¬ 
 ly, that there is as much Preflure in one Hogs-head full o! 
 Water, at the bottom of the Sea, as in the whole Ele¬ 
 ment of VVater, above, or about: for an-Element of 
 V Vater never fo fpacious, if it exceed not 34. foot in • 
 deepnefs, can fuftain no more Mercury, then 29. inches 
 by its PreOure, Yea, though the Veflel with the Bare- 
 jcope^ and imprifoned VVater in it, were brought above 
 to the free Air, yet will the VVater retain the fame Pref- 
 fure, and wxWdtfutfo (uftain 29. inches of Mercury, pro¬ 
 vided the Veflel be kept clofs. It is therefore evident, 
 that as much Preflure may be in one fmall quantity of 
 VVater, as in the whole Element, or Ocean. *Tis td 
 be obferved, that this Theorem is to be underftood chief-' 
 ly of the lower parts of Fluids •, feing therecannot be fo' 
 much Preflure in the VVater P, a* in the Water Q3 for 
 ineffeft, there is as much Preflure in the VVater Q, as 1 
 is in the whole VVater above it, ; or about it. From this 
 Theorem, we fee evidently; that the Preflure, an dBenfit 
 of a Fluid, is not to be meafured, according ro its bulk, 
 and quantity, feing there is as much Benfil in one foot, • 
 nay, in one inch of Air, as is in the whole Element, and as 
 fltong a Preflure in one foot of VVater, orlefs, as there 
 is in the whole Ocean: therefore the greateft quantity of 
 Air, hath not alwayes the greateft Benfil, neither the great- 
 eft quantity of VVater, the greateft Preflure. - But this • 
 will appear more evident afterwards, . 
 
 THE 0-/ 
 
2i §£0*o&artcal £t)eojems. 
 
 THEOREM XXIL 
 The PreflitrC) W Benfil of a Fluid, is u thing, mil] di(lin ft 
 from the natural weight of a Fluid, 
 
 Figure i. 
 
 T His may be eafily conceived j for as in folia bodies, 
 the Benfil, and natural weight, are two diftinft 
 , ^ things, fo is it in Air, and Water, or in any other Fluid. 
 The weight of a Saw, is one thing, and the natural tveight 
 of it,is another. The weight oi the Spring of a Watch ^ and 
 the Benfil of it, are two diftinft things. The weight (per¬ 
 haps ) will not exceed two ounces .* but the Benfil (may 
 be) will be equivalent to two pound. Though thefe 
 may illuiirate, yet they do not convince: therefore I fhall 
 adduce 1 reafon, and it’s this. The natural weight of a 
 Fluid is lefs, or more, as the quantity is lefs or more • but 
 it is not fo with the preifure, becaufe there may be as 
 much Preifure in a fmall quantity, as in a great, as is evi¬ 
 dent from the laft Theorem, therefore they may be dif¬ 
 ferent. The firft part of the Argument is manifeft, be¬ 
 caufe there is more weight in a gallon of Water, then in 
 a pint. A fecond reafon is, becaufe a Fluid may lofe of its 
 preifure, without Iofing of its weight. This is evident 
 from the Schematifm, for if you take away the four foot of 
 Water E F G H, and consequently make the four Pillars 
 fhorter, the foot of Water becomes of lefs Preifure, 
 but not oi lefs Weight, feeing the quantity ftill remains 
 the fame : at Ieaft, thelofsol weight is not comparable, 
 to the lofs of Preifure. I fay, it becomes of lefs Preifure, 
 becaufe there is a lefs.burden above it, Thirdly, the Pref- 
 
 fure 
 
»y6?o(latical Xljcojtms. if 
 
 fure and Benfil may be intended, 2 ndmadeftronger, with¬ 
 out any alteration in the weight: To is the Benfil of Air, 
 within a Bladder, made ftronger by heat, without anyalte- 
 ration, in the weight of it. Likewife, the PrefTure of the 
 foot of Water C^may be made ftronger, by making 
 thefe four pillars higher, without any alteration, at leaft 
 confiderable, in the weight 5 for it ftill remains a foot of 
 water, whatever be the hight of the pillars above it. Laft- 
 ly, the weight of a Fluid is effential to it, but the PrefTure 
 is only accidental t, becanfe it is only generated, and be¬ 
 gotten in the inferiour parts, by the weight of the fuperi- 
 our, which weight may be taken away. 
 
 THEOREM XXIII- 
 
 2 though the Benfil of a Fluids he not the fame thing for¬ 
 mally with the might , jet are they the fame effc&ively. 
 
 T His propofition is true in order to many other things, 
 befides Fluids: for we fee that the Sun, and Fire, are, 
 formally different, yet they may be the fame effectively } 
 'becaufe the fame effects, that are doneby the heat of the 
 Sun, may be done by the heat of the Fire. So the fame ef- 
 fe&s, that are produced by the weight of a Fluid, may be 
 done by the Preflure, and Benfil of it. Thus, the Mercu- 
 ; rial Cylinder in the Torricellian Experimntjmy be either 
 ; fuftained by the Benfl of the Air,or the weight of it.Bjr the 
 Benfil, as when no more Air, is admitted to reft upon the 
 j ftagnant Mercury, then three or four inches, the reft be¬ 
 ing fecluded, by flopping the orifice of the.VefTel, By 
 the weight of it, as when an intire Pillar of Air, from the 
 top of the Atmofphcre ,refts upon the face of the ftagnant 
 
fti»D?o aatical%t)co?cnis. 
 
 Quickfilver, It is alfo evident in a Clock , which may be 
 made to move, either by a weight of Lead, or by the force, | 
 and power of a Steel spring, ' 
 
 THEOREM XXIV. 1 ' 
 
 The fir facts of Waters , are able to (a(lain any weight what - 
 [oever .provided that weight p refs equally, and uniformly. 
 Figure i, 
 
 T His is evident, becaufe the imaginary furface- of ; 
 
 Water OTVX, doth really fupport the whole ! 
 fixteen Cubes of VVater above it, yea, though they were 1 
 fixteen thoufand, And the reafon is, becaufe they prefs: 
 mod equally, and uniformly. VVhat l affirm of the ima- i 
 ginary furface, the fame I affirm , of the firft and vffible. 
 For let a plain body of lead, never fo heavy, be laid upon 
 the top of the VVater A B C D, yet will it fupport it, 
 and keep it from finking, provided it prefs uniformly all, 
 the parts of that furface. It is clear alfo, from the fubfe* 
 quent Theorem. 
 
 THEOREM XXV- 
 
 The (urfaces of all Waters whatfoever , fupport as much 
 weight from the Air,as if they Lad the weight of thirty ■ 
 four foot of Water above them , or twenty nine 
 inches of Quick-fiver prefsing them. 
 
 T His Propofition is evident from this, that thepref-j 
 fureof the Air, is able to raife above the furface of 
 any Water, a Pillar of Water thirty four foot high. Tor,. 
 
 put 
 
XDcojttms* zs 
 
 put the cafe there were a ?mp fourty foot high , erefted 
 among ftagnant Waterand a Sucker in it, for extrading 
 the internal Air, a man will find,that the Water will climb 
 up in it four and thirty foot; which Phanomenon could 
 never happen, nnlefs the furface of the ftagnant Water, 
 among which theend of the tump is drowned, were as 
 much preft with the Air., as if it had a burden of Water 
 tipon it thirty four foot high. The fecond part is alfo 
 evident, becaufe if a man drown the end of a iong Pipe, 
 inaVeffel with ftagnant Quick-filver, and remove the 
 Air that’s within the Pipe by i Sucktr , or more esfilyby 
 the help of the Jir-futnp 4 he will find the Liquor to rife 
 twenty nine inches, above the furface below, which thing 
 could never come to pafs, unlefs the PrdTure of theAic, 
 upon the furfaces of all Bodies , were equivalent to the 
 Preflure and weight oi twenty nine inches of Quick-filver, 
 
 THEOREM XXVI- 
 
 All Fluid todies have afphere of Attivitj, to which thef 
 m able to prtfs up themfelves, or another Fluids 
 and no further, which is lefs or more, according 
 to the altitude of that prefsing Fluid, 
 
 Figure 2. 
 
 F Or undemanding this Propofition, let us Imagine 
 G H C D tobeaVeffel , in whofc bottom, there 
 are five inches of Mercury EFC D, Next,that above 
 the ftagnant Mercury, there are thirty four foot of Water 
 retting, namely A RE F. Laftly, that upon the fur- 
 face of the faid Water, there is refting the Element of 
 Air G H A B, whofe top GH.I reckon to be about 
 | D fix 
 
$pmQ&attcai X0eo*ems* 
 
 fix thoufand fathom above A B. Befides -thefe ■, let as 
 imagine,that there are here three Pipes,open at both ends, 
 the firft whereof C A G, having it’s lower orifice C, 
 drowned among the ftagnant Mercury E F-C D, goeth 
 fo high, that then pner orifice goeth above the top of the 
 Air G H.The fccona,whofe lower orifice I,is only drown¬ 
 ed among the Water. A B E F, reaches to the top of the 
 Airlikewife, The third, whofe open end K , is above 
 the furface of the VVater A N B, and hanging in 
 the open Air., goeth likewife .above the Atmofphere. 
 Thefe things being fuppofed, we fee that no Fluid can, 
 by its own proper weight, prefs any part of it felf, higher 
 then it’s own furface,feing the ftagnant Mercuiy E F C Dj 
 cannot prefs it felf within the Pipe C G, higher then E. 
 Neither can the Water ABEF, prefs it felf higher 
 within the Pipe I L, then the point N.- Laftly,nekhei: 
 can the Air G H A B, prefs it felf within the Pipe K M, 
 higher then M, But when one Fluid prefteth upon ano¬ 
 ther,as the Water ABE F,upon the Mercury E F C D, 
 then doth the faid Mercury afcend higher than it’s own 
 furface, namely from E to O, which point is the higheft, 
 to-which the thirty lour foot of VVater A B E F, can 
 raifet-he Mercury, which altitude, is twenty nine inches 
 above the'furface EIF. But if a fecond Fluid be fuper- 
 added, as the whole Air G H A B, then muft the Mer¬ 
 cury, according to that newpreflure, rife by proportion ; 
 fo rifes the Mercury from 0 to P, other twenty nine; 
 inches. By this fame additional weight of Air, the Wa-i 
 ter rues xhircy four foot in the Pipe IL, namely from N . 
 to R, Now, I fay, the outmoft and higheft point, to ; 
 which the Element of Air GHAB can raife the Mer» : 
 cury, is from .0 to P; for by the Preflure of the Wa- 
 .. ter 
 
^pDjOttaticai Xticoj tins , vy 
 
 ter A B E F, it rife from E to 0 . And the higheft 
 point, to which the faid Air can raife the Water, is from 
 N to R, The reafons of thefe determinate altitudes, 
 molt bp fought for, from the altitudes of the incumbing 
 and preffing .Fluids: for as thefe are lefs or more, fo is the 
 altitude of the Mercury, and of the Water within the 
 Pipes more or lefs. The hight therefore of the Mer¬ 
 cury EO, is twenty nine inches, becaufe the deepnefs of 
 the preffing water A B E F is thirty four foot. And the 
 hight of the Water N R, is thirty four foot,becaufe the 
 hight of the Air G H, above A B, is fix thoufand 
 fathom, or thereabout. And for the fame reafon, is the 
 Mercury O P twenty nine inches, 
 
 THEOREM XXVII- 
 
 A lighter Fluid, is able to j>refs with as great 
 burden , as a heatHer. 
 
 Figure 2. 
 
 T His Propofmon is true, not only of Water in re- 
 fpetft of Mercury, but of Air in refpedt of them 
 , both: for albeit Air be a thoufand times lighter then 
 Water, yet may it have as great a PrefTure with it, as 
 VVater-, as is evident from this fecond Schematifm, 
 where by the PrefTure of the outward Air GHAB, 
 twenty nine inches of Mercury OP are fupported , as 
 well as the twenty nine inches EO, by the PrefTure of 
 the Water A B E'F. So doth the fame Air, fuftain the 
 thirty four foot of Water NR, which are really as hea¬ 
 vy, as the twenty nine inches of Mercury O P. Now, 
 if the weight of the Atmofphere, be equivalent to the 
 D z weight 
 
is §5>b«if}atual£t)cojEms. 
 
 weight of thirty four foot of Water, or of twenty nine' 
 inches of Mercury, ’tis no wonder to fee Water prefs 
 with as great weight as Mercury $ which is likewife clear 
 from this fame Figure, where by the Preffure of the Wa¬ 
 ter A B E B, twenty nine inches of Mercury E 0 are 
 Mpended, as truly as the Mercury CE, within the lower 
 end of the Pipe, is Supported by the outward invironing 
 Mercury. Thereafons of thefe Phenomena , are taken 
 from the altitudes of the pretfing F.uids: for though a 
 Body were never fo light,yet multiplication of parts makes 
 multiplication of weight ^ which multiplication of parts 
 in Fluids, muft be according to altitude: for multiplica¬ 
 tion of parts according to thicknefs and breadth will not 
 do it.. Obferve here,that if as much Air, as fills the Tub 
 between N and L, were put into the fcale of a Ballance, 
 it would exa&Iy coonterpoife the thirty four-foot ofWater ' 
 N R, poured into the other fcale. Item, that as much 
 Water as will fill the Tub between E and A , is juft 
 the weight of the Mercury E O. Laftly, that as much 
 Air as will fill the Pipe, between 0 and G, is juft the 
 weight of the Mercury O P, 
 
 THEOREM XXVIII. 
 
 The Preflure of Fluids, doth not diminifh , while you 
 fubtraci from their thicknefs, hut cnly } when 
 you fubtract from their- altitude,. 
 
 Figure i. 
 
 F Or underftanding this, let us look upon the firft $che^ 
 matiftn, where there are four Pillars of Water. Now 
 I fay, though you cut off the three Columes of Water, 
 upon the right fide, yet thetefhall remain as much Pref¬ 
 fure, 
 
^ptyoftattcal 3lt)eo?ems* 29 
 
 Cure, in the quadrat foot of Water Q, as was, while 
 thefe were intire. But if you cut off from the top, the 
 Water E F G H, then prefently an alteration follows, 
 not only m the loweft parts, nigh to the bottom , but 
 through all the intermedia* parts: for not only the V Va- 
 ter Qlofeth a degree of its Preffore, but the Waters P 
 and 0 fuffer the fame lofs. This Theorem holds true 
 likewife in order to the Element of Air. For if by Di¬ 
 vine Providence, the Air fhould became left in Altitude, 
 than it is ; then furely, th eBcnftl of the ambient Air, that 
 we breath in and out, fhould be by proportion weakned 
 alfo, And contrariwife, if the Altitude became more, 
 then ftronger fhould the Benftl be here, with us, in the 
 loweft parts: both which would be hurtful to creatures, 
 that live by breathing. For if the Altitude of the Air, 
 Were far more then it is, our bodies would be under a far 
 greater Preffure,which furely would be very-hurtful* And 
 upon the other hand, if the Altitude of the Air, were far 
 lefs then ic is. we fhould beat a greater lofs j for then, by 
 reafon of the weak Benftl^ we would breath indeed, but 
 with great difficulty, 
 
 THEOREM XXIX. 
 
 4 thicker Pid/tr of a Flmd b is net *Mc tv prefs up <flen« i_ 
 derer, tirdtfs there be in unequal Prejfun, 
 
 Figure 3 . 
 
 F Or undemanding this, let ns fuppofe this third Sche^ 
 matifra to reprefent a veffel with Water in it,as high 
 as A B, among which is thruftdown.to the bottom, the 
 pipe G H, open at both ends, I fay then, the two thicker 
 
 Pillars 
 
so ^ i^oftattcatXfteomns* 
 
 Pillars of Air E A, and F B, preffing upon the furface of 
 the Water A B, are not able to prefs up the Water H I, 
 or the Bender Pillar of Air IG within the Pipe, the one 
 higher then I, the other higher then G. If it be faid, 
 they are heavier, bccaufe they are thicker. I anfwer, they 
 are truly heavier, for the Pillar of Air FB apart, willbe 
 thrice as heavy, as the Bender Pillar of Air IG. But, if 
 you reckon the Pillar of Air E A, upon the left hand, 
 both together, will be fix times heavier, then the Air 
 IG: yet are they not able, either feverally, orcon;un<ft» 
 Iy, to prefs up the Water H I, higher then I, or the 
 Air IG, higher then G. For folving this difficulty, I 
 muft lay conform to the fourth Theorem, that Fluid Bo¬ 
 dies, counterpoifeth one another, not according to their 
 ibi chiefs, snd breadth, but according to their altitude on¬ 
 ly : therefore, feing the Bender Pillar of Air IG, is as 
 high, as either F B, or E A, it cannot be preft up by 
 them. For by vertueof this equal bight, all the three 
 prefs equally and uniformly, upon the furface of Water 
 AB ; and therefore according to the twelfth Theorem, 
 there can be no motion. But if fo be, the Pillar F B s 
 were higher then the Pillar I G, then furely would 
 the Water HI, be preft up; for in fuch a cafe, there is 
 an unequal Preflure, Or if the Pillar IG, were higher 
 then -the Pillar F B, then furely would the Water I H be 
 preft down, there being again an unequal Preffiire : the 
 Water within the Pipe, being more burdened then the 
 Water about the Pipe, In a word, there’s no more dif¬ 
 ficulty here, then if the Pipe were taken away: in which 
 cafe, there would be but one Pillar of Air, retting upon 
 the furface pi Water A B. If it be faid, the' Pipe being 
 thruft down, makes of one Pillar, three diftindt ones, and 
 
 confe- 
 
Ppoioflaticai Ifltojcms. 31 
 
 cotifequentfy a formal counter-ballance, or mutual fuften- : 
 tation. Be it fo, yet becaufe all thefe preTs uniformly, 
 there can be no motion, ■ 
 
 THEOREM XX X. 
 
 Fluids prefs not only according to perpendicular' 
 
 Lints, but according to crooked Lines, 
 
 Figure 4,. 
 
 F Or. proving this Propofition,let us Aippofe A B C D, 
 to be a large VefTel full of Water,as high as A N B, 
 anda little VelTel lying withinit,near to the bottom,clofs. 
 above at M, but with an open orifice downward , as G, 
 and having other two pafTages going in to it, upon the. 
 right, and left fide, as EO, and FP. . Now, Ifayj the, 
 Preflureof this VVater, is'not only from ;N to M, ina 
 Straight line downwards, but from E to O,-and from F 
 to P, by crooked lines'. Nay, put the cafe this VelTel had)' 
 no pafTage in to it, but by a Labyrinth , or entry full of in¬ 
 tricate windings, yet the PrefTure will be communicated, 
 thorow all-thefe, even to the middle of it: and which is 
 more, the VVater H or I, within the VelTel, would be 
 under the fame degree of PrefTure, with the Water E or 
 L,- without , or with the VVater K or F. And which 
 isftrange, let us-TuppoTe both the entries-E and F, flop¬ 
 ped, and nothing remaining open, but the hole G, which 
 I judge no wider, then may admit the hair of -ones head* 
 yet thorow that fmal hole, (hall the PrefTure be communi¬ 
 cated, to the parts of the Water within, ip as high a de¬ 
 gree, as if the upper part of the VefTel EML, were cut 
 off,’ to let the PrefTure come down direftly, W hit is true 
 
 in 
 
i^ojoftaticai 
 
 ia order to Water, the fame is true in order to Air, or Mer¬ 
 cury , or any other Fluid, For, though a houfe were built 
 never fo dofs > without door, or window, yet if there re¬ 
 main but one fmal hole in it, the PrefTare of the whole At* 
 mofphere, (hall be tranfmitted thorow that entrie, and fhall 
 reduce the Air within the houfe, to as high a degree of 
 Benfil, as the Air without. 
 
 THEOREM XXXI- 
 
 The Preffure , and Benftl of a Fluid , that' sin the Low- 
 eft toot, is equivalent to the weight of the whole 
 Pillar above. 
 
 Figure 5. 
 
 F Or unaerftandLng this Proportion, let us fuppofe EF 
 to be the lowed foot of 3 pillar of Air, cut off from 
 the reft, and indofed in the Veffel E F, fix inches in Dia. 
 meter, or widenefs,ani twelve inches high. Now! fay,the 
 Benftl and Preffure, tilt's in that one foot of Air, is exact¬ 
 ly of as great force and power, as is the weight of the whole 
 Pillar of Air, from which it was cutoff. Let A B be 
 that Pillar of Air, which I fuppofe is fix inches thick, and 
 fixthoufand fathom high. Take it, and weigh it in a Bal- 
 lance, and fay it weighs 500 pound, yet the Preflure, and 
 Btnfil , that’s in the Air E F, is of as much force: and if 
 the one be of ftrength by its weight,to move, v. g, a great 
 Clock , the other by its Benfl , will be of as much. This 
 propofition is true alfo in order to Water. For put the 
 cafe E F, were the loweft of 34 foot of Water: in it will 
 be found as much Preffure, and force, as will be equivalent 
 to the weight of the whole thirty-three foot, From-which 
 
{^Djottatlcat Xtjcojcms, jj 
 
 it was cut off. But here occurreth a difficulty} for if the 
 PrefTure, and Benfil of the foot of Air E F, be equiva¬ 
 lent to the weight of the whole Pillar of Air A B, which 
 weighs 500 pound, then muft the flender Pillar of Air 
 C D, that’s but two inches in diameter, be as heavy 
 weighed in a ballance, as the thicker Pillar A B, which is 
 abfurd. I prove the connexion of the two parts of the 
 Argument thus: as the Benfil of the Air OH, is to the 
 Benfil of the Air E F, fo is the weight of the Pillar C D, 
 to the weight of the Pillar AB: but fo it is, that the 
 Benfil of the Air GH, is equal in degree to the Benfil 
 of the Air EF, according to the Theorem 21. Where 
 it’s laid, that the PrefTure of Fluids maybeas much, in 
 the leaft part, as in the whole: therefore the Pillar CD, 
 and the Pillar AB, muft be of equal weight, when both 
 are weighed together intheoppofite fcales of a Ballance, 
 which is falfe, feing the one is far thicker, and fo heavier 
 then the other. There’s no way to anfwer this obje&ion, 
 but by granting the Air G H, and E F, to be equal in 
 Benfil, and yet the two Pillars unequal in weight, becaufe 
 according to the 22 Thmem,the.Benfil of a Fluid is one 
 thing, and the natural might is another, 
 
 THEOREM XXXI I- 
 
 in all Fluids there is a Pondus and a Potentia, a 
 weight and a power, counterpoifing one 
 another , as in the Staticks. 
 
 T Hat part of the Mathematicks, which is called St a* 
 ticks, is nothing eife, but the Art of weighing hea¬ 
 vy Bodies ; in which, two things are commonly diftin- 
 E guifhed 
 
34 ftptBOftatftalsyeojcms. 
 
 guirhed, via. the pondus and the potentia, die weight and 
 the/wFfr, 'Tis evident, while two things are counter- 
 poifing one another in the oppofite Tales of a Ballance, 
 as Lead and Gold, the one being the pondus , the other the 
 potentia, The Tame two are as truly found in the Hydro* 
 fiaticks : for while the Mercurial Cylinder is fufpended 
 in the Torricellian Experiment, by the weight of the Air, 
 the one is ready the pondus, the other the potentia, Or 
 while into a Siphon, with the two orifices upward, Water 
 is poured, there-arifes a counterpoise, the Water of the 
 6 ae Leg coimter-ballancing the Water of the other*, this 
 taking the name of a pondus, the other the name of a po - 
 tentia. ’Tis evident alfo, while a furface of Water, fu¬ 
 ftains a Pillar of Water, this being the pondu f, that the po- 
 ttntU Or, while a furface of Water fuftains a Pillar 
 of Air, the Pillar of Air being the pondus, and the furface 
 of Water the potentia. Or, while a lurface of Quick- 
 Elver fuftains a Pillar of Water or Air*, the furface is the 
 power, and either of the two is the pondus , or might , as 
 you pleafe.. 
 
 THEOREM XXXIII- 
 
 Fluid Bodies can never ceafe from motion, fo long 
 as the pondus exceeds the potentia, or the 
 potentia the pondus, 
 
 *T“ , Hi$isa fare Principle in the Hydroftaticks , which 
 JL will appear moft evident* while we pafs thorow the 
 fubfequent Experiments, I (hall only now make it appear 
 by one inftance, though afterwards by a huudred. In the 
 TorrictHUn Experiment, lately mentioned, ’tis obferved, 
 
 that 
 
0yo?oltancat Ht)to»niB , 
 
 that though.the Pipe were never fo long^hat ? s filled with 
 Mercury* yet the Liquor fubfides, and falls down alwayes 
 till it come twenty nine inches above the fortace of the 
 ftagnant Mercury below. The reafon whereof is truly 
 this,, fo long as the Mercury is higher then the laid poi% 
 as long doth the pondus of it exceed the fgteytia of the 
 Air; therefore the motion of it downward can never 
 ceafe, till at lafl: hy falling down,and becoming foorter, it 
 becomes lighter, in which inftanr. of time, the motion 
 ends, both of them being now in equippndio, prjneyefj- 
 nefs of weight. 
 
 THEOREM XXXTV. 
 
 When WO fluids of different kinds are in #quiiibrio */>- 
 gether y the height of the one Cylinder is in proportion tp . 
 the height of the other y as the natural might pf the 
 one is to the natural might tf the other. 
 
 F Or underftanding this Theorem,we muft confider,.tftat 
 when two Cylinders of the fame kind, as one of Wa¬ 
 ter with Water, or as one of Mercury with Mercury^ are 
 counterpoifing one another, both are of the fame altitude, 
 becaufe both are of the fame natural weight. But when 
 the two are of different kinds, as a Cylinder of Air with 
 Mercury,or as a Cylinder of Air with Water, or as a-Cy- 
 linder of W'acer with Mercury, then it will be found, that 
 by what proportion., the one Liquor is naturally heavier 
 or lighter, then the other, by that fame proportion, is the 
 one Cylinder higher or lower then the other, For ex¬ 
 ample, becaufe Air is reckoned 14000 times lighter then 
 Quick-filver, therefore the Pillar of Air that counter- 
 E 2 . poifeth 
 
36 ftptyoftactcai SLQcoiems*. 
 
 poifeth the Pillar of Quick-filverin the Torricellian Ex* 
 'ferment, is 14000 times higher. The one is 29 inches, 
 and therefore the other is 406000 inches; which will 
 amount to 33833 foot,or about 67 66 fathom, counting 
 five foot to a fathom. And bec-auie Air is counted 1000 
 times lighter then Water, therefore the Pillar of Air that 
 fuftains the Pillar of Water is iooo times higher. The 
 hight of Water by the PrelTure of the Air is 34 foot,, 
 and therefore the flight of the Air is-a thoufand times 34 
 foot. And becaufe Water is reckoned 14 times lighter 
 than Mercuiy,therefore you will find,evenby experience, 
 that the Pillar of Water, that counterpoifes the Pillar of 
 Mercury, is 14 times higher. For if the Mercury be 
 ten inches, the Water will be exa&ly 140. If it be 29 
 inches, the Water will be thirty four foot, The- reafou 
 is evident, becaufe if one inch of Mercury be as heavy 
 naturally as 14 inches of Water, it follows of neceflity, 
 that for making of a counterpoife, to every inch of Mer- 
 airy, theremuftbe 14 of Water, and thefe in altitude, 
 eacfione above another. 
 
Hyclroltarical 
 
 EXPERIMENTS, 
 
 For demonftrating the wonderful 
 Weight , Force } and Prejjure of the 
 W ater in its own Element. 
 
 experiment i. 
 
 Figure 6. 
 
 explicating the Phenomena of the Hy* 
 droflaticki , and in collecting ipeculative, 
 or pra&ical conclufions from them, I pur- 
 pore to make choife oi the plaineft, and 
 moft eafie Experiments, efpecially in the 
 entry, that this knowledge, that’s not 
 very common, and yet very ufeful, may be communica¬ 
 ted to the meaneft capacities. For, if at the firft , any 
 myftical, or abftrufe Experimentsihould be propofed 
 with intricate deferiptions, they would foon difeourage, 
 and at laft hinder the ingenuous Reader from making pro- 
 
3S i^&oftatfcal experiments* 
 
 grefs. For, itamandonottakeupdiftin&Iy, theExpe- 
 rirnent it felt firft, he (hall never be able to comprehend 
 next the Phenomena, nor at laft fee the inferences of the 
 conclusions, Next, though tome of the trials may 
 teem obvious, yet they afford excellent Phenomena, by 
 which many’profound fecrets of Nature are difeovered. 
 And if that he, ’cis no matter what kind they be of. Then, 
 the grand defign here, is not to multiply bare, and naked 
 Experiments; for that’s a work' to no purpofe, for it’s 
 like i foundation without a fuperftru&ure: but the inten¬ 
 tion is, not only to deferibe fuch and fuch things, but 
 to build fuch and fuch Theorems upon them, and to infer 
 fuch and fuch conclufions, as fhall make a -(lately building, 
 and give a man in a lhort time a full view of this excellent 
 Doctrine. 
 
 For the firft Experiment then, prepare a VefTel of any 
 quantity, as AB CD, near half full of Water, whofe 
 fur-tacc is M H, Prepare alfo two Glafs-pipes, the one 
 wider, the other narrower, openat both ends, which muft 
 be thruft down below the Water, firft flopping the two 
 upper orifices E and F. This done ? open the faid orifices, 
 and you shall fee the Water afeenb in the wider to G,and in 
 the narrower to H. Now, the queftion is, What’s the rea< 
 fon,why the Water did not alcend,the orifices E and F,be¬ 
 ing flopped,and why it afcencs,they being opened f To the 
 fi.ft part I aniwer, the Water cannot afeend, becanfe the 
 imaginary furface of Water LK is equally and uniformly 
 preft .■ for with what weight the outward Water M 'L, 
 an-i H X preis the laid lurface, with the fame weight, 
 doth the Air within the two Pipes prefs it. To the fecond 
 parti anfwer. the Water afeends, becanfe the fame fur- 
 face (the orifices E and F being opened; is unequally 
 
 •preft: 
 
$2&joftat(cal €;pttftnenfo 39 
 
 preft: for the outward Water M L, and HK, prefs it 
 more, then the Air within the Pipes do. The difficulty 
 only is, why it is equally preft, the orifices E and F be¬ 
 ing flopped, and why it is unequally preft, the faid orifices 
 being once opened. To unlo,ofe the knot, I muft ihewthe 
 reafon, why the Air within the Pipes, prefs : the furface 
 LK, with as great a burden, as the outward Water prefs 
 it. For undemandingthis, you muft know, that when 
 the orifice I isthruft down below the Water, thereari- 
 feth a fort of debate between the lower parts of the Wa¬ 
 ter, and the Air within thePipes, the Water ftriving to 
 be in at I, and the Air ftriving to keep it out: but becaufe 
 the Water is theftronger party, it enters the orifice I, 
 and caufeth the Air retire a little up, one fourth part, or 
 fixth part of an inch, above I, and no more, which is a 
 ieal compreffion it fuffers. For the orifice E being flop¬ 
 ped, hinders any more compreffion, than what is faid ■ in- 
 which inftant of time the debate ends, the Air no more 
 yeelding,and the Water no more urging •, by which means 
 the Air having obtained a degree o iBexfd, more then or- 
 dinary, by thePrefliireof that little quantity of Water, 
 that comes in at i, prefleth the part of the imaginary fur- 
 face, it refts upon, with as great weight, as the outward 
 Water prcficth the parts it refts upon. But when the 
 orifice E is opened, the outward water ML, and HK, 
 prefs the imaginary furface L K more, than the Air with¬ 
 in the Pipe can do. And the reafon is, becaufe by open¬ 
 ing the orifice above, the internal Air, that fuffered a 
 degree of Benfil more then ordinary, prefently is freed, 
 and confequently becomes of lefs force,and weight •, which 
 the Water finding, that hath a little entered the orifice I, 
 inftantly afcends to G, it being lcfs preffed, then the Wa- 
 
40 ^pojoftatfcai experiments* 
 
 ter without the Pipe, Now the reafon, why it afce-nds 
 no higher then G, is taken from the equal PrefTure of the 
 Body that refts upon the furface M G H: For, alToon as 
 it comes that length, all the parts of the horizontal Plain 
 of Water, is uniformly preft with the incumbing Air, 
 both within the Pipe,and without the Pipe. The Water 
 in going up, cannot halt mid-way between I and G, for 
 then thereihould be an unequal PrefTure in Fluids with¬ 
 out motion, which is impoffible ; for the Water is ftill 
 ftronger then the Air, till once it climb up to G. 
 
 From this Experiment we fee fiift, that in Water there 
 is a PrefTure and Force • becaufe having opened the orE 
 fice E, which is only cauja per accidtns of this motion, 
 the Water is preft up from I to G. We fee fecondly, 
 that Fluid Bodies 5 can never ceafe from motion,till there be 
 an equal PrefTure among the parts, which is evident from 
 theafcentof the Water from I to G, which cannot halt 
 in any part between I and G, becaufe of an unequal Pref- 
 fure , till it once climb up to G. We fee thirdly , that 
 Fluid Bodies do not fuftain, or counterpoife one another 
 according to their thicknefs and breadth , but only accor¬ 
 ding to thek-jltitude •, becaufe there is pot here any pro¬ 
 portion between the {lender Pillar ofWater HK within 
 the Pipe , and the outward Water that Mains it, I 
 mean as to the thicknefs *, therefore ’tis no matter,whither 
 the Glafs Tubs be wider or narrower, that arc ufed in 
 counterpoifing Fluid bodies one with another. And this 
 is the true reafon, why’tis no matter, whither the Tub of 
 the Barofccpe be a wide one, or a narrow one, feing the Air 
 doth not counterpoife the Mercury, according to thick¬ 
 nefs , that’s to fay, neither the thicknefs of the ambient 
 Air .that fuftains, nor the thicknefs of the Mercury that 
 
 is 
 
i)i>i?oftattcal€)cpettincnts. 41 
 
 is fuftained, are to be cotifidered; but only their altitudes, 
 *Tis true, the element of Air is fourteen thoufand times 
 higher , then the Mercurial Cylinder, yet rhere is a 
 certain and true proportion kept between their heights; 
 fo that if the element of Air, fhouldby divine providence 
 become higher or lower, the height of the Mercury would 
 alter accordingly. 
 
 EXPERIMENT- II- 
 Figure 6 , 
 
 T Ake out of the Water, the wide Pipe E G I, and 
 flopping the orifice I, pour in Water above at E, 
 till the T ub be compleatly full. Having done this, thruft 
 down the flopped orifice I to the bottom of the Veflel, 
 and there open it, then Ml you fee the Water fall down 
 from E to G, and there halt. The reafon is taken from 
 unequal Preflure ; for the Tub being full of Water from 
 E to I, that part of the imaginary furface, upon which 
 the Pillar of Water refts, is more burdened than any other 
 part of it, namely more then L or K 5 therefore feing 
 one part is more burdened than another, the Cylinder of 
 Water that caufeth the burden, muft fo far fall down, till 
 all the parts be alike preft, in which inftant of time, the 
 motion ceafeth. This leads us to a clear difeovery of the 
 reafon , why in the Barofcope , the Mercury falls from the 
 top Of cheTub of any height,alwayes to the twentieth and 
 ninth inch, above the ftagnant Quick-filver. Forex- 
 ample , fill the Pipe N Q,, which is fixty inches high 
 with Mercury, and opening the orifice the-Liquor 
 
 Ml fall out, and fall down from N, till it reft at R,which 
 
4-i woflatical ©cpecfcntnts, 
 
 is twenty nine inch above the open orifice Q. The- res- 
 fon is the fame , namely unequal Preffare, feing one part 
 of the imtg'tvdry furface of Air X S, upon which: the 
 Cylinder of \lercury ftands, is more burthened then the 
 other next adjacent: therefore, fo long and fo far mull the 
 Mercury iubfide and fall down, till the part CL, upon 
 wh : ch the Balls of the Pillar refts, be nomorebmKeired, 
 than the reft of the puts 5 in which inftantof time, the 
 motion ceafeth, and there happeneth an equal ballance,be¬ 
 tween the Silver within the Tub, and the Airwithout, 
 If it be (aid, I fee a cleat reafon, why the outward Water 
 ML, ought to fuftain the inward G I, but cannot fee, 
 why the outward Air T ZS and VRX, ought to fu- 
 ft-ain the inward Mercury R X: neither do I fee a reafon, 
 why itlhould halracR, as the Water refts at.G. I an- 
 fwer though fenfc amiiorperceive the one, as evidently 
 ss the other, yet the one is as fure as the other. For tak¬ 
 ing up the reafon why it halts at R, 29 inchesabove X, 
 youmuftrememberfrom the 25 Theorem, that the 
 Prelfore of the Air upon Bodies, is equivalent to the 
 weight of 54 foot of Water perpendicularly, or 2 9 inches 
 ef Quick-filver, The Pillars of Air then TZS, and 
 VRX,' being as heavy each one of them , as two Pillars 
 of Mercury, each one of them 2p,inches high, it follows 
 of neceflity, that the Mercury within the Tub, muft be 
 as high as R. : Tis no wonder to fee the S/AwhaltatR, 
 provided R X, and Z S, werettvo bulks of Mercury, en¬ 
 vironing the Pipe, as the outward Water environs the 
 wider and narrower Pipe. Neither ought any to wonder, 
 when the Silver falls down, and refts at R, nothing envi¬ 
 roning the Pipe but Air, feing the Prelfure of the Air is 
 equivalent to the weight of 29 inches of Quick-fiver. 
 
ipi'6}ott attcai CE petlmentg. « 
 
 This Experiment is eafily«ade: take therefore a Sender 
 Glafs*pipe of any length, beyond 30 inches, openatboth 
 ends-, but the lower end Q, muft be drawn/o fmall by a 
 fiame of a Lamp,that the entry may be no wider,than may 
 admit the point of a fmall needle, or the hair of ones head. 
 Then flopping the faid orifice, pour in Mercury above at 
 the orifice N, till the Pipe be compleatly full. Next, 
 dofe the faid orifice with wet Paper, and the pulp of your 
 finger; and opening the lower orifice, you lhall find, 
 .(which is very delightful to behold) the Mercury fpring 
 out, likeunto a fmall filver threed, and falling down from 
 the top N, fliall reft at R, the motion ceafing at the nar¬ 
 row orifice Q. This fhews evidently, that there is not 
 need alwayes of stagnant Mercury, for trying the Torricel¬ 
 li m Experiment •, but only when the mouth of the Pipe 
 below is wide: for being narrow, the jitver runs {lowly 
 out, and confequently fubfides flowly above, and coming 
 downflowly to R, there refls.. But when the mouth is 
 wide below, the fiber falls down fo quickly, that it goes 
 beyond R, before it can recover itfelf, which recovery 
 would never be, unlefs there were ftagnant Mercury to 
 run up again. 
 
 From what is faid, we fee firft, that when one part of a 
 Surface of Water or Air, is more burthened than ano¬ 
 ther, the burthened partprefently yeelds, till it be no more 
 burthened than the other. This is dear from the falling 
 down of the Water from E to G, which cannot be fup* 
 ported by the part I, becaufe more burthened than the 
 reft. W.e fee fecondly, that the element.of Air, refts up¬ 
 on the furfaces of all bodies wirh^aconfiderable weight; 
 otherwifeit.could not fuftain the Water,, beforeatfall 
 down from E to G: for if it did not reft upon the furface 
 Fa MH, 
 
44 fepmo ftattcai e spagfincms, 
 
 M H, with weight,, the Water could never be fufpended* 
 feing the application of the finger to the orifice E, is 
 only the accidentd caufe of this Mentation, We fee 
 thirdly, that according to the difference of natural weighty 
 between two Fluids, fo is the proportion of altitudes be¬ 
 tween, two of their CylindersithereforeAir being reckoned 
 14000 times lighter then Mercury, it followes -that the 
 Cylinder of Mercury luftaine d by the Air,muft be 14000 
 times lower and (horter, than the Cylinder of Air that 
 fbftaines itjwhich appears from this experiment to-be true,, 
 feeing by the Preffure of the Air, which is thought to be 
 about 7oooiathom high,20 inches of Mercury is fupport- 
 edbetween R and X. In a word, if Air-be naturally 
 14000 times lighter thaw Mercury, which is verypro- 
 bable 5 then muft the altitude of it, commonly called the 
 Atmofphere , be fourteen thoufand times, nine and twen* 
 ty inches, that is 406000, or of feet 33 833.. 
 
 E X P E RI M E N T I 11- 
 Figure 6 , 
 
 W Hile the outward, and inward Water are of the 
 fame altitude, withdraw the inward Air E G by 
 fusion, or by any other device you think fit, and you will 
 find the Water rife as high as E, which I fuppofe to be 
 3 4 foot above M G H,, The fame Phenomenon happens, 
 in taking the Air out of the narrow Pipe F K. The rea* 
 fon is ftill unequal Preffure 5 . for in removing the Air, 
 that’s within the Pipe, the part of the furface ,M, and the 
 part H, remaines .burthened , while the part G is freed 
 of its burden; therefore this part of the furface, being libe- 
 
$ptyoftat(cal $jcpetirmnt& 45 
 
 rated of its burden, that came down through!' thePipe, irf- 
 ftantly rifes, and climbs up as far, as the outward Air rett¬ 
 ing upon M andH, can’raifeit, which is to E 34 foot* 
 for the Preffure of the Air upon the furfaces of all Waters^ 
 according to the 2 5 Theorem , being equivalent to the 
 weight-of 34 foot of Water, mutt raifethe faid Watet in 
 the Pipe 34 foot,You^do not wonder,why it rifes from I to 
 G, as in the fii (^experiment; no more ought you to won¬ 
 der, why it rifes from G to E, feirig the weight of the 
 Air, doth the fame thing, that 3 4.foot of Water retting 
 upon the furface M H, wojild do. 
 
 From this experiment we fee firft,that the Preffure of the 
 Air,- is the proper caufe of the motion of Water, uptho- 
 row Pump and Siphons , or any other inftrument, that’s 
 ufed in Water-worts of that kind- for if the weight of the 
 Air, retting upon the furface M H be the caufe, why 
 the Water climbs up from G to E, the fame mutt be 
 the caufe ' why the ftagnant Water followes the Sucker of 
 the Pump, while it’s pulled up. And thefame is the caufe, 
 why Water afeendsthe Leg of a Siphon , and is-the caufe, 
 why motion continues after fu&ion is ended. We fee fe* 
 condly, that every Prelfmg Fluid hath a Sphere of aftivity, 
 to which it is able to raife the Fluid, that is preffed. This 
 is evident in this experiment, becaufe the Preffure of the 
 Airreftingupon M H, isableto raife the Water, the 
 hight of E in the wide Pipe, and the hight of F in the 
 narrow, and no further, even though the faid Pipes were 
 far longer: and this altitude and higheft point is precifely 
 34 foot between Air and Water, We fee thirdly, that 
 ’tis all one matter, whether Pumps and Siphons bt wider or 
 narrower,whether the tub of the Rarofcope be, wherein the 
 Mercury is fufpended, of a large Diameter , or of a letter 
 Diameter,. 
 
46 l^ojoftaticai e ppctnnen ts. 
 
 Diameter, This is alfo evident from the fame,experiment-, 
 feing there is-na more difficulty in caufing the Water af- 
 cend the wide Pipe, than in caufing it afcend the narrow 
 one. And the reafon is, becaufe the preffing -Fluid re¬ 
 peats-not the prefied Fluid, according to its thieknefs and 
 breadth 5 but only according to its altitude. Therefore’its 
 as eafie for the Air, to prefsup Water through a ‘Pump four 
 foot in Diameter, as to prefsitup through a Pump, but 
 oneioot in Diameter, 
 
 EXPERIMENT IV- 
 
 Figure 7. 
 
 T His Schematifm reprefentsa large Veffel full of Wa- 
 
 ter, whofe fitft and vifible furface is ,D E H K, The 
 fecond, that ? s imaginary is,- L I, fix foot below it. The 
 third of the fame kind , is M G, fix foot lower. T he 
 fourth, is NFO, fix foot yet lower, Thelaft,and 
 loweft,is ABC. There are here alfo four T ubs, or rather 
 one Tub under four divers pofitions, with both ends open. 
 After this Tub D A is thraft below the Water, till it af¬ 
 cend , as high as D in it, lift it up between your fingers, 
 till it have thepofition of the fecond Pipe E F, and then 
 youfhall fee, as,the orifice of the Pipe afeends, the Cylin¬ 
 der of Water fall out by little,and little,until it be no long¬ 
 er than E F. Again,-lift it further up, till it have the po¬ 
 rtion of the Pipe H G, then fhall you find the Cylinder 
 ,of Water become yet (hotter. Laftly, if it be form ted, 
 as the Pipe.K I,the internal Water becomes no logger than 
 K I. Tkereafonsof thefe Phenomena are the fame name¬ 
 ly unequalPreflbre 5 for,the Orifice A being lifted up .as 
 
$pD?o&attcai comments* 47 
 
 high as F, it comes to the imaginary furface NO, which, 
 is not under fo much Preffure, as the other is. 5 therefore 
 one part of it being moreburdened, than.another, namely 
 the part upon which the Cylinder of Water refts, it pre¬ 
 sently yeelds, and fuffers the Cylinder to become fhorter, 
 and lighter, till it become no heavier, then is proportio¬ 
 nable to its own ftrengch. To make this reafon more evi¬ 
 dent, it is to be noted, that-no furface of Water is. able to 
 fupport a Cylinder higher then its own deepnefs, that is to 
 fay, if a furface be 40 foot deep, it is able to fuftain a Cy¬ 
 linder 40 foot high, and no moretherefore the furface 
 N O, being but-18 foot deep, it cannot fuftaim a Cylin¬ 
 der 24 foot long .- for if that were, then the Potentia, 
 fhould be inferiour to the Fondas, which is impoffible in 
 the HjdroBaticks. In effect, it were no lefs abfurdity, 
 then- to fay, 1 8 ounces are able to counmbalknce 9 4, For 
 afecond trial, lift up the fame Pipe higher, till it acquire 
 the pofition of the Tub G H- 5 in this cafe,' the Cylinder 
 of Water within it, becomesyet fhorter, even no longer,. 
 thanGH. The reafon is the fame, namely unequal Pref- 
 fure *, for when a Cylinder of W ater r 8' foot high, comes 
 to reft upon- this furface, that Is but 1 a foot deep, it makes 
 one part of it more burdened then another; therefore the 
 part that is more preft, prefently yeelds, and fuffers the 
 Cylinder to fall down, till the Pondmoi it, become equal 
 to its own TotmUi For the la ft trial, lift: upthe Tub. 
 till it acquire the pofition of the Pipe KI: in this cafe,the 
 Water within it becomes no longer then K I, the furface 
 LI, that is but fix foot deep , not being able to fuftain a 
 Cylinder 12 foot high. .. 
 
 From this Experiment we fee firft^ that inalj Fluid B<v 
 dies there is a-Preffure,‘ which is-more or-lefsi aceordingro ■ 
 
 the^ 
 
4$ ^pojoftatfcai experiments* 
 
 the deepncfsof that Fruid 5 this is evident from the four 
 feveral furfaces *, there being more Pretfure and force in the 
 loweft A B C, then in the next N 0 5 and more in this, 
 then in the furface M G 5 and more in this, then in L I. 
 We fee fecondly, that in all Fluids, there is a Pondus and 
 a PotentU *, which two are alwayes of equal force, and 
 ftrength; the PotentU is clear and evident in the furface, 
 by fupporting the Pillar 5 which Pillar is nothing elfe, but 
 the Pondus fupported. And that they are alwayes of equal 
 ftrength, is moft evident alfo 5 for when you endeavour 
 to make the Pondus unequal to the PotentU , in making a 
 furface 18 foot deep, to fupport a Pillar 14 foot high,they 
 of their own accord become equal ; the Pillar becoming 
 fhorter, and fuitable to the ftrength of the furface thac 
 fuftainsit. We fee thirdly, that’tis impoflible for one 
 par t of the fame Horizontal furface, to be more burdened 
 then another: for when you endeavour to do it,by fetting 
 a longer Pillar upon it, the part burdened inftantly yeelds, 
 tillicbenomorepreft, then the next part to it. We fee 
 fourthly, that the inequality, that is between the Pondus 
 and the Potentia in Fluids, is the proper caufe of the mo¬ 
 tion of Fluids. For when you endeavour to make a fur¬ 
 face 3 0 foot deep,fuftain a Pillar 40 foot high, this inequa¬ 
 lity is the true caufe, why the Pillar fubfides , and falls 
 down, and why the furface j-eelds, and gives way to it. 
 And this inequality is the true caufe, why the motion of 
 Water thorow Siphons continues. For under Handing this, 
 you muft conceive a Siphon, to be nothing elfe,but a crook¬ 
 ed Pipe with two legs, the one drowned among Water, 
 the other hanging in the open Air. The ufe of it is, for 
 conveying Wine dr Water’from one Veflel to, another, 
 which is eafily done by fusion. Now afterXutf ion is end. 
 
 ed, 
 
ejectments* 49 
 
 ed, the motion of the Water continues, till the furface 
 become lower, then the orifice out of which it runs. The 
 truereafon then,why the Water flows out, is the inequa¬ 
 lity between the Potentia of the Air, and the Pondus of the 
 Water; the Pondus being ftronger then the PotentU. 
 For in Air as in Water, we muff conceive Horizontal 
 furfaces; and thefe furfaces to be endowed with PrefTure 
 and force, as are the furfaces of Water. Now when the 
 leg of a Siphon is hanging in the Air, it muft reft upon one 
 furface or another, and consequently the Water in it, 
 muft reft upon the fame furface. If the Potentia of the 
 furface be ftronger, then the Pondus of the Water; the 
 Water is driven backward, which alway.es comes to pafs, 
 when the orifice is higher, then the furface of the Water 
 of the Veffel, among which the other leg is drowned. If 
 the Potential of the furface of t hat Air, be of equal power 
 and ftrength, with the Pondus of the Water, the Water 
 goeth neither backward, nor forward, but (lands in equi¬ 
 libria : this happens, when the orifice is neither higher, nor 
 lower, than the furface of the V Vater in the Vefiel. But 
 if the Potentia of the furface of the Air be weaker, than the 
 Pondus of the Water; in this cafe, the Air yeelds, and 
 Suffers the Water to runout, even as a furface 30 foot 
 deep, yeelds to a Pillar of Water 40 foot high. The.fame 
 inequality is the reafon, why Water climbs up the Pump; 
 why Water climbs up a Pipe, when a man fucks with his 
 mouth. Before fusion, the Potentia that’s in the furface 
 of Water, among which the end of the Pipe is drowned, 
 is of equal force with the Pondus of the Pillar of Air, that 
 comes down thorow the Pipe, or Pump; but affoon .as a 
 man begins to fuck, the faid Pillar of Airbecomes-lighter; 
 and the Water finding this, prefently afeends, The fame 
 
So $pmoftattcai experiments* 
 
 isthereafon, why the Mercury falls down to 29 inches in 
 the BtrDfcope, and no further: for as long as the Poudas of 
 the Pillar of Mercury,exceeds the Petentin of the furface of 
 Air, fo long doth the motion continue 5 and when both 
 are become equal in force,the motion ceafeth. When the 
 dais-tub is 40 inches long, and filled with Mercmy, and 
 inverted after the common manner, you are endeavouring 
 as it were, to caufe a furface 29 inches deep, fuftain a Pil¬ 
 lar 40 inches high, which is utterly impoflible in fluids. 
 It is judged by many a wonder to fee the deflux of the Mer¬ 
 cury in The B/irojcoje 5 but in effeft, there’s no more caufe 
 of admiration in it, than to fee the Cylinder of Water 
 grow (hotter, by lifting the Pipe up from one furface to 
 another. 
 
 From this Experiment, we fee the truereafon, why the 
 Mercurial Cylinder of the Barofcope becomes fhorter and 
 fhorter, according as a man climbs up a mountain with it. 
 For at the root of the hill, the furface of Air, that fuff ains 
 the Pillar of Mercury, is of greater force, than the furface 
 at the middle part: and this is ftronger than any furface at 
 the top. The Pipe therefore being carried up from one 
 furnace to another, the Mercury in it, muff fubfide, and 
 fall down, even as the Water falls down, and becomes 
 fhorter, by lifting the Pipe from the furface A B C D to 
 the furface N O. And as the whole Water would fall 
 down,if theorifice I,were lifted above the furface D E H K, 
 fo if the B.iro[cofe could be carried fo high, till it came 
 above the top of the Air, the whole Mercurial Cylinder 
 would Purely fall down. And as by thrufting down the 
 faid Pipe to the bottom of the Veffel again, as the Pipe 
 B A, the Water afcends in it; fo by bringing down the 
 Bnrcjcoft to the earth again, the whole 1 pinches would 
 rife again, . E-X PE- 
 
^ptpftaticai experiments* 51 
 
 EXPERIMENT V- 
 
 Figure 8. 
 
 F ill the Veflel A D GH with Water to the brim; 
 
 Next, thruft down the open orifice of the Tub DA, 
 to the bottom, and you (hall fee the Water afcend in 
 it, as high as D, according to the fii ft experiment. When 
 this is done, recline the faid Pipe, till it ly as B E, and you 
 (hall find the Pipe, compleatly lull of Water. Next,ere& 
 the fame Tub again as DA, and you (hallfee the Cy¬ 
 linder oi Water fall down, and become (horter, as at firfi. 
 Forfalving this Phenomenon> and fuch like, I muft fuppofe 
 this Water to be 50 inches deep,and theTub I A,and BE 
 50 inches long: and the faid Tub in reclining., to deferibe 
 the quadrant of a Circle PEG. Now the queftion is,wliy 
 there being but 50 inches of Water in theTub,while'eretf- 
 ed, there fhould be 60 in it, when it is reclined f Second¬ 
 ly,why there fhouldbe 90 inches of Water in theTubB E, 
 and but 50 in it, when it Hands Perpendicular, as DA r 
 if you reply, becaufe there are 90 inflies in retta linen be¬ 
 tween the point B, and the point E, and but 50 between 
 A and D. But this will not anfwer the cafe ■ becaufe, 
 if you flop the orifice E, with the pulp of your Finger, 
 before it be ere&ed, you will find the Tab remain full of 
 Water, even while it (lands Perpendicular ; and fall down; 
 when the orifice is opened. Or, while the Tub (lands 
 Perpendicular, flop the orifice I, and recline itas B^E; 
 yet no more Water will be found in it,than 50 inches: but 
 by utiftopping the faid.orifice, the VVater climbs up from 
 R, to E,and becomes 90 inches. Now, what’s thereafon, 
 G 2 why 
 
5i ^pinoftatical experiments* 
 
 why it runs up from R to E, and why it falls down from 
 I to DC Ianfwerthen, the VVatermuft runup Irom R 
 to E, becaufe of the inequality, that’s between the Pondm 
 of the Cylinder B R, and the Poteniu of the furface of 
 Water ABC, that fupports the faid Cylinder, For 
 underftanding this, know, while the Tub is ereded, there 
 is a peried equality , between the weight of the Pillar A 
 D, and the force or Power of the furface that fuftains it, fe- 
 inga furface 50 inches deep, fupports a Pillar 50inches 
 high. But affoon as the Tub is reclined, there arifes ane 
 inequality between the faids two parties, the Pondus of 
 the Cylinder becoming now lefs than before. If you fay 
 the quantity of the Water is the fame, namely 50 inches,' 
 in the reclined Tub, as well as in the Perpendicular. I 
 grant the quantity is the fame, but the weight is become, 
 lefs. _Now the reafon, why the fame individual Water, is 
 not lo heavy as before, is this ; there are 40 ounces of 
 it, fupported by the fides of the Tub within 5 which 
 were not, while the Tub was ereded: for in this pofici- 
 on,the whole weight of the Cylinder refts upon the furface: 
 but while the Tub isreclrned, the faid furface is eafed, and 
 freed of 40 ounces of it 5 this 40, retting and leaning upon 
 the fides of the Pipe within,. The furface then, finding 
 the faid Cylinder lighter now than before, inftantly drives 
 it up from R to E, 40 inches. And likewife, when the 
 reclined Pipe is made Perpendicular, the Water falls down 
 from I to D, becaufe of the inequality, that’s between 
 the Ponhs of the Pillar, and the PotentU of the furface* 
 this furface 50 inches deep, not being able to fupport a Pil¬ 
 lar 90 inches high, for if this were, then one part, fhould 
 be more burthened than another, which is impofiible, 
 
 Itis tobeobferved, that by how much the more*, the 
 ' Tub 
 
$p&jottatfcai Comments* # 
 
 Tub is reclined from a Perpendicular, towards t he horizon¬ 
 tal furface ABC, byfo much the more growes the in¬ 
 equality, between the Pondus and the Potentia, and that ac¬ 
 cording to acertaine proportion. Hence is it, that the‘ 
 Tub being reclined from 60 degrees to 50, there arifes a 
 greater inequality between the Pondus of the Cylinder, and 
 the Potentia of the furface,than while it is reclined from 70 
 to 60: and more yet in moving from 50 to 40, than in 
 moving from 60 to 5 o,and fo downward, till it be horizon¬ 
 tal, in which pofition, the whole Pondus is loft. And con- 
 trariwife, while the Pipe is elevated, the Pondus begins to. 
 grow 5 and growes more, being lifted up from 10 to 20, 
 than from x to 10;• and yet more in travelling from 20 to 
 30, than from 1 o to 20, and fo upwards, till it be Perpen¬ 
 dicular, in which pofition, the Cylinder regaines the whole' 
 Pondus and weight, it had. This proportion is eafily 
 known, for its nothing elfe , but the proportion of Ferfed 
 Sines upon the line F B; for according to what meafure, 
 thefe unequal divifions become wider, and wider from go 
 to r, according to the fame proportion does the Pondus of 
 the Cylinder become lefs and lefs: and contrariwife,accord* • 
 ing to what proportion the faid divifions become more and 
 more narrow from 1 to 90, according to the fame meafure 
 and rate, does the Pondus oftheCylinder become greater 
 and greater. 
 
 From this experiment we fee fifft, that two Cylinders ■ 
 of Fluid bodies, differing much in quantity, may be of the' 
 fame weight; becaufe though the Cylinder BEpo inches' 
 long, be far more in quantity, than the Cylinder D A,' 
 that’s but 50, yet both of them are of the fame weight, in 
 refpeft ol the furface that fuftaines them; If it be faid, the 
 one. is really, heavier, -than the other, notwithftanding of' 
 
54 $p&* 0 ttat<cal experiments* 
 
 all this. I anfvver, it is fo indeed, in refpedi: of the Libra^ or 
 Artificial Ballance T that we commonly ufe in weighing of 
 things: but it is not fo in refped of this Natural Balance , if 
 I may fo fpeak, wherein Fluid bodies are onely weighed af¬ 
 ter this manner. We fee fecondly a clear ground for fet- 
 ting down the ninth Theorems, namely , that in all Fluid 
 bodies a twofold weight maybe diftinguifhed, one Senfible , 
 another Infafibk'. becaufe the Senfible weight of the Cy¬ 
 linder of Water B E, remaines ftill the fame, even though 
 itihouldbe reclined to G; for take it out, and weigh it 
 in a Ballance, it will be as heavy the one way as the other. 
 But it is not fo with the infnfibk weight; feeing the T ub 
 begins nofooner to recline, but affoon it begins to dimi- 
 n:fh,and grows iefs. This Infenfiblc weight is nothing 
 dfe, bur the (enfibU weight confidered after another manner. 
 For look upon the weight of the Pillar of Water B E , as 
 it weighs m a pair of Scales,it is then Senfible , and weighs fo 
 many ounces, and cannot be more or lefs: but look upon 
 it in reference to the UtentU of the furface, that Mains it, 
 it is then infepfible as to us: for though a man fbould put 
 his hand below the Water, and endeavour to find the 
 weight of the faid Pillar, yet he (hall not find it, though 
 that part of the furface upon which it refts, doth really 
 (if I may fo fpeak) finefthe weight of it. And as it is 
 Infenfibk, fo is it fometimes more, and fome.times lefs, 
 according as the Tub is elevated, or reclined: now thefe 
 two be:ng put together, gives a very probable ground for 
 this dift indtion. Wefee thirdly, that,the Pondus or weight 
 of Fluids, doth not only prefs according to Perpendicular 
 lines, but according to lines falling obliquely upon the 
 imaginary furface 5 fo doth the weight of.the Pillar of Wa¬ 
 ter BE, prefs the furiace ABC. We fee fourthly, that 
 
 Fluid 
 
^ynoftatical €y pet<me« ts. 55 
 
 Fluid Bodies, do counterpoife ortfe another, according 
 to Altitude only: for put the cafe, the Pip'e B E, were ten 
 timeswiderthen.it is, yet will the fiirfacefuftain the Wa- 
 tet in it, provided the Pipe keep ftill the fame pofition of 
 Altitude , namely 50 degrees: the regiondeems tb be this; 
 for if the Ba[e of the Pillar become,niorb in DiXnleter, it 
 neceffarily requires a larger part ofthe Surface tb reil upon ; 
 which larger part is really ftronger than the leffer part, as 
 will be (hewed afterwards. From this Experiment we fee 
 laftly, an evident reafon', Why the Mercurial Cylinder in 
 the Bttrofcope runs up, and fills the empty fpace, When the 
 Pipe is reclined, and why it runs down, when the Tub is 
 eredted again. In effedt, the reafon is the fame,namely, aii- 
 inequality between the Pandits ol the Quick-fi!ver,and the 
 Botentia of the furface of the IfUr • ; for When the Tub be¬ 
 gins to recline, th cPondtti begins tb reft upon the fide of 
 the Tub within • by which means the' Potcntid of the fur- 
 face finding the burden lefs, inftarjtly thrufts up the ftag- 
 nant Mercury to fupply that lofs, fe(ng two Fluids cannot 
 counterpoife one another, unlefs they.be in xquilibrib. 
 And contrariwife, aflbonasthe Tubbegins to bedredfed, 
 the Pandas of the Mercury begins tb grow, and fo over¬ 
 comes the Potentia of the fuiface, till by falling down it 
 can do no more. 
 
 EXPERIMENT vi. 
 
 Figure p. • 
 
 T His Schematifm reprefents a Yeffel full of Ware!, 7 - 
 whole firft and vifible Ur fate is HIK •, theTe^ 
 cond, which is imaginary, is E F G ; the third, A B C D. 
 
 Befides J 
 
$6 ^pfyoftattcaiejcpeciimnts* 
 
 Befides thefethree in Water,conceive a fourth in the Air, 
 above the Water, namely L M N. Upon this aerial fur- 
 face, refts the orifice M, of the Tub TM, open above. 
 Upon the furface E F G, is ftanding the mouth F, of the 
 Pipe S F. And upon the furface ABCD, ftands the 
 Pipe RB , open at both ends. After the orifice B is 
 drowned below the Water, you will find the Liquor rife 
 from B to H. Then clofe with the pulp of your Finger 
 the month R, and lift the Pipe fo far up, till it have the 
 Poficionof the Pipe S F ; and you fhall fee the Water 
 hing in it between F and 0 . Laftly, bring the faid ori¬ 
 fice compleatly above the Water, till it have the pofition 
 of the Tub T M; yet (hall the VVater ftill hingin it, 
 as M P. The firft queftion is, what fuftains the VVater 
 I O ; for the part F I, is fuftained by the ambient Wa¬ 
 ter ? I anfwer, it cannot be the pulp of the Finger clo- 
 fing the orifice S 5 for though, by taking away the Finger, 
 the VVater O I falls down, and by putting to the Finger, 
 it is keeped up, yet this proves not the pulp of the Fin¬ 
 ger to be the principal, and immediat caufe. I fay then, 
 the VVater O I is fufpended by the weight of the in- 
 cumbing Air,refting upon the furface HIK. For under- 
 flanaing this, confider, as I faid before, 25. Theorem, 
 that the Preflure of the Air upon all Bodies, is juft equi¬ 
 valent to the weight of 34 foot of VVater. -Hence then 
 is it, that if the Air be able to fuftain a Pillar of VVater, 
 34 foot highjit muft be able to fuftain the fhort Pillar 01 , 
 that exceeds not four foot. The fecond queftion is, whe¬ 
 ther the part F, be equally burthened with the part E, or 
 G-, for it would feem not, feing the VVater OIF, is 
 but four.foot high 5 whileftupon E or G isrefting, :not 
 only more then a foot of VVater to the top HIK, but 
 
 the 
 
^ptyoftattcal experiments* 57 
 
 the whole weight of the Atmffhere upon the faid top 
 is refting, which is equivalent to the burden of 34 foot of 
 VVater. I anfwer, there’s more to be confidered, than 
 that four foot of VVater, which initfelf is but of final! 
 burden, therefore to this we muft add the weight of the 
 Air between O and S, within the Pipe (remember that 
 the orifice S isftopped with the pulp of the Finger) which 
 in effect will be as heavy as. 31 foot of VVater. Put the 
 cafe then, F, to be one foot below the firft furface HIK, 
 and the VVater OI to be three foot, then ought the 
 Air .0 S, to have the weight of 31 foot, becaufe the fur- 
 face EFG isable tofupport a Pillar of 35 foot. This. 
 I prove, becaufe the part E, defatto^ fuftains 35 loot, be- 
 caufethe Air above is equivalent to 34 foot of it, and 
 there is a foot oi W ater between it and the top, namely 
 between E and H r T he third queftion is, how it comes 
 to pafs, that the Water ftill remains in the Pipe, after the 
 orifice M is brought above the furface of the Water 5 for 
 there is here no ftagnant Water guarding it, as guards the 
 orifice F, I anfwer, that the hfe M, of this Pillar of 
 Water PM, as really refts upon the horizontal furface of 
 this Air LMN, as a Cylinder of Brafs or Timber refts 
 upon a plain Marble Table, and after the fame manner. 
 Remember that the orifice T is flopped all this time, with 
 the pulp of the Finger. If it be faid, that the part M, is 
 more burdened then the part N, feing it fuftains four foot 
 of Water, which the part N fupports not, and the Air 
 P T within the Pipe alfo, which is of as much Btnfihni 
 Preffure, as the Air NY is of. For clearing of this dif¬ 
 ficulty, confider, that the Pillar PM is fhorter now than 
 befo e •, for the orifice M coming up from D, fome inches 
 of Water falls out, as will be found by experience. Sup- 
 H pofe 
 
js_ftpfijoflatfcsi ©cpetiments, 
 
 pdfe thea, that of four foot, fix inches fall one $ if this 
 be, then the indofed Air between P and T, muft be fix 
 inches longer, if this be, then of neceffity the Benfil of ic 
 muft be proportionably remitted and flackened: whence- 
 follows by Metafhffttd neceffity, that it cannot burden the 
 Water P M, with as much weight as it had , and.confe- 
 qUently the furface of Air cannot be fo much burdened. 
 It muff then be tio more burdened with them both toge¬ 
 ther,than it is with the fingle Pillar of Air YN. If then 
 the Water PM, be three foot and an half, the weight 
 of the endofed Air T P, muff be exattly the weight of 
 thirty foot of Water and an half. 
 
 From this experiment, we fee firft the Preflure of the 
 Air, for by it the Water OI is fufpended, and by the 
 fame prefluf e is the Water p M fufpended. We fee fe- 
 condly, that in Air, there is a power of dilating icfelfi and 
 that this dilatation never happens, without a relaxation of 
 the Binfti. We fee thirdly, that one Fluid cannot fuftain 
 another, unlefs the Potentia of the one, be equal to the 
 Pontius the other, as is clear from the Aerial furface, that 
 cannot fuftain the whole four foot of Water, but differs 
 fix inches of it to fall out, that the Pondtts- 6 f the reft, and 
 the Air above it, may become equal to its own Potentia,. 
 We fee fourthly, that Fluid Bodies have not only a power 
 of preffing downward, but of prefling upwardlikewife: 
 as isclear from the Water O I, that’s fufpended by the 
 Air preffiag down the furface of Water HIX. It pref- 
 feth upward alfo,whiIe it fupports the Water P M.. This 
 Experiment alfo anfwers a cafe, namely, whether or not it 
 is alwayes needful to guard the orifice or' the Tub of the 
 Bar of cope with ftagnant Quick- filver ? I fay then,it is not 
 alwayes needful, provided the orifice be of a narrow 
 diameter; 
 
W?oftaticai comments* _ 19 
 
 diameter; for experience tells, that while it is fuch, the 
 Mercury will fubfide, and halt at 19 inches above the ori¬ 
 fice, though no ftagnaut Mercury be to guard. In making 
 this trial, the orifice muft be no wider, than may adipic 
 the point of a needle. Or fuppofe it to have the wideoffs 
 of a Tdaeco'pipt , yet will the Mercury be fufpended, 
 though the end be not drowned among ftagnant jjWw*- 
 fifoer, even as the Water PM, is kept up without ftag- 
 nant Water about it. For trial of this, you muft firft let 
 the end of the Pipe,be put down among ftagnant Mercury, 
 and after the Cylinder is fallen down to its own proper alti¬ 
 tude, lift up the Pipe flowly, till the onfiee come above 
 the furface, and you will find, provided you do not fliake 
 the Pipe,the Cylinder to be fufpended after the fame man¬ 
 ner, immediatly by the Air, as the Water P M is. 
 
 EXPERIMENT VII- 
 
 Figure 10, 11. 
 
 T Ake a VefTel of any quantity, fuch as A B C D E, 
 and fill it with Water. And a Glafs-pipe, fuch as 
 GF D, of 15 or 20 inches long, of any widenefs, clpfs 
 above, and open below. Before you drown the open end 
 among the Water, hold the Glafs before the file, till it 
 be pretty hot, and having put it down, you will fee the 
 Water begin to creep up till it come to F, where it halts, 
 Thequeftionnow is, what’s thereafon, why the Wa¬ 
 ter creeps up alter this manner, 10 or 12 inches above the 
 furface AB r I anfwer, the heat having ratified the. Air 
 within, and by this means, having expelled much of it, 
 and the Air now contra#lag it Celf again with cold, the 
 H z water 
 
60 §ptyoftattcai nunt** 
 
 Water afcends, being preft up with the weight of the in- 
 cumbing Air, jefting upon the fuiface of Water A B. 
 There is -here finely an inequality between a Pondus and a 
 Potentia, thatmuft be thecaufe of this motion.I judge then 
 the inequality to confift between the weight of the Air 
 within the Pipe,and the furface olWater CDE.To expli¬ 
 cate this, I muft fuppofe the Pipe to be thruft down cold; 
 in this cafe, little or no Water can enter the orifice D. And 
 the reafon is, becaufe the Pondus of the Air within the 
 Glafs, is equal to the Potentia of the furface C D E. But 
 when the Pipe is thruft down hot, much of the Air having 
 been expelled by the heat, and now beginning ro be con¬ 
 tracted by cold, the Pondus of the Air becomes unequal to 
 the p-ottntix of the furface, and therefore this, being the 
 Wronger party, drives up the Air within the Glafs, till by 
 this afcent, the Pondus of the Air G F, and the Pondus 
 of the Water F D together, become equal to the Potentia 
 of the furface C D E, that fuftains them. For a fecond 
 trial ; bring a hot coal near to the fide of the Glafs, be¬ 
 tween G and F, and you will find the Water to creep.down 
 from F toward tfte furface AB; and if it continue any 
 fpace, it will drive down the whole Water, and thruft it 
 outatD. To explicate this, I muft fuppofe that heat, 
 by ratifying the Air within the Glafs, intends and increaf- 
 e*h the Btnfil of it,- and the Benfil being now made ftrong- 
 er, there muft arife an inequality between the Pondus of 
 the faid Air, and the Potentia of the furface CDE-, the 
 Air then, being the ftronger party, - caufeth the furface to 
 yeeld. 
 
 By comparing this Experiment with the former, we fee 
 a g-eat difference between the dilatation of Air, of its own 
 accord, aad by conftuint. For while it • is willingly ex- 
 
i^tyoftatscat experiments 6t 
 
 panded, the Benfil begins to grow flack, and'remifs, and 
 lofeth by degrees of its ftrength* even as tbs spring of a 
 Watch by the motion of the Wheels,becomes remifs. But 
 when the dilatation is madeby heat,and the Air compelled 
 to expand and open it felf,the Benfil becomes the ftronger, 
 and the Prefliire the greater, Notwithftanding J , though 
 the Benfil oi this inclofed Air G F, may be made ftronger 
 by heat, to the expulfion of the Water F D, yet if this 
 rarefaifFon continue any time, the Benfil becomes dull and 
 flack. And the reafon is, becaufe Air cannot be expan¬ 
 ded and opened to any quantity 5 an inch cannot be dilated 
 and opened to an hundred, or to a thoufand .• neither can 
 the Benfil of it be intended,and increafe to any degree, v.g, ■ 
 from one to 20,30, or 100. And therefore, as the ex- 
 panfion grows, the Renfilmuft at length flacken; But if 
 fo be the Air were inclofed, as in abladder knit about the 
 neck with a firing, then the more heat, the more Benfil: 
 for in this cafe there is a growth of Pfefliire, without dila¬ 
 tation. And fometimes the Benfil may be fo intended with 
 the heat, that the fides of the bladder will but ft aftinder. 
 
 From this Experiment we fee firft a confirmation of the 
 21 Theorem, namely, that there may be as much Benfil 
 and Preffiire, in the fmalleft quantity of a Fluid, as in the 
 greateft ; as is clear from the Benfil of the Air G F, which 
 in tftert counterpoifeth the weight of the whole 
 jphere , retting upon the furtace of Water A B. We fee 
 fecondly, that when the pondus, and the potentia of two 
 Fluids, are in equilibria, or of equal ftrcngtn, a very fmall 
 addition to either of them, will caftthe ballance. For if a 
 man fhould but breath fofely upon the fide of the Glafs be¬ 
 tween G and F, or lay his warm hand to it, the faid Air 
 will prefencly dilate it felf, afid by-becoming thus ftronger, 
 
 thruft 
 
6i woftattcai ejectments. 
 
 thrufl: down the Water, andfo overcome the potentia of 
 the furface, We fee thirdly a confirmation of the fixth 
 Theorem, namely, that the Preffure of Fluids is on every 
 fide 5 as is clear from the indofed Air GF, that not only 
 preffeth down the Water F D, but with as great force 
 preffeth up the top of the Glafs within, and preffeth upon 
 all the fides of it within, with the fame force. This Ex¬ 
 periment alfo, leads us to the knowledge of two things: 
 Fir#, of the reafon, why with cold the Water afcends in 
 the common W^ather-glaffes 5 and why in hot weather 
 the Water defends, Secondly, from this Experiment 
 we may learn to know, when the Air is under a greater 
 Preffure, and when under a leffer: becaufe when the Air 
 becomes heavier, as in fair tveather, the Water creeps 
 up in fome meafure, it may be two or three inches ; when 
 there is no alteration as to heat and cold: and in foul wea¬ 
 ther, or in great winds, when the Air is really lighter, the 
 faid Water creeps down as much. If it be asked, how fhall 
 I know, whether it be the cold of the Air, orheavinefs > 
 of the Air, thatcaufeth the Water to afcend ; and whe-’ 
 ther it be the heat of the Air, or the lightnefs of the Air, 
 thatcaufeth the Water to defcend? I have propofed this 
 queftion of purpofe, to let you fee a miftake. Many be¬ 
 lieve, that theafcent and defcent of Water in common 
 Weather-glumes, is allanerly from the heat and coldnefs of 
 the Air *, and therefore they conclude a cold day to be,be- 
 caufe the Water is far up: whereas the Water hath afcen- 
 dedfmce thelaft night, by reafon of a greater weight in 
 the Air, which alwayes is, when the weather is dry, and 
 calm, though there hath been no alteration of heat t.o cold. 
 If it be asked, how come we to the knowledge of this, that 
 the piefike and weight of the Element of Air, is fotne- 
 
 times 
 
W?oftatfcaiejcpetfment& 
 
 times lefs, and fometimes more f 1 anfwer, thisfecretof 
 Mature, was never difcovered, till the invention of the 
 Torricellian Experiment, otherwife called the Barefcefe, 
 For alter the falling down of the guitk-fther to a g 
 inches if you fuffer it to (land thus t in; your Parlour or 
 Chamber, according as the Preffure, and weight of the 
 Element of Air, becomes more or iels, fo will the Alti¬ 
 tude of the Mercuiy become lefs or more, and vary fome¬ 
 times above 2 finches, and fometimes below. This alte¬ 
 ration is very fenfible, which is fometimes the tenth part 
 of an inch, fometimes the fixth, and iometimes the third, 
 according as the weight of the Air is lefs or more.. From 
 December to February , I found the alteration become 
 lefs and more from 30 inches to 28, which will be three 
 fingers breadth. The common westker-glaffes then are 
 fallacious,and deceitful, unlefs they be fo contrived, that 
 the Preffure of the Air cannot affeft them, which is eafily 
 done by fealing them Hermetically , and in ftead of common 
 Water,toputin Spiritm Vim reSHficattfsimtKjx the moft 
 excellent Spirit of Wine,and ftrongeft that can be made. 
 
 It may be here inquired, whether or not,Mercury would' 
 afeend in this Glafs, as the Waterdoes t ranfwer it would; 
 becaufe the afeent depends only upon the Preffure of the 
 Air, incumbing upon the ftagnant Liquor in the Veffell, 
 that’s able to drive up Mercury as well as Water.. It may. 
 be inquired fecondly, how fai Mercury will afeend, and 
 how far Water will creep up t 1 anfwer, Mercury can af¬ 
 eend no higher ina Tub, than 2 9 inches •, and Waterno' 
 higher, than 34foot ; and thisonely happens^ when-there 
 is no Air above the tops of the .Cylinder to hinder their : 
 afeents. But when there is Air, as G F above the liquor,, 
 itcan go no higher,, than the point to which the cold is- 
 
6 ^ $ptyoftat(cai experiments* 
 
 able to contrad the indofed Air, which is in this Glafs, the 
 point F. It may be inquired thirdly, which is. the great¬ 
 er difficulty, whether or not Mercury, will rife as ea% in 
 aTub as Water; forfeeing, its retimes heavier, itfeemes 
 the Air ffiould have greater difficulty to prefs it up, than 
 to prefs up Water ' Ianfwer,’tisgreater difficulty for the 
 Air to prefs up 20 inches ofMercury, than to prefs up 20 
 inches of Water ; yet its no greater difficulty, for the Air 
 to prefs up ao inches of Mercury, than to prefs up 23 foot 
 of Water, becaufe the burden and weight is the fame. It 
 may be inquired fourthly, whether or not, it be as eafie for 
 the Air, to prefs.up a thick ana grofs Cylinder of Water, 
 as to prefs up a thin and flender one? For example, whe¬ 
 ther is it as eafie for the Air to prefs up a .Cylinder of Wa¬ 
 ter 10 inches in Diameter, and to foot high, as it is to prefs 
 up one,two inches in diameter,and 10 foot high ? I anfwer, 
 there is no more difficulty in.theone, than in the other; 
 and the reafon is, becaufe Fluid bodies do not counter- 
 poife one another according to their thickntfs , but only ac¬ 
 cording to their altitude , according to the fourthTheorem. 
 Therefore feeing the flender Cylinder is as high as the 
 grofler, it muftbe no more difficult to the Air, to prefs up 
 the one then the other. 
 
 There is one difficulty yet remaining., which is truely 
 the greateft of all 5 namely what’s the reafon, why its 
 more difficult to the Air, to prefs up 20 inches of Mercu¬ 
 ry, than to .prefs up 20 inches of Water: or more difficult 
 to the Air, to prefs up 20 inches of Mercury, than to prefs 
 up 10 ? I anfwer, this comes to pafs, becaufe the Air is 
 more burthened with 20 inches ofMercury, than with 10, 
 Now, if this be, then finely it muft be more hard to the 
 Air, to do the one, than to do the other.- even as it is more 
 
 hard 
 
$ptyoftatical e*periment& 6 $ 
 
 hard; fora man, to lift up from the ground, 20 pound of 
 iron, than to lift up to or 15, Thecafe may be better il- 
 luftrated after this manner. Suppofeaman ftandingonthe 
 ground, with a rope in his hand, coming down from a Pul- 
 ley above, drawing up a weight to the top of the houfe; 
 put the cafe ltkewife, the weight be a ft one,of 20 pound, 
 and the weight of it, to increafe fucceffively., as it is pulled 
 up. Now its eafie for the man to pull up the ftone the 
 firft fathom; becaufeitisbut 20 pound weight: but the 
 ftone becoming 40 pound in the fecond fathom, and 60 
 in the third,and 80 in the fourth and fo forth, untill it be¬ 
 come 1 coo, he will find the greater difficulty,the longer 
 he pulls. Tis juft fo with Air,.or Water, raifing Mercu¬ 
 ry in a. Tub •, for as :the Cylinder of the Mercury grows 
 higher by rifing, fo it becomes heavier, and confequently 
 the imaginary furface, upon which the B«fe of the Pillar 
 refts,is more and more burdened,and fo becomes kfs and left 
 able to prefs it up. This leads us to a clear difcovery of the 
 reafon, why ’tis more difficult by fusion, to pull up Mer¬ 
 cury in a Pipe, than to pull up Water; and more hard to 
 fuck up ten foot of Water, then to fuck up five. For trial 
 of this, which is foon done, take a flender Glafs*pipe 50 
 or 40 inches long, open at both ends, and drown the one 
 end among <j>uick-fiber, and put your mouth to the other, 
 and having fucked, you will find greater difficulty to pull 
 up thorow the Pipe 15 inches of Mercury, than to pull up 
 1.0, or 8; and far greater difficulty to fuck up 20, than to 
 pull up 15. It may be obje&ed, that if a man had ftrength 
 fufficientin his Lungs, to fuck out the whole Air of the 
 Pipe, thirty inches of Mercury would come as eafily up, as 
 three, which feemesto prove, that the difficulty of the 
 Mercurit’s up-coming, depends not upon the weaknefs of 
 I the 
 
the Air,but upon the weaknefs of the Lungs,, and want of 
 ftrength to fuck, I snfwer, chough a’ man. were able, to 
 fuck out the whole Air of the Pipe' yet jo:inehes,.willnei- 
 ver afcend foeafily,as ten,nor ten fo eafily as three-andithat 
 for the reafons already given, But why is it then, ( fay 
 you ) thst the ftronger the (uftion be, the higher the 
 Mercuiyafcends intheP-pe? Ianfwer, the fu&ion ferves 
 for no uie, but to remove the impediment, that hinders the 
 Mercury from coming up , which isnothing elte-, but the 
 Ai: within the Pipe. Now , the moreot this Air that’s 1 
 taken away by fudhon, ( the ftronger the fusion is, the 
 more Air is taken away) the farder up comes the Mercury. 
 But why ought there to be difficulty ;n the fufhon ol Mer¬ 
 cury, to the altitude of i j or 20 inches , more than in the 
 fuftionof Water to that altitude r I anfwer, when I fuck- 
 Water up thorow a Pipe, the fusion of the Air above it, 
 is e: fie 5 becaufe the afeending Water helpes much to drive 
 it up to the mouth , the outward Air driving up both. 
 But the futtion is difficult in Mercury, becaufe the atten¬ 
 ding liquor, does not help fo much, to drive up the Air to 
 themouth, as the Water does. And the reafon is, be* 
 caufe the Air,being more burdened with 15 inches of Mer¬ 
 cury, thmwich 15 inches of Water, cannot fo eafily drive 
 up "the one as the other, and fo Mercury cannot fo eafily 
 drive up the Air of the Pipe to the mouth, as Water does. 
 In a word , accordingtothe difference 0 {fyecifick weight, 
 between Wirer and Mereuiy, fo is the difficulty of fusi¬ 
 on • therefore, becaufe Mercu-v is 14 times heavier than 
 Water,there is 14 ttmes more difficulty, to pull up the one, 
 t-^n rhr other, Note, that [action is not taken here 
 ftrift y, ascontradift ngudhed from pulfm j but in a large 
 feme, as may comprehend it,- 
 
 To 
 
is^tyoftatical cgperfmMh 67 
 
 To proceed a little further 5 letius fuppofe.thePillarof 
 Mercury (fee the n. Figure.) G<H, thatjsraifed by the 
 furface of Air F G, to be 29 inches , and every inch to 
 weigh one ounce. Secondly, that thefeid furface has.ap 
 degrees of power or force in.it: ;for in all countetpoifes the 
 iW«*and thePtientia are equals therefore, if the Mer¬ 
 cury be 2 9 inches, the Potent ui of the furface-mud.have 
 2 9 degrees oi ftrength or .force, in it, to counterbalance 
 the Pondtts, Thefe things beingfuppofed, which are evi¬ 
 dent, let us imagine the lurface of Air, to raife the.Mer- 
 cury one inch above sF G, In this cafe, the furface is 
 weaker than it was ; which I prove evidently., becaiife it 
 is now but able to raife 2 8 of . Mercury. Imagine next, 
 the faid furface to have railed the Mercury two inches 
 above F G, then it follows, that.it muft be yet weaken, 
 becaufe it’s now but,able to raife 27 inches :, tor.hy fop- 
 porting two ounce of th ePondm, .it:lofeth:two. degrees of 
 it’s own Potentia. In raifing threeiinches.of.Mercury, it 
 is three degrees weaker*, and in railing four, it is four.de- 
 greesweaker, andfo:forth; therefore, .having,raifed28 
 inches, there is but one.degree of force .remaining in the 
 furface. And when it hath raifed the whole, namely ,2.9, 
 it is no more able, and can.no more prefs. For confirma¬ 
 tion , put the cafe that the furface of Air F G, were us 
 able, and had as.much.Preflure in it, after it hath raifed 2p 
 inches of Mercury , as it is after the railing of 10.; .then 
 it follows of neceflity, that after ;the;ratfing of ;20, it foall 
 raife 1 9 moe, which is impoflible, fetng^hegreateft.alti- 
 tude is a 9. It follows oi neceflity, (.I.fay.) hecaufe.af- 
 ter.the, railing of ao, it is able tr>raife, i^.moe: therefore 
 if it be as able after. 20, .as;afterno., it: mufti raifeiip after 
 20. Yea, if it be as able .after.a.o^as.iQ, it miifeb^as 
 12 able 
 
68 ^pDjoftatfcai experiments* 
 
 able after 19-is 10. If this be, then it may raife other 2p, 
 and a third 29, and fo in infinitum. Therefore, Icon, 
 dude, that when two Fluid Bodies are mequilibrio one 
 with another; or when the pondus is equal to the poten- 
 /w,none of them doth a&ually prefs upon another, at leaft 
 the furface hath loft all its Power and Preflure, which is 
 alfo evident in the Pillar. For underftanding this, let us 
 fuppofe AC B ( Figure 11.) tobeaPipe 58 inches long, 
 and full of Mercury, and every inch of it to weigh one 
 ounce; Now, when the orifice D is opened, there is here 
 as great an inequality-, between the pondus and the potentia 
 of the furface of Air EB, on which it refts, as was be¬ 
 tween the furface F G, and th t pondus of Mercury H G. 
 For as F G had 29 degrees of power to raife G H, fo the 
 Pillar A B has 29 ounce of weight, to overcome the fur- 
 face EB. And as the furface F G, became one degree 
 weaker,by raifing one inch of the Mercury H G, and two 
 degrees weaker, by raifing two inches, and fo forward, till 
 it loft all its Preflure $ fo the Pillar, by falling down one 
 inch, lofeth one ounce of the weight; by fallingdown 
 two/ it lofeth two ounce , and fo forward, till by falling 
 down from A to C, it lofeth all its Weight and Preflure. 
 
 But here occurreth a difficulty ; for if the furface F G, 
 hath loft all its Preflure, by raifing the Mercury from G to 
 H; and if thePillar C B,hath loft all its Preflure, by fall¬ 
 ing down from A to C *, it follows, that when a pillar of 
 a Fluid, and a furface of a Fluid are in equal termes, or 
 brought to an equipondium, there is no Preflure in them at 
 all. For anfwer , confider firft, that in all counterpoifes, 
 there are neceffarily two things, the movens and the mo- 
 tamy the thing that moves, and the thing that is moved. 
 Secondly, you muftconfider the motum y to have a pondus 
 
 or 
 
$pD?oftaticai ejcpertimnts, 69 
 
 or weight in if,and the movens to havea fotentia ',or power J 
 wherewith it moves that weight. Thirdly, that as the 
 thing that moves, hath a power or force in it felf, whereby 
 it moves, fo the thing that is moved hath a power or force 
 in it felf,whereby it relifts the motion.FourthIy,that fome- 
 times the refiftance of the thing moved, may exceed the 
 power of the movent , as when a Quarrier with a Leaver, 
 endeavours to prize up a ftone too heavy for him: or the 
 power of the movent, may exceed the refiftance of the 
 weight or both may be of equal power. Confider fifth¬ 
 ly, that as the pondus of the thing moved, begins to grow- 
 more and more,fo the power of the «?m»rdecreafeth pro- 
 portionably; not abfolutely , as heat is extinguifhed in 
 Water by the cold Air, when it is removed from the Fire, 
 but refpeftively. For example, when a man holds a bal- 
 lance in his hand, with fix pound in the one fcale, and but 
 one pound in the other, if you add another pound, the 
 weight grows more, and the power and force of the oppo- 
 fite fcale grows lei’s proportionably; not ahfoluiely, for it 
 ftill remains fix pound,but refpecUvely: that’s to fay, fix 
 pound is lefs in relpett of four, than in refpedl of five; or 
 the refiftance of fix pound is lefs, two counterpoifing it, 
 than being counterpoised by one. Whena third is added, 
 the weight grows yet more,and confequently the refiftance 
 of the oppoifite fcale becomes yet lefs, till by adding the 
 fixth and laft pound, you augment and encreafe the von dm 
 to that fame degree of ftrength, that the refiftance of the 
 oppofite fcale is of. . From thefe confiderations, I fay, 
 the furface of Air FG, hath not loft all its Preffure Ab¬ 
 solutely, by raifing the Mercury from G to H, but only 
 reflectively, becaufe it ftill retains 29 degrees of force in ! 
 it. felf,. I ..fay . reflectively , becaufe when the Mercury is • 
 
 raifed- 
 
70 ifwftattcsi Cjcpecmmus* 
 
 Faifed tea inches, the.power of-the Air which is of 29 de¬ 
 grees of force, is lefs in refpedtof ten ounce, then in refpeJt 
 of five; or the power of 29 degrees of force is-lefs, being 
 counterpoifed by ten ounce, than-being counterpoifed .on* 
 ly .by:fivE, And when.it is.raifed 20, it is yet lefs in this 
 refpedt, than in refpeff of ten. And when it has tailed 
 the Mercury to the greateft altitude H, it may be faid to 
 have loft-all ics-Preffure, feing it knot able, by vertue of 
 a counterpoife,to do anymore. Even as fix pound in this 
 -fcale, may be faid to have loft all its refiftance and weight, 
 by putting in the other fcale , firft one pound, next two 
 pound, and then three pound, till the laft be put in, at 
 which time it.hath no more refiftance. Though this be, 
 yet.it ftill remains fix pound. Even fo, the Air F G ftill 
 remains of the fame force and power, while it fufpends 
 the Mercury G H, that it was of before. Likewife, the 
 Pillar A B, cannot be faid to have loft all its preffure abfo- 
 lately, by falling down from A to C, but only refiefiively, 
 became the faid Pillar C B, is ftill 2 9 ounce weight. I 
 fay rtfye&'-vely, becaufe in falling down ten inches, or in 
 lofing ten ounce , the weight that’s now but 48, is lefs, in 
 refped of 29, than while it was 5 8. It is yet lefs,when it 
 hath fallen down other ten, becaufe being now but 3 8, it 
 muft be yet lefs imefpeA of 29, than .48. And when it 
 hath fallen:down to C 29, it may be faid to.have loft all its 
 weight, becaufe it can do no more, having nfiefiively loft 
 all its Preffure, 
 
 From what is faid , we fee a clear ground to diftinguifli 
 in Fluids and a ptentia. Secondly, thatthe;^- 
 
 tcntia mayfometimes^exceed the-pWw, and contrariwife 
 ths.f ondus may exceedthe fotentu. Thirdly, that me- 
 quality of weight, between.thepwdkr and die pteniu, is 
 
 the 
 
^pcioftattcai fiwtmmm. jt 
 
 the caufe of motion of Fluids; Fourthly, that the mo¬ 
 tion never ceafetlr, tillthepW^andthe petentia become 
 of equal force. T his conclufion is nor fo univerfafas rhe 
 reft, becaufe the motion may fometimes ceafe, beforethis 
 be. For example, when the Airis pre fling Mercury up 
 thorowa Tubflrorter then 2p inches, the motion ends 
 before there be a perfedi counterpoife 5 for 20 or 15 inches 
 of Mercury, can never counterbalance the force and power 
 of the Air. In fuch a cafe then, there is an unequal Pref- 
 fure, the Air piefling the Mercury more,than the Mercury 
 doth the Air, 
 
 EXPERIMENT VII E 
 
 Figure x,. 
 
 T Ake theVeflel ABCD, and fill it with Water, 
 ashighasHI. Take next a Cylinder of ftone FGj 
 and drowning the half of it among the Water, fufpend it 
 with a chord to the beam N O, with a ring at E. Now 
 in this cafe, though the ftone do not touch the bottom of 
 the Veflel, yet the Water becomes heavier, than before. 
 For difcovering the truereafon of this, I fuppofe fuftj the 
 weight ot the Water, before the ft one be drowned, to be ' 
 40 pound. I fuppofe next, that after the (lone is drown¬ 
 ed, the faid Water to weigh 50 pound. And laftly, the 
 J,lone to weigh 60 pound. I fay then, the Water muft be 
 to pound heavier thanbefore,becauleit fupports to pound 
 of the (late, ’Tis certain the beam is lefs burdened by 
 10 pound than before. If this be, then furely the Water 
 muftfuftainit. It were great temerity and ralhnels, to 
 averr that neither the Beam >, nor the Water fuftains it, 
 
 which 
 
7 i §pojoftattcai ejectments* 
 
 which is really to (ay, it is fuftained by nothing. It cannot 
 be faid without ignorance, that io pound of the (lone is 
 evanifhed, and turned into a Chimera, If it be faid, how 
 can fuch a Fluid Body as Water, be able to fapport any 
 part of the weight of the / lone , that is fuch a heavy Body i 
 I anfwer, there is here no difficulty, for if the imaginary 
 furface K L, upon which the io pound of the flone refls, 
 be able to fuftain io pound of Water (I fuppofe the /lone 
 taken away, and-the place of it filled with Water) then 
 furely it muft alfo be able to fuftain i o pound of the heavi- 
 efl metal ; feing ten pound of Lead, or Gold, or Stone, is 
 no heavier than io pound of Water. If fome fay, this 
 rather feems to be the reafon, why the Water becomes 
 heavier, after the flone is drowned, becaufe it pofTefTeth 
 the place of as much Water, as would weigh io pound • 
 not (as was faid) becaufe the Water fupports xo pound 
 of it. Therefore it maybe judged, and thought, that if 
 the fpace that the (lone occupies, were filled with Air, or 
 fome light Body, without fenfible weight, the Water 
 would become heavier than before. For example, if in 
 Head of the (lone, there were placed a bladder full of wind, 
 within the Water, and tied to the bottom with a firing, 
 that the furface might fwell from HI to A B, the Wa¬ 
 ter of the VefTel would become as much heavier than be¬ 
 fore, as is the bulk of Water, equal to the quant'ty of the 
 bladder. Therefore, the Water becomes heavier, not 
 becaufe it fupports any part of the (lone, but becaufe the 
 flone occupies as much room and fpace , as would contain 
 io pound of Water: for by this means the drowned flone- 
 raifeth the Water from HI to A B ; and fo the Cylinders 
 AC, and B D, being higher, prefs with greater*weight 
 upon the bottom C D, even with as much more weight, 
 
 as 
 
%gt»oftaticai gtpttimn its, 7} 
 
 as if the fpace that the (tone occupies were' filled with 
 Water. 
 
 For anfwer to this, we fliall make this following Expe¬ 
 riment, Take the Veflel M P V X, and fill it with VVa- 
 ter to QR. Next,take a large bladder W Y .full of wind, 
 and tying the neck with a threed, thruttit below the Wa* 
 ter, and fatten it to the bottom, with a firing* to the Ring 
 Z. This done, the Water fwells, and rifes from Qjf, 
 toMP, Now, if it be true, that the Water in the Vef- 
 fel becomes heavier., not becaufe it fupports 10 pound 
 weight of the (lone, but bccaufe the ft one occupies the 
 room of 1.0 pound of Water; then it ought to follow, 
 -that after the bladder is ryed below the Water, the faid 
 , Water (hould become heavier, than before, even by three 
 .pound; for I fuppofe a bulk of Water,equal to the bulk of 
 the bladder, to weigh as much. And the reafon is, becaufe 
 (as you fay)the quantity of the bladder W Y,makes the wa¬ 
 ter fwell from QR to M P, by which means the Pillars of 
 Water M V,and P X becomes higher,and fo prefleth with 
 greater weight upon the bottom V X. For clearing this 
 difficulty, I fay, when a bladder is thus below the Wa¬ 
 ter, tyed to the bottom, the Water becomes not three 
 pound heavier: for when you place the Veflel with the 
 Water and bladder, in the Scale of a Bailance, the faid 
 .Water weighs no more, than if it wanted the bladder: 
 .therefore the Water becomes not heavier, becaufe the 
 (lone poflefleth the room of 10 pound of Water,but bccaufe 
 the Water fuftains 10 pound of the (lone, Nov/ the reafon, 
 • why the bladder makes not the water heavier, though k 
 raife it from QR to M P, is this; becaufe though verily 
 there be a greater Prefl'ure then before, even upon the 
 bottom ol the Veffd, yet becaufe moe parts are nowdded ^ 
 K the 
 
74 atlcai expert mente* 
 
 the natural weight cannot be augmented, which eflential- 
 Iy depends upon the addition of thefe parts. If it be replyed, 
 the Experiment of-the bladder is to no purpofe, becaufe it 
 being knit to the bottom.pulls up theVeflel, with as great 
 force, as the growth of the-Preflure bears it dawn, andfo 
 the Bladder cannot make the Water heavier. But, if fo 
 be, it werepoflible, chat the Bladder could remaine within 
 the middle of the Water, without being knit to the bot¬ 
 tom, and confequentiy without pulling up the Veflel,,then 
 forely the Pi’lars of W £ter M V, and PX, beinghigher, 
 would prefs with greater weight upon the bottom, and fo 
 makethe VefTel, and the Water weigh more in the bal¬ 
 ance; for ’tis to be fuppofed, that during all this time, this 
 Veflel with the Water, is in one fcale, and a great weight 
 of ftoae or lead, in-the other. So would the Water A 
 -B-CD become heavier likewife, provided the fpace and 
 room, that the fione fills among the Water, remained in¬ 
 tire, after the ftone is taken away: becaufe that room and 
 empty fpace remaining, would keep the furface, as high 
 as AB., by which means, the Pillars AC and B D, be¬ 
 ing higher, would prefs with greater weight upon the bot¬ 
 tom, and caufe the Water weigh more intheballance.’ 
 lanfwer, though by fome extraordinary power, the bladder 
 could remain below the water, of its own accord, as it were, 
 and though the fpace and room, by thatfame/ww, which 
 is left by the (lone , were keeped empty, yet lhali they 
 never be able to make the Water heavier. Astotherea- 
 fon, that’s brought, lanfwer, the riling and fwelling of 
 the Pillars, will make indeed a greater Preflure upon the 
 bottom of the Veffel,but becaufe this Preflure may be pro¬ 
 duced, and generated without the addition of new parts, 
 therefore, it can never make the Water heavier: for if this 
 
C^D?oftatM#]cpef tmentg* 75 
 
 were true, then it would follow, that the more a body is 
 compreft, it ihould be the heavier, which is contrary to 
 fenfe, and experience. This Prefiure is like unto Senftl , 
 that cannot weigh in a ballance, though the thing bended 
 do weigh ; as a Bow that weighs fo many poaadsbut the 
 Benfil of it weighs nothing : Next, will any man think* 
 that a Cub ot Water fix loot high, and fix foot thick, will 
 weigh more in a ballance, then it did, alter it is turned into 
 a long fquare Pillar a 1 6 inches high i I grant,there is near 
 60 times a greater Prefiure, upon the bottom of the Vef- 
 fel,yetbecaufethis Prefiure is generated,without the addi¬ 
 tion of new parts, it cannot make the Water heavier. 
 Moreover, it is mechanically poflible to keep theVVater 
 ST V X, under that fame degree of Prefiure it hath, 
 thoiigh the reft above were taken away: if this be, then it 
 ought to be as heavy, as the whole, feing it ftill Prefies the 
 bottom, with that fame degree of Prefiure, it had from 
 the whole: but what is more abfurd, than to fay, one part 
 of Water,is as heavy,as the whole t e, g, a pint as heavy 
 as a gallon. If it be faid, the Prefiure, and the weight, are 
 but one thing, at leaft effeflively, which is fufficient to the 
 purpofe in hand, as is clear from the Theorem 23. I an- 
 fwer, they are but one thing indeed, in order to the Sal- 
 lance of Nature, but they ixt timberfor mdlly,mx effdlhely 
 the fame thing in order to the -Libra or Artificial Ballance, 
 whereof we are now treating, I lhall conclude with this $ 
 while the Vefiel with the VVater, is thus placed in the 
 Scale of the Ballance, and in equilibria, with theoppofice 
 Scale, cut the firing that tyes bladder to the bottom, 
 and when it comes above, you will find the Water, juft 
 of the fame weight it was of: for though the furface MP, 
 by taking out t-h adder, fettle down to Q.R, yet there’s 
 K 2 no 
 
76 gppjoft attcal e tpectments, 
 
 no alteration made in the weight. 'From this I - gather, 
 that if the fwelling of the Water (hould make it heavier, 
 then the fubfiding and falling down of it, ought to make 
 it-lighter.. 
 
 From-thefe Experiments we gather firft,that in Water 
 there is a PrefTure, becaufe it fuftains i o pound of the float 
 F G. Secondly, that whatever heavy body is weighed 
 in-Water, it lofeth juft as much of its weight) as the bulk 
 of Water weighs, it putsout-of its-place. This is evi¬ 
 dent, becaufe the float is io pound lighter in Wateri 
 than in the Air, becaufe the Water that would fill the 
 room of the float, is juft of thatweight. We fee third¬ 
 ly, that the Prejjure of Water, and the natural weight 
 of it, are two things really diftind', becaufe the Prejfurt 
 may be augmented, without any increment of the natural 
 weight, VVe fee fourthly, that the PrcfjW, or Benfil ot 
 a Fluid, cannot affeft the Scale of a Ballance, but only the 
 natural weight. We fee fifthly, that a body naturally 
 heavier than Water, weighs- in Water , becaufe the (lone 
 FG, makes the Water about it, i o pound heavier. If it 
 be inquired,whether bodies, that are naturally lighter, will 
 weigh in Water i I anfwer,if they be of any fenfible weight- 
 they weigh, as well as the other. For this caufe, I except 
 Air. For though they were never fo light- in relpeft of 
 Water, yet if they have any confiderable- gravity with 
 them, they will make the Water heavier, they are among. 
 Put- the cafe the Body -were a Cube of Timber of fix 
 inches,weighing fixteen ounces, and that a Cube of Water 
 of that quantity, weighed 112 ounces. Here’s a great ine¬ 
 quality,between their natural weights : yet if that piece of 
 Timber, were madetoexift in the middle of Water, as 
 the Biaddtrdoih, it would make it 16 ounces heavier. 
 
$pt>?o&at(cat experiments* 77 
 
 The reafon is thisjthefe 1 6 ounces are either fupported bya 
 furface ofWater,or they fupport themfelves.Thislaft isim- 
 pDiTible, II the Water fupp'Ortthem,then muft they make 
 the faid Water itfounces'heavier. Note, that though 
 a' Body naturally lighter then Water, as Cork , may' be 
 faid to weigh in Water, that’s to fay, to make it heavier, 
 in which fenfe Water weighs in Water , becaufe if you 
 add a pint to a gallon, it makes it heavier 5 yet if you take 
 a piece of Cork, and knit it to the Scale of a BallancC, by a 
 threed, the Cork hanging among the Water, the Scale 
 hanging above in the Air, it will nor. weigh in Water ; be¬ 
 caufe in this fenfe, no Body weighs in Water , but' that 
 which is naturally heavier then Water,as Lead.or Stone; 
 In this fenfe, VVater doth not weigh in Water ,. as will be 
 feen in the 17 Experiment.. 
 
 EXPERIMENT IX- 
 
 Figure 13.. 
 
 T akeaGlafs-pipe 70 inches longer there-abour^nd of 
 any widenels, having the upper end H, hermetically ‘ 
 fealed, the lower end C compleatly open, and fill it with 
 Mercury, and caufe a Diver carry it down to the ground 
 ofthefea M N, where I fuppofe is Handing theVeflel 
 ABDE with ftagnant Mercury, and drown the end 
 below the furface AB. This being done, the Mercury 
 falls from the upper end H, to the point G, and there 
 halts 5 the fpace HG being empty. For underftanding ' 
 this Experiment, I fhall propofe feveral queftions, and an- 
 fwere them, Firft, what’s the reafon, why the Mercury ’ 
 fubfides, and finks down from H to G ?I anfwer, as for¬ 
 merly^ 
 
78 ^moftattcal ewitniim. 
 
 aerly in the like cafes, inequality of weight between the 
 fonim of the impending Quick-fiber , and the Potextia of 
 the furface, of the ftagnant Quick-ft her D C E. For 
 while the Tub is compleatly lull, the weight is fo great, 
 that the furface D C E, is not able to fuftain it, therefore 
 it muft fall down, feing motion neceffarily followes in 
 Fluids, upon inequality of weight. It may be inquired fe- 
 condly, why it halts at G, 5 8 inches from AB , and 
 comes no farther down i I anfwer it halts at G, becaufc 
 when it hath fallen down to that point,there happens equa¬ 
 lity of weight, between the fufpended Pillar, and the fore- 
 faid furface: for whatever weight the faid Pillar is of, the 
 furface on which it refts, is of the fame. In a word, the 
 Fondiij of the one, and the Potentia, of the other are now 
 equal. For undemanding this, confider according to the 
 25 Theorem, that the weight of the Element of Air, up* 
 on the furfaces of waters, is equivalent to the burden of 34 
 foot of water, therefore the firft and vifible furface of this 
 Water LIK, is really as much preft, with the burden of 
 the Atmoftherc , as if it had 34 foot of Water upon it. 
 Confider next,that between the faid furface,and the ground 
 MN, are 3 4 foot of Water indeed, Confider thirdly, 
 thata Pillar of Water 34 foot high, is exa&lyof the 
 fame weight, with a Pillar of Mercury 29 inches high • 
 for if Water be 14 times lighter than Mercury, then they 
 cannot be of equal weight, unlefs the one be 14 times 
 higher than the other. Now,fuppofing the weight of the 
 Air upon the furface LIK, to be equivalent to 34 foot 
 of Water, or (which is the fame thing) to 2 9 inches of 
 Mercury, the furface 6f the ftagnant Mercury AB, muft 
 be its much burdened with the incumbing Water, and the 
 Airtogether, as if it had really refling upon it, a Pillar of 
 Mercury 
 
% )ta;oqat<ta> SypcKromts. _79 
 
 Mercury 58 inches high. If this be, then it follows by 
 Beceffity, that there muft be an equality of weight, be¬ 
 tween the fendus of the Mercury in the Tyb,and the 
 fotentia of the furface DCE ; Or (which is aH one thing) 
 that the partC, on which the Pillar refts, is no more bur¬ 
 dened, than the part D or E. For if 34 foot of Water, 
 and 34 foot of VVater, be equivalent for weight, to 58 
 inches of Mercury, then muft the part D and E, be as 
 much burdened with the faid weight, as the part C is bur¬ 
 dened with the Pillar within the Tub, feing both are of 
 the fame height: therefore the power, and force of the 
 imaginary furface of the ftagnant Mercury D C E, is of the 
 fame ftrength, with the weight of the Pillar G F B. And 
 this lets us fee the reafon, why the whole 70 inches cannot 
 be fufpended 5 for if the outward PrefTure that’s upon A B, 
 be but equivalent to the Preilureof 58, it can never make 
 the furface D C fi able to fupport 70. 
 
 To make it evident (if any doubt) that the Mercury 
 is fufpended by the weight of the Water, and the weight 
 of the Air fuperadded, let a Diver bring up this Engine to 
 the top of the Water, and he will find the one half to 
 have fallen clown, namely from G to F, the other half 
 F B remaining. And if it were poffible, to convey this 
 Experiment to the top of the Air, the Beater would fee, 
 the remaining half to fall down likewife, and become level 
 with A B •, for where no PrefTure of Airis, there can be 
 no Mercury fufpended. This falling down, is not all at 
 once, but by degrees, and keeps a proportion with the 
 Preifure of the Air, that grows lefs and lefs, from the 
 ground to the top. 
 
 From this Experiment we fee firft, the great PrefTure 
 and weight, the Elements of Air and Water are under,. 
 
 . feing 
 
go %gOEO( tat(cai e jectments, 
 
 felng this Water, that’s hot 34 foot dcepffuftains the Mer¬ 
 cury berweea G andF, 2 9 inches, as much between F 
 and E,being kept up by the Preffure of the Air. We fee 
 
 fecondly, that this Preffureis according to Arithmetical 
 Progression , as 1,1, 3,4, 5. becaufe in going down the 
 firft 14 inches, theMercury rifes one inch- ? in going down tire 
 fecond 14 inches, it riles two 5 in going down the third 
 r 4 inches, it rifes three, and fo forward. We fee third¬ 
 ly, though a Water were x 00 fathom deep, yea 1 000,yet 
 the Preffure of the Air above is found at the bottom: 
 for fuppofing this Experiment were 100 fathom deep, yet 
 would the Air from above have influence upon it, to fu¬ 
 ff ain fo many inches of the Mercurial Cylinder. A Diver 
 then, 1 o or 1 j fathom under the Water,muff be burden¬ 
 ed with the weight of the Air, as well as with the weight 
 of the Water, fo mult the Fifties, though never fo deep. 
 We fee fourthly, that the parts of a Fluid cannot ceafe 
 from motion , fo long as there is an inequality of 
 weight between the fondus and the fotentia. This is 
 clear from the falling down of the Mercury from H to 
 G. And affoon as equality of weight happens, the moti¬ 
 on ends. This is clear from the Mercurie’s halting at G, 
 Fifthly, that in Mercury, as well as in Water, or Air, 
 furfaces may be diftinguilhed, and that thefe furfaces, are 
 endowed with a Potentia or power, begotten in them by 
 fuperior and extrinfick weight. This is clear from the 
 imaginary furface D C E, that’s made powerful to fupporc 
 58 inches of Mercury in the Tub, and that by the weight 
 and Preffure of the Air reft ing upon A B. Sixthly, that, 
 as two Fluids differ in fj>ecifck and natural weight, fo .they 
 differ in altitude , when they counterpoife one another. 
 This is clear from the difproportlon that’s between the al¬ 
 titude 
 
$ptyoftatfcai ejcpertente* sc 
 
 titude of the Mercury fufpended, find the height of the 
 Water, and Air fufpending, G F then is 29 inches, and 
 the deepnefs of the Water from K to N is 34foot,becaufe 
 Water is naturally 14 times lighter than Mercury. F B is 
 likewife 29 inches, and the hight of the Air, that refls 
 upon the furface of Water is fix or feven thoufand fathom 
 high; becaufe Airis 14000 times naturaSj lighter than 
 Mercury. Seventhly, tnat Fluid Bodies counterpoife one 
 another, not according to their thicknefs and breadth , but 
 only according to their altitude. This is evident * for 
 though this Tub were never fo wide or narrow, yer the al¬ 
 titude of the Mercury is unchangeable. Hence it is, that 
 the tbickeft Pillar of Water in the Ocean, is not able 
 to fufpend more Mercury, than the flendere /?, I mean as to 
 altitude. And hence it is, that the fmalleft Cylinder of 
 Mercury, no thicker than a filk threed, is able to coun¬ 
 terpoife a Pillar of Water, of any thicknefs whatfoever. 
 We may conclude laftly, that when a Diver is 20 fathom 
 under the Water, he is under as much burden, as if he were 
 under 14 orT 5 foot of Quick-filver, Suppofea raanlying 
 on his belly, within a large Veffel, and 1401-15 foot of 
 Mercury poured in upon him, furely it may be thought, 
 that fuch a burden were mfupportable. But put the cafe, 
 the Diver were down 40 fathom, then muft the burden 
 be doubled. This follows, becaufe if a Pillar of Water 
 34 foot high, with the weight of the Air fuperadded, be 
 as heavy, as j 8 inches of Mercury, then furely a Pillar 20 
 fathom high, or 100 foot, muft be as heavy as 170 inches, 
 which is more than 14 foot. 
 
 L 
 
 •EX PE- 
 
Si ^pfyoft atical 
 
 EXPERIMENT X- 
 
 Figure 14. 
 
 A Gainft the former Experiment, there occurres fome 
 . difficulties, which mult be anfwei ed. As.firft, if it 
 be the Preffiire of the Water, that fuftains the Mercury in 
 the Tub (fee the 13. Figure)- then the weight of the {aid 
 Mercury ought not to be found, while the Tub is.poifed 
 between a mans lingers... But fo k is, that when a Diver 
 grips the Tub about the middle-, and raifes it a little from 
 the bottom of the Veffel, he not only finds the weight of 
 the Tub it felf, but the weight alfo of the 5? inches of 
 Mercury that’s within it. But this ought not to be,if the 
 feid Mercury, be fuftaiaed by the outward Water. In a 
 word, it ought not to be found, becaufe the- fhid Pillar o£ 
 Mercury, 2s really franc's, and refrs upon the imaginary fur- 
 fece D C E, as. a Cylinder of Brafs or Stone, refts upon a 
 plain Table of Timber or Stone. If then, itbefupport- 
 ed by the {aid furface, why ought I to find the weight of 
 it, when I lift up the Pipe a little from the bottom of the 
 Veffel ? Por clearing this difficulty, confider, that when 
 the Mercury falls down from H toG, it leaves a fort of 
 vacuity behind it, wherein there is neither Air nor Water. 
 Confider fecondly , that for this caufe, there happens an 
 unequal preffnre 5 the top of the Tub without, being bur¬ 
 dened with the Pillar of Water I H , which: actually 
 preffeth it down, and nothing within between G. and H, 
 that may counterbalance that downward Preffnre. Thefe 
 things being confidered, I anfwer to the difficulty and fay, 
 it is not the weight of the fufpended Mercury that I find, 
 but the weight of the Pillar of Water IH, that refts up- 
 ' ” on 
 
eflspettmttits* S3 
 
 on the top of the Tub, If it be faid, the Preflirreof fi 
 Fluid is i»\tn(ibk % and cannot be found... I anfwer>it’strue, 
 when the PrefTure is ecpial and uniform, but not when the 
 Preffure is unequal, as here. Hit be asked, how corn® 
 it to pafsj that the Pillar of Water IH, is. exa&ly the 
 weight of the 5 8 inches of Mercury * I anfwer, befides 
 the faid Pillar, there is another of Air, that refts upon thfc 
 top of it, which two together are exa&ly the weight of the 
 fufpended Mercury 5 I H being of the fame weight with 
 the Mercury G F, and the forefaid Pillar/of Air, being ol 
 the fame weight with the.Mercury F B. To make it more 
 evident, remember that one inch of Mercury, is exa&ly 
 the weight of 14 inches of Water 5 and that one inch of 
 Mercury, is of the fame weight with 14000 inches of Air, 
 If this be,‘ then mull the Pillar of Water IH, that's 34 
 foot high, and of the fame thicknefs with the a 9 inches of 
 Mercury G F, be of the fame weight with it, feing 20 
 indies are to be found 14 times in 34 foot. For the fame 
 reafon, is the Pillar of Air, namely S i, that refts upon 
 the top of the Pillar of Water IH, of the fame weight 
 with the 2 9 inches of Mercury F B. For after a juft tec* 
 honing,you will find, that 20 inches will be found 14000 
 times in the Pillar of Air, that refts upon the. Pillar IH. 
 Or in a word, the highc of the Air is 14000 times, 20 
 inches. . . • : 
 
 But hereoccurrs another difficulty. Let us fuppofe there 
 were a Tub fix foot high, one inch wide, having the (ides, 
 
 3 inches thick. Imagine likewife the faid Tub to be un- 
 der the \yater ; 3 4 foot, with 58 inches of Mercury in jt, 2 s 
 isreprefented in this. 14 Figure.'.:This' being fuppo fed* 
 the Pillar of WaterFtAFC.GD, mHll.be far heavier, 
 than the 5 8 inches of Mercury HB. ’The reafon is clear, 
 L 2 becaufe 
 
§4 ^ptyoftattcal Comments, 
 
 becaufe thefaid Pillar, is not only 34 foot high-, bat as 
 thick, as the Diameter of the Tub, whofe fides are three 
 inches thick.' lanfwer, the whole weight of that Water 
 E A F C G D is hot found, while a man- poifes the Tub 
 between his fingers, but only the weight of the part G A, 
 which is exa&ly the weight ol the Mercury H B. But 
 here occarrs the great queftion, namely, why I find only 
 the weight of the Water G A, and nothing of the weight 
 of the Water, C E, orDF? lanfwer, Icannot find the 
 PrefTure of the Water C E, becaufe it is counterpoifed 
 with the upward PrefTure of the Water IK. And for the 
 fame reafon, Icannot find the weight of the Water D F, 
 becaufeitisconnterpoifed by LM-* but becaufe there 19 
 nothing between H and A, to counterpoife the downward 
 PrefTure of the Water G A, therefore I find that. If ic 
 be obje&ed, that the Water IK, cannot counterpoife the 
 Water C E, becaufe the one is farder down than the 
 other, and confequently under a greater PrefTure, than the 
 other. lanfwer, though IK be ftronger than C E, yet 
 a compenfation is made by the weight of the Tub. For 
 undemanding this,let us fuppole theWater C E,and D F, 
 toprefs downward with the weight of fix pound, and the¬ 
 Water K I, and L M, to prefs upward with the weight 
 of ten pound, there being four pound in difference. Sup* 
 pofe next, the Tub to weigh in the Air ten pound, and 
 in the Water only fix pound. If this be. then according 
 to the eighth Experiment, and eighteencn Theoreffl, four 
 pound weight of the Tub muft reft upon the furface IL, 
 And if this be, then muft the Water IK, and LM, be 
 four pound weaker with the Tub, than without it, and 
 muft only have fix pound of upward PrefTure,. 
 
 From 
 
fo ptyoftatt cflt ejcpenment& ar 
 
 From tlicfe Experiments we conclude firft, the truth of 
 the tenth Theorem, namely that the weight of a Fluid is 
 only found by fenfe, when the Preffure is not uniform, and 
 equal. This is evident from our finding the weight of the 
 Pillar of Water IH, as in the 13 Figure. We conclude 
 fecondly, that in all Fluids, there is a pndus and a potcn* i 
 tia ; as is clear from the fondus of Water E A F C G D,; 
 that prefleth down the Tub, and the fotentia of the Wa¬ 
 ter IK L M, that prefleth up the fame Tub. We fee 
 thirdly,, that there cannot be two furfaces of Water dif¬ 
 fering in altitude, but they muft differ in degrees of Pref- 
 fure: becaufe the furface E A F, is weaker, than the fur- 
 face IL, that being higher than this. We fee fourthly,! 
 that two furfaces differing in ftrength, may be made equal' 
 by fome Body or other interveening 5 becaufe,though IL 
 be ff longer than E A F, yet feing it fupports four pound of; 
 the Tub, it prefleth up with no more force, than EA F," 
 prefleth down with. We fee fifthly,that a Body fufpended 
 in a Fluid, as in Air,or in Water, may have one part of it 
 preft equally with that Fluid, and another part unequally: 
 this is evident, becaufe the parts E and F, are equally! 
 preft with the Pillars C E, and DF, feing this PreP 
 fure is counterpoifed with the Preffure of Water, IK, 
 a^ndLM. But the middle paitofthe Tub A, is unequal¬ 
 ly preft, feing it is preft downward, with the Water G A, 
 but not preft upward with the Mercury B H. We fee 
 fixthly, that whatever be the thicknefs of a Pillar of a 
 Fluid *, yet no more of its weight is found, or is fenfible, 
 than the pan, which prefleth unequally: for though 
 EAFCGD, be a pillar fix or feven inches thick, yet 
 no more of the Preffure is fenfible,. than what comes from 
 
 GA, 
 
8s e?pertments + 
 
 <s A, VYe fee feventhly, that a Body equally preft 
 with a Fluid, weighs lefs, but a Body unequally preft, 
 weighs none at all. This is dear in many particulars 5 for 
 a Stone weighed in Water, lofeth not all the weight, but 
 apart, becaufe it is equally preffed. ButaBody.unequally 
 preft, as is the Mercury H B, hath no weight at all, as 
 know Hands. For underftanding this, you muft confi¬ 
 de:, that the whole weight of it refts upon the furface of 
 Water I L. Therefore though it could be weighed by a 
 firing, palling from the top H, to a Bailance exifting in 
 the Air 5 yet the {aid Bailance would find none of its 
 weight, leing it is wholly futpended by the Water- 
 but a Stone fo weighed, is only fufpended in part, by the 
 Water. 
 
 EXPERIMENT XI- 
 
 Figure i). 
 
 A MZC is a Water 15 foot deep, ABaGIafs-tub 
 14 inches long^nd full of Mercury, B C a Pillar 
 ■of Water 1 3 foot, 10 inches high, thorow whole middle 
 goes a firing to the lcale of the Bailance K, exifting in 
 the Air, D E is a Tub full of Mercury 28 inches long, 
 with a Pillar of Water above it E F, 12 foot and eight 
 inches. G H a Tub 42 inches long,with a Pillar of Wa¬ 
 ter above it HI, 11 foot and fix inches high. Andlaft- 
 lv, A D G S M an imaginary furface, 15 foot deep. This 
 Experiment is brought hither, to demonftrate that a heavy 
 .Boiy,we:ghs as much in Water, as in Air, which is point- 
 Blank to the common received opinion, and deftrudive of 
 the 18 Theorem, To evince this, Imuft fuppofethe 14 
 
 inches 
 
i^Dzoftattcai experiments, 87 
 
 inches of Mercury in-the TUb AB to weigh 14 ounce-* 
 apd- the2-,8'mches of Mercury E>E, to-weigh-28 ounce-^ 
 tfie 42 inches G H to weigh CTmeaa-inthe-Air) 42ounce-. 
 Now I fay,, to make a between the two-' 
 
 Scales K and L,, there muft be 1-4 ounce put into the- 
 Stale L. If after this manner you weigh-the Tub and 
 Mercury- D E, 2 8 ounces will berequired in- the Scale L, 
 and 42, if you weigh the Tub and Mercury G H, Fbr 
 proving this Do6hine,I muflrappeal to Experience, which- 
 will not fail in this. If you reply, and fay, upon fuppofi- 
 ti'oa the Tub and Mercury G H,were a folid piece of brafs,, 
 or iron- thus fufpended- in.theWater,oughtitnoc to weigh- 
 lefs here chan in- the Air, even as- much l'efs, as is the weight 
 of the quantity o.f Water, it puts- out of its place: why- 
 then (hould not the Pipe H G, with the Mercury-in it, do- 
 the fame, feing- there is no apparent differencebetween- 
 them,as to this i 
 
 But to leavethis, which will appear afterwards, andto- 
 let the Reader fee the truth of the i 8'Theorem, Iaffirm, 
 Tis not the weight of the 14 ounces of Mercury AB,thae 
 burdens the fcale of the Ballance K 3 andthacmakes a coun- 
 terpoife with the 14 ounces of Stone, or L.ead-, thats in the 
 fcale L. What then is ;t, you fay * I anfwer’tis 14 
 ounces of the pillar of Water B C that does this. Nei¬ 
 ther doth the weight of the. 28 ounces of. Mercury DE- 
 burden theBallance,but only 28 ouncesof the-WaterEF;-- 
 Neither doth the Ballance fupport the weight of the-4* 
 ounces of Mercury. G H, but it is only burdened with 4# 
 ounces of the Water H I. The reafon is moft evident 
 becaufe according to the principles of the HyJrofttfick* 
 already laid down, the Cylinder of Mercury A B, within; 
 the Tub A B, refts immediatly upon the imaginary fur- 
 
88 i^Djofcatfcai ejectments* 
 
 face of the Water A D G, and therefore cannot bur¬ 
 den the fcale in any wife. The fame is true of the 
 other two Cylinders of Mercury. But in this I find final! 
 difficulty. The greater is, how to make it out, that the 
 fcale K, fapports 14 ounces of the Water B C,and 28 of 
 theWaterEF, and 42 of the Water HI. To make 
 this feem probable, confider firft, as was noted, that this 
 Water is 15 foot deep, and confequently the Pillar of 
 Water BC, 13 foot xo inches. The Water EF 12 
 foot eight inches. And HI, 11 foot and a half. Con- 
 fia'er fecondly,though this be true, yet we muft count the 
 Pillar of Water Z M 49 foot high. The reafon is evi. 
 dent,becaufe the PrefTure of the Air, upon the furface of 
 ail Waters (accordingro the 2$ Theorem) is equivalent 
 to 34 foot of Water: this then being added to 1 j, makes 
 4p, and by this reckoning the Water B C is 47 foot ten 
 inches: the Water E F 45 foot eight inches: And laft- 
 ly,the Water HI 45 foot fix inches. Thirdly, for eafie 
 counting, I muft fuppofe the whole Cylinder Z M to 
 weigh 42 ounces, every 14 inches one ounce: and con¬ 
 fequently the Water B C to weigh 41 ounces • the Wa¬ 
 ter E F to weigh 40 ounces 5 the Water H I 3? ounces. 
 Note, that in Phjfical demonftrations, ’cis not needful to 
 ufe MjthcmaticJ ftrieftnefs in counting ; and fo leaving 
 out fra&ions, we fhall onely ufe round numbers, Confi¬ 
 der fourthly, that in all Fluids, as hath been frequently 
 marked, there is a fondtu and fotentia, the Water B C be¬ 
 ing the. fsndus, and the Mercury AB the potentia,the one 
 driving to prefs down the Tub, the other ftriving to prefs 
 it up. Confider fifthly, that by how much the more a 
 Body fufpended in a Fluid is preffed up, by fo much the 
 Ids the weight that prefteth it down is foend: and con- 
 trarivvife, 
 
$ptoofta«cal <£jcperttmnt& $? 
 
 trariwife,by how much the lefs it is prefled up, by fo much 
 the mote the Preflure above is found. Confider fixthly, 
 the lefs that a furface of Water is burdened, the more able 
 it is to counterbalance the oppofite Preflure, and the more 
 it is burdened,it is the lefs able. Confider feventhly, that 
 the Mercury AB, (which is evident in all Fluids) not 
 only prefleth downward, and burdens the furface ADG r 
 but alio prefleth upward, and therefore adtually endeavour* 
 to thruft up the Tub * and fo it is, that the Tub is prefled 
 between two, namely between the Water C B, and the 
 Mercury within it. 
 
 Now from thefeconfiderationslfay, thefcale K,muft 
 fupport,and bear up 14 ounce of the Water B C: for feing 
 the Mercury is fupported by the furface of Water on 
 which it refts, it cannot by any means burden the ballance 
 with its weight-5 and feing it a&ually prefleth up the 
 Tub, (according to the feventhconfideration ) it muft fo 
 much the more counterpoife (according to the fixch) the 
 oppofite Preflure of the Water BC, and confequently 
 diminifh the weight of it: fo that the Ballance cannot fup- 
 port the whole, but a part. For according to what de¬ 
 grees of force, the Mercury prefleth up the Tub with, ac¬ 
 cording to the fame, muft the Preflure upon the top of the 
 Tub be diminifhed, and fo if the Mercury prefs up the Tub 
 with the force of 27 ounce , the Water BC muft prefs 
 itdownwith 14ounce only, and fo the Cylinder BC, 
 that weighs-really 41 ounce, muft prefs the top of this 
 Tub only with 14, which 14 ounce really counterpoifeth, 
 the 14 ounce of Scone in the Scale L. But how is it made 
 our, that the Mercury AB, prefleth up with 2 7 ounce? 
 For undemanding this, remember, that the Water is 42 
 foot high, taking in the Preflure of the Air, and that a 
 M water 
 
9i {^aioflaticaictpermims. 
 
 VVatcr of chit deepaefs is able to fupport 41 inches of 
 Mercury, every inch weighing one ounce. For if 14 of 
 Water, be able to fupport one of Mercury, 49 foot, or 
 567 inches, muft fupport 41, If then, the part of the 
 furface A, be able to weigh 41, it muff have of upward 
 Preflure 2 7 ounces, feing it's counterpoifed de facto only 
 with 14, Take notice, that in the Hydro ftatkks , the 
 wo: df ref sing, ox weighing, as really ana tiu'y fignifies a 
 weighing up, as a weighing down, feing it is no ldVeffen- 
 tial to Fluid Bodies to move upward, than downward, and 
 that with equal force, and weight. According to this rea- 
 foning,the Ballance fupports 28 ounces of the Water E F, 
 (Imagine the fecond Tub to be fufpended as the firft) feing 
 the Cylinder of Mercury D E, preffeth up the Tub only 
 with the weight of 12 ounce , which 28 ounce, really 
 counterpoifeth the 28 ounce of Stone in the Scale L. But 
 why doth the Mercury A B prefs up with 27 ounce, and 
 the Mercury D E with 12 c 1 For anfwer, remember, (sc- 
 cording to the fixth confideration) the (hotter a Cylinder 
 of Mercury is,the furface upon which it refts, is the ftrong- 
 er, and more able, to prefs it up; and contrariwife, the 
 longer it is, the furface is the more unable and weak : 
 therefore A B being fhorter, and lighter than D E, the 
 furface of Water muff prefs it up with greater force: fo that 
 if the faid furface A M, be able to prefs up the Mercury 
 AB with 27 ounce, it muft prefs up the Mercury D E 
 only with 12 ounce. According to this rule, if the Mer¬ 
 cury A B were 1 5 inches high, it would prefs up only with 
 25 ounce, if it were i 5 , with 25 : if 17, with 24: if 
 18, with 23, and fo forward. This leads us to a clear dif- 
 covery of all the fecrets here .• for if the Mercury A B, 
 thruft up the Pipe, with the weight of 27 ounce, , then 
 
 muft 
 
H gt?ofta t<caieypet(mem c 93 \ 
 
 mnft the Scale K, be eafed of fo much weight, and fo much 
 muft be fubtra&ed from L. Now let us imagine the Pipe 
 AB, to be empty both of Air, Water, and Mercury : 
 in this cafe 41 ounce muft be in the Scale I, to counter- 
 poife It, feingthe whole Cylinder B C, that weighs fo 
 much; does now really counterpoife it. Let us imagine 
 next, thefe 14 inches of Mercury to rife, and fill the Tub 
 A B: in this cafe,there happens a great alteration* becaufe 
 the rifing of them, are really equivalent to the fubtrafr- 
 ing of 27 ounce from the Scale L * and the reafon is, be¬ 
 caufe by fo rifing and filling the Tub, they thruft up the 
 (aid T ub, and by this means eafeth the Scale K, of fo much 
 weight. Now this Scale being eafed, you muft of necef- 
 fity takeout from L 27 ounce for making a new coun¬ 
 terpoife. - 
 
 And laftly, the Scale K muft fupport the whole weight 
 ol the Water H I, which is 551 ounce, nothing remaining 
 to counterballance this downwardPrefiure,and cohfequent- 
 ly to eafe the Ballance.' How then is itcounterpoifedf 
 For clearing this, you muft remember that this Water, 
 that’s really 15 foot deep, muft be reckoned f as I faid ) 
 
 49, becaufe of the Preffure of the Air upon the. top, that’s 
 equivalent to 34. If then it be fo, it cannot raife Mer¬ 
 cury higher in a Tub than 42 inches* the one being 14 
 times heavier than the other: fo that if 14 inches of Wa¬ 
 ter, cannot raife Mercury higher than one inch, 4 9 foot 
 cannot raife it higher, than 42 inches: for as 14 inches, are 
 to one inch* fo is 49 foot to three foot and an half, which 
 is 42 inches. Now I fay, the whole weight of the Wa¬ 
 ter H I, refts upon the top of the Tub, and fo preiTeth 
 down the Scale K,'to which you muft imagine’this Tub, 
 knit by a firing, as the former was, nothing remaining to 
 M 2 counter- 
 
9 i i^tuottattcai cjcpernmntsb 
 
 counterpoifc this downward Preffbre: for the top of the 
 Mercurial Cylinder being raifed as high within the Pipe, as 
 the forface of Water DGS, is able to raife it, thefaid 
 topanimprefs no force upon the Tub within, to thruflic 
 ap, and fb to cafe the Scale K. For example, when a man 
 ere&s upon his hand a Cylinder of Timber, or any fuch 
 Uke thing, which is the outmoft he can fupport, he will 
 aotbe ableto imprefs any impulfe, upon the Ceiling of a 
 room above his head •, but if. fo be, in (lead of that taken 
 a way, there be one lighter eredied, which he is able to 
 command, hecan eafily thruft up the Ceiling at his plea- 
 fore. Juft fo it is here •, for the 42 inchesof Mercury, be¬ 
 ing the outmoft, that the furface of Water DGS is able 
 to bear, it cannot imprefs any. impulfe therewith upon the 
 top of the Tub within: but eafily can the Cylinder D E; 
 imprefs an impulfe and more eafily the Cylinder A B, 
 feing they are lighter, and- fo more powerful,. To evi¬ 
 dence this a little more, let us imagine two things * firft, 
 the Tub G H to be empty, as if vacuity were in it^ In 
 this cafe the top of the Tub ought to bear the whole bur¬ 
 den of the Water, and confequently the Ballance to bear- 
 italfo: becaufethereisnoraptfefffwwithintheTub, to. 
 counterpeife this f endue,. Next, let us imagine the Tub 
 to be only full of Water: according to this fuppofition,. 
 the Ballance cannot be in the leaft part burdened •, becaufe 
 the Water within the Pipe, preffeth it up with as much- 
 force, as the Water I.H preffeth it down; and if any 
 thing. fhould burden the Ballance, it would be only the 
 weight of the Pipe, that’s not confiderable. 
 
 From what is demonftrated, we fee firft, that though 
 this Experiment would feem to prove at the firft, that a. 
 heavy Body weighs as much in the Water,as it doth in the 
 
 Air ; 
 
^fyoSattcal ®jcp2riinenf& n 
 
 A ir, becaufe the whole weight of the Mercnry A B is 
 found in the fcale L,yet ’tis not fo,becaufe the 14 ounce of 
 Stone Ljdoth not councerpoife any of the Mercury AB,but 
 14 ounceofthePillarofWater BC.Secondly,there’s herea 
 clear ground/or aflercing a fondm and a fotentia in Fluids 5 
 becaufe this Tub A B,is preft down with the Water B C, 
 and preft up with the Mercury within it. Thirdly,there’s 
 here a clear ground for averting the Preflure of Water, 
 even in its own place 5 becaule the Water BC, counter- 
 poifes by it’s weight, the 14 ounce of Stone L. Fourth¬ 
 ly , we fee an excellent way for finding the weight of any 
 Cylinder of Water? for whatever be the weight of the 
 Mercury in the Tub, the Cylinder of Water,that refts up¬ 
 on the top, will be of the fame weight exactly ? this is 
 evident in comparing the weight ol the Mercury G H, 
 with the weight of the Water H I, Fifthly, that what¬ 
 ever be the height, and weight of a Pillar of Water, yet 
 the Ballance can fuftain no more of it, than the juft weight 
 of the Mercury: this is alfo evident, becaufe the feale of 
 the Ballance, fupports no more of the weight of the Wa¬ 
 ter B C, than the juft weight of the Mercury A B. We 
 ■fee fixthly, the lurther down a Pipe with Mercury goes■ 
 through Water, the greater is the Preflure it makes upon 
 the top of the Tub within: focputthe cafe, this were 
 100 foot deep, the Mercury G H, that wants all upward 
 Preflure now, would prefs up the Tub with 40 ounce : the 
 Mercury DE with 55, and the Mercury A B with 70, 
 We fee feventhly, the fhorter a Cylinder of Mercury be, 
 itistheftrongerin preffing; and longer it be, it is the 
 weaker-, for there’s more ftrength in AB; than in DE. 
 We fee eighthly,that the ftrength decayes,and grows, ac. 
 cording to Arithmcticdl.progrefsm^ as 1,2,3,4j becaufe 1 
 
96 ■■ ^?p?oSat(cal etptrtmentg, 
 
 if you make the Cylinder GH 4!, that’s now 42, it 
 preffeth up with one ounce.Make it 40 inches,it will prefs - 
 up with two ounces of weight. Make it 39, it preflcth up 
 with three. And contrariwife,make the Cylinder D-E 2 9 
 inches, that’s now but 28, it will prefs up with 1 r ounce 
 only. (With 28 it preffeth up with 12 ,) Make it 36 
 inches high, it will prefs up with 10. If it be 31 inches, 
 it preffethup with nine, and fo forward, Laftly, make the 
 Cylinder A B 15 inches, that’s now but 14, it prefseth up 
 with 2 6 (with 14, it prefseth up with 27 ) make it 15, 
 it prefseth up with 25 5 make it 17, it prefseth up with 
 24. We fee ninthly, that in Fluids, we may make a di- 
 ftin&ion between a fuflentation, and an tqutyondium. ’Tis 
 evident here, becaufe there’s a perfe& cfiipondiumbt* 
 tween the 42 inches of Mercury G H, and the outward 
 Water that’s 49 foot deep. But ’tis not fo, between the 
 faid Water,and the Mercury D E; becaufe the faid Wa¬ 
 ter is able to raife the faid Mercury 14 inches higher: 
 therefore the Water only [u(Lti»s the Mercury DE, but 
 cdHHterbillnicu the Mercury G H. We fee tenthly, that 
 the pondas of the pillar of Water BC is counterpoifed by 
 two diftinft pflnw/ really. The one is the 14 dunce of 
 Stone in the fcale L, the other is the 14 inches of Mer¬ 
 cury A B, that as really thrufls up the Water, as the fcale 
 K pulls it up,by vertueof the oppofite weight. Eleventh¬ 
 ly, take away the Stone L, and you will find the Pipe with 
 the Mercury AB fink down: this happens, not becaufe 
 the furface of Water on which it refts is not able to fuftain 
 it, but becaufe the 14 ounce of the Water B C, that was 
 fopportedby the Stone,doth now prefs it down. Twelfth¬ 
 ly, the more a Body is unequally prefsed by a Fluid , the 
 more of the weight of that Fluid is fenfible 3 and the 
 
^jDjofiaticat crpetmittus. ^ 
 
 more equally a Body is prefsed, the left fenfibleisthe 
 weight of that Fluid: this is evident, becaufe there's a 
 greater weight of the Water H1 found in the Ballance 
 (it takes 42 ounce to counterpoife it) than of the Water 
 E F,which is counterpoifed with 28 ounce; and the rea- 
 fbnisj becaufe the top of theTubH, fuppor.ts the whole 
 3P ounce of Water HI, the Mercury within the Tub, 
 not being able in the leaft to counterpoife it, or thruft it 
 up. But becaufe the Tub D E, is more equally prefled 
 (the Water E F preffeth down with 40, and the Mercu¬ 
 ry D E preffeth up with 12) therefore left weight of the 
 VVater EF burdenstheBal!ance,only 28 ounce. Hence 
 it is, that becaufe the Tub A B, is more equally prefTed, 
 than either D E or G H, there’s left of the weight of the 
 VVater B C, found in the Ballance,only 14 ounce. Thir¬ 
 teenthly, if in the infiant of time, while theTqbsare 
 thusfufpendedin the Water, the Preflure of the Air 
 above were taken away, and annihilated ; then find, r!ie 42 
 inches of Mercury G H would fall down, to about 13 
 indies. Secondly,the 2 8 inches of Mercury D E, would 
 fall down to as many. And laftly, the 14 A B, would 
 fink down to the fame height. The reafon is, becaufe the 
 Preffure of'the Air being equivalent to 34 foot of VVa¬ 
 ter, no more would remain but iy foot, which is the real 
 height,according to Z M. But 15 foot of Water, can- 
 notfuftain moeinches of Mercury than about 13. And 
 confequendy, firft, 14 ounce of Stone in the Ballance, 
 would counterpoife thewhole Water B C. The reafon 
 is,becaufe the Water BC is but of 14 ounce $ and the 
 Mercury A B, being but 13 inches high, could imprefs no 
 impulfe upon the cop of the Tub within, thatVi4 inches' 
 high. Secondly, 13 ounce of Stone in theScale L, would 
 
96 l^oQatital eypetimrotsi 
 
 ■counterpoife the whole Water EF, feing EF is but 13 
 ounce. Thirdly, the fame weight (one ounce being de¬ 
 duced) would counterpoife the Water H I,becaafe in this 
 cafe,it weighs but 12 ounce, 
 
 To proceed a little further, imagine the Pipe G H to 
 be fufpended by the ballance, as the Pipe A B is ; and 
 then a little hole opened in the top H, to fuffer the Wa¬ 
 ter to come in, till the Mercury fubfide 14 inches, namely 
 from Qjo O ( imagine this Tub to be the other) and 
 then ftop it. The reafon why the Waterrufheth in,and 
 p-effeth down the Mercury, is the force and Preffure of it: 
 for the faid Water, finding the Cylinder in equilibria with 
 the outward Water, prefently by its own weight, calls 
 the fcales, which is eafily done, feeing the furface GSM 
 Supports as much burden as .it can. But that which is more 
 confiderable is this 5 after the fubfiding of the Mercury 
 from Q..to 0-, the equilibrium that was between the fcalc 
 of the ballance, and the Water QR is deftroyed: for 
 whereas 42 ounces were required before ; ap will now do 
 it. For undemanding the reafon of this, confiJer that 
 between CLand O, are 14 inches of Water rulhed in, 
 which are equivalent to one inch of Mercury. Next, ac¬ 
 cording to former reafonmgs, the ballance mull fupport 2p 
 ounces of the Water QR-, becaufe in this cafe, the top 
 of the Pipe within., is prefled up with the weight of 13 
 ounces 5 which in effeft, diminilhech as much of the down¬ 
 ward Preffure of the V Vater R Qi which before had the 
 burden of 3 p ounces. But why is the Tub preft up with 
 13 ounces ? I anfwer, becaufe the Mercury,that before was 
 4a inches,is now but 28, or having the 14 inches of Water 
 Q^O above it, it is 2^, therefore being (hotter, the furface 
 G S M is the more able to Prefs it up, even with as much 
 more force, as it is in inches (horter. In 
 
$ptyoftaHcal€ieperfoimt 04 97 
 
 In the fecond place, let in as much Water more, as will 
 deprefs the Mercury other 14 inches, namely from O to P. 
 In this cafe, 1 6 ounce of ftonewill make an equifondium • 
 becaufe, the 14 inches of Mercury P S> and the 28 inches 
 of Water P O Qj being a far lighter burden by 16 , than 
 the 41 inches of Mercury, the furface GSM muft be far 
 abler to-prefs them up now,than before: and therefore,muft 
 diminifh as much of the downward PrefTureof the Water 
 QR, that burdens the Ballance, as themfelves wants of 
 weight:feing then,thewholeCylinder of Mercury,andWa- 
 ter together, aie but equivalent for weight to 16 inches of 
 Mercury, the top of the Tub within,muft be preft up with 
 26 ounce ; and -therefore they by their upward Preflure, 
 muft diminifh 2 6 ounce of the weight of the Water R Q^, 
 that weighs 39. Laftly, let in fo much V Vater, as will 
 deprefs the laft 14 inches PS 5 and you will find no more 
 weight required in the Ballance to make an equiftndium , 
 than counterpoifeththe fimple weight of the Tub, which 
 is not confiderable. The reafon is, becaufe, the part S, of 
 the furface GSM, being liberated of the burden of Mer¬ 
 cury, and fuftaining only the Water within the Tub, in 
 {lead of it, this furface prefleth up the Water within the 
 Tub, and coniequently the top of it, with as great force, 
 and weight, as the top of the Tub without is deprefled, 
 with the outward Water RQj therefore, 39 ounce de¬ 
 pleting the Tub, and 39 ouncepreffmg it up, the Ballance 
 muft be freed of the whole weight of Water R Q. If it 
 be objected, that the 42 inches of Water Q_S, are equi¬ 
 valent in weight to three inches of Mercury-* therefore the 
 part of iChe furface S, being burdened with this, cannot 
 prefs up, with as great force, as the Water,R QprefTerh 
 down. Foranfwer, confider, .that the part S, is able to 
 N fupport 
 
9$ Ippo^0ftattc«fle]cpenment£i» 
 
 fupport 42 ounce of Water, and next, that the Water 
 R 4 weighs bat 59. Then-I fay, feing the 4-2 inches of 
 Water within the Tub, weighs only three ounce, the*- 
 part S,thats burdened therewith,being able to fupport 42-, 
 it muftprefs up with the weight of 59, andTo counterbal- 
 lance the Water R Q. 
 
 If it be in mired, whether or not, would the-i 4 inches of 
 Mercury A B fall down, aftoall hole being made in the 
 top of the Tub at B ? I anfwer, they would. If it be obje¬ 
 cted, that thefe 14 inches of Mercury,are not in equilibria) 
 with-the. Preifuie of the ambient Water, as the Mercury- 
 GH,and therefore they cannot be fa eafily depreffed by the 
 Water, that comes in at the faid hole, I anfwer,they mufc 
 all fall down, and as eafily, as the other, and'that becaufeof 
 inequality of weight between the P strati a of the furfaceof 
 Water, and the panda,\x:s ceitain.the part A of the fur- 
 face, cannot fupport more weight of any kind, than 42 
 ounce; but when a hole is opened in B-, and the Water 
 comes in, ’tis then burdened with the weight of 14 ounce 
 0! Mercury, and with the weight of 41 ounce of Water ; - 
 fa much the V Vacer B C weighs, which- is j j ounce: but 
 a furface that hath only the Petunia of 42. can never fup¬ 
 port a?^^of55,nonotof45. 
 
 It may be objected thus .• Put the cafe a Cylinder of 
 Cold, or Brafs were fufpended in- this- Water; as the 
 Pipe and Mercury G H are fufpended by the Ballance, 
 would not the Ballance fupport the whole weight of it, 
 without fupporting any part of the weight of the Water 
 IH, that refts upon the top ot it, I anfwer, there’s a 
 great difference between the two 5 becaufe a Cylinder of 
 Gold or Brafs, fuffers both the upward and downward 
 Preflure ot the Water; but the Mercury GH, fuffers 
 
 only 
 
jjvwoftatical ©tpetfmtnts. 99 
 
 only the upward Preflure, being fteed qi thedownwatd, 
 by the top of the Tub. From this E^perim.entofkttiqg 
 in the'Water upon che.top oft he, Mercury,, wefeefirfi, 
 that when two Fluids are [n^^mUbriotm with another, 
 a very fmall weight will caft and turn the Scales, becaufe, if 
 the fixth part of an inch of Water come in at Q_, it pre- 
 fently alters the hight of the Mercury from 42 inches to 
 lefs. Secondly, ’tis impoffible for a furface of Water^o fup- 
 port more weight, than its own proper burden; becaufe the 
 partS, cannot fupportmore, nonota,grain,than 42 ounce. 
 We fee thirdly, that it is as impoflible for a furfaceof 
 V Vater, to fupport lefs, than its own burden; beaufe 
 whatever Iofs of weight the Pillar of Mercury S Q_ fuffers, 
 by the ingrefs of the Water Q O , its made up again by 
 the fame Water. If it.be objected, that the 14. inches-of 
 Water QO, are not fo heavy by far, as the i4inchesaf 
 Mercury, that fell down, I anfwer, its true, yet the fart 
 S, is as much burdened as before, becaufe what is wanting 
 in weight, its made up, and compenfed by PrefTure, Wo 
 fee fourthly, that the PrefjureoU Fluid is a thing really 
 diftind from the natural weighty according to the 22 The¬ 
 orem : becaufe though.the 14 inches of Water QO, ; aue 
 ■not fo heavy naturally as the 14 inches of Mercury chat fell 
 down, yet the Preflure of them uponthefurfaceS,isas 
 .much. We fee fifthly, that. 14 inches of Water, that’sm 
 flmdy fourteen times lighter than Mercury, may have as 
 much weiglmvitlvthem.;as 14ounceofMercury. ■ Weifee 
 fixthly, that a Cylinder.of Mercury cannot.be fufpended in 
 Air,. or,in Water unlefsjtfoe guarded witha Tub,iopre- 
 fervedrirom the downward Preffure of that Air or Water.* 
 tforrby opening.anbole.in the;Mercury iubfides. .We 
 
 ifeeXeventhly^lm ’tislmpoffiblefor two-Flurds to fhfpend 
 :N ; one 
 
ioo ^ptyoftaticai experiments* 
 
 one-another mutually, unlefs there be a lort of equipondi- 
 ttm between them ; becaufe no fooner you deftroy the 
 equipondi'um, between the 42 inches of Mercury Q_S; and 
 the part of the furface S, by the ingrefs of the Water QjO, 
 but affoon there arifeth a new one. We fee eighthly (as- 
 we noted before) the nearer a Body comes to be equally 
 prefled with a Fluid, thelefsis thePrefsure of that Fluid 
 ftnfiblt : becaufe iefs weight is required in the Ball a nee, 
 to counterpoife the Prefsure, and weight of the Water 
 R after the ingrefs of the Water Q 0 P, than after the 
 ingrefs of the Water QO. We fee ninthly, tharwhen 
 a Body is equally, and uniformly prefled with a Fluid, the 
 Preflu: e rs injenfible ; becaufe, after the Water hath thruft 
 down all the Mercury from Qjo S, there’s no more weight 
 at all oi the Water R CL found in the Bailance. We fee - 
 tenthly, that not only in Water, the Preflure of Water 
 may be found,- but out of it, namely in the Air ; as is clear 
 from the Bailance,-that fupports the Prefliireof the Wa¬ 
 ter RQ. ^ We fee eleventhly, a ground to diftinguifh be¬ 
 tween the nutftrd BiUdnce , and the artificial Bdllance. The 
 artificial Bailance , is the Bailance K L: the natural , is the 
 Pipe QS. We fee twelfthly, that they keep a corre- 
 fpondencebetweenthemfelves, or fome Anally : for by 
 what proportion the Water thrufts down the Mercury, by 
 that fame proportion thtpondns L, of the Bailance islef- 
 fened: and by what proportion the Mercury rifes in the 
 Pipe,by .that fame,is the weight Laugmented in the Scale, 
 We may fubjoyn laftly, that the eafieft way of explicating 
 tbePkincmfnaoi Nature, is not always the beft,and trneft. 
 For fome may think,it were far eafier to fay, that the Bai¬ 
 lance fupports the Mercury AB,or D E,and not any partof 
 the Water. B C, or EF. But fuch a way would be falfe,and 
 abfurd,andcontrary to all tf\e former DoQrine. E X- 
 
^tyoftattcai experiments io i 
 
 ■ EXPERIMENT XII- 
 
 figure 1 5 . 
 
 T His Schema tifm reprefertts a Water ioo foot deep, 
 whofe fiift and vifible furface is IH K. And L M 
 is the ground of ir. CD is a piece of brafs 30 inches 
 high, and 12 inches in diameter, fufpended upon the ima¬ 
 ginary furface of Water A N B, which is diftant from the 
 top IH K, 25 foot. This Brafs cannot go farder down, 
 when demitted from H ; becaufe it’s keeped up, by the 
 Force and Preffure of the furface of Water A N B, which 
 I prove thus. The part B Mains de fatlo, a Pillar of 
 Water KB 1400 pound weight: therefore the part 
 N is able to Main as much. I fuppofe here, the faid 
 piece of Brafs to weigh 1400 pound. The Water KB 
 is 1400 pound, becaufe its a Pillar 2 5 foot high, and 12 
 inches thick, lor one cubical foot weighs j 6 pound Trois. 
 The connexion the argument is evident, becaufe it is as 
 eafie for a furface of Water, to Main a folid Body, as to 
 Main a Fluid Body: therefore, if the part B, fupport ! 
 the Fluid Pillar KB, the part N mull be able to fupport 
 likewife the folid Pillar C D,which is of the fame weight. . 
 If it be obje&ed, that the part N, Mains befides the Brafs ' 
 C D, a Pillar of Water EF 22 foot high, and a half, , 
 which two will weigh 2260 pound. I anfwer, upbnfup- 
 pofitlon,that neither Water nor Air fucceeded, the fpace J 
 E F being void of both, the Brafs -would be’ fufpended 
 with the force and power of the Water N- : And though 
 this cannot be made frafticable , yet the Theory of it may ' 
 conduce much for explicating-the fecrets and myfteries of ■ 
 the Hydrofiaticks, But why ought the BrafstobeftiC- 
 
 pended ; 
 
ioi $pDjQ8atteal e^pertments* 
 
 pended at 25 foot from the top i I anfwer, becaufe the 
 fotcntiioi the furface A N B, is equal to the fndtts of 
 the Brafs, To evidence this,confider that Brafs is a Body 
 naturally heavier then Water, ‘I (hall fuppofe ten times, 
 that’s to fay,one inch of Brafs will counterpoife ten inches 
 of Water, If this inequality be, then muft this Pillar of 
 Brafs go Co much farder down,than the fii ft furface IH K, 
 as the one is heavier in fpecic, or naturally , than the other: 
 therefore it muft fink 25 foot exattly 5 feiag a piece of 
 Brafs 3 0 inches high,requires 400 inches of Water, or 2 5 
 foot-to counterpoife it: for if one inch of Brafs require 
 ten inches of Water, then furely 30 inches muft require 
 300, Yet it is no matter,what the thicknefs be,provided j 
 it-be no higher than 30 inches, 
 
 T0 advance fome farder, let us make a fecond fuppofi- 
 tion, namely, while the Brafs is thus fufpenaed upon the 
 furface ANB, fuppofe the Air to come down, and fillup 
 the imaginary fpace E F, then muft the Brafs be thruft 
 down as far as the furface 0 P, that’s 34 foot below the 
 furface A N D , and 59 from the top. The reafon of it 
 is this, becaufe the weight of the Air luperadded, is equi¬ 
 valent to the Preffiire of aPillar of Mercury 2 9 inches high, 
 and 12 inches thick •• therefore the Brafs being burdenud 
 with this, it muft go fo farder down, till it meet with a fur¬ 
 face,' whofe pettntia is equal in weight, to th ejxwdus of both, 
 which is precifely 59 foot from the top : for if one inch of 
 Mercury require 14 of Water, then 2 9 inches muft require 
 405 inches, or 34 f oot. In a word,it muft go as far down, 
 as that furface, thatfuftains a Pillar of Water, that would 
 counterpoife in a Ballance, the Brafs C D, and.a Pillar of 
 Mercury 29 inches high, ,and 12 inches thick, .both which 
 weighs 3 290 pound, 
 
 Fipm 
 
{^ojoftaticai expettments* 103 
 
 From what is faid,,wefee firft, ; that of two heayy-bo¬ 
 dies differing.in weigKt, the lighter may go.fnrtlier down; 
 than the heavier. This is clear, becaufea flender Cylin¬ 
 der,o\ Gold, in form of an Arrow, half,an inch thick, and 
 2 8 inches long,weighing 2 8 pound (’tis no iiiatter,though 
 the juft'weight of it be not determined ) will go down 3 5 
 foot in Water, before it.meet with a furface, whof efoten- 
 tia is equal in weight to its own pndus j for if Gold be 1$ 
 times heavier naturally than Water, then the faid Cylin¬ 
 der muftgo down before it reft,, 4^0 inches,, or 35 foot. 
 But a piece of Gold 12 inches long, and fix inches thick, < 
 that perhaps will weigh 208 pound, wiil fink no further. 
 
 I than 15 foot. And the reafon is,, becaufe, if one inch of 
 Cold require 15 ofVVater to counterpoife it,then 12 mufti 
 only require.i 80, or 15 foot. Note,, that both the bodies 
 muftgo down Perpendicularly,. and not as-it were Hori¬ 
 zontally , with their Tides downmoft: for if 1 they-go- 
 down after this manner, they cannot fink fo far. The 
 reafon of this, is alfo evident, becaufe. a heavy body, 
 goes fo far down, and no further, till it hath thruft as 
 much Water out of its.place, as. will counterpoife icfelfin. 
 a Ballance. That’s to fay, ifan heavy, body weigh 100 
 pound , it muft go no further down, than, after it-hath 
 thruftout 100 pound of Water, Butfoit.is, thatapiece. 
 of Gold,, in form ofan Arrow, going down frdo-wife, or 
 with the two ends parallel to the Horizon,, will. thruft as. 
 much Water out of its place, as, will be the,weight of it 
 felf, before it can go down,15 or 1 5 inches from the top: 
 becaufe for every inch it goes down fide-wife, it expells 2 8. 
 inches of Water. In going down two inches, it expells 
 In going down three inches, it expells 84, and fo forward, 
 till it go down 15 inches, where it expells 420 inches: 
 
104 f^ajoBatical exjpet: mums* 
 
 but 420 inches amounts to 3 5-foot, Now, take a Cylin¬ 
 der of Water 35 foot high, and juft the thicknefs of the 
 Cylinder of Gold, which I fuppofed to be of half an inch, 
 and put them in a ballance, and you will find the one juft 
 the weight of the other. Neither can the piece of Gold 
 go io far down as before, if it go down fide-wife ^ .becaufe 
 for every fix inches it is drowned, it expells a bulk of Wa¬ 
 ter 12 inches long, and fix inches thicks therefore it muft 
 be impended, before it go beyond $0 inches,or fevenfooc 
 and an half: now, if fix inches give one foot, 90 inches will 
 give 15 foot: but ij of Water in hight, and fix inches 
 thick,is the juft weight of it in a ballance, wc. 208 pound. 
 We fee fecondly, the broader and larger the furface of a 
 Fluid be, his the more able and ftrong to fupport an heavy 
 burden: therefore the part of a furface of Water fix inches 
 fquare every way, will carry a far greater weight, than a 
 part four inches fquare. Though a furface of Water 34 
 or 3 5 foot deep, be not able to fuftain a Cylinder of Gold, 
 if it exceed 28 or 29 inches in hight, yet take a Cylinder 
 of Gold, 1 o foot high, and reduce it, by making it thick, 
 er. to the hight of 20 inches, a furface of Water little more 
 than 24 foot deep will fuftain it. Or reduce a Cylinder 
 ic foot high, which requires a furface more than 100 foot 
 deep, to a Cylinder fix inches high, a furface little more 
 than feven foot deep will fupport it. We fee thirdly, the 
 reafon why bodies that .are broad and large, move flowlier 
 through Air and ■Water, than bodies that are more thin, 
 and (lender, though both be of the fame weight in a bal¬ 
 lance. For example, %o pound of Lead, long and {len¬ 
 der like an Arrow, will go fooner to theground of a deep 
 Water, than a piece of Lead of the fame weight, in form 
 of a Platter or Bafon. T he reafon is, becaufe as the body 
 
 is 
 
$pu?oftat(cai c*petfment&- 10? 
 
 is broader, fo it takes a broader part of a furface, which 
 broader part is ftronger and abler,than a nairowerpatt,and 
 fo makes the greater refiftance. The fame is the reafon, 
 why a Bullet fix inches in Diameter, movesflowlier tho- 
 row the Air, fhoc from a Cannon, than a .Bullet one inch 
 in Diameter. For the fame reafon, Ships of (even ortight 
 hundred Tun, move far flowlier thorow the Air, and Wa¬ 
 ter, than VefTels of lefs burden. Item, large and big 
 Fowls, as Eagles, move flowlier, than fmall Birds, as 
 Swallows. Yea, of Fowls of the fame quantity, one may 
 move quicklier than another, as is evident in long-wing’d 
 Hawks , as Falcons., that by the iharpnefsof their Wings, 
 move far more fpace in half an hour, thanKites, orGofe- 
 Hawks, whofe wings are rounder. We fee fourthly, that 
 there’s nobody how heavy foever, but it may be fupport- 
 ed by the furface of a Fluid, either in Air or in Water. 
 I grant, the ftrongeft furface of Air, that can be had, is 
 not able to fupport more weight, than a Cylinder of Gold 
 28 inches high.- yet though it were as large, and broad, as 
 a Mill-{lone , if it do not exceed the faid highc, the Air is 
 able to fitftain it. For the fame caufe, if it were poffible 
 to been (JMill-(tone oi the Air, that refts upon it, the Air 
 below would lift it from the ground, and carry it tip many 
 fathoms, even till it came to a furface, equal in power to 
 the weight of the Stone. Or, ifalarge Mill-(lone were de- 
 
 mitted from the top of the Atmfyhere, towards the Earth, 
 it could hardly touch the ground, being detained by the 
 way, by a furface counterpoifing it. Or if it did touch, 
 thiougb the fwiftnefs of the motion, it would furely, 
 as it were, rebound, and be carried up again. It is 
 alwayes to be remembred, that in fuch trials, the Air is 
 fuppofed not to follow, or to be united, after the Stone 
 0 pafieth 
 
io6 ^ajoftattcai ejcpermunts. 
 
 paffeth thorow, Now if the Air be able to do this, far 
 tnore the Water, that’s a body a thoufand times- heavier. 
 We fee fifthly the reafon, why heavy bodies move fo 
 eafiiy thorow Air, and Water, namely becanfe the parts 
 that were divided, by the body that is moved, are pre- 
 fe'ntly reunited, and clofed again, by which means it is 
 driven forward, the Preffure upon the back, being as much 
 as the Preffure before. If this were not, nobody what- 
 foever would be able to move it feif one foot forward. 
 For example , if, when a man hath advanced one ftep for¬ 
 ward, the Air did not clofe again upon his back, the force 
 of the Air upon his belly and breaft, would not only flop 
 him, but violently thruft him backward, We fee fixthly, 
 the reafon, why the fame body defcends with more diffi¬ 
 culty thorow Water, than Air, becaufe a furface of Water 
 :s far ftrongev, than a furface of Air. We fee feventhly, 
 that a heaxw body is never fufpended by a furface of 
 Water, or Air, ingoing down, till once it hathdifplaced, 
 as much Water c: Air, as will counterpoife it felf in a bal¬ 
 ance. This is clear from the Brafs C D, that goes al- 
 wayes down, till it expell its own weight of Water. For 
 this caufe, if a Mill-(lone were demitted, or fent down 
 from the top of the Air, and never refted, till it came 
 within 40 fathom of the Earth, then fo much Air, as is 
 expelled by the defeent, is the juft weight of the ftone. 
 We fee eighthly,the heavier a body be naturally, than Wa¬ 
 ter, it goes the further down, and the lighter it is, it finks 
 the lefs. For if CD were of Gold, it would go fur¬ 
 ther down, than being of Brafs orlron: and if CD were 
 a ftone, that’s lighter;';; fpecie than Brafs, ir. would not go 
 fo far down. This lets us know the reafon, why thicker, 
 blacker, and heavier clouds comes nearer to the Barth, 
 
^jcpertments* 107 
 
 than thinner, whiter, and lighter. We fee ninthly, that 
 the PrefTure of the Air is determinable, even in its Jieigheft 
 degree, and feejnes to be the fame in all places of the 
 world $ but the PrefTure of the Water is not fo. The 
 reafon of the firft part is, becaufe the Element of Air feeiris 
 to be of the fame hight in all places, and therefore jyp 
 may know its outmoft PrefTure, which is juft equivalent to 
 the weight of 2 8 or 29 inches of Gold, or Mercury. But 
 becaufe the deepnefs of the Sea is variable, therefore the 
 PrefTure is variable likewife. Yet if the exatft: deepnefs, 
 of the deepeft place were known, it wer.eas eafie to de¬ 
 termine the greateft PrefTure of it, as to determine the 
 -greateft PrefTure of the Air. We Tee tenthly, that a very 
 fmall weight added or fubtra&edin height, will.change 
 and alter the counterpo.ife of a Fluid. Becaufe if you % 
 bu t one ounceupon the top of the brJs at F, it prefently 
 TubTides accordingly: or take one ounce from it,and k rifes. 
 But though never To much weight be added to it, or fob* 
 traced from it in thicknefs, no alteration follows. There¬ 
 fore, though this piece of Brafs CD,' that’s now but *2 
 ■inchesin thicknefs, were made.24,b.yjwhich;meaps t fhe 
 weight would be tripled and more, yet the famefiirface A 
 iN B would Tuftain it: yet, add to it in altitude, /butane 
 inch, and prefently it finks down propartionahly. This 
 evidently difeovers the reafon, why.itsas.eafif for. the. Air, 
 ,to:fupp6rt 2 Cylinder ofMei'Cury 3 inches thick,, ss.tofop- 
 port a-Gylindei half an inch thick: and why it cannot fop- 
 port.more in height than 19 inches, and why.it cannot,Tup- 
 . port iefs. Now.riiereafon, why.aihickeirPillaf, isaseafi- 
 ly Lufpe'nde.ci, .as .a tlrinner,is this,hec aufeiffa. Pillar, of,Mer- 
 . curybe thicker, and, .Gonfequendyheavier ,, than k takes a 
 : broader, .and confequently.a ftronger'furiace of Aintor.eft 
 0 2 upon: 
 
io$ %?s?o ftatfcal eyptmn ents, 
 
 upon: if icbe but (lender, and fo But light", thenit takesa 
 leflerpart of a furface to bear it up, and confequently’a 
 weaker 5 by which meansthe Pandits of the one, is alwayes 
 proportionable to the Potentu ohhe other. Is it not as 
 eafie for a-Pillar of (lone, 6 foot in Diameter, tofupport 
 another fix foot in Diameter 5 as it is for a Pillar one foot 
 in'Diameter, to fupporta Pillar one foot in Diameter { 
 Bat as a Pillar one foot in Diameter, cannot fupport a Pil¬ 
 lar 6 foot in Diameter, neither can a furface of Air, one 
 inch in Diameter, fupport a Pillar of Mercury 6 inches in 
 Diameter. But why fhould a larger part of a furface be 
 ftronger than a narrower part i I anlwer.the one is ftronger 
 than the other,for that fame reafon, why a thicker Cylin¬ 
 der is heavier than- a thinner: for what I call ftrength in a 
 furface, itsnothing elfe but might, and what I call might 
 in a Cylinder, its nothing elfe but (Irtngtb, The fame 
 thing hath two names 5 becaufe the pillar of aFluid preffeth 
 down, and the furface fupports: - therefore, in the one its - 
 called fondtts, in the other ptentia, As when two feales 
 are in equilibria, either this, or that may be called the fon- 
 dus - or either this, or that', may be called th tpotentit. 
 Now I fay,if a part of a furface four inches broad, haveas 
 much weight or force in it , as a Pillar of Mercury four 
 inches thick• then furely -, a part of a furface eight-inches 
 broad, muft have as much weight and force in it, as a Pillar 
 of Mercury eight inches thick. But why ought a furface to 
 fuccumb, when the Pillar grows in hight, and not :to fail 
 whenit grows only in breadth: t'Anf, VVhen itgrows in 
 breadth, the pndtts never exceeds the fotentia 5 .but when 
 it becomes higher, then ir becomes heavier. That’s to 
 fay, when a Pillar grows broader, there’s not one part of 
 tbefurface thatfuftains it, more burdened than, another ; 
 
tyc?oftat(cate]c pcumcn tg« 109 
 
 fting the pan eight inches' broad, , is no more pl-eft with" a 
 pillar eight inches thick • than the part four inches broad, 
 is preft with a Pillar four inches thick: a* eight ounce of 
 Lead in this Scale, is- no more counterpoifed with eight ' 
 ounce in the other Scale, than four ounce in this Scale, is 
 counterpoifed with four in the other. But when a Cylin¬ 
 der grows-in hight,. theexceeds the potentta ; one 
 part of a furface being more burdened than another. We 
 fee eleventhly, that in a large furface of a Fluid, wherein 
 are many parts-, each part is^able to fuftain its own proper 
 burden. So a part eight inches in Diameter fupports a 
 Pillar eight inches thick; and a part four inches, fupports 
 a'Cylinaer four inches thick; but cannot fupport a Pillar 
 lix inches thick. But this Teems-rather to flowfrom the 
 disproportion of CM agnitudes,king a circular pjain^. inches 
 in diameter,cannot receive a Bafe of a Pillar 6 inches in dia¬ 
 meter. But this is certain from the vei y nature of Fluids, 
 
 that in a deep Water, wherein may bediftinguifhed ioo, 
 or iooo different furfaces, each one is able to fupport his 
 own burden, and no more. 
 
 EXPERIMENT XIII- 
 
 Figure 17, 18, 19, 
 
 F Or making this Experiment, take two plain Bodies of 
 Brafs, or Marble well polifhed. Make them of any 
 quantity -, but for this prefent ufe, let each of them be four 
 inches broad fquare-wife. Upon the back part, let jeach 
 one have an handle about fix inches long,of the famenfetal, 
 formed with the plain it felf, in the founding (if they be 
 of Brafs ) as is reprelented in this Schejnatilm. When: 
 
no Upmoftaticai experiments* 
 
 they are thus prepared# anoint their inner-fides with Oyl 
 or Water, and having thruft the one face alongft upon the 
 other,with all theftrength you have, till all the four edges 
 agree,two whereof are reprefented by A B, and C D, you 
 will find them cleave fo dofs together, as if they were but 
 one Body. The effed is this, that ordinary ftrength will 
 not pull them afunder 5 and that under a furface of Water, 
 a ftronger pull is required than in the Air.- 
 That we may deduce fome Hydro fratied conclufions 
 from this Experiment, let us fuppofe thefe two plain Bo¬ 
 dies to be united in the middle of the Water IK PQ^ 
 that’s 34 foot deep, and fufpended by a beam or long tree 
 T V exifting inthe Air, near the top of the Water, by a 
 chord SE paffmg between the middle of the beam, and 
 theend of the handle at E. Suppofe next a great weight 
 of Lead R, 350 pound, to be appended to the end of the 
 handle at H, of the under plain Body CDNO, This 
 cone, I affirm,that the beam T V, neither fuftains the un¬ 
 de: plain Body CDNOGH, nor the 350 pound 
 weight of Lead R,that hangs down from the handle GH. 
 If itbeobjeded, that the beam fupports the upper plain 
 Body ABLMFE5 therefore it muff bear the weight 
 alfo of the under plain CDNOG H,with the weightR- 
 firing they are both united together, and cleave fo dofs", 
 as if they were but one Body. I anfwer, it fupportsthe 
 one unqueffionably , hut not the other. To explicate 
 this Hydreftaticalkiy&tty, Itnuft aver three things •, firft, 
 that the inferior plain is fupported by the upward PrefTare 
 of the lower Water P Q.N O. Secondly, that the 
 • burden which thebeam fuftains, is nor the weight of -the 
 mnder plain, butthe-weightof-the34-foot'of Water IK 
 ■L M. Thirdly,' -that this weight is -e-xadly the weighc 
 
1 ^'OjortatM Cfpcrimtnts. m 
 
 of the inferior plain, and Lead R, But is it not more 
 eafieto fay , that the beam (upports both the plains t I 
 anfwer, if I fay fo, I can neither affirm tiuth,nor fpeak con- 
 fequentially, But may it not be faid, that the inferior 
 plain is fupported both by the beam, and the lower water 
 P QN 0 ? I anfwer, this is impoffible $ becaufe one and 
 the fame weight, cannot be fupported totally, bytwodi- 
 ftinft fupporters. 
 
 For making thefeaflertions evident, I muft fuppofe the 
 fuperior Water IKLM to be 34 foot deep, and to 
 weigh,ii it were put into a ballance,4oo pound: and'which 
 is unqueftionable, that the faid Water lefts upon the back 
 of the fuperior plain EM. I fuppofe fecondly, that the 
 lower Water PQjsf O weighs as much , and thrufts up 
 the inferior plain with as great weight, as the fuperior 
 plain ispreftdown with, by the fuperior Water.- This 
 is evident from former Experiments, And laftly, I fup¬ 
 pofe each plain to weigh two pound, and the weight of 
 Lead R 3 5 0. It is to be obferved here,that no miftake may 
 arife in the calculation afterwards, that though it be faid, 
 this 34 foot of Water weighs'400 pound, yet in it felf it 
 weighs but 200: but confidering the Preffureof the Air 
 upon IK,which is as much, it may be truly faid to Weigh 
 400. Thefe things being premitted,I fay the weight that 
 the beam TV fuftains, is not the weight of the inferior 
 plain , and the Lead R , but 352 pound of the fuperi¬ 
 or Water IK L M, and cortfequently, that the infe¬ 
 rior plain is- fupported by the lower Water PQJSf O. 
 The.reafon is, becaufe the lower Water preiTeth up' with 
 the weight of 48 pound. It is in it felf 400 pound: but 
 being burdened with 3 5 2 , it cannot thruft up with mbre 
 weight than 48. Now, it preffing up with 48, muft cafe 
 
in ^pt&oftatfcal Crpertmentsu 
 
 the beam or 48, and counterpoife fo much of the fupe- 
 rior Water, and confequently the beam muft fupporc 
 only 55* pound of it, But put the cafe (you fayj the 
 weight R, were 130 pound, x 6 0 pound, or 180 pound, 
 would the beam be lefs or more burdened with the fuperi- 
 or Water i I anfwer, if R be 130 pound,then the beam 
 fupports only 13.2 pound of the fuperior Water ■ for if 
 the inferior be only burdened with 130, the weight of R, 
 and with two the weight of the inferior plain , then muft 
 it prefs up with 368, and by this means,muft eafe the beam 
 of fo much, itfuftaining 132 pound only. According to 
 this compcing, when the Lead R weighs 160 pound, the 
 beam fupports only 238 pound of the fuperior Water. 
 If it weigh 180 pound,it fuftains 218. And if the weight 
 R were taken atvay, the beam fupports no more of the 
 fuperior Water than two pound. 
 
 To proceed a little further 5 imagine the two Plains to 
 be drawn up x 7 foot nearer the Hi ft furface IK, namely as 
 high as Z W. This done, the union breaks up, and they 
 prefently fall afunder. Thereafon is, becaufe the fur- 
 face Z W is not able to fupport 352 pound, but only 300, 
 which I prove thus. If 68 foot Main 400, then 51 
 foot muft Main 300. I fay 68, and not 34, becaufe as 
 was noted, thePreflure of the Air upon the furface IK, 
 is equivalent to other 34 foot: and therefore though 
 the deepnefs of this Water, between IK and L M be but 
 34 foot really, yet it is 68 foot virtually, and ineffeft. 
 Imagine fecondly the furface IK to lubfide 17 foot, name¬ 
 ly to ZW. In this cafe the union is broken alfo, and the 
 lower Plain falls from the upper. The reafon of this, is 
 the fame with the former 5 becaufe by what proportion 
 you diminifh the bight of the fuperior Water, by that 
 
%yp?ofta ttcal eypettoiew t& n$ 
 
 fame proportion you diminifh the upward Preffure of the 
 lower VVater. Therefore, if you fubtraft from the fu- 
 perior Water 17 foot, that weighs 100 pound,you fub- 
 tratt Ukewife 100 pound from the inferior Water, and 
 confequently, you make it prefs- up. only with 300, but 
 300 is not able to counterpoife 352, 
 
 Xet us fuppofe thirdly, the fuperior Plain , and the fu- 
 perior Water to be annihilated 5 then I fay , the Preffure 
 and force of the.under Water would thruft up the inferior 
 Plain and the weight R. about eight foot higher then X Y 
 and there fufpend them. The reafon is, hecaufethe fur- 
 face X Y, being able to fuftain 400, and being burdened 
 only with 352, muft have the weight of 48. Now 
 the upper Plain being taken away, and the upper Water 
 alfo, and the empty fpace of both remaining,•the faid 
 weight of 48 pound, muft carry the under slain as high as 
 is faid. Let us fuppofe fourthly, the Preffure of the Ele¬ 
 ment of Air, that refts upon IX, to be taken away, then 
 muft the two Plain bodies be difunited, the inferior falling 
 from the fuperior. The reafon is, becaufe in this cafe, 
 the fuperior Water would have but the weight of 200 
 pound, and confequently the inferior, would prefs up only 
 .with as much .-but 200 is not able to counterpoife 3 j.2. 
 From what is faid we fee iiift , that in all Fluids there is 
 an upward Preffure, as well as a downward and that the 
 .one is al wayes of equal force to the other: becaufe the in* 
 lerior Plain is prefled up with as great force , asthefupe- 
 rior Plain is preffed down with. We fee fecondly, that 
 •in Fluids, there is a Pondus and a Potentia. The Potenti* 
 here is the inferior Water, and the Pondus is .the fuperi¬ 
 or. Or, the 350 pound of Lead R, may be called r he 
 Pondus^ which counterpoifeth the Potential the fur face 
 P of- 
 
H4 ^pt&oSatfcal experiments* 
 
 of Water X Y. We fee thirdly, that though the Pref. 
 fare of a Fluid, be not the fame thing with the natural 
 weight, yet it is equivalent to it: becaufe the 3 5 2 pound 
 of Lead R , is fuftained by the Preffure of the inferior 
 Water, which could not be, unlefs they were virtually 
 the fame. We fee fourthly, that there may be as much 
 Preffure in one foot oi Water, as there is weight in ioo, or 
 in 1000 foot, or in 1000 fathom, For put the cafe, thefe 
 two plain bodies were fufpended, 100 fathom below the 
 furface of the fea, and within a foot or two of the ground, 
 as much weight would be required to pull them afunder,as is 
 the weight oi a Pillar of Water x 00 fathom high, and 4 
 inches thick everyway, which will be more then 3000 
 pound weight, befides the weight of the Air above, that 
 will weigh 200 pound. This could not be, unlefs there 
 were ssYnuch preffure in the Ioweft foot of this Water, 
 that’s ico fathom deep, as there is weight in the whole 
 Pillar above. We fee fifthly, the more the potmia of a 
 furiace is burdened, the more fenfible is the ponhs : 
 becaufe the heavier you make the Lead R, that burdens 
 the inferior Water, the more weight of the fuperior Wa¬ 
 ter refts upon the Beam, We fee fixthly, the more un« 
 equally a body is prefled, the more the Preffure is fenfible* 
 For undemanding this, confider that the under-face of the 
 fupeko : Plain, is more and lefs prefled, according to the 
 more and lefs weight the Lead R is of: for put the cafe, 
 the inferior Plain were taken away, the face of the fuperior 
 Plain, would be equally preft with the back of it. But 
 when the inferior Plain is united to it, the Preffure of the 
 Water is kept off * by which means the back is preft more 
 than the face. Kow, as the inferior plain becomes hea¬ 
 vier and heavier, by making the weight R more and more 
 weighty, 
 
%pD;ofla t(cal c^pecimen tg. n$ 
 
 weighty, the lels and lefs is the face of the fuperior Plain 
 preft up. Hence it is, that as this inequality of PrdTurc 
 becomes greater and greater; fo the weight of the fuperi¬ 
 or Water, affefts the Beam more and more. Or, if the 
 fuperior Plain were a feufible body, as Animals are, it 
 would find the back of it more and more burdened, accor¬ 
 ding as the weight R, becomes heavier and heavier. We 
 fee feventhly, that Water weighs in Water: becaufeall 
 the weight the Beam fupports, is the burden of the fupe¬ 
 rior Water, and not the burden of the inferior Plain, or 
 of the weight R- It fupports the weight alfo of the fupe. 
 rior Plain, but this is not confiderable, This is only to be 
 underftood, when the Preffure is unequal ; for if the up¬ 
 per Plain were as much preft up, as it’s preft down, the 
 weight of the fuperior Water would not be found by the 
 Beam, We fee eighthly, that the higher a furface'be, it 
 is the weaker ? and the lower it be, it is the ftronger: be- 
 caufe when the two plain bodies are pulled up,i 7 foot,they 
 fall afunder. We fee ninthly, the vanity of the common 
 opinion,, that maintains two plain bodies to cleave clofs to¬ 
 gether for fear of <; vacuity ; and that neither Humane nor 
 Angelick ftrength is able to break this union, without the 
 rupture and fradure of them both. 
 
 It may be enquired, upon fuppofition, that the inferior. 
 flain had four holes cut thorowthe middle, fquare-wife, 
 as ABCD in the 18Figure, what Phenomena would 
 follow ? Before I anfwer,confider that this Figure repre- 
 fents the inner face of the Brafs-plate C D N O, of the 
 17 Figure, which as was fuppofed, is four inches from fide 
 to fide,and confequently contains 1 6 fquare inches. Now, 
 imagine the under flain CDN 0 , while it- is united to 
 the uppermoft, to have four fquareinchescut redout of it, 
 
u 6 j i^tyoftatfcai experiments* 
 
 as A B C D. Thefe things being rightly conceived, and' 
 nnderftood, I fay, when the faid holes are cutted thorow, 
 the beam T V, that now fuftains 350 pound, (hall by this 1 
 means, only fufbin 250 pound. T0 make this evident, 
 confider tbit the under plain (as was faid; contains 16 
 fquare inches. Next,that the top of the inferior Wate* 
 upon which the plain refts, contains as many,and that every 
 inch of the Water weighs 25 pound, feing the whole, as 
 was fuppofed before, weighs 400 pound. Now, I fay,the- 
 beam muft fupport only 250 pound of the Water IK L M ? 
 becaufe, thefe holes being made, the top of the inferior 
 Water comes through them,and preffeth up the face of the ■ 
 fuperior plain with 100 pound, and fo eafeth the beam oh 
 fomuch. I affirm next, that though the inferior Water 
 N 0 PQJ>e in it felf 400 pound , andconfequently able 
 to fupport the inferior plain } with the weight R, albeit 
 they weighed fo much , yet the faid holes being cut out, 
 itisnot able to fupport more burden than'300. The rea- 1 
 fonis, becaufe of 16 parts that did a&ually bear up be¬ 
 fore,there are only 12 now that fuftains. And every one 
 of thefe twelve, being but able to fupport 25 pound, it 
 neceffatily follows, that the greateft weight they are able 
 to fuftain, is 300 pound. I affirm thirdly, thatif a fifth 
 hole were cut through, the under plain would fall from the 
 upper ; becaufe in this cafe, the inferior Water is not able 
 to fupport 350 pound as before, feing of 1 6 parts, there 
 are five wanting,and eleven remaining,cannot fupport more 
 weightthan 275 pound. Moe queftions of this kind might 
 be propofed 5 as firft, what would come to pafs/ if the 
 theupperp/4j»hadas many holes cut through it, anfwer* 
 ing to the four of the nether ? Secondly, what would fol- 
 cw,if the Qether plain were intire, and four bored through 
 
 the 
 
i^ojoftattcai eypertm entsi 117 
 
 the upper ? But I-fliatl fuperfede' and leave thefe to be 
 gathered by the judicious Reader. 
 
 From this Experiment we fee firft, that the broader and 
 larger a furface of a Fluid be, it’s the more able to fuftain a 
 burden,- and the narrower it be, ’cis the lefs able. Second¬ 
 ly, that each part of a furface, is able to fuftainfo much 
 weight, and no more, and no Iefs. 
 
 Before I put a clofe to this Experiment, it will be need¬ 
 ful' to anfwer an obje&ion, propofed by Dotfor More in his 
 Antidote again ft Atheijm , againft the Prelfuve of the Air, 
 which in effeft militats, by parity of reafon , againft the 
 Preflure of the Water likewife.. Hearguesthus. Ifthe 
 Air were indowed with fo much Preflure, as is commonly 
 affirmed, then it ought to comprefs,fqueez,or ftrain toge¬ 
 ther, any foft body that it environs, as, v.g. Butter. Put 
 the cafe then,there were a piece of nutter, four inches broad 
 every way, and one inch thick, containing 1 6 fquare 
 inches, upon every fide $ as may be reprefented by the 
 Figure ip. In this cafe, there is a far greater Preflure, 
 upon the two faces, than upon the four edges 5 and there¬ 
 fore, it ought to be compreft, and ftrained together, to 
 the thinnefs of a fheet of Paper. For anfwer, let us fup- 
 pofe the piece of Butter^ to be 30 or 40 foot below the 
 furface of a Water, where it ought to fuffer far more Pref- 
 fure, than above in theAir. Next, that it lies Horizon¬ 
 tal with one face upward, and the other downward. 
 Thirdly, that the upper face fupports a Pillar of Water 
 200 pound weight, and confequently,' that the under face 
 is preft up with as much. And laftly, that every edge is 
 burdened with 50. It may be reprefented, with the help 
 of the fancy, in the 19 Figure, where A B is a piece of 
 Butter four inches fquare, and one inch thick. Only take 
 
 notice, 
 
n8 eai Cicperttmnts* . 
 
 notice, that nothing here is reprefented to the fight, fave 
 one of the four edges, namely A B; the other three, and 
 the two faces being left to the fancy : Yet, the upper face 
 may be reprefented by F H K M, and the under by N 0 
 P Thefe things being rightly underftood, it is won¬ 
 
 dered, why the two great and heavy Pillars of Water, the 
 one E GIL F H K M, that prefleth downward, and the 
 other NOP Q.R S T V , that prefTeth upward, do not 
 Train together the fides of the Butter ■ feing the Prefliire 
 of the Water B C , and the Prefiure of the Water 
 U A, are far inferior to them for ftrength, even by as 
 much difference, as four exceeds one. Though this ob¬ 
 jection feem fomewhat, yet it is really nothing, which 
 I make evident after this manner. Fi:ft, I grant that 
 the upper face FHKM is burdened, with 200pound, 
 and the nether face NOPCf with as much. Secondly, 
 that the edge B, is only burdened, with 5c pound, as is the. 
 edge A, The other tw r o edges, fuftains each one, as 
 much. Secondly, though this be, yet I affirm'the two 
 fides to be no more burdened, than the edges: that’s 
 to fay, the Preffure upon the fides, is equal to the Pref- 
 fureupon the edges, which I prove thus. The Prefiure 
 upon the part M, is equal to the Prefiure upon the part K, 
 but the Prefiure upon the edge B, is equal to the Prefliire 
 upon the part M : therefore the Prefiure upon B, is equal 
 to the Prefiure upon K. The major Propofition is evident, 
 becaufe the Pillar of Water LM, is of the fame weight, 
 with the Pillar of Water IK. The Minor is alfo evident, 
 becaufe, the Pillar B C, is of the fame weight, with the 
 Pillar L M. Now, if the Prefiure upon the edge B, be 
 equal to the Prefiure upon M and K, it mufi be likewife 
 equal to the Prefiure upon H and F. If this be, then the 
 
tpn?oeaticalC]cpenmcnt 0 4 119 
 
 edge of the Butter B, muft be no more preft, than the fide 
 F H K M : therefore the Water B C, can no more yeeld 
 to the Water E F G HIK L M, and fuffer the Batter to j 
 be fqueezed out at B, than the V'Vater L M, can yeeld to | 
 the Water E F G HIK, and fuffer the Butter to be i 
 fqueezed out at M, If any man fhall infill and fay, that; 
 the upper face bears the weight of four Pillars, which;', 
 weighs 400 pound $ but the edge B is only buidened with j 
 50: therefore 50 ought to yeeld to 400, I anlwer, ac-j 
 cording to the 29 T heorem, namely, that a t bicker Pillar 
 of a Fluid is not able to prels, or move a f:,;derer , unlefs j 
 there be an unequal Preffure, therefore";.'^ thick Pillar, 
 that preffeth the face, cannot move the feeder Pillar, that; 
 prefleth the edge: but there is here no mi equal Preffure,: 
 feing the Water X Y L V, is of the fame night with the! 
 fourPillais that rejfts upon the face of the Butur. _ T gran* ' 
 if the faid Water were not fo high, as the other is, by 
 one half 5 then fufely the Butter would be fqueezed out a • 
 
 B; becaufe the fhorter a Pillar be, the lefs Preffure is in tfc. 
 furface under it ; therefore, there muft be lefs Preffure, ; 
 cording to that fuppofition in the Water B C,then now j- 
 Or put the cafe, the Pillar IK were fhorter then GH, 0: 
 L M, the fame effefl would follow, namely, a fqueezing 
 out of the Butter from K. Or, let us fuppofe the Pillar I 
 If, to be higher than G H or L M. In fuch a cafe, the 
 weight of the faid Pillar would prefs through the Butter. 
 
 From what is faid, we fhall only inferr this conclufion, 
 that equality of hight between Pillars of a Fluid makes e- 
 qual Preffure, and inequality of hight makes unequal Pref- j 
 fine. Therefore ’tis no matter, whethei they be grofs or i 
 fmall, thick or flender, provided they be all of the 
 
 flmeAltitul,e ' . EXPE:.' 
 
II illliilMlti |!1! : . , .ihAui 
 
^pmoSattcai £Epet:fmrnt& 
 
 EXPERIMENT XIV- 
 
 Figure 20, 
 
 T H:s Scnematifm reprefents a Veffel full of Water 
 8 foot deep, E F is a Glafs-Pipe, open at both 
 ends,about $> foot highland one inch in Diameter. ABC 
 D is a Veffel oi Giafs,or of any other metal, thorow whofe 
 orifice above, the laid Pipe comes down. B H I is a Pipe 
 go : ng out from the faid Veflel, crooked with a right angle 
 at H, that the orifice I may look upwards. That fomc 
 Hjdroftitic.il conclufions may be inferred from this Expe¬ 
 riment, fill the lower Veffel ABCD withQuick.filver 
 almoft •. then pour in as much Water above it, as will 
 fill the fpace AB H, leaving from H to I full of Air, 
 Nest, thi uft down the orifice of the Pipe E, below the 
 Paid Water and Mercury, till it reft upon the bottom C D. 
 Laftly, ftopwell with cement the paffageof the lower 
 Veffel, through which the Pipe came down, that neither 
 Air nor Water may go out, or come in. Thefe things 
 being done, let down this Engine to the bottom of the 
 large Veflel, which, as was noted, is full of Water from 
 M N to K L, 8 foot, and you will find the Mercury 
 to rife in the Pipe from A B to G, 6 inches, and more. 
 The reafon is, becaufe there is a Pillar of Water K I,that 
 enters the orifice I, and preffeth down the Air, from I to 
 P, 3 inches, which before was 6 , This Air being fo bur¬ 
 dened; inftantly prefleth forward the Water HB A: 
 and this p retting the furface of the ftagnant Mercury AB, 
 caufes the liquor run up the Pipe from A B to G, inches; 
 The reafon, why it rifech <5 inches, is this; between the 
 furiace of the ftagnant Mercury A B, and the top of the 
 
 water 
 
s^moftattca! experiments 1*1 
 
 ■Water LOK, are 84 inches. How Water being 14 
 times naturally lighter then Mercury, there muftbe 14 
 inches of Water, required for fuftaining one inch of Mer¬ 
 cury, and confequently 84, for fupporting 6 , Fora 
 fecond trial, lift up the whole Engine to the top of the 
 Water, and you will find the 6 inches of Mercury BG 
 fink down, and become no higher within the Pipe, than 
 the furface of the ftagnant Mercury A B without. The 
 reafon is, becaufe by coming up above the Water, the 
 PrelTure of the Water K I, is taken away from the orifice 
 I, by which means the compreft Air H P, extending it 
 felf to I, liberats the Water A B H of the Preflure it had, 
 and this freeth the Mercury of its Preflure, and fo the 6 
 inches falls down. For a third trial, flop clofely the ori¬ 
 fice I, and let all down as before; In this cafe , you 
 will find no afeent of Mercury from B to G: be- 
 taufe the Water K I cannot have accefs to thruft 
 down the Air from I to P , as formerly. 
 
 Fora fourth,open the faid orifice I,while the Engine is 
 below the Water, and you will find the Mercury rife from. 
 B to G: becaufe the Pillar of Water K I, hath now accefs 
 to prefs. For a fifth trial,flop the orifice I, and bring up 
 all to the top, and you will find the fix inches of Mercury 
 BG fufpended , as if the Engine were under the Water, 
 The reafon is,becaufe the flopping of t he orifice, keeps t he 
 inclofed Air P, H , under the fame degree of Preflure it 
 obtained from the Water KI. Forafixth proof, open 
 the fame orifice I, while the Engine is above the Wa¬ 
 ter , and you will find the fix inches of Mercury fall down, 
 becaufe tlie imprifoned Air H P, obtains now its liberty; 
 and expanding it felf from H to I, eafes the Water BH 
 cl the burden it was under. For a feventh, pour in 14 
 
 inches 
 
iii ^ojoftattcai €£ptrtment0* 
 
 inches of Water at the orifice F, till it reft upon the top ■ 
 of the Mercury at G, and you will find one inch fall 
 down. Pout in as much, and two inches falls down. In . 
 a word, pour in as much Water,as will fill the Pipe to 0 , - 
 and you will find the whole fix inches fall down.' The 
 reafon is } becaufe the Water K If is not able to fuftain, 
 both the fix inches of Mercury and the Water, that’s 
 poured in 5 any one of them being able and fufficient to 
 counterpoife it, . For an eighth trial, empty the Pipe of 
 the laid Water, and after the Mercury is afcended from 
 ABtoG, as formcily , Turk out the whole Air between 
 G and F, and you wdl find the Mercury to rife from G to 
 R 29 inches. The-reafon of this is evident from the 
 Pillar of Air S K , thitrefts upon the top of the Pillar of 
 Water KI: for by fucking out the Fid Air, you take 
 away thepWar or weight, thatcounterpoifed the weight 
 of the Pillar S K , therefore it finding its counterpoife 1 
 removed, prefently caufeth the Water KI,-to enter 
 faraer within the crooked Pipe, till it hath preft up the 
 liquor to R. For a ninth trial, take the fix inches of 
 Mercury B G, and put them into the fcale of a ballance . 
 then take as much Water, as will fill the Tub between 
 A B and 0, and put it intp the other fcale, and you 
 will find a moft exa<ft counterbalance between them. 
 The reafon is, becaufe if the Water KH, or a Pillar of 
 that hight, be able to raife and counterpoife the Mercury 
 B G- then muft as much Water, as fills the Pipe 
 betwen B and 0 , be the juft weight of it. The reafon of 
 this conlequence is, becaufe thefe two Waters are of the 
 fame weight : therefore, if the one be the juft weight of 
 it, the other muft be fo too. If it be faid, that the 
 Water, that ps the Pipe between B and 0 , is far 
 
 thicker. 
 
Wjoftattoal $jcp.ttf mtnt& n$ 
 
 thicker, then the Water KH 5 therefore they cannot be 
 both of one weight, I anfvver, equality of altitude, in this 
 Ballance of Nature , is equality of weight : therefore, 
 feing the one Water, is as high as the other, theymuft 
 be both of one weight. If it be faid, that a Pillar of 
 Water between K and H, cannot counterpoife the fix 
 inches of Mercury BG, both being put into aballance .* 
 and the reafon is, becaufe the one is thicker than the other. 
 Ianfwer. this only proves that two Pillars differing in 
 weight in the Libra or Artificial Ballance, may be ofone 
 weight in the Natural Ballance : becaufe in the Artificial 
 Ballance, bodies counterpoife one another, according to 
 all their dimenfions, but in the Natural Ballance, fuchas 
 this Engine is, Fluids counterpoife one another, accord¬ 
 ing to their altitude only. 
 
 From the firft trial, we conclude firft , that Water 
 even in its own place gravitate and weighs , becaufe this 
 Water by its Preffure, de facto thrufts up 6 inches of 
 Mercury. We fee in the next place , that the Preffure of 
 a Fluid, is as eafily communicated Horizontally, as Perpen¬ 
 dicularly * becaufe the Preffure runs alongft from H to B. 
 We fee thirdly, that Fluids, may have as much Preffure 
 begotten in them, even while they are environed about 
 -clofely with folid bodies, whereby the fuperior Preffure, 
 immediatly and dire&ly by perpendicular lines is keeped 
 off, as if they were immediatly under the Preffure: becaufe 
 the Mercury A B C D, is as much burdened with the 
 P.elfu.e, that comes from H, as if the upper part of the 
 Veffel AB, were open to let in the fuperior Preffure, by 
 perpendicular lines. T he Air then under the roof of a houle, 
 is under as great a Benfil and Preffure, as the Air without, 
 that’s dire&ly under the Preffure of the- Atmofpher*. 
 
 0^2 VVe 
 
ii4 Wioitaticai experiments* 
 
 We fee fourthly, that'the Preflareofa Fluid, may be as 
 eafily communicated thorow the pu ts of Heterogeneous 
 Fluids, as thorow the parts of Homogeneous ; becaufe the 
 Preffure of the Water KI, is as eafily communicated 
 thorow the Air PH, thorow the Water H B, and tho¬ 
 row the ftsgnant - Mercit-y BD to the orifice E, as if 
 nothing interveened but Water. We fee fifthly, that 
 Mercury can fuffer a Preffure, as well as Water or Air ; 
 becaufe the fix inches cannot rile from B to G, unlefs the 
 flagnant Mercury AB C D were comprefsed, even in 
 alhhe parts of it. 
 
 From the fecond trial, we fee, that there cannot be a 
 Pondus in a Raid, unlefs there be a Potent ia, to counter- 
 poife it: for when you take away the Water R I, by 
 lifting up the Engine to the top of the Water, the Mer¬ 
 cury B G' prefently falls down* From the third trial, we 
 conclude, that the Preffure of a Fluid, cannot be commit 
 nicated thorow folid Bodies: for when the Engine is 
 drowned below the Waterwith the orifice I, flopped, 1 
 no afeent of Mercury follows. We conclude from the 
 fourth trial, that it is impoffible for two Fluids to coun^ 
 rerpoife one another, unlefs they be in Equilibria-, becaufe 
 the Water KI cannot fuftain-the Mercury BG, unlefs 
 it be ot the fame weight. From the fifth,we conclude, that 
 a Fluid may be keeped under the fame degree of compref- 
 fion, after the fuperior weight that begat it, is taken 
 away: for after the Engine is brought above the Water, 
 wrth the orifice I flopped, the Mercury B G is ftill fuf- 
 pended, even by vertue of the Preffure, that’s in the flag¬ 
 rant Mercury. This tells us, that a fphere of glafs full of 
 Air, may retain its Benfil , even though the whole Ele¬ 
 ment of Air , that begat it, were deftrfyed. From the 
 
t?p djoftattcat ex perimen ts, ny 
 
 fixth we gather, that a Fluid cannot abide under Prcfliire, 
 when the burden is taken away that begat it, or that keep* 
 ed it under Preflure: for by opening the orifice I, the 
 Air P H extends it felf: and fo are the Water, and Mer¬ 
 ely within the VeiTel freed of their Prefture likewife. 
 We gather from the feventh trial, thac in the Ballanceoi 
 Nature, one Scale cannot be more burdened then another; 
 or that two Fluids cannot counterpoife one another, un- 
 lefs they be in equilibria : for when you pout in 14. 
 inches of Water, upon the top of the Mercury at G, they . 
 thruft down one inch, that there may be a equipon- 
 dium, bet ween them,and the oppofite weight K I. We ga¬ 
 ther from the eighth trial, which was obferved before 5 
 firft,that there cannot be a Patentia in a Fluid, unlefs there 
 be a Pondus to counterpoife it .*■ for when you fuck out the 
 Air G O , which was the Pondus , that counterpoifed the 
 Air S K, this prefently in ftead of it, raifeth 29 inches of 
 Mercury from G to R. We fee fecondly, that one pil¬ 
 lar of Air can counterpoife another, Fluids’ of diverfe kinds 
 interveening: becaufe the Air S K, counterpoifestheAir 
 within the PipeG 0 , theWater K Pfirft interveening- 
 the Air P H next interveening, and the ftagnant, and 
 fufpended Mercury interveening alfo. We fee thirdly from 
 this eighth trial, that thePreffureof the Atmofthcre, may 
 be communicated thorow diverfe kinds of Fluids, without 
 the leaft diminution of its weight: becaufe the weight of 
 the Pillar of Air S K, is communicated, and fent down 
 thorow the Water K I, thorow the Air P H, thorow the 
 Water H B, thorow the ftagnant Mercury BD,' and up 
 tkorow the fufpended Mercury B G, till it fufpend the 
 2.9 inches between G and R, which is the juft counter- 
 ballance of it, We fee moreover, that Fluids counter- 
 
 poife 
 
- 32.6 gy^oftattcaieyperimentfli* 
 
 poife one another, according to altitude only, and not 
 according to thichefs and breadth •, by comparing the Wa¬ 
 ter K I, that’s but half an inch thick, to'the Mercury B G, 
 that’s a whole inch thick. We fee from the laft trial, that 
 when a Fluid is necefficated , to counterpoife a Fluid of 
 another kind, in ftead of a Fluid of its own kind, it fuftains 
 no more of it, than what is the juft weight of the Fluid of 
 its own kind, becaufe the Water K I, being under a 
 neceffity to counterpoife the Mercury B G, in ftead of fo 
 much Water as would fill the Tub, it fuftains no more of 
 it, than the juft weight of fo much Water, as is faid, 
 Weleefecondly, that when two Fluids of divers kinds, 
 do counterpoife one another, that which is heavieft in 
 flecie, hathalwayesthefliorteftCylinder. Next, that 
 the difference between their altitudes, is moft exadtly ac¬ 
 cording to the difference between their natural weights, 
 therefore B G is 14 times lower than B O 5 becaufe Mer* 
 cury is 14 times heavier than Water. We Tee moreover, 
 tha"t though two Cylinders of a Fluid, can counterpoife 
 one another in the Natural Ballance , fuch as this Engine 
 Is, yet they will not do it in the Artificial Ballance : be¬ 
 caufe though B G counterpoife KI in this Ballance, yet in 
 a pair of Scales, the Mercury will be as heavy again as the 
 Water. We fee laftly, that notwithftanding of this, 
 yet fuch a thing may be ; for if the o.ifice I, were made as 
 wide as the orifice F,that the Cylinder KI might be equal 
 to the Mercury B G in thicknefs, then furely the one 
 would counterpoife the other in the libra or Artifi¬ 
 cial Ballance. 
 
 EXPE- 
 
$yDjoftat<cal ^jcperimentsu 127 
 
 EXPERIMENT XV- 
 
 Figure a 1. 
 
 T HisSchematifm reprefentsa Water 72 foot deep, as 
 C D A B, together with a crooked Pipe ofglafs IN 
 H,the one half whereof is IP, 56incheshigh,andoneindi 
 wide, the other half is P N R H, of a far narrower diarne* 
 ter,with an orifice H. There is alfo an orifice at L, with 
 a neck, about which is knit a fmall chord M L, for letting 
 down this Engine to the bottom of the-V Vater A B. For 
 trials caufe, fill the wide glafs with Mercury from P to K; 
 and you will find it rife in the nagow Pipe, as high as the 
 orifice H. This being done, clofe hermetically, or with 
 good cement the orifice L ; then by help of this chord, 
 let all go down from the furface C D, till it be exaftly 17 
 foot from the top, and you will find the Mercury thruft 
 down in the narrow Pipe, from H to R, 14 inches and an 
 half. Let it down next, as much, and the Mercury will be 
 yet further thruft down, namely from R to N, the part H 
 RN being full of Water. For underftandmg the reafon 
 of this, confidei that between N and E, are 54 foot .• for 
 fo high is the'flender Pillar of Water, that comes from the 
 top,and entring the orifice H,comes dpwn thorow the Pipe 
 to N.Confider-next,that between the faid Pillar of Water, 
 and the Mercury N P K, there is a counterpoife: but this 
 counterpoife cannot be, unlefs the Pillar of Water be 54 
 foot high, feing between N and K are 2p inches of Mer¬ 
 cury 5 for each inch thereof requires 14 of Water. Upon 
 this account it is, that when the glafs is 17 foot drowned,14 
 inches and an half are thruft down from H to R. If it be 
 obje&ed, that the Prejjure and Benftl of the indofed Air 
 
 IK-, 
 
u8 %po?o Sattcal cjcpetmi ents* 
 
 IK; is equivalent to the weight of other 29 inches * and 
 therefore the Pillar of Water E H RN, muft be 68 foot 
 high,before a counterpoife can happen. I anfwer/tis true 
 that’s Paid, but you do not confider, that there is a Pillar of 
 Air F E, refling upon the top of the Pillar of Water, that 
 makes a compenfation exa&ly. T o fpeak then truely and 
 really, the.29 inches of Mercury N P K, have the weight 
 of 58 inches • and the 34 foot of Water E H R N, have 
 the weight of 68 foot. 
 
 For a third trial,let down the glafs 6 foot further,and you 
 wdl find the Water pierce up thorow the thick Cylinder of 
 Mercury PK, and reft upon the top K. Theonly diffi¬ 
 culty is*to determine, how much will fpring up before the 
 motion of it ceafeC ’Tistvident, that the Water will af- 
 cend, be.caufe coming to the Eafe of a thick and grofs Cy¬ 
 linder, that it cannot intirely lift, it muft pierce thorow it, 
 feing the force of fuch a Pillar of Water, is now much 
 ftronger, than the Mercury: forineffedt, the glafs being 
 drowned 6 foot further, the Pillar that comes down thorow 
 the {lender Pipe, hath, the juft weight of 34 inches of Mer¬ 
 cury : but 29 cannot refift 34: therefore the Water not 
 being able to lift it, by reafon of the difproportion that’s 
 between the thicknefs of the one,and the flendernefs of the 
 other, it muft pierce up thorow it. For clearing this diffi¬ 
 culty , confider, that this glafs cannot go down from one 
 imaginary lurface to another, v.g, from 34 foot, where it 
 was^ till it come to 40, where it now flanJs,but there muft 
 be an alteration in the cquifondimn^ feing by going down, 
 the Pillar of Water E H R N grows h'gher, and confe- 
 quently heavier ; and therefore, fome Water muft pierce 
 up thorow the Mercury, for making a counterpoife 5 for 
 ’tis impoffible for two Fluids to counterpoife one another, 
 
 unlefs 
 
$pfyQftatical experiments* 129 
 
 unlefs they be in equilibria, -Confider fecondly, thataftet 
 the Water is come to the top of the Mercury at K, it will 
 find difficulty to find a room for it felf, feing the fpace be¬ 
 tween S and I is lull of Air. Notwithftanding of this, it 
 muff afeend. I fay then,after the glafs is gone down from 
 34, to 40 foot, there will be about four inches of Wa¬ 
 ter above K, which have reduced the 2 9 inches of Air 
 KI, to 25, SI. 
 
 If it be asked, between what two things is th iequipn- 
 ctinwnovr! Ianfwer, the firft was at R, between E HR, 
 andRNPK. Thefeeond was at R, between NR HE, 
 and NPK. The third is now at S, between the 2 5 inches 
 of inclofed Air IS, as one Antagonift, and the four inches 
 of Water S K, with the 2 9 inches of MercuryK P, and 
 the Water PNRHE, as the other. To make a fourth 
 eqnifondinm, fink the Glafs other fix foot, till it be 46 
 foot from the top C D , then muft fome more Water 
 fpring up thorow the Mercury =, this of necefficy muft be, 
 feing the Cylinder of Water N R H E, isfix foot higher, 
 and lo far heavier, than it was: if this be, then muft the 
 2 j inches of Air IS, be reduced to lefs quantity; feing ’cis 
 impoffible, for one Eluid to become heavier, -unlefs its 
 oppofite and antagonift become heavier too, for an cqni- 
 fondiutns fake. Note, that the Air IS, will nor lofe 
 ocher four inches, with this fix foot of Water, as it did 
 with the former. Tbereafon is, becaufe, if for every fix 
 foot the Glafs goeth down, the Air were compreft four 
 inches, it were eafie at laft to reduce it to nothing: for if 
 fix reduce it to four, and 12 to eight, 38 ought to reduce 
 it to no inches, \\hich is impoffible. Therefore I judge it 
 muft fuffer compreflion, by a certain proportion, as we 
 fee upon a Scale, the divifions of Artificial or Natural 
 R Sines 
 
i$o ^Djoftaticai $Epetmutit 0 « 
 
 Situs grow lefs and lefs, there being more fpace between 
 i and a, than between 2 and 3 •, more between 2 and 3, 
 than between 3 and 4, and fo upward till you come to 90, 
 Therefore the iecond fix foot, muft reduce the 25 inches, 
 not to 2i j but to 23 cirri! er, and fo forth. By the which 
 means, though the Glafs fhould go down ininfimtam^ yet 
 the Air ihali never be reduced to nothing, and there fhall 
 frill fome (mall quantity of Water come up. Or in fuch 
 a cafe, the Air may be fo compieft, that it can be no more, 
 all the di([e,r.inate vacuities being expelled. But fuppofe 
 this to be at 1000 fathom, then at 1500, where the Pref- 
 fure is ftronger, there can be no 'quifondtum^ which is ab- 
 furd, for where the fondtss becomes ftronger, the potenti.i 
 ought to grow ftronger likewife, I anfwer, the motion of 
 eondenfatlon ceafeth indeed; but there (till remains a po~ 
 ientia , or rather in fuch a cafe, a perfedl refi(lentia } where¬ 
 by the Air is able to refift the greateft tveight imaginable, 
 before it can be reduced to nothing, or fuffer a penetration 
 of parts, that’s to fay, two parts to be in one fpace. 
 
 Prom the explication of thefe Phenomena we conclude 
 firft, that in Water there is a confiderable PrelTme , feing 
 inletting down the Glafs 17 foot, the Mercury is preft 
 down from H to R, and from RtoN, in going down 
 other 17 foot. Secondly, that 2 9 inches of Mercury are 
 as heavy as 34 foot of Water.- becaufe the Mercury K 
 P N makes a juft equifondinmmth. theVVater EHRN, 
 Thirdly, that Fluids not only ol the ftme kind, but of 
 different kinds, do counterpoife one another according to 
 altitude , and not accoraing to tkicknefs ; becaufe though 
 the Mercury K P N be far thicker, than the Water E 
 yet they counterballance one another, becaufe a proporti¬ 
 on is kepi according to their altitudes,. Fourthly, that a 
 
i^r^oftattcai expert ment** 131 
 
 Fluid naturally lighter, may move a Fluid naturally heavi¬ 
 er, and thruft it out of its own place, becaufe the Water 
 coming in at H, thrufts down the Mercury to R, and from 
 R to N, andfo forth. Fifthly, that of two Fluids un¬ 
 equal inftrength, debating together, the weaker of ne- 
 ceflhymuftyeeld to the ftronger, though the weaker be 
 far heavier naturally than the ftronger, as is evident in the 
 Mercury, that yeelds to the Water. Sixthly, that it is 
 impoflible for two Fluids, fo lon° as they are unequal in 
 ftrength, to ceafe from motion, till they come to an equi- 
 fondium • becaufe the Water ahvayes fpringsup thorow 
 the Mercury, till an equal Ballance happen. Seventhly, 
 that one Fluid of this kind, can counterpoife another Fluid 
 of the fame kind, though there be divers Fluids interveen- 
 ing: becaufe the Air F E, counterpoifeth the Air IK, or 
 IS, notwichftanding of Water and Mercury interveening. 
 Eighthly, that there may be as much Preffure in one inch 
 of a Fluid, as in a million ^ becaufe the inches of Air 
 I S,have as much Benfil in them,as is in the whole Pillar of 
 Air E F, that goeth up from the top of the Water, to 
 the top of the Atmofthere, Ninthly, that when one Fluid 
 is under Preffure, the next muff be under the fame degree 
 of Preffure, though they be not of the fame kind, but of 
 different forts ; becaufe the Air IS, the Water S K, and 
 Mercury K P,are furely under the fame degree of Preflure; 
 other wife the motion could not end. Tenthly,that when 
 two Fluids of divers kinds do prefs one another, that which 
 is naturally lighter, afeends alwayes to the higher place,and 
 the heavier to the loweft: becaufe the Air IS, is above 
 the Water S K, and the Water S K is above the Mercury. 
 Note, that this is not univerfal, but only happens when 
 the lighter Cylinder, is flenderer than the other, for if the 
 1 R 2 Mercury 
 
i$i i’pDfoUacical expcauicitts. 
 
 Mercury K P, were no thicker than the Water P N R H> 
 this would raife it. intirely. Eleventhly, that the com- 
 preffion of Air- to lefs fpace, is not according to Arith¬ 
 metical frogrcfsion, r, 2, $> 4, y, but according to fomc 
 other proportion, which may be called Uniform-difform\ 
 Note here, that though this be true of the Air, while it 
 is compreft from a more quantity to a lefs, as here, or in a 
 Wind-Gun ; yet it is not true of the Preffureof the Ele¬ 
 ment of Air, which is more and more from the topof the 
 Jtmofhtre to the Earth , according to Arithmetical Pro• 
 grcfsiothzs in Water. We fee laftly, that the heavieft 
 of Fluids, luch as Mercury, prefs upward, as Well as down* 
 ward; becaufe the top of the Mercury K, thruftsupthe 
 Water K S, as well as it thrufls down the Water P N 
 R H. It may be enquired here, how far this Glafs would 
 go down, before the inches of Air IK were reduced 
 to one inch 1 I anfwer,its hard to determine ; but it feems 
 it ought to go down more than 300 fathom. In this 
 cafe, there would be a 8 inches of. Water above K. Let 
 us fuppofe the orifice H to be flopped at that deepnefs, 
 and the Glafs brought above the Water; then, when the 
 Laid orifice is opened in the Air, you will find the whole 
 VVater PNRH thruftout: and not only this, but the 
 whole Mercury. P K, fpring out at the orifice H like- 
 wife, except a little that remains between N and H: the 
 reafonis, becaufe the 29 inches of Air, being reduced to 
 one,, would be under a very great B enfil ; therefore the 
 weight being taken away that begat it', of its own accord, 
 it would expand it felf to'its old dimenfions; which it 
 could not do, unlefs both the 2 8 inches of Water, that’s 
 fappofed to be above K, and the Mercury KP were, 
 tbiult out of their places,, 
 
 EXPE-, 
 
Wioftatical experiments. 133 
 
 EXPERIMENT XVI- 
 
 Figure 22. 
 
 T His Schematifm reprefents a veil'd full of ’Vvater 84 
 inches deep, namely from L N the firft furface, to 
 M R the bottom, From M to R in breadth are 20 
 inches. T here are here alfo two Glafs-Pipes open at both 
 ends; the one, two inches wide, the other halfan inch 
 wide. Both of them are 85 inches long, X Y 0 is a 
 furface of ftagnant Mercury, among, which the two ends 
 of the Pipes are drowned. EC is a Pillar of Mercury 
 fix inches in height, and fo is GD, both of them raifed to 
 that altitude, by the PrefTure of the Water upon the fur¬ 
 face X Y O. The Pillar E C A is fupported by, and 
 refts upon, the imaginary Pillar A P. And fo is the Pil¬ 
 lar G D B,fupported by the Pillar B There are three 
 
 things that occurres here from this operation of nature to 
 be enquired after. Firft , why ought the Mercury to rife 
 in the two Tubs -, after the Veftel is filled with Water ? 
 Secondly, why rather fix inches-, then feven or eight? 
 T hirdly,what’s thereafon, why it rifes as high in the wide 
 Tab,as in the narrow i Ianfwer, the Mercury rifes from 
 C to E, and from D to G, by the Preflure of the 
 Water, that lefts upon the furface X Y 0 .. Before 
 that the Water is poured into the VefTel, there Is herea 
 m .ft equal and uniform PrefTure upon the furface XYO, 
 both without and within the Tub, namely from the Air 
 that refts upon it. But no fooner is the Water poured in, 
 but as foon the PrefTure becomes unequal •, the parts of 
 the furface without the Tub, being more burdened, then 
 the parts Gaud D within. Therefore, the part that’s 
 
ij4 Ipptttoftaticai ©jcpenments, 
 
 lefspreft, muft rife and climb up, till the Preffure become 
 equal : for it’s impofllble that a Fluid can ceafe bom mo¬ 
 tion, fo long as there is inequality of weight between the 
 pr.diu and the potentia. It any doubt, let him pieice the 
 fide of the Vend, and when the whole Water is run out, 
 he will find EC and GD to have fallen down, which 
 clearly proves the climbing up of the Mercury, to depend 
 upon the in-pouring of the Water. For undemanding 
 the re.ifon of the fecond, remember that Mercury (as we 
 have often noted ) is counted 14 times heavier then Wa¬ 
 tertherefore EC muft be fix inches, feing X YO is 
 p-eft with the altitude of 84 inches of Water. It would 
 be judged no marvel, to fee the Mercury rife from C to E, 
 and from D to G, provided the face of the ftagnant Mer¬ 
 cury were as high as Z F. No more ftrange it is, to fee 
 the two Mercuries rife , with the Preffineof the Water; 
 for in effed and really, the faid Water is the juft weight 
 of as much Mercury as would fill between X O and Z F. 
 For underftanding the third, remember (as was noted be¬ 
 fore) that Fluid Bodies counterpoife one another , only 
 according to altitude : therefore ’tis no matter, whether 
 the Tubs be wide or narrow. If it be enquired, how can 
 one and the fame Water, counterpoife two Fluids of diffe¬ 
 rent weights ? To fay, that Fluids counterpoife one 
 another according to altitude, doth not clear the difficulty; 
 for it ftill remains to be asked, why they countej poife one 
 another after this manner ? Therefore it feems, that if 
 the Water raife the Mercury from C to E in the wide Pipe, 
 it muft raife it in the narrow one from D to K. For 
 anfwer, confider firft, that as there are here two Pillars of 
 Mercury C E, and D G within the two Tubs, fo there 
 are here aifo two Pillars of Mercury A P and B Q.J under 
 
^D?oftat(cal^icpcnment^ w 
 
 the two orifices, upon which the faid two Pillars ftand, 
 and reft. Confider fecondly, that the Potentia or force of 
 the Pillar A P, is juft equal to the Pondus of the Pillar 
 EC A: Item, that the Potentia ol the Pillar BQ, is 
 equal to the Pondus G D B. Thirdly, that the Potentia 
 ol A P. is moft exa&ly equal to the Potentia of B 
 and thereafon is, becaufe their tops A and B , are parts 
 of the fame horizontal furface. I fay then, if AP be 
 equal to E C A, and B Q equal to G D B, and A P, 
 and B Q, equal among themfelves, then muft E C A 
 be equal to G D B. The fame Water then , doth 
 not counterpoife two Bodies of different weight. I grant 
 E C A to be far heavier, than G D B, while they are 
 weighed in a pair of fcales, but the one is not heavier than 
 the other, as they are weighed in this ballance of nature. 
 
 From what is faid , we feefirft , that in Water there 
 is a PrefTure, and a confiderable weight. This is evident- 
 from the rifing of the Mercury. We fee fecondly, that ■ 
 Fluids counterpoife one another, only according to Alti¬ 
 tude, Thirdly,that when a lighter Fluid preffeth up a hea¬ 
 vier, there is no more pi eft up of it, than is the juft weight' 
 of the prefling Fluid, becaufe the Mercury E C , is juft 
 the weight of the Water that preffeth upon XYO, That’s 
 to fay, the part of the furface-C, is no more preft with 
 the Mercury E C , than the part X, is preft with the 
 Water LZX. Fourthly, if Mercury were 28 times 
 heavier than Water, only three inches would bepreft 
 up: if it were but feven times heavier, the altitude would 
 beat S, 12 inches above C. Fifthly, it’s aseafie fora 
 large part of a furface, to fuftain a large Pillar, as ’tis 
 for a narrow part, to fuftain a narrower Pillar: becaufe 
 AP fuftains EC A, aseafily, as BO fuftains GDB, 
 Sixthly, 
 
ij6 i^oftattcal experiments* 
 
 Sixthly, that in Fluids there is a pondm and a potentia as 
 is clear rromth £potentia 6f AP, that Curtains th z pondm 
 of E C A. The Water likewife that Curtains, hath a 
 potentia , 2nd the Mercury E C is the po??dm of it. Se¬ 
 venthly, that there is ahvayes equality of weight between 
 the pondm and the potentia. So is the pettntU of Ap, 
 equal to the pondm E C A. Eighthly, that the pondm 
 begets the potentia, So the weight of the Water, be¬ 
 gets the potentia that’s in AP. For make this Water 
 deeper, and you augment the potentia of A P. If you 
 -fubt:a£ from it, the potentia of AP grows lets by pro¬ 
 portion. Or the weight of E C A, may be faid to beget 
 the potentia of A P. To proceed a little further, let us 
 Cuppofe the Air HE to be removed. In this cafe, the 
 Mercury rifes 29 inches higher than E ,* or 3 5 above C; 
 even as high as S. In the narrow Tub it will climb up to. 
 K,if you take away the Air IG. This comes to pafs, 
 by vertue of the Preflure of the Atmosphere , that refts 
 upon L N. Fronwhis we gather ninthly, that there is 
 a counterpoife between the Air H E, and the weight of 
 the Air that rerts upon LN; and that a {lender Pillar of 
 Art, is able to counterpoife a thicker: for HE is far nar¬ 
 rower than L N. Tenthly, that the Prerture of the Air, 
 can be communicated thorow divers kinds of Fluids 5 be. 
 caufe the weight that refts upon L N, is fent down tho¬ 
 row the VVaster L ZX, and down thorow the fhgnant 
 Mercury,and thrufts up the Liquor from A to S>3 5 inches. 
 Eleventhly, that a lighter Fluid may be made to prefs with 
 greater burden,than a Fluid naturall) heavier-, becaufe the 
 weight of the Air upon L N, raifes 29 inches of Mercu:y, 
 but the Water raifes-oaly fix. We fee twelfthly, that 
 fluids have a fphere of activity, to which they are able te 
 
t^fooftaticai experiments* 137 i 
 
 prefs up themfelves, or Fluids of different kinds: becaufe 
 fii ft, the ftagnant Mercury can raife it felf no higher with¬ 
 in the Pipe, than it is without, Next, the 84 inches of 
 Water, can raife the Mercury no higher than E. Laftly, 
 the weight of the Atmfj)hcre^ can raife the Mercury no 
 higher than S, 2 9 inches above E. j 
 
 ' For another trial, take out from among the Water, the ;; 
 two Pipes, and Hopping clofely the two under orifices, 
 fill them with Mercury to the brim. Then thruft them 
 down as before, and open the faid two orifices, while they 
 are below the furface X Y O, and you will find the whole 
 Cylinder fall down from H to E, and there halt • and the 
 whole Cylinder in the narrow Pipe falls down from I to . 
 G. Or, if youpleafe, before this be done, flop clofely 
 the orifice H, and the orifice I, and you will find the Mer¬ 
 cury go no further down than S, by opening the orifice A; 1 
 and no further down than K, by opening the orifice B. 
 This leads us to a clear difcovery of the reafon, why the 
 Mercury fubfides, and finks down from the top of the Tub 
 in the Barofcopt, to the 2pth inch, whatever the diameter 
 of the Pipe be. And this lets us fee, that the Mercurial 
 Cylinder is fufpended by the Air, after the fame manner, 
 that the Mercury E C is fufpended after: and that there is 
 tio more difficulty in the one, than in the other. 
 
 EXPERIMENT XVII- 
 
 Figure 23, 24. 
 
 T His Schematifm reprefents a Water 30 fathom deep.' 
 
 Under the firft furface A, there are fix imaginary, as 
 B C D E F G. every one whereof, is five fathom below 
 S another, 
 
i$9 i^fijoSaticaiejcpecmients* 
 
 another. There are here likewife two Glaffes, each one 
 12 inches high, and j inches broad, like unto thefe, 
 wherein Wine,Sack, or Brandy is preferved, T he Glafs 
 G M hath its orifice G upward. The other Glafs is com- 
 pieatly open below, without a narrow orifice. For making 
 Experiment, take a long chord, as long as the Water is in 
 ceepneis, and knit the end of it round about the neck of 
 the Glafs atG. Take another line of the fame length, 
 and laden it to the bottom of the other Glafs at L. Next, 
 ibr fiakmg the two Glades, take two weights of Lead, 
 and laden the one to the bottom at M, and the other to 
 the open part or the Glafs at S, and T. The two weights 
 then, are P and Q, each one of them about io or" im¬ 
 pound weight. Thefe things being done, let firddown 
 the Glafs G M, till the weight Cffink ; t fi ve fathom, 
 namely from A to B, and if you pull it up, you will find 
 the bottom covered with Water, from M to I, about four 
 or five inches. Let it down next, from A to C, ten fa¬ 
 thom , and you will find more Water in it • even as much 
 as fills it from M to 2, about feven or eight inches. In 
 pafilng from C D, the Water rifes from 2 to 3, If 
 you fink it, from Dto E, the Water rifes from 3 to 
 4. The Water rifes from 4 to 5 , when the glafs 
 is come the length of F. Analadly, when the Glafslsac 
 G, the lowed fathom, the Water is as high as K, Let 
 down next, the other Glafs from A toB, and you will 
 find the Water rife in it from H to 1, four or five inches, 
 as in the other Glafs, In going down from B to C, it 
 rifes from 1 to 2. From C to D, it riles from 2 
 to. 3. From D to E, it rifes from 3 to 4, and fo for¬ 
 ward , till the Glafs come to the lowed fathom, where 
 the Water rifes as high as I, 
 
 There 
 
gyi»otta«caic|Bptt(mt nt& 
 
 There are here feveral Phenomena to be conficfered. 
 Firft, that the Water creep in at the orifice G, and fills 
 the under part of the Glafs from M to K. Secondly, v that 
 net one particle of Air comes out, all the time the Water 
 is in going in. Thirdly, that this Air is compreft from 
 M to IC, nine inches. Laftly, that the ingrefs of the Wa¬ 
 ter, is according to unequal proportion : becairfe while the 
 Glafs pafieth from AtoB, more Water creeps in at G, 
 and fills the bottom, then in palling from B to C. Ana 
 more in going down from B to G, than in going down 
 from C to D, as is clear from the unequal diyifions i, 2,-. 
 3, 4, 5, 6, For undemanding the reafon of the firfi:re¬ 
 member that in this deep Water, there is a PrelFure, and 
 that this Preflure grows, as the Water grows in deep- 
 nefs, Itisthenbyvertueofthis, that the Water creeps 
 in, and fills the bottom of the Yelfel; forineffea, every 
 part being under a burden, and being therefore defirous to 
 liberat themfelves from it, they take occafion to thruft in. 
 themfelves, finding, as it were, more eafe here, than, 
 without, the Air within the Glafs, being, under lefs Pref- 
 fure, than the Water without. The fecond' Phenomenon 
 is caufed by the ftraitnefs and narrownefs of the holeG: 
 for this entry being no wider, than the thicknefs of a Sack- 
 Needle, the Air cannorgo out, while the Water is com-' 
 ingin 5 that is, thepafiage isfoftrait, that the one can¬ 
 not go by the other. This leads us to the reafon of the 
 third, for if nor one particle of Air go out, all the while 
 the Glafs is in going down, then finely, the VVater fil¬ 
 ling between M and K, muft comprefs the Air, and reduce 
 it from twelve inches to three. But the greater difficulty 
 is, why the ingrefs of the VVater is accordmg.co unequal 
 proportion. For undemanding this, confider, that this 
 . \ S 2 inequality 
 
140 ^ptttoftatical ejectments* 
 
 inequality, is not caufed by any unequal Preffure that’s’ in 
 the Water ; for if this were true, then there ought to be 
 lefs Freflure in the furface F, than in the furface E, and 
 lefs in E, than in D, which is falfe and abiurd. This in¬ 
 equality then, muft flow from the nature of the Air it felf, 
 that naturally fuffers compreffion after fuch a manner. ’ Tis 
 evident from the compreffion of Air in whd-guns ; for 
 lefs force is required to comprefs the fi ft fpan, than to 
 comprefs the fecond: orcontrariwife, more ftrength is re¬ 
 quired, to comprefs the third fpan, than the fecond; 
 more to comprefs the fourth, than the third and fo forth. 
 ’Tis evident in all bodies endowed with Be.-ifil, as in the 
 Spring of a much, that requires more ftrength to bend it,, 
 in the end, than in thebeginning. 
 
 For a lecond'trial, pull up from the bottom of the Wa¬ 
 ter the Ghfs LI.H, and when it comes above, you will 
 find nothing in it. Thereafon is, becaufe the Veflel be¬ 
 ing open between T and S, the whole Water IH r falls- 
 down by degrees 5 but in effecft, is really thruft out, by the 
 ftrong Benjiioi the compreft Air IL, that now expands 
 it felt, when it finds the Glafs go up thorow the Water, 
 whofe Preffure is lefs, and lefs from the bottom to the top. 
 but the contrary effeft follows, when the other Glafs is 
 pulled up ; namely, the Water remains within the Glafs, 
 and the Air above it, is thruft out by degrees, as the Glafs 
 comes nearer to the top. Forunderftanding the reafon of 
 this, confider fiift, that while the orifice G, is level with 
 the loweft furface, where it now is 5 - that’s fuppofed to be- 
 30 fathom deep, there is a real counterpoife between the 
 inclofedAir GK, and the ambient Water without : for 
 with what force the one ftrives to be in, with the fame force 
 the ocher endeavours to be out; and becaufe they are in. 
 
 equal 
 
i^joftaticai comments* 4* 
 
 equal terms, therefore the one cannot yeeld to the other. 
 
 If you pleafe to give the vi&ory to the Water, then let 
 the Glafs go further down; but if you defife the Air to 
 overcome, then muft the Glafs be pulled up. Pull it then 
 up from the place it is in 5 till it come to F, and you will find 
 a confiderable quantity of Air come outat G, and after 2 or 3 
 minuts of time, emerge and come to the top A * in form of 
 round Bells,or Bubbles. Thedeepnefs and grofenefs of the 
 Water thorow which theBubbles come,makes theirmotion 
 fo flow.Therenfonofthis eruption, muft be lefs Preflure of 
 Water in the fur face F, than in theloweft G, from whence 
 theGlafs came.Suppofe then,the loweft to have fix degrees 
 of Pre{Ture,F to have five,E to have four,D three, C two, 
 and B to have one.-and fuppofing the inclofed Air KG, to be' 
 equal in force to the Preflure of the loweft fathom, it muft 
 then have fix degrees of Eenfil in it. Put the cafe then, 
 that with fix degrees of Benfil, it come to the furface F, 
 that hath but five, it muft finely break forth , and over¬ 
 come the force and^onw of that furface : for ’tis impoffibfe 
 that two Fluids can be unequal in force and power, but 
 the ftrongeft mufl> overcome , and the weakeft yeeld: 
 therefore , when the orifice comes to F, the Air being 
 ftionger than the Water, breaks forth5 and as long 1 
 doth this eruption'continue, as inequality of power con¬ 
 tinues between the one and the other. In pulling up the 
 Glafs from F to E, other five fathom, more Air comes' 
 out. The reafonisthe fame, namely lefs PrefTurein E‘ 
 than in F: therefore , when the inclofed Air, that hath 
 five degrees oiBenftl^ comes to E, that hath but four, it 
 muft overcome, and fo long muft it be vi&orious, till by 
 expanding it fell, it be reduced to the Begftl of four. In’ 
 pulling up the Glafs from E to D, more Air yet breaks 
 
i4i ^Djoftatfcal hums. 
 
 °at, became a furface of three degrees of Preflure, is not 
 able to relift four degrees of Benfil. In pacing from D to 
 C , more Aircomes yet out for the fame reafon, till in 
 going up to the top, where there is no Preflure, no more 
 Air breaks out. 
 
 'Tis to be obferved firft, that the motion of the Air 
 up thorow the W2ter is but flow,the mcditmbm° thick, 
 and grofs. Secondly,that if the Glafsbe pulled up quickly, 
 from one forface to another, or contrariwife, let down 
 quickly, it prefently breaks in pieces. This comes to pafs 
 through the ftrong Benfil of the inclofed Air, that muft 
 have time to expand it felf, othenvife it breaks out at the 
 neareft: for it being of fix degrees of Benfil) and coming 
 quickly to a furface of five, there happens an unequal 
 Preflure, the Tides of the Glafs being thruft out, with 
 greater force, than they are thruft in with. But it fo be, 
 the Glafs move (lowly up, the inclofed Air gets time to 
 thruft it felf out by degrees, fo that whatever furface the 
 Glafs comes to , - there is little difference between the 
 Preflure of the. Water, and the Benfil of the Air, The 
 reafon why rhe Glafs breaks in pieces, while it goes quickly 
 down , is likewayes unequal Preflure upon the fides.* for 
 in pilling quickly from a furface of five degrees,to a furface 
 of fix, the fides are preft in with greater force, than they 
 are preft out with, and the reafon is, becaute through the 
 ftraitnefs of the hole G, the Water cannot win infoon 
 enough, to make as much Preflure within, as there, is 
 without. ’ T is to be obferved thirdly; that if the orifice 
 G be flopped , before that the Glafs be fent down, it 
 will not go beyond three or four fathom, when it (ball 
 be broken in peices 5 though the motion were never fo 
 flow: ana this comes to pafs, through the ftiong Preflure 
 
Comments* 14$ 
 
 of the Water. Fourthly, the ftrohger the Glafs be in 
 the fides, it goes the further down without breaking.- 
 therefore^ round Glafs Bottle, will fink 20 or 30 fathom, 
 before that it be broken with the Prefiure of the Water. 
 
 If a Vefiel of iron were fent down, it ought to go much 
 further, ^ An empty Cask , or Hogfhead, will not fink 
 beyond feven or eight fathom , without breaking, or 
 buifting 5 yet a Bladder full of wind, knitabout theneck 
 with a Pack-Tbreed, will go down 100 fathom, yea 
 1000 without burfting. 
 
 It may be here inquired, what fort of proportion is 
 keeped by th tumqnd iwrejs of the Water ? I anfwer, it 
 may be known alter this manner. Let firft down the 
 Glafs one fathom, and having pulled it up again, meafure 
 the deepnefs of the Water in the bottom , of it. Next, 
 having poured out that Water, let it down two fathom, 
 and pulling it ap, meafure the deepnefs, which you will 
 find more, than afore. Do alter this manner, the third 
 time, and the fourth time, till you come to the loweft 
 fathom, and you will find the true proportion. 
 
 From what is faid we fee firft, that in Water there is a 
 Prefiure, becaufe through the force and power of this 
 Water, the 12 inches of Air that filled the Glafs, are 
 reduced to three. Secondly, that this Prefiure growes, 
 as the Water growes in deepnefs: becaufe there is more 
 PiefTurein B, than in A, more in C, than in B •, and lo 
 downward. Thirdly, that when Air is compreft, by 
 fome excrinfeck weight, th eBenfd is intended, and grows 
 ftronger by unequal prof onion, as is clear from the un¬ 
 equal diviflons, 1, 2, 2,4,5,6 . Fourthly, two Fluids 
 cannot Ccafe from motion, folong as the potentia of the 
 one, is unequal to the pondus of the otherthis is evident 
 
*44 iwoftactcal experiments* 
 
 from the Water’s creeping in at G, all the while the Glafs 
 is in going down ; and from the Air’s coming out, all the 
 while the Glafs is in coming up. Fifthly, that no fooner 
 two Fluids come to equality of weight, but as foon the 
 motion ends: becaufe, if the Glafs halt at D,E or F, in the 
 going down,-upon which follows a counterpoife, then 
 dotfnhe creeping in of the Water ceafe. Sixthly, there 
 may be as much Prefliire in a fmall quantity of a Fluid,as in 
 the greeted : becaufe there is as much Benfil in the fmall 
 portion of Air, included between K and G, as there is of 
 PrefTure , and weight , in this whole Water, that’s 30 
 fathom deep. Seventhly, that the Preflure of a Fluid, 
 is a thing really difhndt, from the natural weight-, this is 
 evident from the PrefTure of the inclofed Air G K, that’s 
 more and lefs, as the PrefTure of the Water ICM, is 
 more and lefs, but the natural weight is dill the fame, feing 
 the fame quantity remains. Eighthly, one part of a 
 Fluid, cannot be under PrefTure, but the next adjacent, 
 mud be under the Tame degree of Preflure: this is alfo 
 clear, becauiewhat ever degree of benfil the included Air 
 K G is under, the Water K M is under the fame. There¬ 
 fore, when the one is under fix, as in the lowed fathom, 
 the other is under fix likewife. And when the one is 
 under five degrees of PrefTure, as in the furface F, the 
 other is under as much. Ninthly , Benfil and Preflure are 
 equivalent to weight : becaufe the Water KM, is as 
 much burdened with the Benfil of that fmall portion of Air- 
 above it , as if it had a Pillar of Water 30 fathom high 
 upon it. Tenthly, that the Preflure of Fluids, is mod 
 uniform and equal, and that two Fluids of different kinds, 
 may prefs as uniformly, as if they weie but one: this is 
 evident from the fides of the Glafs, that are not broken 
 
ir?gs?ohat(cai erptnmttitg, 
 
 in pieces, by the ftrong Ben ft l of the indofed Airland 
 heavy Preffure of the inclofed Water* and this happens 
 becaufe the Preffure without, is as ftrong as the Preffure 
 within. We fee laftly, that Water does not weigh in 
 Water, becaufe when a man lets down this Glafs by the 
 chord, to the loweft lurface, he finds not the weight of 
 the Water K M, that’s within the Glafs, but only the 
 weight of the Lead ’Tis certain } he finds not the 
 weight of the Water IH-, becaufe it refts not upon the 
 Glafs within, but is luftained by ’its own furface, the 
 •mouth of the Glafs being downward > and open. When 
 I fay Water does not weigh in Water ; the meaning is not, 
 that Water wants weight or Preffure in it, but that this 
 weight andpreffure is not found,as the weight andPreffure 
 of other bodies are found , while they are weighed in 
 Water. For example, a piece ot Lead or Gold, hung in 
 the Water by a firing, the other end being fattened to a 
 Ballance in the Air ,gravitats, and weighs down the Scale ? 
 and the reafon is, becaufe Lead and Gold, are naturally 
 and fierifically heavier than Water ; but a piece of Metal 
 of tnc fame ftectfick weight with Water, or Water it 
 felf, cmnot gravitatm Water, or weigh down the Scale 
 of a Ballance• and the reafon is, becaufe the furface of 
 Water upon which they reft, bears them up with as great 
 weight and force, as they prefs down with. If it be faid, 
 that the Water K M, refts upon the bottom of the Glafs 
 within *, and therefore,if the man above, find the weight of 
 the Glafs, he muft find the weight of the Water within it. 
 I anfwer, the confequence is bad, becaufe the weight of the 
 Water within,is fuftained,and eounterpoifed by the weight 
 of the Water without, whereupon the bottom of the Glafs 
 rtfts.That’s to fay,as there is a Pillar of Water K M within 
 T the 
 
i4<$ Jfi?Djo 8 attcai ejcpertriunts, 
 
 the Glafs, that prelTeth down the bottom, fo there is a 
 Pillar of Water without the Glafs, whereupon the bottom 
 of the Glafs refts, and which bears up both. But the great¬ 
 er difficulty is this, the further down the Glafs goes, 
 it grows the heavier, becaufe of more and more Water, 
 that creeps in at G. How s tis certain, the weight Qjrows 
 not heavier, therefore it muft be the Water within the 
 Glafs, that makes the increafe of the weight ; and there¬ 
 fore Water muft ftill weigh in Water. II this argument 
 had any ftrength in it, it would prove the weight of the 
 Water IH to gravitat and weigh likewife 5 becaufethe 
 further down this glafs goes, it grows the heavier, becaufe 
 of more, and more Water, that creeps up from H to I. 
 Now ’tis certain, the weight of Lead B grows not heavier. 
 Behold, the d’fficulty is the fame in both, and yet it were 
 rafhnefs to affirm the Water IH to be found by a mans 
 hand, when he puds up the Glafs with a firing, feing it is 
 fuftained by itsownfuiiace , and not by any part of the 
 Glafs. Though this might fuffice for an anfwer, yet be¬ 
 caufethe contrary is mantaiued by fome, and that with a 
 new Experiment to prove it, I fhall be at fome more pains 
 to vindicat the truth of what I have faid. 
 
 This new Experiment to prove that Water weighs in Wa¬ 
 ter , I found in a Philofophical Tran fact ion , oiAuguji 16. 
 Anno r 669. Numb, 50, the Invention whereof is 
 attributed by the publifher, to that honorable and worthy 
 Perfon Mr. Bojl, whofe conclufions and trials, I never 
 much called in queftion,but finding this oppofite, and con¬ 
 trary to what I have demonftrated , I fhall crave liberty to 
 amicus Socrates , amicus Plato, fed magis arnica veritas ; 
 and fhall therefore examine it as briefly as may be, The 
 words of the Publifher are as follows, 
 
 ' • The 
 
{^Djoftatfcai €jepertment& 147 
 
 The Author if this Invention is the Nchle Robeit '&yl - 
 who was plcafed to comfy with our de fires, of communicating 
 it in Englifhto the curious in England , as by inferring the 
 fame in the Latine Tranflation o/Hr Hydroftatical Para¬ 
 doxes, he hath gratifedthe Ingenious abroad. And it will 
 doubtlefs be the more welcome,for as much as no body,we know 
 of , hath fo much as attempted to determine, hew much Wa¬ 
 ter may weigh in Water 5 andpofftbly, if Inch a Problem had 
 been propojed , it would have been judged impraBicable. 
 
 The Method or Expedient ,he made ufe of,to perform it,as 
 near as he could, may eaftly be learned by the en filing accompf 
 of a Trial or two, he made for that purpofe, which among his 
 Notes he caufed to be regifred in the following words , 
 
 A Glajs- bubble of about the bignefs of a Pullets egg, was 
 pt/rpofely blown at the fame of a Lamp, with a fomewhat long 
 (kem turned up at the end,that it might the more conveniently 
 be broken off. This Bubble being well heated to rarify the Air, 
 and thereby drive out a good part of it, was nimbly fealed at 
 the end, and by the help of the Figure of the fern, was by a 
 convenient Weight of Lead deprefed under Water, the Lead 
 and Glafl being tyed by a firing to a Scale of a good Ballance , 
 in whofe other there was put fomuch weight,as /ufficedto coun¬ 
 ter foife tbeBubble,as it hung freely in the midfl of the Water, 
 Then with a long Iron Forceps, I carefully broke off the feal’d 
 end of the Bubble under Water,fo as no Bubble of Air appear d 
 to emerge or efcape through the Water, but the Liquor by the 
 weight of the Atmofyhere,Jprung into the un*repkni(ti d part 
 of the Glafs-Bubble,and fill’d the whole cavity about half full ; 
 andprefently, as I foretold, the Bubble fubftded, and made 
 the Scale ’twos fafned to, preponderate fo much, that there 
 needed 4 drachms, and 3 8 grains to reduce the Ballance to 
 an equilibrium. The# taking out the Bubble with the Wa¬ 
 ll z ter 
 
I4-S §p&zo&attcal experiments* 
 
 nr iUft,we di&M the help of a flame of a Candle,warily apply - 
 td-.drive out the Water {.which other wife is not etfily excluded 
 at a very narrow (lew) into a GUfs counter pot fed he fere ; 
 and vet found it , as we expefttd , to-weigh about four 
 drachms :.r,d 50 grains, beftdes feme It .tie t'.at remained in 
 the Ezz- and feme (mall matter tl at might have been rarified- 
 into vaters , which added to the piece of Glafs that was bro¬ 
 ken ef under Water and-lcf there , might very well amount to 
 ~ cr"S grains- By which it appears not only , that Water- 
 hat': (ome weight tn Water , but that it wighs very near , 
 or altogether as much its Water, as thefelf (ame portion of 
 Liquor would weigh in the Air, 
 
 The fame day we repeated tbe Experiment with another feal~ 
 tdBubble-Jarver then the {ermafheing as big as.a great tiens- 
 ezg) and having b. uleen this under Water , it grew heavier 
 hf ~. drachms and 34 grains. 5 and'having taken out th%- 
 Bubble , andd> iven out the Water into a counterpois'd Glafs ,. 
 we found the tranfvafated Liquor to amount to the fame 
 weight , abating 6 or 7 grains , which it might well have lofl 
 upon [uch attempts, as have been newly mentioned. Thus he, 
 
 Figure 24. 
 
 T He cefign then of this Experiment is to prove 
 that ‘i ater weighs in Water ‘ but, it Teems, there 
 is here 2 very great mifhke, which I lh.ill make out after 
 th : smanner. For which caufe, let this Schematifm 24 
 re prsfent the Experiment already defci ibed. T he Glafs- 
 bubbl : then is E P F R, The ftem is H C: the weight . 
 that links the Glafs is B. The furface of Water unler 
 which it is drowned, is*AD. The Ballance to which the 
 Glafs is knit by 2 firing is N O. And Iaftly E F R is 
 the Water that C2me in } and filled |he halt oi the Bubble,. 
 
i)pc?oftat(cal Cjcpettments. 149 
 
 Nowlfay, it is not the weight of the Water E^R, 
 that turnes the Scales above, and makes an alteration in 
 the Baliance, but .’its only the weight of the Lead B, 
 that does it. For evincing this, confider that all heavy 
 bodies,, are either lighter in (pccie than Water* ascork, 
 or oi the fame jpccifick weight with it, as fome Wood is, 
 Of laftiy heavier in fpeciet han Water, as Lead or Gold, 
 Now ’tis certain, that bodies of the fiift fort cannot 
 weigh in Wat a , and the reafon is, becaufe they being 
 naturally lighter, their whole weight is fupported by the 
 Water, and therefore not one part of them, can be born 
 up. by a Baliance above. A piece of Cork that weighs 1 2 
 ounces in the Air, weighs nothing in Water, becaufe as 
 foonas it toucheth the furface, the whole weight of itis 
 fupported, and therefore cannot affe& the Baliance above. 
 But bodies of the third fort, as is clear from experience 
 and reafon, does really weigh in Water .• And the reafon 
 is, becaufe they being naturally heavier than water, their 
 whole weight cannot be fupported by it, and therefore 
 fome part of them muft burden the Baliance, to which the 
 body is knit. A pieceof Lead, that weighs 12 ounces in' 
 the Air, will not lofe above 2 ounces, when’its weighed 
 in Water 5 or may be lefs. But here there is no difficulty.. 
 The queft.on then is, in order to bodies of the fame fpcci- 
 M weight with Water, asfomc Wood is, oras Water' 
 is. I fay of fuch alio, that they cannot weii-h in Water 5 - 
 and the reafon is, becaufe they being ufr ol the fame' 
 weight, muft have their whole weight fuppoited-by it 5 
 even as one foot of Water, fupports the whole weight of 
 the foot above it. It may be evidenced after this manner. 
 Take a piece of Wood, that’s lighter in fpecie than W^ter, 
 and add weight to it by degrees, till- it become of the 
 
ifo ^p&jDftaticai espenments* 
 
 fame^weight With Water. Knit -it with a firing to i 
 Ballance, ond weigh it in W2ter, and you will find the 
 whole weight fupported by the Water, And the reafon 
 is, becaufe, being left to it felf, it can go no further down, 
 than till the upper part of it, be level with the furface of 
 the Water, Now, the whole weight being thus fup¬ 
 ported , not one ounce of it can burden the Ballance. In 
 a ward, the Ballance can never be burdened, unlefs the 
 body that’s knit to it, have an inclination to go to the 
 ground, when left to it felf, which a body of the fame 
 weight with Water can never have. I conclude then, 
 if a body of the fame weight with Water , cannot 
 weigh in TTiter , neither can Water weigh in Water , feing 
 Water is of the fame weight with Water. And There¬ 
 fore the Water E F R, that’s now within the Bubble, can¬ 
 not in anywifeburden the Ballance above 5 but muff be 
 fupported wholly by the Water IKGH, upon which 
 the bottom of the Glafs refts. If it be faid, that the 
 Glafs it felf is fupported by the Ballance, becaufe ’its 
 heavier in [fecit than Water • therefore the Water 
 within that refts upon the fides of it, muft be fupported 
 likewife by it. I anfwer , the whole weight of the Glafs 
 is not fupported, by the Ballance, but only a part 5 the 
 Water IK G H fupporting the other part. And this 
 part is juft as much as is the weight of Water, that’s 
 expelled by the Glafs. Now, if the faid Water fup- 
 port fo much of the Glafs, becaufe it is the juft weight of 
 fo much Water, why fhoula it not alfo, fupport the 
 Water within the Glafs ! Seing the Water within the 
 Cflafs, is juft the weight of as much Water, as will fill 
 the fpace EFR, 
 
 I come in the next place to (hew, that it is the weight 
 
 of 
 
^oftattcaic^nimn^^ in 
 
 of the Lead Bthat turns the Scales, when the VVater 
 comes in at C, and fills the half of the fphere, 'For 
 undemanding this, Ietusfuppofe firft, thfe weight that’s 
 in the Scale 0 to weigh fix ounces. Secondly, that'the 
 Glafs takes 12 ounces'to fink it compleatly under the fur- 
 face A D. Thirdly , the weight B to be x8 ounces ; 
 namely for this caufe, firft, that 12 of it may fink the 
 Glafs 5 next, that the other fix may counterpoife the fix 
 in the Scale O. Laftly, that the VVater within the 
 Glafs weighs fix ounces. I abftraft from the weight of the 
 Glafs it felf, which is not confiderable, feing the moft pare 
 of it, is fupported by the Water, and not by the Ballance. 
 Now, I fay, ’tis fix ounces of the weight B that makes 
 this alteration, andturnesthe Scales. For if 12 ounces 
 fink the Glafs below the VVater, when ’its full of Air, 
 and no Water in it, then furely fix are fuffident to fink it, 
 when it is half full. And the reafon is, becaufe there is a 
 lets Potentia or force in fix inches of Air, by throne half, 
 to counterpoife a weight of 12 ounces, than in 12 inches of 
 Air. Therefore this Air, being reduced from 12 inches 
 to fix, it muft take only fix ounces to fink it. If this be, 
 then rhe other fix ounces that now wants a party to coun¬ 
 terpoife them, muft burden the Ballance,and be fupported 
 by the Scale .• and therefore , to make a new tquipendium 
 again, you muft make the weight Oi2 ounces, by adding 
 fix to it, that it may counterpoife 12 of B, the other fix 
 being counterpoifed by the Air EPF. Let us fuppofe 
 next, this Glafs to be compleatly full of Water, and 
 the whole Air expelled. In this cafe rhe Scale 0 , muft 
 have x 8 ounces in it, for making a new eqmforJhtn, The 
 reafon is, becaufe there being no Air in the Glafs to coun¬ 
 terpoife any part of B, the whole weight of it muft be 
 fuftained 
 
i $2 t^DjoSaetcai experiments, 
 
 fuftained by the Ballance, and therefore in the Scale 0 , 
 there mail be 18, Now, I enquire, whether thefe 18 
 ounces,are the equifiondiumd theVVater within theGlafs, 
 or of the weight of Lead'S i ’Tis impoffibleit can coun- 
 terpoife them both, feing the V Viter is now 12, and JB 
 18. It muft then either he the counteiballance of the 
 Water, or the counterbalance of the Lead. It cannot be 
 thefirft, becaufeia cannot be in equifondio with 18, It 
 muff then be the fecond. Or if thefe 18 ounces in the Scale 
 0 ,be the counterpoife of the Water within the GIals,I en¬ 
 quire what fuftains the weight of the Lead B C The weight 
 of it, cannot be fuftained by the Water, becaufe his a 
 body naturally heavier than Water, it muft therefore be 
 fuftained by the Ballance, I conclude then, that Water 
 cannot weigh in Water. If it be objected, that this con- 
 cluflon feems to contradidt, and oppofe the Preffure of the 
 Water, that’s been hitherto confirmed with fo many 
 Experiments. Ianfwer, the Prejfure of the Water is one 
 thing, and Water to weigh in Water is another. The 
 firftis, when one Pillar of Water counterpoifes another, 
 or when a Pillar of Water counterpoifes a Pillar of Mercu¬ 
 ry, or is counterpoifed by a Pillar of Air, all which is in 
 order to the Natural Ballance, wherein bodies weigh only 
 according to altitude. The fecond is, when Water is 
 not counterpoifed by Water, or by Mercury, or by 
 Air, or by any other Fluid 5 but when ’its weighed by a 
 piece of Lead or ftone in an Artificial Ballance , for know¬ 
 ing how many ounces or pounds it is of, as if a man ihould 
 endeavour to weigh the Water E F R by help of the 
 Ballance above, which in effe# i? impoftible. 
 
 EXPE- 
 
n^tyoftattcal eicpcrtments* m 
 
 EXPERIMENT XVIII. 
 
 Figure zs. 
 
 M Ake a Wooden Ark after this following manner. The 
 Planks rauft be of Oak, an inch thick. The height 
 40 inches.The breadth 3 tf.Clofs on all fides,and above,and' 
 open below. And becaufe the form is four-fquare,there muft 
 be four Standarts of Timber, in each comer one,; to which 
 the Planks muft be nailed. Four.likewife upon the top, 
 crofting the other four at right angles, - to which the cover 
 muft: be joyned, The fides muft be plained, and the edg¬ 
 es both plained and gripped in all the parts, that the joyn- 
 ingsmiybeclofs. Upon the top fallen a ftrong Iron Ring, 
 asatN, through which muft be faftned a Rope, of fo ma¬ 
 ny foot or fathom. And becaufe the ufe of this Engine is 
 for Diving under the Water, it muft therefore be all co¬ 
 vered over with Pitch within and without, efpecially in the 
 couplings. And becaufe this.Inftrumtnt cannot fink of its 
 own accord, it muft have a great weight oi Lead appended 
 to it, for thatcaufe, whereupon the Divers feet muft ftand, 
 while he is in going down. The precifequantrty and weight 
 of it cannot be determined 5, becaufe it depends upon the 
 quantity of the Ark, which if large, requires a great weight: 
 if of a lefler fize, requires a lefler weight. But whatever 
 the dimenfions of the Jrk may be, the weight of the 
 XM«?f»-/Mt*/w/caneafilybefoundoutby trial. This In¬ 
 vention then, is for Diving, a moft excellent Art, for lift¬ 
 ing up of Guns* Ships , or any other things, that are drown¬ 
 ed below the Water. And it is in imitation of the Div¬ 
 ing hell, already found out, and made ufe of with fuccefs. 
 Ins-called a Bell, becaufe of the form, that reprefentsa 
 V Church- 
 
>54 bpwsftatfcal Ctpmments. 
 
 Church-bell indeed, being round, wide below, and nar¬ 
 rower in the top: only, the matter is of Lead. It feems, 
 it is of this mettal, firft, becaufeLead is weighty, and will 
 therefore eafiiy fink: fecondly, becaufe it’s eafiiy founded, 
 and will by this means, being of one piece, be free of rifts, 
 and leaks: thirdly, it being of Lead, will be of a confi- 
 derableftrength for refitting the force of the Water,' that 
 ordinarily breaks in pieces Veffels that are weak. I cannot 
 vreli drvine and guefs the reafon, why firft it is round, and' 
 next nirrower above, than below, unlefs, becaufe its more 
 eafily rounded after this way, than after another. This 
 device here defcribed is named a Diving Ark •, firft,becaufe 
 it is of Timber, and next, becaufe it fives a man from be¬ 
 ing overwhelmed with the Waters. I prefcribe it of Wood, 
 becaufe of iefs trouble, and expence in making of it. ’Tis 
 four lquare, becaufe it contains under this Figure, far more 
 Air, than if it were round 5 even as much more, as a fquare 
 Vcfreijo inches wide, contains more than a round Vefiel 
 30 inches wide. Now, the mo:e Air, that’s in the VefTel, 
 the eafier is the refpiration, and the longer time is the man 
 able to abide under the Water, which two things a:e of 
 great advantage to this Art. For if by a guefs w-e reckon, 
 how much more Air is in the one,than in the other,we will 
 find in the Ark , as before it is defcribed, 30 fquare foot of 
 Air, but in the 5 c//, though it be 36 inches wide, as well 
 above, as below 1 , yet little more than 23 will be found, 
 which is a conftderable difference. But far lefs muft be in 
 it, feing it’s narrower above, thanbelow\ Befides this ad¬ 
 vantage, there are-others very ufeful: for being of Wood, 
 it’s more traftable. Next, feveral Knags of Iron may be 
 fattened conveniently to the fides within, to- which a man 
 faftning his hands, may keep his body fixed and fine in go- 
 
iSS 
 
 ing.down, and coming up. Moreover, if a man were in 
 hazard to be confpundedwith' fear, .or lofe the right exer- 
 cife of his fenfes, and fo be in danger of falling out of the 
 Ark or if his feet ihpuld flide off the fcot-ftool^ *&d his 
 hands fail him too, .a chord knit to oneof thofe,and fallen- 
 ed about his waft or middle , might bring him up, though 
 he were .dead. Then, its far eafier to cut out a window or 
 two in the Tides of it, not very large, but little, as fC and 
 I, whereby, they being covered with Glafs, a man may fee 
 at a diftance, what’s upon the right hand, and what’s upon 
 the left, and what is before. This device is of excellent 
 life,for through the want of it,the Diver fees no more,bnc 
 what is juft below him, which fometimes, when he is near 
 'the ground, will not exceed the compafs of a large Miln- 
 wheel. But if fo be, three holes be cut thorow, one on 
 every hand, and one before,he may fee as much bounds,and 
 all things in it,as il he were not in.dofed,andmv:ironed with 
 a cover. A little fchelf likewife may be fixed upon • the 
 one fide or the other, for holding a Compafs with a Mag- 
 netical.Needle,for knowing how fuch and fuch a thing lies 
 in the ground of the Sea, In one of the corners may hing a 
 little bottle with fome excellent fpirits, : for.refiefhing-the 
 ftomach, under Water, Many moe advantages I 
 might name, this Engine being of Timber, but ihall for¬ 
 bear ; leaving the colle&ion of them to the ingenious 
 Reader, and proceeds to anfwer fome objections, that may 
 be made.againft it. 
 
 Firff, if this Engine be made of Wood., it will not fink 
 fo eafily, as being made of Lead. Ianfwer, this difficulty 
 isfoon overcome, namely by making iheXool-foal .the 
 heavier: therefore how light foever it be, a weight may 
 be found to counterpoife it in the Water 6 : :If. it be judged 
 V -2. too 
 
i?6 ifptyo8atfcal ocpecmunt0* 
 
 too light in Timber, it may be lined with Lead, efpecially 
 without, Secondly, if it be of Wood, there muft be 
 couplings and joynings in it, and fo rifts and leaks in it, 
 through which the Water may come. I anfwer, there 
 is lets difficulty here , than in the former •, becaufe the 
 joyuts may be made fo dofs in-all the parts, and may be-fo 
 covered over with pitch, or with fomefuch like matter, 
 that it may defie either Water to come in, or Air to go 
 out. T hirdly, if it be made of V Vood , it will be in ha¬ 
 zard of breaking by the force of the Water; for oft times 
 its found, that theftrongeft ffogjhealmll burft a funder by 
 the Preflure of it, if they go but down 7 or 8 fathom. 
 I anfwer, this objection flows from the ignorance of the 
 nature of Fluid bodies. If lobe then., that a man knew, 
 that the Preflureof Water is unifoim, moft equal, and 
 pjefleth upon all the parts of a body within it alike , no 
 fuch lcruple would occurre. I fay then, the Ark, though 
 no thicker in the files, than a thin fawen dale, will go 
 down, in fpightofall the Preflure that’s in the Water, 
 not only 10, but 20, or 30 fathom, without all hazard. 
 And thereafon is, becaufe what Preflure foeveris without, 
 to prefs in the fides, the fame degree of Preflure is within 
 to prefs them out. By this means, there is not one pare 
 of die Water, howdeep foever, to which the Ark may 
 comedown, but there will be found as much force in the 
 Air within,as will counrerballance the whole weight with, 
 out,as will be infallibly demonflrated afterwards, Thisan- 
 fwers a fourth objection , namely if holes be cut out in the 
 fides of the Ark,in ftead of windows,the force of the Wa* 
 ter will break the Glafles in pieces,that covers them.There 
 is here no hazard, though the faid windows were 12 inches 
 ia Diameter: bucks not needful they be fg large. , It’s fuf- 
 
i^p^ofiattcal Cicptttnuttts* 157 
 
 ficient, if they be 2 inches wide: for a mans eye near to 
 a hole, 4 inches wide, will fee a great way about him. 
 There’s a neceflity the Glaffes be joyned in with cement, 
 that Water may not have accefs to come in, or Air to go 
 out. In fuch a cafe ther’s no hazard, that the Preifure of 
 the Water, will break through the windows, or break 
 the Glaffes-, becaufe the Preffure of the Air within, being 
 of the fame force with the ftrength of the Water without, 
 the Glaffes are keeped intire. It may be enquired, what 
 hazard would follow, upon fuppofition a fmall hole were ' 
 pierced in the head of the Ark above, when it is going 
 down ? I anfwer, ther’s not fo much hazard, as a man 
 would think-, provided the hole be not wide, but narrow. 
 Ititbewide, not only the Water comes in , buttheAir 
 goes out, the one thrufting it fell by the other. If the hole 
 be no wider, than the point of a bodkin is in thicknefs; 
 ther’s no danger at all: for by reafon of the ftrait paffage • 
 the one cannot thruft it fell by the other, and therefore 
 neither the Water can come in, nor the Air go out- And 
 this comes to pa fs, by reafon, that the Air within, is as 
 ftrong as the Water is without. Now, if they be both of 
 the fame ftrengch and force, why ought the Air rather to 
 go out, then the Water to come in 5 or the Water rather 
 to come in, then the Air to go out? I am confident, 
 though the hole were as wide, as a man might thruft in his 
 little finger, yet no irruption of Water, or eruption of Air 
 would follow. This demonftrats clearly, that though a 
 fmall rift, or leak fhould happen in the Ark , yet no haz¬ 
 ard or danger would follow thereupon. If it be inquired, 
 whither the greateft hazard is from the ingrefsof the Wa¬ 
 ter , or from the egrefs of the Air ? I anfwer, ther’s no 
 danger from the coming in of the Water from above 5 be- 
 
159 $pfyQ{lattcai CEpenmentSu 
 
 canfe as it comes in, it falls down, and fo'mingleswith the 
 reft below. But if the Air Ihould go out, the Ark fills pre- 
 fently full of Water, and drowns the man that is in it. 
 
 The next thing confiderable in this Diving Inflrumcnt , 
 is the foot-ftool of Lead C D, that’s not only ufeful for a 
 man to let his feet upon, when he dives? but efpecially 
 for finking of the Ark. For this being made of Timber-; 
 and full of Air, cannot of’its own accord go down, unlefs 
 it be pulled, and forced by fome weight. It may either 
 be broad and round, or fquare: if fquare, a large foot over 
 from fide to fide, or 1 6 inches will determine the breadth. 
 By this means, it will happen to be pretty thick, feing.a 
 great quantity of Lead is required. In each corner, there 
 mail be a hole, for four chords, by which it is appended to 
 the mouth of the Ark, Between it, and the roof-within, 
 muft be the height of a man and more. The weight of 
 it, cannot be well determined without trial • ferng it 
 dependsuponthedimenfions ofthe Ark. Firft then try, 
 how much weight,will bring the top E F G H level with 
 the furface of the Water. When this is found, add a 
 little more weight till it begin to fink, and this will Purely 
 take it to the ground, though it were 40 fathom. ’Tis to 
 be obierved, that when the top E F is level with the fur- 
 face, there is here a juft counterpoife, namely between the 
 Lead foot-(tool on the one part, as a pndtts ^ and thzArk 
 on the other part, as a potential for with what force the 
 Ark endeavours to pull up the Lead ; with the fame force 
 ftrives the Lead to pull down the Ark. Hence it is, that 
 as a fmall weight will turn a pair of Scales , when they 
 are in tcpiltbrio 5 fo a fmall weight added to the fo*t-(lool 
 will fink the Ark. Though it may feem difficult to 
 determine the juft weight of the foot-ftool, without trial 
 
^pDjoftattcal experiments* 15s 
 
 as I faid, yet I purpofe to efiay it. For this cafe con' 
 fider that there is no VefTel of Wood aImoft,if it be once 
 full of Water, but the orifice of it will ]y level with the 
 furface of the Water, wherein it fweems. This propo¬ 
 rtion is fo evident from experience , that it needs no con¬ 
 firmation. From this I gather, that as much weight of 
 Lead or Stone will bring the top of the Ark E F G H, 
 level with the furface of the Water, as is the weight of 
 the Water, that fills it. It you fuppofe then the Ark 
 to be 5 <5 inches broad , and 40 inches high, it muft con¬ 
 tain 30 cubiquefoot of Water. Now, fuppofingeach 
 fquarefoot of this Water to weigh 56 pound, 30 loot 
 muft weigh itfSo pound. This is gathered from trial 
 and experience, for after exadl fearch, I found a cubique 
 foot of Water, in bulk about 1 6 pints of our meafure, to 
 weigh 5 6 pound. Take then a piece of Lead of that 
 weight, and you will find it make a juft counterpoife with 
 the Ark, It any be defirous to know the quantity of it. 
 
 I anfwer,if lead be 13 times naturally heavier then Water, . 
 you will find that a piece of Lead about 16 inches every 
 way will do it. If it be. objetted, that when a mans body 
 is within-the Ark, the weight of the foot-ftool muft be 
 lefs, even as much lefs, as is the weight of the man,whom 
 I fuppofe to weigh 224 pound, or 14 ftone. I anfwer, 
 the whole weight of the man is not to be deduced from 
 the foot-ftool, but the one half only, and the reafon is, 
 becaufe a mans body being of the fame fpecifick. and na* 
 rural weight with Water, it cannot preponderat or weigh 
 in Water, becaufe magnitudes only naturally heavier ' 
 then Water weigh in Water, as Lead , or Stone$ • 
 therefore feing the one half of the man is within the Ai k, 
 and the other without among the Water, that part only 
 
 muft - 
 
i6o ^ptyoftatJcai experiments, 
 
 muft weigh, that’s invironed with Air. This mayTeem 
 a plau'fible anfwer,and might do much to fatisfy thefe, that 
 are not very inquifitive, yet, being examined, it will be 
 found unfufficient. Therefore, I fay, there’s not one part 
 of the mans body, that weighs within the Ark, or makes 
 it havier. -Yet, I affirm, that when the mans body is 
 withmtheArk, a lefs weight will fink it, then when his 
 body is out of it, even as much lefs than before , as is the 
 juft weight of the one half of the man. For example, if 
 1680 pound be the juft counterpoife of it without the 
 Man, then after the Man is in it, it will take only 
 1568 pound to counterballance it, fuppofing the one 
 half of the man to weigh 11 2 pound , or feven ftone: yet 
 it is not the weight of the man that makes this difference. 
 For underftanding what’s the caufe of this alteration, con- 
 fider,that when a mans body is within the Ark,there is lefs 
 Air in it, then while his body is out of it, even as much 
 lefs in quantity, as the bulk of the parts are, that are 
 within. If this be, then muft the Ark become heavier, 
 not becaufe the mans body makes it heavier, but becaufe 
 there is lefs Air, in the Ark, then before, and therefore, 
 there arifes an inequality between the weight of the foot- 
 ftool and the weight, or rather lightnefs of the Ark. For 
 if 1680 pound of Lead, was the juft counterballance of it, 
 when it had 30 Qubique foot of Air within it, it muft 
 exceed, when there is lefs Air in it. But there occures, 
 here two difficulties, the firft is, whit’s the reafon, why as 
 much weight muft be deduced fromthefoot-ftool,as is the 
 the precife weight of the one half of the man? Secondly, 
 how {hill we come to the true knowledge of that weight • 
 that is, to know diftinftly how many pounds or ounces it 
 is of ? For anfwer, let us fuppole, that the one half of 
 
 the 
 
IjfD?oltat (cal experimen ts, i6i 
 
 the ram, is juft; as heavy., as To much Water equal inbuilt 
 to his own half. This may be granted without fcruple, 
 feing a mans body is judged to be of the fame fpecifick, 
 and natural weight with Water .• and though there fhould 
 be fome fmall difference, yet it will not make, or produce 
 any infufficiency in the argument, for thefe demonftrati- 
 ons, are not Mathematical but Phyfical, Therefore, as 
 much Water in bulk, as is equal to that part of the man, 
 that is within the Ark, muftbe as heavy, as the half of 
 the man. Now fuppofing the half of the man, to weigh 
 112 pound , and confequently that Water, to weigh 
 as much , I affirm the faid Water to contain 345 6 
 cubique inches; but 3456 cubique inches, makes exa&Iy 
 two cubique feet, which I gather thus. Seven pound of 
 Water'requires 216 cubique inches, becaufe a Cubed 
 fix inches, weighs exactly fevenpound, therefore accord¬ 
 ing to the rule of proportion, 112 pound will require 
 3456 inches, which amounts to two cubique foot. The 
 Ark then by receiving the one half of the mans body, 
 lofeth two cubique foot of Air, therefore if 3 0 foot of Air, 
 require 1680 pound weight of Lead to counterpoifeit, 
 28 foot of Air, muft require only 1568 pound: therefore 
 to make a new counterbalance, you muft deduce 112 
 pound from the foot-ftool. This anfwersboth the diffi¬ 
 culties, If it be faid, that the foot-ftool weighs lefs in 
 VVaterthanin Air, therefore it muft be heavier, then 
 1680 pound. I anfwer, ’tis needful to abftradt from that 
 difference, till the juft calculation be once made, and 
 that being now done, I fay , that a Cube of Lead 1 6 
 inches weighing 1680 pound , ( If Lead be 13 times 
 heavier than VVater ,) will lofe about 130 pound. The 
 reafon is evident, becaule a heavy body weighs as much 
 X lefs 
 
i6i ^pDjo&aticai e&pcrtmems* 
 
 lefs in Water than in Air, as is the weight of the 
 Water it expeils. But fo it is, that a Cube of Lead 
 of 16 inches expeils a Cube of Water 16 inches : 
 But aXnbe of Water 1 5 inches weighs 130 pound, 
 which I gather thus, 216 inches.or a Cube of fix inches, 
 weighs fevea pound, therefore 4032 inches, muff weigh 
 130 pound. For if 21 6 give 7,403 2 muff giver 30. But 
 to return. Though there be finall difficulty to let it 
 down and to fink it 20 or 30 fathom, yet there is no fmall 
 difficulty to *pull it up again, And the reafon is this, 
 becaufe the further down it goes, the Ah within, is the 
 more contracted, and thruft up, by the Preffure of the 
 Water,towards the roof. By this means,though near the 
 top of the Water, there was little difference between the 
 weight of the Lend and the Ark-, yet 9 or 10 fathom down, 
 the difference is great, the weight of the one,far exceeding 
 the weight of the other,and therefore there muff be great¬ 
 er difficulty to pull it up from x 0 fathom,than from 5 : and 
 yet more difficulty from 20 than from 10. However, 
 yet’tis obfervable that, as the Ark in going down, be¬ 
 comes heavier and heavier, fo in coming up, it growes 
 lighter and lighter: therefore lefs ftrength is require!, in 
 pulling it up from the tenth to the fifth fathom, than 
 from the fifteenth, to the tenth: the reafon is, becaufe 
 incoming up, the Air within expands it felf, and fills 
 more fpace in the Arkwhich in effeCt makes it lighter, 
 and more able to overcome the weight of the Lend, To 
 make thefe things more evident, kt us fuppofe, that when 
 the Ark is down 18 or 20 fathom,the Air to be contracted 
 by the force of the Water, from L M to P Qf' 12 inches. 
 Next, that the weight of the foot-(lool is i 62 o pound. 
 Now, if this weight was the juft counterpoife of the Ark, 
 
@pBjottaflcai experiments. 163 
 
 at the top of the Water, then furely it mull far exceed 
 itnOw, when it's 20 fathom down, becaufethe Air that 
 was 3 o foot, is now reduced to 21. Count then, and you 
 will find, that if 30 require id8o, 21 will only require 
 1176; therefore the weight of the Lend, will exceed the 
 weight of the Ark^ at 20 fathom deep, byjc>4 pound. 
 This will be yet more evident, if we confider, that while 
 the top of the Ark E F G H , is level with the furfacc 
 above, the Water thruft out of’its own place by this 
 bulk, is juft the weight of both. Lead and Ark. But 
 when ’its down 20 fathom, and the Air reduced-from L M 
 to PQ, there cannot befo much Water expelled now 
 as before, feing the fpace LMP'Ql is full of Water, 
 Now, I fay, theZtWat 20 fathom, muft be exaftly fo 
 much heavier than the Ark , as is the weight of the faid 
 Water LM PQ, which in effect will be 504. pound; 
 for ’itsafquare body , 3 6 inches in thicknefs and 11 in 
 deepnefs. The weight of the rope is likewife to be 
 confidered, that lets down the Ark : for the longer it be, 
 and more of it goes out, it’s the heavier, and more trouble- 
 fome to pull up. 
 
 There is no way to cure this difficulty, but by finding 
 out away, how to keep a juft counterpoife between the 
 Lead and the Ark , all the time it is in going down. If 
 the Air within did not contrad it felf, no difterence-would 
 happen: but this is impoflible', fo long-as the Water is 
 ■under a Preftiire. The expedientthen muft be found out 
 another way, namely by kniting a fmall rope to the iron 
 ring N, in length with the other, to which at certain di- 
 ftances, relating to the fathomsthe^goesdown, muff 
 befaftned empty little VefTels of Wood, or bladders, 
 which by their lightnefs, may compenfe the decrement 
 Xi and 
 
i64 ^ptyoftaticai experiments* 
 
 and decreafing of the Air. Firft then, let down i\\?Ark 
 three fathom, and fee how much it is heavier than before .• 
 and as. you find the difference, fo faften to R one Bladder* 
 or two, till the Ark be brought near to a counterpoife; 
 Secondly, let it go down .other three fathom, andobfeive 
 that difference alfo,. and accordingly fallen to T as many^ 
 as will reduce .the two to a counterpoife again. Do after 
 this manner, till it fink 15 or 30 fathom. ’Tistobeobi 
 ferved,that the further down the Ark goes, the difference 
 is the Iefs: therefore lefs addition will ferve: and the 
 reafon is, becaule there is lefs Air contra&ed, in paffing 
 between the fifth snd the tenth fathom $ than in paffing 
 from the fi: ft to the fifth. The proportion of contra&ion 
 is reprefented by the.unequal divifions within the mouth 
 oitheArk, asi, 2.3.4.. In a word, by whatpropor- 
 tion the decrement of the Air is, by that fame proportion 
 muft the addition be, upon the rope SN. Suppofethen, 
 the Air to be diminifhed four inches, in going down lour 
 fathom, which will be 5184 fquare inches, or three fquare 
 foot, then furely as much Air muft be added to the rope 
 S N, by bladders. In going down as far, let us fuppofe 
 three inches tobecontraded*then lefs will fuffice.Though 
 it cannot be determined without trial, how much Airis 
 contra&ed in three fathom, and how much in fix, and 
 how much in nine 5 yet this is fure, that the decreafing is 
 according to unequal divifions, that’s to fay, lefs in fix 
 than in four lefs in 8,- than in fix, and lefs in 10, than in 
 8,-and fo downward: and that this is the rule, namely 
 according to what quantity,the Air within the Ark is con-- 
 traded, according to that fame meafure,muft the addition 
 of Air be.to the rope If it be faid, that Bladders full of 
 wisd, cannot go down thorow the VVater without burft-, 
 
i^oaatical e^pertmentsb 16 $ 
 
 ing. I anfwer, ’tis a miftake, becaufe their fides being 
 pliable, and not ftiff like the- fides of a Timber Veflel, 
 theyjeeld , and therfore cannot burft. It's obfervable 
 that when a bladder goes far down, the fides becomes 
 flaccid and flagging. In this cafe, the Air, that before, 
 had the forme of the Bladder, and was fomewhat ovall, 
 muft now become perfectly globular, and round: for ’tis 
 fare , that the dimenfions of it are altered by the PrefTure 
 ofthe Water, namely.from more quantity to lefs: ifthis 
 be, then the form muft be round, feing the PrefTure of the 
 Water is moft uniform; even as drops of Water, or 
 Rain from a houfe fide are round upon this account. This 
 fecond way,may be thought upon alfo. Make t\\tlcade»- 
 foot-flool that finks the Ark, not of one piece,but of many, 
 that fo, when the Air within it, begins to be contrafted 
 by degrees, in going down, a proportionable weight may 
 be fubtra&ed, for keeping a iuft counterpoife, all the 
 while of the defcent. Or becaufe the greateft trouble is 
 in bringing of it up, let the Diver, when once he is at the 
 bottom, fabtraft fo much weight from the foot-ftool, as 
 he thinks will go near to make a counterpoife, at that 
 deepnefs. For example, if the weight of the foot-ftool 
 be 40 pound heavier than the Ark, then let him fabtradt 
 30 or 36, which may ly, and reft upon the ground, till 
 it be drawen up, at a convenient time, by a chord. By 
 his means it will be eafie to move the Ark y from one place 
 to another. Next, there {hall be little or no difficulty to 
 pull it up. Nay, upon fuppofition, the rope were broken, 
 by which it was let down, yet if the Diver pleafe, he may 
 come up without any mans help. And this is moft eafily 
 done, namely by fubtra&ing as much weight,as will make 
 the Ark the ftronger party* ’Tis to be obferved, that 
 -wtat 
 
i66 comment* 
 
 when you are at the bottom, and if you make the Lend but 
 one pound lighter than the Ark^ it will furely come up, 
 and cannot flop by the way. Thereafonis, becaufea 
 very fmall weight will turn the Scales,between two bodies, 
 thus weighing in Water. Next, the further the Ark 
 comes up, it becomes the lighter, becaufe the Air within 
 it, expands it felf the more. But leaving this, let us come 
 to explicit the reafon, why the contraction of the Air 
 is not uniform, but rather difform. For if in going down 
 three fathom , three inches be contracted , there will not 
 be other three contracted in going down the fecond three, 
 but lefs: and yet lefs in going down the third three. Two' 
 
 things then are to be explicated here, Firft, why there • 
 is a contraction. Next, why it is after fuch a manner. 
 As for the firft 5 the contraction is caufed by the Preflure 
 of the Water, which gradually increafeth from the top to 
 the bottom; as is clear from thelaft Experiment: there¬ 
 fore , there being a greater Preffure in a furface fi.x 
 fathom deep, than in a furface three fathom deep, the Air 
 within the Ark , muft be more contracted in palling 
 between the third and fixth, than in palling between the 
 firft and third. When I fay more contracted,the meaning 
 is,that more quantity is contracted to lefs,whereby theBen* 
 ft l of it is more intended ; or that the Air is more bended. 
 As for the fecond, we muft remember from the laft Expe¬ 
 riment, that the caufe of this, is not from the Water, 
 asforfooth the Preflure of it, were according to unequal 
 proportion, but from the Air it felf, whole kind and 
 nature it is, to fuffer comprefllon after fuch a way. ’Tis 
 evident in Vf'ivd-gmis, whofe fecond fpan of Air is com* 
 preft with greater difficulty, than the firft-v and’the third 
 with greare; difficulty, than the fecond. ’Tis- fo with 
 
ty oioftiuical ecp tcimcneg. 167 
 
 all bodies endowed w'th Benfil: for ay the longer you 
 bend , you find the greater difficulty. As there is a great 
 disadvantage to the man that Dives , from the contra&ion 
 of the Air, to there is a great advantage to him, from this 
 manner and way of contraction $ for if it were uniform, 
 according to the Preflure o{ the Water, then if three 
 fathom compreft three inches, fix fathom ought to com- 
 preffe fix inches, nine fathom nine inches, and fo forward, 
 till by going down, either the whole Air, (hould be com¬ 
 preft to no inches, or eife very little ftiould remain for 
 refpiration. . 
 
 • The next thing to be taken notice of, is that all the 
 while,during the down going of the Jrk ,there is ftill equa¬ 
 lity of weight,between the Pondusol the Water, and the 
 Potent ia of the Air, for with what degree of weight, the 
 Water prefteth up the Air, with the fame degree of force 
 and power, doeth the Air prefs down the Water. If this 
 were not, it would beimpoffiblefor a man to go down; be- 
 caufe of pain. For when one pai t of a mans body, is Jefs 
 preft than another, there arifechaconfiderable pain, which 
 fomettmes is intolerable, as is evident from the application 
 of Ventofo-gbffes, This equality of weight,is the true rea* 
 fon , why refpiration is fo eafie. Yet ’tis to be obferved, 
 that a man cannot breath fo eafily in the^r'A,under the Wa¬ 
 ter,as above in theAir ; not becaufe there is any inequality, 
 between the weight of the Water, and the force of the 
 Air 5 but only becaufe the quantity of it is little. For 
 when a man fucks in as much Air,as fills his lungs,the quan¬ 
 tity muft be diminifbed: if this be, the Water muft afcend 
 ay proportion,though infenfibly. When a man thruftsouc 
 :he fame Air again, the quantity is increafed 5 if this be, 
 :hen the Water muft fubfide a little; both which cannot be } 
 
 with- 
 
i68 i^Djoftatical experiments, 
 
 without difficulty 3 feiBg there is a fort of ebbing and flowing 
 both of the Air and of theWater,in every refpiration. But 
 it rather feems ( you fay ) that this difficulty flowes from 
 the ftrcng, extraordinary benfil, that the Air is under. I 
 anfwer, as long as the preffure of a Fluid is uniform,though 
 in a high degree, yet there can be no trouble in refpiration 5 
 becaufe with what force foever,it is driven in upon the lun°s, 
 with the fame force it is driven out again: therefore,though 
 the Air we live in, were as much again bended as it is, yet 
 (as is probable) we would find no more difficulty in breath¬ 
 ing than now. There is one thing makes breathing eafie un¬ 
 der the Wateryin the Ark,namely this 5 when a man fucks 
 in the Air to his lungs, his breaft and belly goes out, and fo 
 fills the ipace deferted by the Air, that goes in. This 
 makes the ebbing and flowing far lefs. 
 
 From this equality of weight between the preffure of 
 the Water, and the preffure of the Air, we fee good 
 ground to fay , that though the^/T,were no thicker in the 
 fides, than a thin fawed dale, yet there would be no haz¬ 
 ard o: breaking, I am confident, though it were no ftronger 
 in the fides, than awine-glafs, that’s foon broken 5 yet it 
 might go down 40 fathom without hazard, or danger of 
 burfting, This affords good ground likewife to make 
 windows in the Ark covered with glafs: for if the Preffure 
 be uniform, and equal, its impoflible they can be broken. 
 The Water cannot thruft them inward, becaufe the Pref¬ 
 fure of the Air, is as able to thruft them outward. 
 
 It’s certain, the more Air be in the Ark, the more eafie 
 is refpiration: therefore its more eafie to breath, when 
 the-Ark is but down 5 fathom, than when it is down 10 or 
 1). It’s probable a man might live within the Ark, it be. 
 ing 40 inches deep, and 3 6 inches wide, at the deepnefs of 
 
 ten 
 
i-Wotfatirai cjcpcctincnt^. m 
 
 ten fathom ,near two houres.*, whereas if it were rouhd,and 
 narrow above in form of a Bell, he coaid not continue an 
 hour. It were very eafie to try how long other creatures 
 might live in it,for example dogs, and fuch like,or fowls,as 
 hens,pheafants ordoves.They might eafily be inclofed from 
 coming out-, for though the whole mouth of the Ark were . 
 fhut up, except as much paffage, as would receive a mans 
 fift,yet it will operate,as well that way,as the other. And 
 there,a little door might be made to open,and fhut at pleai- 
 fure.. ’Tis obferved,that by long tarrying under the' Wa¬ 
 ter in the BtH, the Air becomes grofs and mifty , which 
 hinders a man from feing about him, The caufe of this, 
 are vapors that come from the ftomach , lungs and other 
 parts of the body, efpecially from the ftomach, when the 
 ventricle is full of meat. It’s not fit then,that a man abotft 
 to dive , fliould eat too much, or drink too much, efpecially 
 fuch liquors as Sack or Brandy, that beget many fumes and 
 vapors. If a man were neceffitated to tarry apretty while 
 below, frefh Air might be fe'nt down from above, in bottles 
 or bladders,even as much as might fill uptheplace deferted 
 by the contra&ed Air, ’ Tis obferved by feme, that' have 
 been under the Water, that their eares have been fo trou¬ 
 bled , that for a long time, they have found difficulty to 
 hear diftin&ly. Thereafon of this muft be from thegredt 
 Preflure , the tympanum hath fuff ered from the imprifotfed 
 Air of the Bell. The Organ of hearing is foon troubled, 
 efpecially when a man is near to a great£«»,wh6ri it’s fired. 
 And furely,whenamanisbut 34 foot down, the Air with¬ 
 in the Ark,will be of double Benfil .* put the cafe the man 
 go down 68 foot, or 13 or 14 fathom, the Benfil is tri¬ 
 pled : that’s to fay, if the Air above have fivO degrees Of 
 Preffure in it, the Air of the 5 c//, at <58 foot deep, will 
 y hae 
 
170 i^Djoftattcai €£petmietU0* 
 
 have 15 degrees of Preffure;therefore th e tympanum of the 
 ear that’s but a fmali and thin mmbun , muft be fore 
 diftreffed; that is overbenied, and prefl inward; even 
 as, while a man fets. upon a drum head a great weight, 
 v. g, a Bullet of-Lead or Iron, of 20 or 30 pound, the skin 
 by this, fuffers an extraordinary Preffure, whereby it is in 
 hazard to be rent, ’ Tis probable, if a man ihould go very 
 far down,, the tjmfmm might be in hazard of breaking, or 
 being rent in two pieces, there being a greater Preffuv.e 
 upon the one fide from the Air without, than upon the 
 ocher fide, from the internal Air within, which is thought 
 to be within the 
 
 There remains another Phsnomtnsn to be explicated ,and 
 it’s this: the further up the Ark comes from the ground of 
 the Water, towards the top,the Water within it, fubfides 
 and fettles down more and more,towards the mouth. The 
 reafoh of it is, becaufe the further up , the Preffure of the 
 Water is the lefs ; and therefore the contracted Air gets 
 liberty to expand, and dilate it felf, and fo thrufts down the 
 Water from P QjoLM. In a word , by-what propor¬ 
 tion the Air is contra&ed in going dowrt, by that fame pro¬ 
 portion it dilates, and opens it felf in coming up. This 
 lets us fee, as there isdifadvantage in going down, from 
 the contraction of the Air, fo there is advantage in com¬ 
 ing up , from the dilatation of it. Some think, that the 
 coldne&.of the Water is thecaufe, why the Air is con¬ 
 tracted in the Ark,, fuch are thofe, who deny the Preffure 
 of it. But this fancy is eafily refuted •, . becaufe in affert- 
 ing this , they muft maintain, the further down, the cold 
 is the greater. If this be, then far more Air muft be con¬ 
 tracted, in going down from 10 to 15 fathom, than in 
 pafiing from 5toiO; felng as they fay ? the further down, 
 
$p&pftattcalCjcpertomit& 171 
 
 the cold is the greater • and therefore the contraction of 
 the Air muft be the greater ; that’s to fay, there muft be 
 more quantity of Air concra&ed in the one fpace, than in 
 theother. But.foitis, that the further down, the con¬ 
 traction is thelefs. They judge likewife the coldnefs of 
 the Water to bethecaufe, why the fides of empty Vef- 
 felsare broken in going down. But if this be, then a 
 ftrong Veflel fhould go no further down than a weak Vef- 
 fel 5 feing cold can pierce thorow the fides of the one, as 
 well as thorow the Tides of the other. And why is it, that 
 a bladder full of wind will go down 40 or 50 fathom with¬ 
 out burfting, yea 100, and yet a hone-bottle or glafs- 
 bottle, cannot go beyond 20 or 30 ? If cold have in it, 
 that power to break the fides of a ftrong bottle, it muft be 
 far more able tobuift the fides of a thin Bladder, This dif¬ 
 ference is clearly explicated from the Prefiure of the Wa¬ 
 tercut I defy any man to fhew the difference from the cold¬ 
 nefs of it. ’ Tis to be obferved, that in all fuch Experi¬ 
 ments of finking of Veffels, as Hogf-beads , Barrels , and 
 Bottles , they muft be clofs on all fides. T herefore,ifa man 
 defire to know, how far down a Glafs-bottle is able to go 
 without burfting, he muft flop the mouth of it exactly, 
 with a piece of wood, and cement. 
 
 In fetting down the dimenfions of the Ark , I have re- 
 ftri&ed them to 40 inches high, and 3 6 inches wide. 
 But if any man be defirous to enlarge them, or make them 
 lefs, he may doit. Only Tis to be obferved, that the 
 larger the Ark be, the Foot-(tool that finks it, muft be the 
 heavier. Yet it hath this advantage,that itcontains much 
 Air, which is the great perfection of it. One of a letter 
 fize hath this advantage, that it’s more tradable, and eafi- 
 er to let down, and to be pull’d up. But thefe things are 
 Yi beft 
 
i7* experiments* 
 
 beft known from Experience, or if a man pleafe, he may 
 calculate. 
 
 As the Ark is a moft afeful device for profit, fo ’tis excel¬ 
 lent for pleafure, and recreation, if a man were difpofed to 
 fee the ground and channels of deep Waters, or were in¬ 
 clined to find out ffydroflatical condufions, a knowledge 
 very profitabie^nd which few have attained to. Though 
 itfeem fomewhat difficult to enter the Ark, and go down 
 below the Water, yet a little ufe will expell all fear. 
 Then, a man may go down with Iefs hazard, and fear in 
 the Ark , then in the Beil , becaufe he may conveniently 
 fatten his hands, to each fide of the Aik, if need were. 
 He may conveniently fit, as in a Chair,all the time of down 
 going, and up-coming, by fixing a little feat in it: he 
 may have windows to look out at: his body may be fo 
 fixed, that there needs be no fear of falling out. 
 
 If a man were defirous to make Hydrofiatical condufions, 
 by Diving under the Water, the dimenfions of the Ark 
 might be enlarged , fo that it might conveniently cover 
 a mans whole body, by which means, having much Air 
 in it, a Diver might continue under Water half a day, if 
 need were, Letusfuppofe then, the hightof it to be 8 
 foot, and the breadth 3 foot, or more. In fuch a cafe, a 
 man might continue under the Water many hours• and 
 yet not one part of his body wet; for if the Ark be 8 foot 
 high, and the man 5 foot in ftature, at the deepnefs of 
 10 fathom, the Water can fcarce rife 3 foot in it. But 
 why may not a man come up every half hour, when he 
 finds difficulty to tarry down in a little Ark ? I anfwer,he 
 may • but it’s trouble and pains to pull him up,and let him 
 down fo frequently. And it may fo happen, that through 
 want of Air in a fipall ^Ark, he be necefficated to come up 
 
 before 
 
$jcperftnent& 173 
 
 before he end his work. And leaving the work imper¬ 
 fect, he may find difficulty in the fecond down going, to 
 find fometimes the pl&e where he was,or the thing he was 
 about to lift, v. a cheftof Gold, If it be faid, thac. 
 agreat weight of Stone or Lead is required to fink an 
 Ark 8 foot high, which will amount to 4032. pound 
 weight. I anfwer, ’tis fo indeed: but here is theadvan" 
 tage 5 when it is once below cheSurface, there’s little more 
 trouble^then with an Ai k of leffier dimenfions * becaufe of 
 the tquifondtum that’s between it, and the weight, that 
 finks it. 
 
 In fuch a Veffel many trials might be made. As firft, 
 that of the Torricellia^Expermext, which is nothing elfe, 
 butaGlafs-Tubfo many inches long, with a Mercurial 
 Cylinder in it of 2 9 inches high, that’s fuppofed tube 
 keptupatthathightby the Preffure of the Air. If this 
 were taken down about 34 foot, ’tis very probable the 
 Mercury would rife other 2 9 inches. The reafon is, be¬ 
 caufe the Air within the Ark, that preffeth upon the Sur¬ 
 face of the ftagnant Mercury, muft be under as much prtf- 
 fure again, as the Air above 5 but the Air above, is able 
 to fupport 29 '■> therefore this Airmuftfuftain 58. The 
 reafon why the Bcnfil is exa&Iy doubled is this, 34 
 foot of Water hath exadfly as much Preffure in it, as the 
 whole element of Air 5 therefore, the Air within the Ark, 
 being 34 foot down, muft not only have in it the Preffure 
 of the Air above, but the Preffure of the Water likewife: 
 this neceffarily follows, becaufe when two Fluids touch, 
 or are contiguous toother, the one cannot be under five 
 degrees of Preffure, unlefs the other be under as many.' 
 According to this reafoning, if the Ark go down 58 foot, 
 the Mercury will rife from 5 8 to 87, If to 102 ; it rifes 
 
 116, 
 
174 j^njoftattcai comments* 
 
 11 6, This reckoning is founded upon this, namely that 
 Water is 14 times lighter than Mercury 5 and therefore 
 one inch of Mercury requires 14 of Water to fupportit 
 in a Tub* and therefore, before Water is able to raife2p 
 inches of it, the Pipe muft be 34 foot deep. 
 
 • For a fecond trial, blow a Bladder as full of wind as it 
 can hold, and having knit the neck about w th aPack- 
 threed, place it in the Ark ^ and youwili find the fides, 
 that hath been ftifly bended become flaccid and feeble, as 
 if the one half of the Wind had gone out, and this will 
 come to pafs, before the Ark can go down eight or nine 
 fathom. The ftrong benfii of. the Air within the Aik is 
 the caufe of this : for as the Ark goes down, the Air 
 grows ftronger, and fo at length becomes of that power and 
 force, that it eafily overcomes the force and Benfii of the 
 Air of the Bladder, and reducing it to lefs room, caufes 
 the fidesbecome flagging. In this cafe, the faid Air, 
 that was oval, and had the form of the Bladder, muft 
 become round in form of aGlobe, becaufeoftheunifoim 
 Prefture, that it fuffers from the Air of the Ark. When 
 once the Ark is down 14 or 15 fathom, take the fame 
 bladder, and blow itftiffwith Wind, and knit the neck 
 as afore. And you will find that in the up-coming, the 
 frees of it will Surft afundef with a noife. When the 
 Bladder is thus full of Wind, ’tis fuppofed, that there is 
 a fort of counterpoife between it, and the Air of the Ark . 
 But as the Ark afeends, the Airofit, becomes weaker 
 and weaker, while in the mean time, the Air of the Blad¬ 
 der fuffers no relaxation; therefore, when the Ark comes 
 near the furface, there arifes a great difproportion between 
 the one Air and the other, as to ftrength, and therefore 
 the Air of the Bladder being theftrongeft, rents the fides 
 
. !^D?o8at(cal experiments* ' ijj 
 
 in pieces, and comes out with'a noife.' Or, blow it 
 but half full of wind, and you will find before, the Ark 
 come near to the top, the fiaid Bladder to be bended to 
 the full. 
 
 For a third trial, take a Glafs, fuch as they ufein 
 Caves, for preferving of Brandy, and flopping the mouth 
 clofely, take it down with yon in the Ark ; and you will 
 fee, the fides of it break in pieces, before you go down' 
 fouror five fathom. The ftrong Benfil of the ambient 
 Air, is the caufe of this. If you take it down with the 
 orifice open, no hurt fhallbefal it.. Or if you flop the 
 orifice in the up-coming, you will find the fame hurt 
 come to it. But here is the difference, inthefirft burft- 
 ing, the fides are preft inward, by the ambient Air ; in 
 the fecond, thefides are preft outward, by the Air with-- 
 intheGlafs,. 
 
 For a fourth trial, take a round Glafs-bottle, pretty' 
 ftronginthe fides, and when it is down with you in the 
 Ark 14 or 15 fathom, flop the mouth of it exactly, and 
 when it comes above, you will find a confiderable quan¬ 
 tity of Wind come out of it, when the orifice is opened. 
 Tnis evidently demonftrats , that the Air within the 
 Ark, 12,13, or 14 fathom down, is under a far ftronger- 
 Benfil then the Air above. 
 
 For a fifth trial, let a man apply to his skin a cold 
 Cupping-Glafs , when he enters the Ark; and he will 
 find fuch a fwelling arife within it, as when it is applied 
 hot by a Chyrurgion. This tumor begins to rife*; affoon 
 as the Ark- begins to go down. The reafon is evident 
 from unequal Preffure, the parts within the Glafs being*,. 
 lefs preft, than the parts without. 
 
 For a fixch trial, take a common Wt«ther*Gl*ft >' and* 
 
 place - 
 
176 ^DjoftaticaieKpetfinews* 
 
 Place it ia the Ark , and in the going down, you wiilfee 
 the liquor creep up in it, by degrees, as the Ark goes 
 down, as if fomeextraordinary cold , were the caufe of 
 it. And as the Ark comes up by degrees, the faid 
 liquor creeps down by degrees. The caufe of this Phe¬ 
 nomenon is not cold, as fome might judge, but the ftrong 
 Benftl of the Air within the Ark, that fo prefTeth upon 
 the furface of the ftagnant Water, that it drives it uo. 
 If you take with you , a Weather-Glafs t hermetically 
 fealled, no fuch thing will follow ; becaufe the outward 
 Preflare is keeped off. ’Tis not then cold, that’s the 
 caufe, but weight. By the way take notice , that all 
 Common Wuther-Glafes are fallacious and deceitful 5 
 becaufe the motion of the Water in them, is not only 
 caufed by heat, bur by the weight of the Air, which 
 fometimes is more, and fometimes lefs , as frequently! 
 have obferved, and as hath been obferved by others. 
 T his difference is found,by the alteration of the altitude of 
 the Mercurial cylinder, in the Barofcope, which is more and 
 lefs, as the Prcffure of the Air changeth. In fair weather, 
 and before it comes, the Mercury creeps up. In foul and 
 rainy weather, and a pretty while, before it fall out, it 
 creeps down, Becaufe in fair weather, the weight of 
 the Air is more, than in rainy and dirty weather. Decern - 
 her, 13. 1669. Ifoundthe altitude 29 inches, andnine 
 ten parts of an inch: at this time the heavens were cover¬ 
 ed with dry and thick clouds, and no rain followed. 
 March 26,1670, Ifound the altitude no morethan 27 
 inches, and nine ten parts, at which time, there was a 
 ftrong Wind with ram. Between thefe two termes of 
 altitude, I have found the Mercury move.near a twelve 
 moneth, "Tis a moft fure prognofticator, for if after 
 
%t >Diottattcal Cypn iments, 177 
 
 rain, you find the Mercury creep up in the mottling, yoR 
 may be fore, all the day following will be fair, notwith¬ 
 standing that the heavens threateneth otherwayes, If 
 after fair weathsr,. the Mercury fubfide, and fall down a 
 little, you may before of rain within a foort time, though 
 no appearance be, in the prefent. It falls down likewife, 
 when winds do blow. What the true caufo is, why there 
 is fuch an alteration in the PrefTure of the Air, before foul 
 weather, and fair, and in the time of it, it is not eafie to 
 determine. 
 
 But we proceed. Trial likewife might be made, by 
 firing a great piece of Ordnance above, whether the re¬ 
 port would be heard btlow the Water or not? This 
 would determine the queftion, whether Water be a fit 
 medium for conveying found as Air is. ' Item, whether or 
 not, the Sea water be fre/her at the bottom, than near the 
 top, which is affirmed by fome. Item, whether founds 
 be as diftinft in fuch a fmall portion of Air, as they are 
 above. This might be tried with a Eell of a Watch. If 
 need were, a little chamber Bell might be hung within the 
 'Ar^ and a fmall chord might pafs up from it, through the 
 cover, whereby the perfons above, might by fo many 
 tingles, fpeak fuch and fuch words to the Diver, I have 
 demonftrated before, that though there were a little nar¬ 
 row hole made in the cover above, yet neither Air would 
 go out, nor Water come in. If a man were curious, he 
 might have a window not only in the Tides, but in the roof 
 above, covered with a piece of pure thin Glals, thorow 
 which he might look up, after he is down two or three fa¬ 
 thom, and fee whether there appeared any alteration in 
 the dimensions of the body of Sun or not, or feemed 
 nearer. 
 
 VVfl 
 
 Z 
 
17s 
 
 c^sioSatfeal e^pcrtmcitfsh 
 
 Wen 
 
 come to infer tome Hfdroftatical conclufions, 
 
 _ - 
 
 orme: Experiments, V» 
 
 T e fee then firft, that in 
 
 Were: ; 
 
 ^e~eis :p:eliu:e 5 name! 
 
 yrrom theftronq Benpl 
 
 0-'the ‘ 
 
 fir within the Ark, that 
 
 sroweth ftronuer. and 
 
 ft. oncer 
 
 . 1; the Water sroweth a 
 
 eeper. and deeper. We 
 
 i~r r =v - 
 
 . that the neffure 0: the 
 
 : VViter hath an incre- 
 
 rr.en:: 1 
 
 :e;:ufe the further down 
 
 the Ark goetn, the Air 
 
 is them 
 
 trebenteu. Thrrdiv, tt 
 
 vo Fluids cannot becon- 
 
 
 we to another. inlets bo 
 
 th or them be under the 
 
 We de. 
 
 „ - lure: became 
 
 the Air of the A-k, and 
 
 
 lepethup w;t: 
 
 tin the mouth of it, are 
 
 newer:: 
 
 rr-e- the feme ceur 
 
 ee cf power, and force, 
 
 rA---— 
 
 "-efsbe. Feu: 
 
 thlVj that in Fluids the 
 
 - „ _ , 
 
 Tww-n * bwCZUit tF.S 
 
 Air of the Ark , and the 
 
 W. . 
 
 fttbeut- crefs moft equal: 
 
 :v. one asainft the other. 
 
 r.f-m-.-, 
 
 the more that the Air h 
 
 s bended, it is the more 
 
 r ■■■-■-■,• - 
 
 r.o onfeqi 
 
 lently, that the diminu- 
 
 t.cn 0: 
 
 the cuma.ty, :s iccorckn 
 
 ig to unequal proportion. 
 
 s. 
 
 that when. toe Ark At 
 
 own 34 foot, the Benfil 
 
 c: the’ 
 
 Air is doubled : end trip 
 
 led, when its dotvn 6& 
 
 
 ectute the nreiture of 34 
 
 . foot of Water, is as 
 
 r.^:h a 
 
 s the whole prefture, tha 
 
 fs from the Atmfphere. 
 
 lift be 
 
 encuirec. how much we 
 
 ightrefts upon the palm 
 
 ct anna 
 
 ns time, vweathe Ark: 
 
 s down about 68 foot? 
 
 I imiwe: 
 
 the preiTure of the W 
 
 'aterupon a mans hand, 
 
 
 ceepnef; with thepreftur 
 
 ■e of the Air above, will 
 
 beer:: 1 
 
 client to the weight of 1 p: 
 
 illar of Mercury 87 inches 
 
 hfthf, a 
 
 
 ■hich wIII exceed in real 
 
 weftr: 
 
 too pound. It fomuch 
 
 reft upon the palm, how 
 
 r-:c L “• 
 
 tuft reft uoon the reft oi 
 
 the parts of the body ? 
 
 Let us 
 
 ■'uppoie then, the quantity 
 
 7 of the palm, to be found 
 
 :a a m: 
 
 ns skin, a00 times, the. 
 
 n mufthe iuffer as much 
 
 Prefiiire, 
 
i^DjQftattcai 179 
 
 prelfure, and a&ually fupport as much burden, as will 
 amount to 40000 pound weight. Seventhly, our bodies 
 may be under a huge prelfure, and yet that burden not 
 perceptible ; as is evident from the Diver, who findeth 
 little or no weight, while he is under the Water. Or if 
 there be any Prelfure found, it’s not comparable to that, 
 which really is.. Eighthly, when a man is 14 or 15 fathom 
 down, at every infpiration and expiration, his breaft and 
 belly mull lift up the weight of 1800 pound: becaufe, if 
 the whole burden be 40000, the weight that refts upon 
 the breaft, and belly, will be about 1800, Ninthly, that 
 between every infpiration, and expiration, there happens 
 a perfect counterpoife, namely by the Air, that goeth in¬ 
 to the lungs, and the outward Air of the <^trk: for if the 
 Prelfure of the one, were more, than the Prelfure of the 
 other, there could be no motion of the lungs. Tenthly, 
 when a man draweth his breath, the Air cometh not in by 
 futtion , but by pulfion. For this caufe,. though the 
 Wind-pipe were flopped, yet a man might live by having 
 a hole in his fide, going into the lungs. Laftly, that 
 there is no fuch thing as futlion properly $ and therefore 
 the motion of all Fluid bodies, is caufed by Prelfure and 
 weight. The motion of the blood then thorow the heart, 
 is driven, and not fueled. Infants properly do not fuck, 
 but have the milk fqueezed into their mouth. ’ T is evi¬ 
 dent from the fucking-glafs that fome women ufe for milk¬ 
 ing their own breafts: for by help of this, the Air that 
 guardeth the head of the Pap is removed, and fo the Air, 
 that preffeth the parts about,and without,fqueezes out the 
 milk. 
 
iSo $p0!0(latlcal erperimcnts. 
 
 EXPERIMENT XIX, 
 
 Figure 26, 
 
 T His Figure reprefents a deep Water, whofe firft and 
 vifible furface, is F G. The imaginary Mace, is 
 E L C, 34 foot below it. A D B is a siphon, working 
 below this Water with Mercury. A E L isa VeiTel with 
 ftagnant Mercury, among which the orifice A is drowned, 
 the other orifice B exifling among the Water, DM is 
 the hight of the Siphon above the line of level, which I 
 iuppofeis 58 inches. For making it work, flop the two 
 orifices ciofely, and pour in as much Mercury at a hole 
 •made at D, as will fill both the legs. Then flopping the 
 (aid hole, open the two orifices A and B, and you will find 
 the liquor run as long out at B,as there is any almoft in the 
 veflel A E L. For evincing this, which is the only dif¬ 
 ficulty, confider, that if this Siphon, \vere filled with 
 Water, and made to work only with Air, (as is clear from 
 daily experience ) the liquor would run outconftantly at 
 B, Becaufe there is here an unequal Preflure •, the furface 
 of Air N B, being more burdened, than the furface E L C, 
 but where unequal Preflure is in Fluids (according to the 
 12th Theorem) motion muft follow, I prove the fur¬ 
 face N B to be more burdened, than the furface E L C, 
 becaufe the Water B D, is heavier than the Water L D, 
 as is evident to the eye. The Air B therefore, fuftaining 
 far more weight, than the Air E L3 muft cede and yeeld. 
 Next, there is here a pondt'.s and apitentia, the pontlus is 
 the Water L D ; the potentU by which it is counterpois¬ 
 ed, is tfie Water B D 5 but thefe are unequal, B D being 
 
 heavier. 
 
if pojoftatfcal extents* 1S1 
 
 heavier, than L D - therefore according to the 3 3 Theo¬ 
 rem, thefetwo Fluids cannot ceafe from motion. If it 
 be faid, that the furface N B is Wronger; than the furface 
 ELC, feingit is lower. lanfwer, the difference is fo 
 unfenfible, that they may be judged but one. Now, I 
 fay, if this Siphon work in Air, with Water, it muft 
 likewife, work in Water with Mercury. Therefore, this 
 Siphon being 54 foot below the firft furface F G, the liquor 
 muft run outconftanrlyatB.’ Becaufe, there is here, an 
 unequal Preffure, the furface of Water N ’B, be ng more 
 burdened, than the furface ELG. Though there be 
 more weight in N B, than in E L C, becaufe it is lower, 
 yet becaufe the difference is not fomuch, as is between the 
 weight of B D, and the weight of t D, it proves nothing; 
 Notehere, that fo long as D, iswithin 5; 8 inches of E L 
 C, this Siphon will work. The reafon is, becaufe the 
 Preffureol 34 foot of Water, with the Preffure of the 
 Air, upon F G, are able to raife Mercury exadfly 5 8 inches. 
 But if D exceed that hight, no Ait will make the liquor 
 run out at B.' Note fecondly, that this Siphon will ope¬ 
 rate with Air and Water , though the top D were 34 
 foot above Ms and the reafon is, becaufe the Preffure of 
 the Air, is able toraife a pillar of Water to that hight. 
 Note thirdly, that if there were an orifice opened at Cj 
 upon the level line ELC, the two Waters would become 
 of the fame weight, the one not being able to move the 
 other. If you bore a hole at Ri the liquor afccnds from 
 R to D, and’goeth down from D to A, and (o the motion 
 ends. But, if the leg AD Were fix! times wider, than 
 B D, the liquor would not run out at B, I ihall anfwer 
 this in the clofe. 
 
 From 4his EKperiment we fee firft, that the motion of 
 Fluid- 
 
i8z ijptifoGaticai experiments. 
 
 Fluid Bodies up thorow Pumps, and siphm is not for 
 fhuning vacuity, but becaufe they are preft up violently. 
 We fee next, that when the PrefTure is uniform , there 
 is no motion in Fluids 5 but afloon, as one partis more 
 preftj than another, motion begins •• becaufe, this Siphon 
 will not operate,if the orifice be made in C 5 but if fo be,it 
 be in D, then the motion begins ; becaufe there is here 
 an unequal PrefTure, which was notin the other. We 
 fee thirdly , that Fluids have a determinate Sphere of 
 atfivity, to which they are able to prefs, and no further: 
 becaufe this Water, is not able to prefs Mercury higher 
 than 5 8 inches. So the Air cannot raife Water higher 
 than 34 foot. If this Water were 6 8 foot deep, the 
 Sphere of it’s activity would be 116 inches. We fee 
 fourthly, that inF'uids there is a Pondus and a Potential 
 and that the inequality of weight between the two, is the 
 only caufe of motion. We fee fifthly, that as long as 
 this inequality of weight continues, as long continues the 
 motion, becaufe , as long as B D. is heavier than L D, 
 the motion perfeveres. We feefixthly, the poffibility 
 of a perpetu.il motion in Fluids; becaufe the liquor runs 
 perpetually out at B, If it be faid, the motion ends 
 when the ftagnant Mercury A E L faileth. I anfwer’ 
 this flop is only accidental, and not ellentially from the 
 nature of Fluids. If it be enquired, whether or not,would 
 the Mercury run out at B, upon fuppofition, the flunk 
 LDwere twice as wide, as the fhank B Dr Ianfwer 
 it would. If it be faid that the one is far heavier than th§ 
 other, namely L D than DB. I anfwer, weight in 
 Fluids is not counted according to thicknefs, but ac¬ 
 cording to altitude. 
 
 EX PE- 
 
^pDjoftaftcai $£pecftmnt£u 183 
 
 EXPERIMENT IX 
 
 Figure 27. 
 
 '■'TpHis laft is for demonftrating the precife and juft 
 JL weight of any Pillar of Air, Water, Mercury, or 
 of any other Fluid body , if fome of their dimenfions, be 
 but once knowen, A B then is a fquare Pipe 12 foot high, 
 and fix inches in widenefs, full of Water, refting upon 
 the furface of Air AC, And E G is a fquare Pipe 12 foot 
 high, and 12 inches wide, full of Water, refting upon 
 the furface of Air E F, None needs to doubt, but 
 the two Waters, will be fufpended after this manner, 
 even though the orifices A and E were downward, efpeci- 
 ally if they be guarded with Water, but thedemonftra- 
 tions, will be the more evident, that wee fuppofe the 
 two Pillars of Water to be fufpended as they are. From 
 this Experiment I fay firft, that the Pillar of Air C D is 
 168 pound weight, at leaft 5 which I prove thus. The 
 Water A B is 168 pound: therefore the Air C D, muft 
 be as much. I prove the Antecedent , becaufe it’s a Pillar . 
 of V Vater 12 foot high, and fix inches thick: but every 
 half cubical foot of Water, that conraines 2 r <5 inches, 
 weighs feven pound: therefore feing the Pillar is 12 foot, 
 it muft contain 24 half feet ? but 24 times 7 is 168. The 
 only difficulty is to prove the Connexion , which I do thus, 
 from the feventh Theor, all the farts of a Fluid in the fame 
 Horizontal line , are equally frefl, but fo it is, that the 
 part A, and the part C, are in the fame horizontal fur¬ 
 face ^ therefore the part A, and the part C, are equally 
 preft. But if the parr A, and the part C, be equally 
 preft, the Pillar of Air C D, muft be as heavy, as the 
 
 Pillar 
 
is 4 Wioftatical Cicpertments* 
 
 Pillar of Water A B. I fay fecondly, that the Pillar 
 of Air F H, weighs 672 pound, I prove it thus, The 
 Water E G weighs 67a pound 5 therefore the Air F H, 
 weighs as much. The Antecedent is clear, becaufeEG, 
 is z fquare Pillar of Water 12 foot high, and 12 inches 
 thick ; but every cubical foot of Water weighs 5 6 
 pound .■ but 12 times 56, is 572. I prove th 2 connexion, 
 as before. All the parts of an horizontal furlace, are 
 equally preft 5 therefore the part F, muft fuftainas much 
 burden, as the part E. 
 
 To proceed a little further, let us fuppofe the Pipe 
 AB to be 34 foot high, and the Pipe E G to be as 
 much, Iaffertthen thirdly, the Pillar of Air C D to 
 weigh 475 pound , which I prove as before. All the 
 parts of the fame furface , are burdened with the like 
 weight, but the part A fuftains 47 6 pound, therefore the 
 partC muft fupport as much. The Connexion is evident, 
 and the Antecedent isfo too, becaufe the Water A B 
 being 34 foot high, and fix inches thick, muft weigh 
 475'pound: for, if 216 inches , w r eigh feven pound, 
 14688 inches, muft weigh 476pound. I aftert fourth¬ 
 ly, the Pillar of Air F H to weigh 15104 pound, which 
 Idemonftrat by the former Medium. All the parts of a 
 Fluid that ly in the fame horizontal furface, are equally 
 preft ; but fo it is, that E and F , do fo ly ; therefore F 
 muft be as muchburdened as E$ the Water therefore E G, 
 weighing 1504 pound , the Air F H, muft weigh as 
 much. For if 216 inches of Water weigh feven pound, 
 )87)2:nches (for fo many are in the Water E G) muft 
 weigh 1904 pound. 
 
 Let us fuppofe fecondly, the Tub A Bto be only 29 
 inches high, and the Tub E G, of the fame hight, and 
 
 that 
 
i^mofta tical ffy pcrimentg, jgy 
 
 that fix inches wide, and this 1 1 inches wide, I affirm 
 then fifthly, the Air C D to weigh yet 476 pound, and 
 the Air-FH, to weigh 1^04 pound. Becaufe the.Pillar 
 of Mercury A B , weighs 476 pound , and the Pillar 
 of Mercury F G, weighs 1^04 pound: therefore, if A B 
 be 476, C D muft be as much. And if E G be 1504 ; 
 F H, muft be of thefame weight. .1 prove the Mercury 
 ABto weigh about 476 pound, though it be but 29 
 inches high j becaufe it is 14-times heavier then Water. 
 For the fame caufe,, doth the Mercury E G weigh about 
 1504 pound. Ilay^fl##., becaufe 34foot, containes2? 
 inches, more than 14 times. 
 
 Let it be fuppofed thirdly, the Pipe E G, ( being 34 
 foot high ,) to have the one half of ft IG, full of Air, and 
 the other half E K full of V-Vater, I affirm then fixthly, 
 the part E, and the part E, to be yet equally burdened. 
 That’s to fay, the VVater E K, that’s now but 17 Foot, 
 makes as great a PrefTure upon E, as when it was 34 foot. 
 The reafon of this, is furely .the PrefTure of the Air IG, 
 that bears down the Water K E, with the weight of 9 j.z 
 pound, the half of 1^04 pound. If it be faid according 
 to the Theorem 21, that there is as much.PrefTure and 
 weight in the leaft part of a Fluid, as in the whole 5 there¬ 
 fore the AirlG, muft be as heavy as E H, Ianfwer 
 IG, is not fo heavy as E H, becaufe the Water EK 
 impending in the lower part of the Tub, hath occafioned 
 the Air IG, to expand it felf fo many inches, by which 
 means, it lofeth fo many degrees of it’s Benfil, ■ If you 
 remove the Water EK, then will the Air IG, be as 
 heavy, as E H3 becaufe E K being Air, it reduceth 
 IG to that fame degree of Benfil with it felf * but when 
 the Ail' E is burdened with the Water E K , it can- 
 A a not 
 
186 lipDiottaticaic.tpctlmenc?. 
 
 not make the Air IG, of that fame weight with it felf. 
 
 Let us fuppofe fourthly, that only eight foot and an 
 half of Water, are in the Tub, namely between E and N. 
 
 I fay then feventhly, that the part E, is as much bur¬ 
 dened with it, as when the Pipe was full * becau'fe the 
 foot, and an half of Air N G, is ex idly as heavy, 
 as the 2) foot and an half of the Water that’s gone. I 
 prove it thus. The Air E hath the weight of 1904. pound 
 in it felf, feing the weight of the furface , is alwayes 
 equal to the weight of the Pillar, but being burdened 
 with the VVaterEN, that weighs 476 pound, it can* 
 not prefsupwith more weight then with 1428 pound.* 
 and therefore the top of the Water N , mull prefs upon 
 the under part of the Air, that’s contiguous with it, with 
 1428. If this be, the Air N G, muff-prefs down with 
 as much, feing according to the 20 Theorem , it is im» 
 poffible, that one part of a Fluid , can be under Preflure, 
 unlels the next adjacent part, be under the fame degree 
 of Preflure. Therefore I conclude, that the 25 foot and 
 an half of Air NG, is as heavy , as the 2 > foot and an 
 half of the Water that’s gone, This makes it evident 
 alfo, that when the Pipe is half full of Water, asEK, 
 the Air IG, hath the weight of 95 2 pound. Becauie E 
 being in it felf 1904, but being burdened with E K 952, 
 it cannot make the top of the Water K , prefs upon I 
 with more weight than 952; and therefore ( by the 20 
 Theorem,) the Air G I, muft weigh 952 likewife. 
 
 I affirm eighthly, that, when the Pipe is full ofWaterf 
 from E toG, if a man poife it in his hand, he doth not 
 find the weight of the Water E G. And the reafon is, 
 becaufe it’s fuftained by the part of the furface E. But 
 lithe Air E fuftain it, my hand cannot Main if. I find 
 
 then 
 
$!>D>oflat(f.al cjcpetimcnts. 1S7 
 
 then only the weight of the Tub, but not the weight of 
 the Water within it. I fay ninthly, that when I poife 
 the faid Tub, I find the whole weight of the Pillar of Air 
 L M, which is exactly 1904 pound, I prove it thus. 
 The pondus of a Fluid is then only found, when there is 
 not a fotcntU to counterpoife it, oracleaft, when the po- 
 tentia is inferior to the pondus: but there is here no foten - 
 tid, counterpoifing the pondus of the Air L M. There- 
 fore, I muft find the weight of it, when I lift up the Tub. 
 The major proportion is clear from the tenth Theorem. It’s 
 evidenc alfo, from common experience; for while a bal¬ 
 ance is hanging upon a nail, with fix pound in the One 
 fcrle, and nothing in the other, you will find the. whole 
 burden, if you prefs up that one fcalewich the palm of 
 your hand.. But if fo be, there were fix pound in the op* 
 pofite fcale, you will nor. find the firft fix •, and the reafon 
 is, becaufe it is in equilibria with other fix. ’Tis juft fb 
 here, I muft find the weight of the Air L M, while I 
 poife the Tub, becaufe it wants a weight to couflterbal- 
 lance it. I prove the minor proportion thus. If any thing 
 counterballance the Air L M, it muft either benhe Air 
 below, namely the part E; or the Water EG: btit'nei¬ 
 ther of the twain can do it. Not the Air E, becaufe it 
 hath as great a burden upon it, as it is able to fupport, 
 namely the Water.E G, that weighs 1904 pound. And 
 for thisciufe, not the Water irfelf,- feing. alt the'force 
 it can have to counterballance L Mi is ffom the furface of 
 Air E •, but this is in equilibria with it already, I faid 
 that the Air L M, was exa&ly JP04 pound weight. This 
 alfo is evidervt, becaufe it is juft of theft? fa’tfiedimerifions, 
 with the Air F H. If it be faid-the 1 Air ENPitJuft be thick¬ 
 er; feing it’s equal to the Tub without 5' but the Air 
 A a 2 ^ PH. 
 
i8s $p.D*Qftaucat experiments. 
 
 F H, is only equal to the Tub within. I anfwer, it is fo in¬ 
 deed ^ but here is a folution to the difficulty. I do not 
 find the whole weight o{ the Air L M, but only as much 
 of it, as is equal to F H. Suppofe the Tub to be 12 inches 
 within, from fide to fide, and 1 6 without, from fide to 
 fide. I fay then, I find only the burden of fo much Air, 
 as answers to the cavity of the Tub,becaufe the reft of thefe 
 inches, are ccunterpoifed, by as much below, namely by 
 the Air,that environs theoiifice E: for it’s fuppoled, that 
 it the Tub be two inches thick above, it muft be as thick 
 in the lips. So that the whole Tub, is not unequally prefix, 
 but only fo much ol it within upon the top, asanfwers to 
 the cavity. Tenthly, that when the Pipe is but-half full 
 of Water, namely from E to K> I find only 952 pound 
 of the Air L M, .though before I found 1904. The rea* 
 fonis, becauCe the one half of it is now counterpoifed by 
 the Air IG, and therefore the weight of it becomes infen- 
 fible,. ’Tis dear from the fixth affiertion, that the Air 
 IG, preffeth down with 95 2 ; therefore it muft prefs up 
 with as much, feing according to the fixth Theorem, .the 
 Preffure of a Fluid is on every fide. Eleventhly, that when 
 there is only eight foot of Water and a half in the Tub, 
 namely between E and N, I find only 476 pound of the 
 Air L KG Becaufe in this cafe, the Air N G counter- 
 poifeth 1428 pound of it. For if the (aid Air, burden the 
 Water N E, with 1428 pound,as is clear from the feventh 
 affertion, it muft likewife prefs up the Tub with as much, 
 and fo counterpoife as much of the Air L M. Twelfthly, 
 that when there is nothing within the Pipe but Air, the 
 whole weight of the Air L M becomes infenfible to me. 
 The reafon is evident, becaufe it is wholly counterpoifed 
 by the Air within the Pipe, I affirm thirteenthly, that 
 
 the 
 
^ytyoftattcai experiments 18* 
 
 theVVater EG, is \w equilibria with the Water A E 
 that’s to fay impound, is in equilibria with 475 pound. 
 
 I prove it-evidently* by the firft medium % all the parts of' 
 an Horizontal fuiiace, are equally preff; therefore the 
 part A, fuftains nomoreburden, then the part E, there¬ 
 fore A B, is as heavy as E G, -and confequently, the Air 
 CD, nauO.be as heavy, as the Air FH. Left this pro- 
 pcfition may ieem to contradict what is already faid ,1 muft' 
 diftinguifha twofold laIlance,according to the third Theo¬ 
 rem, one Natural^ another Artifcid, In the Artificial 
 Ballance, where magnitudes do weigh according to all their 
 dimenfions, viz. Longitude , Latitude, and Profundity, the 
 Water A B, and the Water E G, ar e not in equilibria to- 
 gether,feing the one is 1428 pound heavier than the other. 
 But in the Balance of Nature , fuch as thefe Pipes are, all 
 the {our makes an equifondium together becaufe they do 
 not weigh here, according to their thicknefs , but only ac¬ 
 cording to their altitude. Therefore leing A B is as high 
 as E G, and feing CD is as high as F H, they-muft all 
 be. of the fame weight.- 
 
 From the firft aftertion I infer, that one and the fame 
 Fluid, even in the Ballance of Nature , may fometimes be 
 in equilibria with a left’er weight, and fometimes with a 
 greater, becaufe the Air C D, that weighs really 476- 
 pound, is in equilibria with the Water A B, that weighs 
 but 168. This is, when A B is fuppofed to be only 12 
 foot high. It’s likewife in eqnilibriomth it, when its 34 
 foot high. But how can A B, that’s 12 foot high, prefs' 
 A, with as much weight, as when its 34 foot high ? I an- 
 fwetbya fimilitude, when a Cylinder of Wood 12 foot 
 high ftands upon a Table, it may burden it as much,' as if 
 it. were a Cylinder 34 foot high. For, fuppofingit to be- 
 
i9o £pDjoftaticai cicpenmetus* 
 
 thmft in, between it, and v, g. the ceiling of the room 
 above, it muft prefs down with more weight, then if it 
 were not thruft in. So, this Cylinder of Water AB, 
 that’s but 12 foot high, being preft between thefurface A, 
 and the top of the Tnb within, muft burden A, as much, 
 as if it were 34 foot high; for being of this hight, it only 
 ftasds upon the furface, without preffing up the top of 
 the Tub. 
 
 I infer from the fecond affertion, that each Pillar in a 
 Fluid hath a determinate weight. This is evident from 
 the determinate weight of AB, that weighs firft 168 
 pound, being 12 foot high, and 467 pound, being 34 
 foot high, and fo of the reft. I infer fecondly, that the 
 thicker, and groffer a Pillar of a Fluid be, it is the heavier, 
 (even in the Artificial Ballancc ) and contrariwife, the more 
 flender and thinner it be, it is the lighter. This is evident 
 from the Water A B, fix inches thick, that weighs 476 
 pound, and from the Water E G, 12 inches thick, that 
 weighs 1904 pound. So doth the Pillar of Air C D,weigh 
 lefs, then the Pillar F H, Here is ground for knowing 
 the certain and determinate weight of a Pillar, in any fort 
 of a Fluid w'hatfoever. As to Air, its clear and evident, 
 that a four-fquare Pillar thereof, 12 inches everyway, 
 weighs 1904. That's to fay, if it were poffible, to take 
 theiPiiiarof Air F H, in its whole length, from thefur¬ 
 face of the earthy to the top of the Atmoffhcre , and pour 
 it into the Scale of aBallance, it would be exadtly the 
 weight of 1904 pound. Here isafecret .• though that 
 fameJPillar of Air, were no longer., than 6 or 10 foot, yet 
 theiPreflureofit, upon the body, itreftsupon, is equiva¬ 
 lents. 1904 pound. If this be, (you fay) what is the 
 weight of Air, that refts upon this Table, that’s 3 6 inches 
 
 fquare £ 
 
K^mofta tical Cjc ptEftrontg, 191 
 
 fquare i I anfvver, it muft be as heavy, as a Pillar of Wa. 
 ter 34 foot high, and 36 inches thick, which will, by juft 
 reckoning, amount to 17136 pound, or to 1071 ftone 
 weight. It may be inquired next, what’s the weight of 
 the Air, that burdens the pavement of this parlour, 
 that’s 16 foot fquare ? I anfwer 487424 pound. Becaufe 
 it is exadly the weight of a bulk of Water 34 foot high, 
 and 16 foot thick, ’Tis to be remembred, that though 
 the Pi effure of it, be fo much, yet being poured into 
 the fcale of a Bailance, it will not weigh fomuch: for 
 not only as much as fills the room mnft be taken, but as 
 much as pafteth from the pavement to the top of the 
 Atmofphere. According to this method ’tis eafie to deter¬ 
 mine the weight ofany Pillar of Air whatfoever, provided 
 amanbutonceknowthethicknefsofit, both thewayes, 
 e,g, there’s a flmm 12 inches long, and fix inches broad, 
 upon which reftsa Pillar of Air. The weightofit then 
 is, juft the burden of a magnitude of Water 34 footin 
 hight, 12 inches in length, and fix inches in breadth. 
 
 Though the weight of any Pillar of Air may be known, 
 by knowing only the dimenfions of it, in breadth and 
 length-, yet the weight of a Pillar of Water cannot be 
 known, unlefs all the three common dimenfions of ir, 
 be fivft known. The reafon is this, the Pillais of Air, 
 are all of the fame highr, but the Pillars of Water in the 
 Ocean, are of different hightstherefore, not only muft 
 they be known, [ecundtm longitudintm , & Utitudhem,, 
 in length and breadth, but [ecundum frofunditatem , that 
 is, according todeepnefs, ’Tis eafie to know then, whac 
 each particular Pillar weighs. ' Fhftthen, try how much 
 weight is in a cubical foot of Water, and having found 
 this to be v.g, 56 pound, you may determine, that a 
 
 Pillar 
 
i9i $ptyo&atfcai experiments. 
 
 Pillar of Water 34 foot high, and 1-2 inches thick,weighs 
 1904 pound. A Pillar 34 foot high , and fix inches 
 thick weighs 476 pound. Note, that in a Cube of 
 Water fix inches thick, there are 211? inches, which 
 weighs feven pound. In a Pillar 12 inches thick, and 2 0 
 fathom, or 100 foot high, you will find 5600 pound 
 weight. In one, of the fame thicknefs, but 200 fathom 
 high, there are 56000, fifty fix thoufand pound weight. 
 In a Pillar three foot fquare, and 20 fathom deep, there 
 are ' 0400, fifty thoufand, and four hundred pound 
 weight. Make it 200 fathom high with that thicknefs, 
 and it will weigh 5 04000, five hundred and four thoufand 
 pound. But, if according to the Theorem 25 , you 
 confider. the weight of the Air above , it will weigh 
 521136, five hundred, twenty and one thoufand, one 
 hundred thirty and fix pound. A Pillar x 2 foot fquare, 
 and 300 fathom deep, weighs 1205)6000, twelve million, 
 ninety and fix thoufand pound, Laftiy fuppofe there 
 were a bulk of Wacer 500 fathom deep, and 5 00 fathom 
 thick, fucha magnitude would weigh 8750000000, 
 eight thoufand feven hundred , and fifty million of 
 pounds. But if the PrefTure of the Air, that refts upon 
 a furface of Water 500 fathom in- breadth and length, 
 be taken in, that weighs 119000000, a hundred and 
 nineteen million of pounds, the total, that the bottom 
 of the lea fhftains,muft be 8940000000, eight thoufand, 
 nine hundred and fourty million of pounds, or 5 5 8750000 
 five hundred fifty and eight million, feven hundred, and 
 fifty thoufand ft one weight. 
 
 I infer from the fifth aflertion, that the lighteft of 
 Fluids may be brought to an equilibriun^mth the heavieft. 
 For though Mercury be 14000 times heavier than Air, 
 . " ~^ 
 
$pmoftatfcaieKpertment& i 93 
 
 yet the part of the furfaceA, is no more preft with 
 the Mercury A B, th^n the part C is preft with the Air 
 C D. Secondly, that 29 inches of Mercury, are of the 
 fame weight with 34 foot of Water. Thirdly, the heavier 
 a Fluid be naturally, it hath the lefs altitude in the 
 Natural Ballance ; and contrariwife, the lighter it be, it 
 hath the more altitude. This is clear from the Mercury, 
 that’s 19 inches, the Water that’s 34 foot, and the Air, 
 that’s counted 6867fathom. 
 
 I infer from the fixth afTertion, that two Fluids of 
 different gravities , may make an equilibrium with a third 
 of the fame kind. Becaufe the 27 foot of AirIG, and 
 the 17 foot of WaterEK, arein^»//;'^/>with the Air 
 F H. I infer fecondly, that 17 foot of Air, may be as 
 heavy as 17 foot of Water, becaufe the Air’I G, isexa&ly 
 as heavy, as the Water E K. I infer thirdly, that the 
 Benfil of a Fluid, is a thing really diftinft, from the 
 Natural weight of it: becaufe the PrefTure of the Air IG, 
 is 9 j z poHnd 5 but the natural weight of it will not exceed, 
 if it were weighed in a .Ballance, two or three ounces. 
 I infer fourthly, that Air cannot fuffer dilatation, but it 
 muft lofe of it's PrefTure. Becaufe the Air IG, that ought 
 to weigh 1904 pound, weighs only 9 5 2. For under- 
 ftanding this , you muft know , that when a Pipe is 
 about half full of Air, and halffull of Water, and inver¬ 
 ted, fo much of the Water falls out, and confequently 
 fo many inches doth the Air above it, expand it feJf. So 
 to make this Pipe that’s 34 foot high, half full of Air 
 and half full of Water, youmuftpourin about 19foot 
 of Water, and the 15 foot of Air that’s in it befides, 
 will, when the Pipe is inverted, go up and expand it fell 
 to 17 foot, two foot of Water falling our, 
 
 B b I in. 
 
iH $po?ottattca! erpccimctits. 
 
 ■ I infer from the feventh afTertion , that when there are 
 two Fluids of different gravities, and weights counterpoi- 
 flag a third, by what proportion the one grows lighter, 
 by that fame proportion the other becomes heavier. For, 
 when the VVater E K, that weighs 952 pound, becomes 
 EN, that weighs 47 6, the Air above it, that weighed 
 9)2, becomesnow 1428pound. 
 
 I infer from the eighth, that the pndus of a Fluid, can¬ 
 not be counterpoifed, by two diftin«ft pwers. Becaufe 
 the 34 foot of Water E G, cannot be both fuftained, by 
 the part of the furface of Air E, and my hand. I infer from 
 the ninth, that the Preffure and weight of a Fluid, may 
 be found, even in its own Element, by fenfe. Becaufe 
 inpoifing of the Tub, I find the weight of the Air LM. 
 
 I infer fecondly, that the weight of a Fluid is only found is 
 its own Element, when there is not a ptentia to counter^ 
 poife the pndus of it, becaufe I find only the weight of 
 the Air L M, becaufe it wants a ptentia to counterpoife 
 it. I infer thirdly, that it is very poffible even in the Ar¬ 
 tificial B.:/lance > to weigh a Fluid in its own Element, and 
 to know the precife weight of it, to a grain. For this 
 caufe, take a fmall chord, and fatten therewith the top of 
 the Pipe G, to the Scale of a Ballance, and the Lead or 
 Stone that makes the counterpoife in the oppofite tole, is 
 the juft weight of the Air L M. 
 
 I infer from the tenth, that by how much the nearer, 
 the ptentia of a Fluid, comes to the pond vs, by fo much 
 thelefs, is the pndus found, or is fenfible. This is clear, 
 becaufe I find lefs of the weight of the Air L M, it being 
 counterpoifed with the Air I G, than before. This fol¬ 
 lows Iikewife from the eleventh afTertion, . I infer from the 
 twelfth, that when the pndus of a Fluid, is counterpoifed, 
 
^yfyo ftaHcal ££pertment 0 , 195: 
 
 by an equal pote»tk h It becomes altogether infenfible. I 
 infer {rom the laft, that two Fluids differing in weight, ac¬ 
 cording to the Libra or Artificial Ballance^ may agree in 
 weight,according to the Natural Ballance, I infer fecondly, 
 that Fluids in the Ballance of Nature^ do not councerpoifr 
 one another according to their thickness, but only accor- 
 ding to their altitude. *> ! 
 
 To put a clofeto this Experiment, let usfuppofe the 
 Pipe EG to be 6 S foot high, and void of Air, If 
 then the orifice E be drowned among fbgnanc Wa¬ 
 ter, the Liquor of its own accord fas it were) will rife 
 from E to K 34 foot, the other half I G remaining 
 empty. This evidently fhevvs, that the PrefTureofthe 
 Air, hath a Sphere of Atftvity, beyond which it is not 
 able to raife or prefs up a pillar of VVater. 'Tis folly then 
 to think that Water maybe conveyed over high places by 
 thehelpofo Siphons v,g. from the one fide of a Hill over 
 the top, to the other fide. For, if that hight exceed 
 perpendicularly 34 foot, no Art will do it. Yet contra-, 
 riwife, it is poffible to tranfport Water, by Pipes and Si¬ 
 phons, not only 34 foot below the fmrce, but 3400. 
 Nay, if there were a siphon paffing from the furface of 
 the Earth to the Center, and thence rifing to the furface 
 again, it would convey Water from the one place to the 
 other. For ’tis a certain and infallible rule in the Hydro- 
 (Uticks , that Water will rife as high in this place, as the 
 hight of the place is, from whence it comes, even though 
 the windings and turnings of the Lead-Conduits under¬ 
 ground were as a Labyrinth^ and though this place, were 
 not only 1000, but 5000 pace diftant from the other. 
 ’Tis to be obferved, that if the mouth of the Conduit 
 b b 2 here, 
 
i96 Qpti;otta ticaietpmmc ntg, 
 
 here, be exa&ly as high as the other end at the-Foun¬ 
 tain, the Water {lands ftill, And the greater the dif¬ 
 ference be, the Water flows out with the greater force.- 
 By the help offuch Conduits , ’tis eafiero convey Wa¬ 
 ter to a City many miles. Such Pipes are ordinarily- 
 made of Lead.. But for faving expence, they may be^ 
 made of Timber, or Clay well burnt, in an -Oven,-.. 
 
AN ACCOMPT OF 
 
 Mifcellany 
 
 Observations, 
 
 Lately made, by the Author of the- 
 
 foregoing Experiments. 
 
 observation T 
 
 \669 y theie was need of a new 
 Sink, on the eafl fide of Tranent^ for 
 winning ot Coals .. But while the Coal-, 
 hemrs were in digging down y and had 
 hk c ° me t^edeepnefs of 13 or 14 fathom* : 
 -j—they were flopped- from-working by. • 
 OX i\\.kxr that flowed out plentifully .from-the 
 fides of the fink, wherein there were a great number of 
 tuners , or .rifts, out of which that ill Air came. To try 
 the natuieand.power of Damps., I took a dog, and faftned 
 him in a bucket, with a fmall roap,. that he might not leap 
 over and when he had gone down 7 01 8 fathom, hepre- 
 ientlyjjegins to howl, and cry pitifully, as if he had been 
 
 beaten 
 
i5>3 gJBtfcelian? ^Dbfectiations* 
 
 beaten fore with a rod, and a little after, he begins to flag¬ 
 ger and his feet failing him, he falls down, as one overtaken 
 with the Epilepfy, and in going down to the bottom, his 
 eyes turning in his head, they appeared very fhining and 
 dear like two large bright Diamonds. Fearing, that the 
 Damp ihoald have killed him out of hand, he was inftantly 
 pulled up from the bottom, where he had nottarried 15 /*- 
 conds of time, And when the bucket had come to the mouth 
 of the fink, he was pulled out,and laid upon the ground, to 
 get frefh Air, When he had liena while as dead, he begins 
 at laft to gape,and gafp,and makefome refpirations,as if he 
 had been rather expiring,than recovering.Next,he began to 
 Air and move his feet, and after, to'raife him fell upon his 
 knees, his head ftaggering and wavering from fide to fide.. 
 After a minut or two, he was able to ftand upon his feet, 
 but fo weakly, that he was not in capacity to walk or run. 
 Yet at laft,being much refrefhed,he efcaped from us,and ran 
 home,but flowly. In the afternoon, the fame Experiment 
 was repeated, with another dog, whofe cafe was the fame 
 in all things. But after he was perfe&ly recovered, for a 
 further trial, we let him down the fecond time, and fuf- 
 fered him to tarry in the bottom of the fmk ,about the. fpace 
 of three minuts: but when he was pulled up, and taken 
 out, we found nolymptomes of life in him; and fo after 
 half an hour and more, his body began to fvvell, which or¬ 
 dinarily befalls fuch, who are killed after this manner. Af¬ 
 ter this, we fent down in the Bucket, a little Chicken, 
 which, when it came near the Damp, prefently flapped 
 with the wings, and falling down, turned over and over 
 for a pretty while, as if it had been taken with a vertigo , or 
 giddinefs. But by drawing up the Bucket in hafte, and 
 bringing the Bird to the frefh Air, it recovered. In the 
 
 evening. 
 
spfccuanp iDurcrbat<on0* 199 
 
 evening, we letdown a lighted Candle, but it was Toon 
 extinguifhed, when it came near raid-fink-, for here} ra¬ 
 ther than in the bottom, was the ftrongeft Damp. Laft. 
 ly, we let down by a chord, a Brand-iron, with burning 
 Coals, whofe flame was foon put out, and after a little 
 while, we perceived the red Coals to be extinguiflied by 
 [ degrees; yet not totally, becaufe, as the Coal-hewers ob- 
 ferved, the power of the Damp was not fo ftrong, as before, 
 
 T hefe Damps then have their ebbings and flowings, which 
 feem to depend upon the weather,or rather upon the fitua- 
 don of the winds,and their force. For’cisobferved, that a 
 high South-weft wind caufeth ill Air in this place • and 
 that, by reafon of much waft ground , that lies upon the 
 South, and South-weft hand of this Sink, whence are con¬ 
 veyed under ground by fecret paflages, which are nothing 
 
 I elfe butfo many rifts and openings, commonly called by 
 the Coal-hewers , Cutters, corrupted and rotten Air, full 
 of fulphurious ftems. T he reafon why thefe paflages are 
 open*, and replenifhed with nothing, but corrupted Air, is 
 this, the Water, that’s ordinarily called the Blood of the 
 Coal, being withdrawn with fubterraneous Gutters (com¬ 
 monly called Levels) that are digged, and wrought under 
 ground,fomc-times a very long way,for drying of th zMines, 
 and the veins of the earth being now empcy, there fuc- 
 ceeds Air; which Air, by procefs of time, and long /land¬ 
 ing, rots, and contrafts a fulphurious quality, which 
 caufeth bidden death. Now, when the wind is high, and 
 I ftrong from the South or South-weft, that fulphurious Air 
 1 is driven through the ground, and coming to Sinks and 
 Mines, where men are working, prefently infe&s the place, 
 and hinders the work.- ’Tis often obferved, that thewind 
 andAir under ground,keep a correfpondence in their moci- 
 
too ^ifceUaitpDbfecDations* 
 
 on, with the wind above ground : and therefore, when the 
 wind is in fuch a point above, ’tis found, that the motion 
 of the Air below runs fuch a way, and the contrary way, 
 when the wind above ground, is in the oppofite point. 
 When there is a free.paffage between the bottom of the 
 two Sin^j, you may obferve the wind come down through 
 the one, and running alongft under the ground, rife up tho- 
 row the other, even as Water runs thorow a Siphon, .For 
 this caufe, w 7 hen the Coal-hewers have done with fuch a 
 Sink, they do not ufe to flop it, or clofe it up, but leaves 
 it ftanding open, that the Air under ground may be kept 
 under a perpetual motion and flirting, which to them is a 
 great advantage, ’Tisveryftrangetofeefometimes, how 
 much Air, and how frefh it will be, even at a very great 
 diftance,namely four or five hundred pace, from the mouth 
 of the Sink, T his could never be,unlels there were a confi- 
 derable Preffure and weight in it, whereby it is driven for¬ 
 ward,thorow fomany Labyrinths. And even in the utmoft 
 room,where the Coal-hewers are working, the Preffure is as 
 great, as it is above ground, which is found by the Torricel¬ 
 lian Experiment, In fuch a cafe,the Air cannot prefs down 
 thorow the Earth and Metalls, therefore the Mercury muff 
 be fufpended, not by a Pillar from the Atmofphere , but by 
 the Eenjii of it. Nay, put the cafe, that the whole Element 
 of Air were aeffroyed, and tlrs remaining, yet would it be 
 able to fupport 2 9 inches.To (hut up this difcourfe,it is ob- 
 ferved'by the Coal-hewers , that when there is ill Air in a 
 Sink*, man may perceive diftin£ly,\vhat is lying in the bot¬ 
 tom, fo clear and tranfparent is the Air of it: but when the 
 Damp is gone, the Medium is not fo clear. In temperat and 
 cold weather,the Damps are not fo frequent.From this Sink, 
 in (oft winaSjOr in Northerly winds, or when it blows from 
 Eaft 0: North-eaft,the Damps are driven away, 0 B- 
 
QMcetianp Dbf ctfratfons, _*°i 
 
 OBSERVATION II- 
 
 J Upiter upon Wednefday night, at eleven a cloclf, 
 being 24 of November , 1669 , had the following 
 pofition with the flars of Gemini, He was fo near to the 
 Star C, that to appearance, the points of his rayes did 
 touch it. T his Star by looking upon the material Glob, 
 is fixed in the very Zodiack , and in the 13 degree of 
 Cancer, and is the very navel of the following Twine, T he • 
 Star A is Caflor, T he Star B is Pollux, T he ftar D , is 
 fixed in the forefoot of the following Twine. -From this 
 place he moved, with a retrograde motion, till he came 
 to the 5 of Cancer , about the 20 of February , 1670, 
 and from that time became Direft in his motion, andfo 
 upon the 27 of March , 1670 at pa clock, he wasin a 
 right line with Cants minor , and the brighteft Star in 
 Auriga 5 and was in a right line with the eaftmoftfhoulder 
 of Orion , and Ca(ior in Gemini , or with that Star 5 when 
 South-weft, that’s higheft, andWeft-moft. 
 
 OBSERVATION III- 
 
 I T is written in the Hiftory of the Royal Society , that 
 fuch a member of it, whofe name 1 have forgotten, 
 hath found out, among many other curious inventions, 
 this, namely a way for knowing the motion of theSun 
 m fecondsQi time .• but is not pleafed to reveal the manner 
 how. Becaufe fuch a device may be ufefull in Aftronomy, 
 and likewife for adjufting the Pendulum Clocks I fliall 
 therefore briefly drew, the manner and way how fuch a 
 thing may be done, as I have tried it my felf. I took an 
 optick Tub, about n foot long, only with two Convex- 
 f C c gltf's 
 
201 £gffceUanp jDbferfcatumF* 
 
 gla(fes laity and did fo place it in a dark room, by putting 
 the one end, in which was the object-glafs , without the 
 window, and keeping the other within,- that Icaufed the 
 beams of theSun fhlne thorow it,which were received upon 
 2 white wall four or five foot from the Tub. This image, 
 which was perfedly round , and fplendid , did move 
 aiongft the wall very quickly, fo that in a minut of time, 
 it did advance feveo inches and a half, which will be the 
 eight part of an inch in a fecond^ amotion very fenfible. 
 Now, this beam that came thorow the Tub, and lighted 
 npon the wall, would not have moved one inch in a minut, 
 it it had wanted the two Glafles; for as they magnify, 
 and feem to bring nearer the object, fo they quicken the 
 motion of it. In a word , by what proportion the object 
 :s made more, by that fame proportion is the motion 
 quickned. Tistobeobferved, that the longer the Tub 
 be, the motion is the fwifter : for as the longeft Tub 
 doth ordinarily mod magnify the objed ; fo doth itmoft 
 quicken the motion. Next, the farther diftant the 
 white wall is from the end of the Tub, the larger is the 
 image; and contrariwife , the nearer it be, it is the lefsj 
 Thirdly, the faither the wall be from the end of the 
 Tub, the circumference of the image is the more con- 
 fufed , and the nearer it be , it is the more diftind. 
 Fourthly, the darker the room be, it is fo much the 
 better. Laftly, this trial may be made with ordinary 
 Froftcift, ofafoor, two foot, or three foot long, which 
 will really do the thing, but not fo fenfibly, ualefs the 
 glaffes be very good. 
 
 As to the ufe of this device in Aftronomy , Ifhallnot 
 lay much. But fhall only mention what it may ferve for 
 m order to the Pendulum Clock, For this caufe, let a. 
 
 man 
 
■©tfceuanp Obferfr aKons, 10 $ 
 
 man choife a convenient room,with a window to the$buth, 
 wherein this Tab may be fofixed, that itmaylyjuff, 
 or very near to the true meridian and may move vertically 
 upon an axil-tree, becatjfe of the Suns declination every 
 day. Then at a certain diftance from the end of it, 
 fix and fettle a large board of timber, fmooth, and'well 
 plained, and well whited, Tor receiving the image. In 
 the middle of this board, draw a circle with Charcoal’, 
 equal in diameter to the circle of the image. Now, this 
 being done, you will find that affoon as the weft fide of 
 the Sun, begins to come near to the Meridian , theimage 
 begins to appear upon the board, like the fegmencofa 
 circle, and grows larger, and larger, till it become per¬ 
 fectly round, Now in the very infhnt of time, wherein 
 the image, and the circle are united, fetthe wheels of 
 your Clock agoing, from the hoar, mi nut, and/rcWof 
 XII. To morrow , ol 3 or 4 dayes after, when you 
 defire to make an examination, wait on about ia a dock, 
 when the Sun is coming to the Meridian, and you will 
 find what the difference is. If the Clock go flow, obferve, 
 affoon as the image is united with the circle {'which you 
 will perceive in a fecond of time) the variation, that’s 
 to fay, how many [ecottds interveens between that fecond* 
 wherein the union fell, and that fecond, that clofes XII 
 hours in the clock. If it go faff, obferve how many 
 feconds paffes from tha l fecond , that endsXII’hours, and 
 that wherein the image of the Sun is united with tKecircIe a 
 which ifyou do, you will know exaffly , what the differ¬ 
 ence is, even to a fecond. But without this , you will 
 find great difficulty to know the variation in 15 or 20 
 feconds , efpecially in a common Dial, But here, yon 
 will fee diftinftly theimage of the Son’move every fecond 
 Cc 2 of 
 
194 jMfce Uattj? £>bfetPatt ons, 
 
 of time, the eighth part, orthefixth part, or the fourth 
 partofaninch, according to the length of your Tub, and 
 gooanefs of yourglafles. ’Tis to be obferved, that in 
 adjufting the Pendulum Clock , refpedl muft be had to 
 the table of Equation of dayes , commonly known in 
 Aftronomy. For if this be not, it is impofllble to make 
 it go right, and that becaufe all the natural dayes of the 
 year, are not equal among themfelves; that’s to fay, the 
 time that’s fpent by the Suns motion.frora the Meridian. 
 this day , to the fame Meridian the next day, is not 
 equal, but is more or lefs, than the time fpent betwixc 
 Meridian and Meridian , a third or fourth day after. For 
 inftance, the Sun this day being 11 of $uty y comes foonet 
 to the Meridian by three feconds of time, than he came 
 yefterday, Within 9 or 10 dayes,(fuppofe the zz of fuly) 
 he will be longer in coming to the Meridian by 4 feconds, 
 than upon the 21 _ This difference I grant, in fhort time 
 is notlenfible, yet once in the year, it. will amount to 
 more than half an hour. This inequality of dayes arifes 
 from two caufes. Firft, from the Suns eccentricity whereby 
 he moves {lowlier in one part of the Zodiack, than in 
 another: for in Summer when-he is furtheft from the 
 Earth, he goes {lowlier back in the Ecliptick, than in 
 Winter, when he is. nearer to it. . The.fecond caufe, 
 which is truly the far greater, is this , becaufe in the 
 diurnal motion of the. Sun, equal parts of the Equator, 
 does not anfwer to equal parts of the Zodiack. . Hence 
 it follows, that if the natural dayes be not equal among 
 themfelves, the hours muft be unequal alfo: but this is. 
 not confiderable. 
 
 By help of fuch a Tub placed in a dark room, it is 
 eafie, when the Sun is under Edipfe, to enumerat diftinft-; 
 
 iy 
 
^ifceUanp £>&fettoaefong* iq $ 
 
 ly the digits eclipfed,' Likhvife, if you take out the 
 objed Glafs, and cover a hole in the window board with 
 it, you (hall fee diftindiy upon a whitewall, thefpecies 
 and true reprefentations of all' objefts Without, And by 
 comparing the quantity of theobjeftwithout, with the 
 quantity of it within, youmay'know the diftince of it 
 from the window, though it were many miles. For as the 
 one quantity, is-to the other, fo-is the diftance between 
 the Glafs and the object OH the wall, to the diftance be¬ 
 tween the Glafs and the objedt without.' 
 
 It may be inquired whether or not, th e retrograde, as 
 well as the diurnal motion - of any of the Planets, may 
 be difcerned, in minuts ■ or fetonds , by the help of a long 
 Telefcope t In anfwer to this, we muft fuppofe the 
 Planets only to have amr0gr^motion,andconfequently 
 to move flowly from Weft to 'Eaft, Sat nr nonce imp 
 years, orjo, to run about the Zodiack •, Jupiter in 12, 
 Mart in 2 years, the Sun in one year, Venus and Mercurf 
 in lefs time, and laftly the Moon-m a moneth. Now I 
 fay, it isimpofllbleby thelongeft Tub, that thegreateft 
 Artift can make, to difcern the motion of the inferior 
 Planets, far lefs the motion of the fup.erior, either in 
 Minuts or in Seconds, and- tharby reafon of the great 
 tardity, and flownefs of the motion; Notwithftanding 
 of this, I am induced to think, that the retrograde motion 
 of the Moon might be difcerned,' at leaft in Minuts, For- 
 evincing of this, let us fuppofe which is true', that the 
 Sun runs from Eaft to Weft half a degree in two Minuts 
 . of time, feing in an hour he runs 15 degrees. . Next, that 
 the Moon goes about the Zodiack in 2 7 dayes and 7 hours, 
 namely from that fame point, to that point again, and 
 confequeritly runs back every day 13 degrees and about 
 
 10 
 
206 ifcellanp ^Dbfertoations. 
 
 io Minuts. By this account, fhe muft retrograde half a 
 degree, and about 2 minuts of a degree every hour. T he 
 Sun then runs half a degree in two Minuts , and the Moon 
 half a degree in 60 Minuts ; therefore the Moon muft be 
 30 tiraerflower in her retrograde motion, than the Sun is 
 in his diurnal motion. Let us fuppofe next, as I obferved 
 with a Tub 12 foot long, that the image of theS«» 
 runs the eighth part of an inch every fecond, and confe- 
 quentiy, feven inches and an half, in a Minut: then 
 mull the image of the Moon with that fame Telefcope, 
 run the thirtieth part of feven inches and a half in a 
 Minut, feing fhe runs 30 times flowlier; therefore in 
 every Minut of time fhe muft advance the fourth part 
 of an inch, which will be- very fcnfible, Though we 
 grant, that the Moon hath no retrograde motion properly, 
 yet by comparing the diurnal Motion of the Moon, that’s 
 flower, to the diurnal motion of the Sun , that’s fwifter, 
 we fhall really find the thing it felf. Therefore in the 
 time of a Solar Eclipfe , this retrograde motion is confpi- 
 cuous, which by an ordinary 7 elejcope may be difcerned 
 in Minuts. AfToon then as the Eaft fide of the Moon 
 begins to enter upon the Weft fide of the Sun ( the 
 greater the Eclipfe be, it is the better ) obferve, and 
 you will find the one image, which will be black , cover 
 the other by degrees, that’s fplendid, and run in every 
 minut of time, the fourth part of an inch of the Suns 
 diameter, provided alwayes, that the Sun run the eighth 
 part of an inch in a fccctuL 
 
 OBSER- 
 
fMceUanp Werbattons* 207 
 
 OBSERVATION I V-' 
 
 U PonTuefday the 19. of $uly 1670. the following 
 Experiment was made,. In the middle Marches be¬ 
 tween Scotland and .England, there is a long tra& of Hills, 
 that run from Flotvdon, many miles South and Sotlth-weft, 
 amongft the which,, the Mountain cheviot is famous be¬ 
 yond, and confpicuous above all the reft for altitude, from 
 whofe top a man may difcem. with one turning of his eye, 
 the whole Sea-coaft from New- caftle to Berwick ^ much of 
 Northumberland , and very many Leagues into the great 
 German Ocean', the whole c Friers and Teviotdale , from 
 the foot of Tweedy to very near the head ofit: Lauderdale , ! 
 and Lammer-moor , and Pent land-hi I/s above Edinburgh* 
 The North fide of this Mountain is pretty fteep, yeteafie 
 to climb, either with men or horfe,. The top is fpacious,. 
 large and broad, and all covered with a Flotv'mofs , which 
 runs very many miles South,. When a man rides over it, 1 
 it rifes and falls. ’Tis eafietothiaft a Lance over the head 
 in it. T he fides of this Hill abounds with excellent Weli- 
 fprings, which are the original of feveral Torrents, amongft 
 the which Co Hedge- Water is famous, upon which, not a 
 mile from the foot of this Mountain is white-hall, . The 
 adjacent Hills are for the moft part green, and excellent 
 
 I for the pafturage of Cattel. Not many years ago, the 
 whole Valleys near the loot of Cheviot ^ were Forrefts a- 
 bounding with Wild-Deer, 
 
 Upon the higheft part of this Mountain was eredled the 
 ionicellian Experiment for weighing of the Air, where 
 we found the altitude of the Mercurial Cylinder 27 inches 
 and an half, T he Air was dry and clear, and no wind, III 
 lour Valley-Countreys, near to the Sea-Coaft, in fuch 
 Weather, 
 
io 8 tgifce Uany £>bfccD attons, 
 
 Weather, we find the altitude 29 inches and an half. 
 When this difference was found, care was taken to feal up 
 clofly With;£ec-WAx, mixed with Turpentine, the orifice 
 of the Veflel, that contained the ftagnant Mercury, and 
 thorow which the end of the Pipe went down. This being 
 
 done with as great exadbnefs as could be, it was carried to 
 the foot of the Mountain in a Frame of'Wood, made on 
 purpofe, and there opening the mouth of the Veflel, we 
 found the Mercury to rife an inch and a quarter higher than 
 it was. The reafon of this ftrange Phenomenon muft be this, 
 namely a greater Preflure of the Air at the foot of the Hill, 
 than upon the top: even as there is a greater Preflure of 
 Water in afurface 40 fathom deep, than in a furface 20 
 fathom deep. 5 Tis not to be doubted, but if the root of 
 the Mountain had been as low as the Sea Coaft, or as the 
 furface of Tweed at .Kelfo , the Mercurial Cylinder would 
 have been higher. This way of obferving, feems to be 
 better than the common : for while the Barcfcope is carri¬ 
 ed up and down the Hill, without flopping the orifice of 
 the Veflel, that contains the ftagnant Mercury, the Cy 
 Under makes fuch reciprocations,by the agitation of a mans 
 body, that fometimes abundance of Air is feen to afcend 
 up thorow the Pipe, which in efteft makes the Cylinder 
 lhorter than it ought to be. But if fo be, the end of the 
 Pipe be immerged among guick-filver , contained in a 
 Glafs with a narrow orifice, fo that it may be flopped com- 
 pleatly, you will find no reciprocations at all. And to 
 make all things the more fure, theGlafs may be filled up 
 either with Mercury , or with Water above the Mercury 5 
 by which means the Cylinder mihe down-coming, or in the 
 up-going (hall remain immoveable. Befides the. flopping 
 of the orifice of the faid Glafs, you may have a wider Vef- 
 
SgifctHani? ©Wetbatfens. 209 
 
 fel, that may receive the lame Glafs into it, and it being 
 lull of Water, may fo cover the fealed orifice, that there 
 lhall be no hazard of any Air coming in. Or this Experi¬ 
 ment may be firft tried at the root of the Hill, and having 
 flopped compleatly the mouth of the Veffel, the whole 
 Engine may be carried up to the top, where you will find 
 the Mercury fubfide and fall down fo much; namely alter 
 the faid orifice is opened: for as the flopping of the orifice 
 at the root ol the Hill, is the caufe, why that fame degree 
 of Preffure remains in the ftagnant Liquor ; fo the open¬ 
 ing of ic upon the top of the Hill, is the caufe why it be¬ 
 comes lefs. 
 
 This Expeiiment lets us fee, that the Preffure of the 
 Air feems to be as the Preffure of the Water, namely the 
 further down the greater; and the further up the lefs .• and 
 therefore, as by coming up to the top of the Water, there 
 is no more Preffure, lo by coming up to the top of the Air, 
 there is no more weighc in it ; which in effed fayes, that 
 the Air hath a determinat bight,as the Water hath. From 
 this Experiment we cannot learn the determinat hight of 
 the Air, becaufe the definit hight of the Mountain is not 
 known. I know there are fome, who think that the Air 
 is indefmitly extended, as if forlooth, the Firmament of 
 fixed Stars were the limits of it, but I fuppofe it is hard to 
 make it out. 
 
 OBSERVATION V-' 
 
 J W/^5.1670. I obferved the Sun within 3 mimits of 
 fetting, to have a perfedi oval figure, the two ends ly¬ 
 ing level with the Horizon. His colour was not red as 
 ordinarily, but bright and dear, as if he had been in the 
 D d Mendian ■ 
 
©ifceUanpDbfcmtmt^. 
 
 Meridian: neither was the Sky red *but clear alfo, And by 
 the help of the Pendulum Clock , I have obferved his body 
 to be longer in fetting than it ought, by eight minuts, and 
 fometimesby ten, and his Diameter longer in going out of 
 fight than it ought, by two, and fometimesby three mi- 
 nuts, The reaion-of thefe Phenomena, muft be the Re- 
 fraci im unqueftionibly. 
 
 OBSERVATION V I- 
 
 U pon Saturday evening the 30 of fitly x 670, and the 
 nigh: following, till about two a Clock in the Sab - 
 bath morning, there fell out a confiderable rain, with great 
 thunder, and many lightnings. About thecon- 
 
 vocation 0: black clouds appeared fir ft towaids the Kori- 
 zm in the South-weft, with leveral lightnings 5 and the 
 wind blowing from that point, carried the clouds and rain 
 over Mid and Lajl-Lothian, towards the Firth and Sea - 
 coaft. About 9 a clock, the whole Heavens almoft were 
 covered with dark clouds, yet the rain was not very great, 
 neither were the//;; rnder claps frequent, but every fifth or 
 (ixth fccond of time, a large and gieat lightning brake out. 
 But before the thunder crack was heard, which happened 
 every fourth or fifth minut^ the lightning was lo terrible 
 for greatnefs, and brightnefs, that it might have bred afto- 
 nhhment. And becaufe the night was very dark , and the 
 lightning very fplendid, a man might have perceived 
 houfes and corn-fields at a great difhnce. And if any had 
 refolved to catch it, in the breaking out, it did fo dazle 
 the eyes, that for half a minut, he was not able to fee any 
 thing about him. - 
 
 Sometimes the lightning that went before the thunder, 
 
 brake 
 
^tfcetianp £)bfertoatton& 
 
 2fl 
 
 brake forth from the clouds, like a longfpout of fire, or 
 rather like a long flame raifedhigh, with a Smiths Bd; 
 lows but did not continue long in fight. Such an one 
 above the Firth was feen to fpout downward upon the Sea, 
 Sometimes there appeared from the one end of the cloud 
 to the other, an hiatus, or wide opening, all full of fire, 
 in form of a long furrow, or branch of a River, not ftraighr, 
 but crooked. I fuppofe the breadth of it, in it felf, would 
 have been twenty pace and more, and the length of it five 
 or fix hundred pace: the duration of it, would have been 
 about a fecond of time. Sometimes a man might have per¬ 
 ceived the nether fide of the cloud, before the crack came, 
 all fpeckled with ftreams ot fire, here and there, like the 
 fide of an Hill, where Moor-burn is, which brake forth 
 . into a lightning. But there was one, after which followed 
 a terrible thunder crack, which far exceeded all the reft, 
 for quantity and fplendor, It brake out from the cloud,be¬ 
 ing fhot from North to South, in form of fire from a great 
 Cannon, but in fo great quantity,as if a Gun ten foot wide, 
 with 500 pound weight of Powder in it,had been fired. And 
 fin ely the lightning behoved to be far greater in it felf, fee¬ 
 ing it appeared fo great, at fo great a diftance. It did not 
 evanifhinaninftant, like the fire of a Gun, but continued 
 about a fecond and an half $ by reafon (itfeemsj that it 
 could not break out all at once. This did fo dazle the fight, 
 that for halfaminutalraoft, nothing was feen, but like a 
 white mift flying before the eyes. The whole Countrey 
 about was feen diftinflly. 
 
 All thefe great lightnings were feen a confiderable time, 
 before the crack was heard. Sometimes 30 [econds num¬ 
 bered by the Pendulum clock interveened , namely when 
 the thunder was at a diftance, about 7 or. 8 miles. Some- 
 Dd a times 
 
m SjMceltanp Sbftttiaticms. 
 
 times 15 or v6 only Interveened. Butwhen the thunder 
 wis juft above our head, no moe patted, than 7 or 8, 
 which Teems to demonftrat, that t-hefe thick black clouds, 
 out of which the thunder breaks-, are not a Scottijh mile 
 from the earth, when they are directly above us. 
 
 ’Tis obfervable, that in all lightnings, and thundering*, 
 there is no fmoke to be teen, which Teems to evince, that 
 the matter whereof they are generated, muft be moft pure, 
 and fubtil. Who knows, but this Countrey, that abounds 
 with Co.il, may occafion more thunder and lightnings, than 
 other places, namely by fending up fuiphurious exhalati¬ 
 ons to the middle region of the Air, wherewith theWr 
 mints abound. 
 
 OBSERVATION VII- 
 
 T His is a method for finding out the true South and 
 North Points, which are inefted very difficult to 
 know. Take therefore four pieces of Timber, each one 
 of them-five foot long, and about fix inches thick, Tquare- 
 wife. Sharpen their ends, and fix them fo in the ground, 
 that they may ftandPerpendicular,and as near to South and 
 North, by a Magnetick Needle, as may be. The place 
 would be free of Trees, or of any Tuch impediment, that ic 
 may have a free profpeft of the Heavens. As for their 
 diftance one from another, let the two North-moft, and 
 the South-moft be two foot afunder: let the two Eaft- 
 moftj and two Weft-moft, be but one foot, making as 
 they ftand, an oblong quadrangle. For keeping them equi- 
 diftant above, as well as below, take four bars of Wood, 
 about three inches broad, and one inch thick,and nail them 
 . round about upon the four fides, on each fide one,. To that 
 
fipifccliatip iDOfttfiations. v 3 
 
 being nailed on Horizontally they may make right angles, 
 with the tops of the ftandards above. There are then for 
 diftinftions caufe, the North-bar, and the South-bar, 
 thatruns Eaft and Weff, and the Eaft-bar, and the Weft- 
 bar, that runs South and North, There is here no diffi- 
 culty in the (filing it lelf, but only in the fancy to conceive 
 it. Betides thefe four, there muft be other four of the 
 fame form and fafhion, nailed on ! arder down about the 
 middle of the four ftandards. Take next fome lmall Brafs 
 Wyre ftrings,fuch as are uled in Virginals a nd fix one from 
 the middle of the South-bar, that’s upmoft, to the middle 
 of the South-bar juft under it. Fix it fo, that it may be 
 exactly perpendicular, which may be done, with a great 
 weight of Lead. Takea lecond Wyre firing, and hang it 
 plumb from the Weft end of the No; th-bar, and another 
 from the Eaft end of the fame Bar, I mean the Bar that’s 
 neareft to the top. Thefe three firings fo fixed, will go 
 near to make an equilateral triangle . 
 
 Now becaufe the device is for finding out the Meridian 
 by the Stars in the night time, not by any indifferently, 
 but by thefe that are neareft to the iW<\ therefore obferve 
 in $uly and Augu(l , when the Guard-fiars in the evening 
 begin to come down towards the Weft, and keeping clofs 
 one eye, bring the other fomewhat near to the South- 
 moft firing, and order your fight fo, that this firing, and 
 the Weft- moft firing upon the North fide, may catch the 
 foremoft Guard-^ar in the down-coming,when it is furtheft 
 Weft, and there fix it. When the fame Star is turning 
 up towards theEaft* catch it by the South-moft firing, 
 and the Eaft-moft firing on the Noith fide, and your work 
 is done, if fo be, you divide exattly, between the Eaft- 
 moft and Weft-moft,and there hang a fourth firing, which 
 
 with: 
 
214 
 
 ©ifcellan? €)ofcr^atioa 0 , 
 
 with the firing upon the South-fide, gives you the true 
 South and North, For better undemanding, notefirft, 
 that, when the Guard-ftjrs are coming down, or going up, 
 the Altitude varies quickly, but the Azimuth, or motion 
 from Eaf: to Weft.will not vary fometimes fenfibly in two 
 hours almoft, which is a great advantage in this cafe. But 
 when vou find cut the Meridian with a P/.-?/> 3 and a Perpen- 
 c S , by the thadow of the Sun, if it be not when 
 he is about Eaft and Weft, the Azimuth alters tno.e than 
 the Altitude, whch is a great diladvantage. Now its 
 certain, the ilower the motion be from Eaft to Weft of any 
 S t eatier to obierve, and it is the more fure 
 way. Note fecondlv, that (pedal care muft be had, to 
 caufe the ftrings hang Perpendicular. Note thirdly, that 
 before you begin your OblervatiQn3,tne South.moft firing 
 muft be made immoveable, but the Eaft-moft, and Weft- 
 moft, onthe other fide, muft notbefo, becaufe as the 
 Stars :n uoinj about move from Eaft to Weft, fo muft the 
 laid two'ftrings be left at liberty, to move a little hither 
 and thither, till the Obfervations be ended. Note fourth¬ 
 ly, that aflbon as you perceive fenfibiy,the foremoft Guard* 
 ii.ir ro decline towards the Weft, then you muft begin to 
 obfeive, which is nothing elle, but to fix your eye fo, 
 that the South*moft and Weft-moft firing, may cover the 
 (rid Star, And becaufe in coming down, it goes Weft, 
 therefore, let the Weft-moft firing move towards the left 
 hard by degrees , following the Star to its utmoft, till it 
 be covered by them both. Follow the fame method,, in 
 obferving the fame Star in going up towards the Eaft, Note 
 fifthly,that when you make the two ftrings cover the Star, 
 that which isneareftto the eye, will appear tranfparent, 
 and of a larger fize, fo that you may perceive diftindlly 
 
 thorow 
 
^MfceUanp Dbferfcatfcms* m 
 
 thorowit, not only the Star it felf, but the Other firing al- 
 fo which is a great advantage. This is evident to any, 
 who holds a bended filk threed between their eye and a 
 Star in the night time ; tor when you dired your fight to 
 
 I the Scar, the"firing appears like the fmall firing of a Vir¬ 
 ginal when it trembles. Note fixthly, that in obferving 
 in a dark night, you muft have a Cutthroat, that by the 
 light of the candle you may perceive the firings. Some 
 other things might be noted, but you will find them bet¬ 
 ter by experience, than they can be expreft here, 
 
 I named fitly and Augujl in the evening for obferving 
 the Guard-jlars, when they are Weft-moft, but there are 
 feveral other feafons, when this may be done as conveni¬ 
 ently, They are Eaft-moft in the latter end of Oclokr , and 
 beginning oiNovember about 5 or 6 a clock in the morning.. 
 
 , If a man were defir-ous to make thisobfervation quickly, I 
 fuppofe he might in the end of Otlober , find the faid ftars 
 Weft-moft in the evening,andEaft- moft the next moining. 
 Befides the Guard jlars ,"a man may make ufe of the Polar- 
 \ par ^ for as it goes higher, and lower than the true Pe/c,by 
 ' 2 degrees and 26 minuts, fo it goes as much to the Eaft, 
 and as much to the Weft,' once in 24 hours. In the end 
 of3Wy, youwill find the Pohr-flar Eaft-moft, about 9 ■ 
 a clock at night ,and in the end of January Weft- moft at-9 
 a clock. Note, that every month, the fixed ftars come 
 fooner to the fame place by two hours : therefore in the 
 end of Augujl the Polar- jar muft be Weft, at 7 a clock at 
 night, and Eaft at 7 a clock in the morning. When the 
 Meridian is found out.after this manner, there is no Star or 
 Planet can pafs it, but you may know exactly when, be it 
 never fo high, or never fo low. For there is nothing to 
 he done, but to wait, till the South-moft and North- 
 
 moft 
 
2i6 ® uceuanp ^Dbfemations* 
 
 meft firing cover the body of the Star. If it be the Sun, 
 hold up a white Paper, behind the two firings, and when 
 their fnadows co co-incide, and are united , then is his 
 Center in th s Meridian. It the Sun do not fhineclear, as 
 when he is under mift, or a thin cloud, you may exaftly 
 take him up in the Meridian , with the two firings. This 
 Frame will ferve as well, to know when any of the North 
 Stars comes Souther North, and confequently when they 
 arehigheft, and when they are lowed : for being fixed in 
 an open place of the Orchard , there’s no Celcftial Body can 
 pafs the Meridian ,either on the one fide, or the other, but 
 It may be catchec, what ever the Altitude be, and that 
 mofteafilv. 
 
 OBSERVATION VIII- 
 
 T Here hath been much inquiry made by feme anent 
 the reafon, why the dead body of a man or beafl, 
 rifeth from the ground of a Water, after it hath been there 
 three or Sour days. But though many have endeavoured to 
 folve the queftion, yet the difficulty remains 5 and in efledl 
 it cannot be answered, without the knowledge of the fore¬ 
 going Doctrine, anent the nature of fluid Bodies. To 
 find out the reafon then of this Phenomenon , confider, that 
 all Bodies, are either naturally heavier then Water, as 
 Stone and Lead, or naturally lighter, as Wood and Tim¬ 
 ber. If they be heavier, they fink: if they be lighter, 
 they fwim. Now I fay, a mans body immediatly after 
 he is drowned, his belly being full of Water, mufl go to 
 the ground, becaufe in this cafe, it will be found fpecifi- 
 ally or naturally heavier then Water. That’s to fay, a 
 mans body, will be heavier, than as much Water, as is 
 
fiptfcellan? £)bf cttat(on g, 217 
 
 the hulk of amans body. For pleafmg the fancy, imagine 
 a Statue to be compofed of Water, with all the true di- 
 menfions of the perfon that’s dead , fo that the one fhall 
 anfwer moft exaftly to all the dimeniions of the other. In 
 this cafe, if you counterpoife them in a Ballance, the real 
 body, that’s made up of flefh, blood, and bones, fhall 
 weigh down the other. But after this dead body hath lierr 
 a fliort time among the Water, it prelently begins to fwell, 
 which is caufed by the fermentation of the humors of the 
 blood, which goeth before putrefaction, and after three or 
 four dayes fwells fo great, that in effedt, it becomes natu¬ 
 rally lighter than Water, and therefore rifeth. That is 
 to fay, take that body, that is now fwelled, and as much 
 bulk of Water, as will be the preci r e quantity of it, and 
 having counterpoifed them in a Ballance, you will find the 
 Water heavier than the body. 
 
 OBSERVATION I X- 
 
 U pon Thar [day the 2 5 of Augufi 1 6jo, the following 
 Experiment was made in a new Coni-fink, on the 
 Weft fide of Trnmnt, When the Conl-hcrvers had digged 
 down about 6 017 fathom, they were interrupted fome- 
 times with ill Air : therefore to know the power and force 
 of the Dnm^we let down within the Bucket a Dog. When 
 he had gone down about 4 fathom,'-or' middle Sink,- we. 
 found little or no alteration in him, Tave'only t'hat.he 
 opened his mouth, and had fome difficulty ifi breathing, 
 which we perceived evidently: for no fooner he.was pul¬ 
 led up to the top, whefe the good Air was ; , but he left off 
 his gaping. We let him down next to the bOttom,wdiefe 
 he tarried a pretty.while, but no more-change we loUrid-in- 
 E e ' him 
 
nS £0ffcclianp ©Metbattons. 
 
 iim than before. After this we let down a great quantity 
 i>{ whins > well kindled with a bold flame, but they no 
 'ooner came to the middle of the Jink, but the flame was in 
 minShnt extinguished: and no foonerwasthe Bucket pul- 
 ledup, but they took fire again. This was 5 or 6 times 
 tried, with the fame fuccefs. If we compare thisObfer- 
 vationwith the firft, we will find, that all Damps are not 
 of the fame power and f^rce 5 but that fome are Stronger, 
 and kills men and beafts in an inftant: and that others are 
 Iefs efficacious, and more feeble, and doth not fo much 
 hurt, and that men may hazard to go down into a Sink, 
 where iS Air is, even though fire be fometimes extinguish¬ 
 ed, We fee next, that thefe Damps doth not alwayes 
 infed the whole Air of a Coal-pit, but only a certain quan¬ 
 tity: for fometimes it is found in the bottom, fometimes 
 in the middle. And we fee laftly, that they are not al¬ 
 wayes of long continuance: for it is found, that though 
 the Air be ill in the morning,yet it maybe good ere nightj 
 lad totally evanished ere the next day. We may add, as 
 was noted in the firft Gbfervation, that thefe Damps de¬ 
 pend much upon the feituation of the winds,feing in ftrong 
 Southerly winds, they are frequently in thefe places. 
 
 OBSERVATION X- 
 
 O f thefe many excellent devices, that have been found 
 oat of late, the Air-pump is one, firft invented in 
 Germani, and afterwards much perfected in England by 
 that Honourable Perfon Mr Bojl, who for his pains, and 
 indaftry in making Experiments therewith, deferves the 
 thanks of all learned perfons. Several trials hath been made 
 <ef late by it, fome whereof, are as follows, I took a Slender 
 
i^ifccuanp iDbfctbations* w 
 
 Glafs-tub about 40 inches long, dofs above, and open be* 
 low, and filled it with Water. I next inverted it, and 
 fet the orifice of it, juft upon the mouth of the Brafs-pipe, 
 that bends upward thorow the board, whereon the Receiv¬ 
 er ufeth to ftand, and cemented them together. At the 
 firft exfu&ion, the whole Water in the Pipe fell down, 
 and ran thorow the Brafs-conduit to the Pump. Having 
 for a (hort while flopped the paflage, and thruft down the 
 Sucker , I next opened it again, and the Pump being full of 
 V Vater, it was driven with a confiderable force up thorow 
 the Pipe ; yet was it not compleatly fill’d as before, by 
 reafon of fome Air, that I faw in the top. After this was 
 done, with pleafure five or fix times, I opened the Stop¬ 
 cock more quickly, than I had uled, but the V Vater, by 
 this means, was fo furioufly driven up thorow the Tub, 
 that in effeft, it broke the end of it, that was Hermetically 
 fealed 5 and the piece that flew off, did hit the Ceiling lo 
 fmartly,that it rebounded a very far way. From this we fee 
 the reafon, why Water falls not down from Veflels that 
 have narrow necks, though they be inverted, becaufeit’s 
 kept in by the force and power of the environing Air. ’Tis 
 obfervable, that though this Pipe had been 30 foot high, 
 yet the whole Water in it would havefubfided, and fallen 
 down, with one exfudiion. 
 
 The next trial was with the help of a fmall Receiver, 
 which in effedf was a real Cuffing-glafs, This had a hole 
 made in the bottom of it, and was cemented to the Brafs - 
 flute, and the mouth of it looking upward, had a lid for 
 covering of it. I took next the lately mentioned Glafs- 
 pipe, and filled it with good Brandy, and having drowned 
 the end of it among ftagnant Brandy ,1 fet the Veffel where¬ 
 in it was within the Receiver, the Pipe coming up thorow 
 Ee a the 
 
£@tfceuanp £)bfccfcanousu 
 
 the lid, and having cemented it clofly, I made the firft 
 exfnftion, and found no defcent of the Liquor from the 
 top of the Tub. At the fecond, it fell down about an 
 inch. At the third, it fell down four or five. But here 
 appeared a great multitude of fmall Bubbles of Air,. like 
 broken Water, near the top of the Pipe within. And 
 befices this Phenomenon, there afcended from the ftagnanc 
 Liquor up thorow the Pipe, an infinit number of fmall 
 Bubbles, no bigger than Pin-heads,, for a very large'time. 
 
 V Vith a fourth exfuiftion, it fell down within two or three 
 inches of the fugnant Brand], And thinking to make the 
 one level with the other, I made a fifth *, but here appear¬ 
 ed a firing eft'edi, namely, not only the whole Brand] in 
 the Pins tubfidedjSnd was mingled with the flagnant Bran¬ 
 ds , but at this exfuftion, there came a great quantity of 
 Air from the mouth of the Pipe, and rofe up thorow the 
 fhgnant Liquor in Bubbles. Having made another exac¬ 
 tion, there came yet more Air out, and fo copioufly, that 
 I thought there had been fome leak in the Tub, through 
 which'the outward Air had entered 5 but knowing the 
 contrary, I continued Pumping a very long time, till I 
 found lefs and lefs come out, and at length, after near 30 
 exfudtions it cealea. This Air to appearance, was fo much 
 as might have filled twenty Tubs, everyone of them as 
 large, as the Tub it came out of. And furely all of it came 
 out from among the fmall quantity of Brandy that filled the 
 Pipe, and that environed the mouth of it, I mean the flag- 
 nant £r<j«dy,both which would not have been eight fpoon. 
 ful. After this I opened the Stop-cock leafurely to let in 
 the Air to the Receiver •, then did the Brand] climb up the 
 Pipe flowly, till it came near to-the top, and there made 
 fome little halt, by reafon of half an inch of Air that ap- 
 
2X1 
 
 spfceuanp £>bfertwtton& 
 
 peared there. But more and more Air coming into the 
 Receiver^ that halt inch in the top of the Pipe, did fodi- 
 minifh, that it appeared no bigger than the point ofa Pin, 
 and was fcarcely difcernable to the eyes. What a .ftrange 
 and wonderful faculty of dilatation and contra&ion muftbe 
 in the Air, feing that which prefenjly had .filled the whole. 
 Tub, that was 40 inches long, and thefixtb part of an inch 
 wide, was contracted to as little room, as the point of a 
 Needle. And by making fome new exfuf- 10ns, that (mall 
 Atome of Air did fo dilate it felf again, that it filled the 
 fame.Tub, and not only that, but, as tormeily, it bubbled 
 out from the mouth of the Pipe feveral times. 
 
 ’Tisto beobferved, that though at thenrft falling 
 down of the Brandy ^ it appeared like broken Water, near 
 the top of the Pipe within, yet no fuch thing .was feeu the 
 fecond time it fell down $ thereafon is, becaute by the firft 
 exfudtions, it was well exhaufted of its aerial particles. 
 Once or twice I found, after the Brandy within the Pipe 
 was well freed of Air, that no exfu&ions could make it 
 move from the top of the .Tub; and obferved a round 
 Bubble of Air to march up , which when , once it came to 
 the top, did feparate the one from the other. If this hold 
 good, itfeemsto prove, that neither Mercury, nor any 
 other Liquor would fall down in Pipes, unlefs there 
 were Air lurking amongft the parts to fill up the defert- 
 ed fpace. 
 
 From this Experiment we learn, that no pei fon can well 
 apprehend or conceive , how far, an! to what bounds the 
 fmalleft part of Air is able to expand it felf. And it proves 
 evidently , that when the Receiver is as much emptied 
 as it can be> by the Art of man, yet it is idi of Air 
 compleatly. 
 
m $)tfceumip $>dfertoattous* 
 
 The third trial was after this manner: I fet within the 
 Receiver a little Glafs half full of Brandy, and the lid being 
 cemented on, I began to pump,but there appeared no alte¬ 
 ration at the firft exfuftion, Atthefecond, I perceived a 
 great company of very fmali Bubbles, that for a long time 
 attended from the body of it, and came to the furface. At 
 the third, they were fo frequent, and great, that the Bran* 
 ^appeared to feeth and boil, and by reafon of the great 
 ebullitions, much of it ran over the lips of the Glafs, and 
 fell into the bottom of the Receiver, This boiling conti¬ 
 nued for the fpace of 7 or 8 exfu&ions, and by procefs of 
 time, the Bubbles grew fewer and fewer,and when about 30 
 0:40 exfuSions were made, no more appeared. With this 
 fame fort of Brandy , I filled the fore-named Pipe, and fet it 
 within the Receiver , the mouth of the Tub being guarded 
 with the fame fort of Liquor. When it began to fubfide, 
 there appeared no Bubbles near the top as before .• the rea- 
 ron teems to be , becaufe the Brandy was well exhaufted 
 from its aerial particles. Fora fourth trial, I filled the 
 fame Tub with Ale, that was only 5 or 6 dayes old , and 
 crowning the end of it among ftagnant Ale of the fame 
 kind, I began to Pump, and found, thataffoon as the Li¬ 
 quor began to fubfide, from the top of the Pipe, the whole 
 Ale within the Pipe, aimoft turned into Air, and Froth, 
 and fo many large Bubbles came up from the ftagnant Li¬ 
 quor, that I thought the whole was converted into Air. It 
 was moft pleafant to behold their feveral forms and fhapes, 
 their order and motion. This fame Tub being filled 
 with foeet milk , I found very few Bubbles in it, when by 
 the exfu&ions, it began to fubfide. I likewife took a little 
 Glafs-viol, and fill’d the half of it full w ; ith common Ale, 
 and fet it within the Receiver, At the firft exfu&ion, 
 
 Bubbles 
 
fXfceiiany DWecwmons. 213 
 
 Bubbles of Air began to l ife oat of it. At the fecond and 
 third, they did fo multiply, that they fill’d the other half 
 of the Glafs, and ran over, as a Pot doth when it boileth, 
 And before I could exhauft all the Air out of it, moe than 
 20 exfu&ions parted. 
 
 Fora fifth trial, I filled the often mentioned Pipe with 
 Fountain-water, and when it began to fubfide by Pump¬ 
 ing, I found it leave much Air behind it. Bat all the ex- 
 fudionsl made, could not make the Water of the Pipe 
 go fo low, as the ftagnane Water, by which impediment, 
 
 I could Pump no Air out of the Pipe,as I did, while I made 
 ufe of Brandy. This tells us, that either there is not fo 
 much Air lurking among Water, as among Brandy ^ or that 
 the Air among this, hath a more expanfive faculty in it, 
 than the Air that lurks among Water, If any think, that it 
 is not true and real Air, which comes from the Brandy, but 
 rather the Sprits of it, which evaporats, I anfwer, if a man 
 ' taft this Brandy that’s exhauftedof its aerial f articles , he 
 will find it as ftrong 3 as before, which could not be, if the 
 Sprits were gone, 
 
 For a fixth trial, I took a Frog and inclofed her within 
 the Receiver, But all the exfu&ions I was able to make, 
 could not fo much as trouble her, Only, when the Re- 
 tmwwasexhaufted, I perceived her fides tofwellvery 
 big, and when the Stopcock was turned, to let in the Air 
 again, her Tides clapped clofs together. I obferved like- 
 wife, when the Air was pretty well Pumped out, that the 
 Frog had no refpirations,or if there were any,they were ve¬ 
 ry infenfible. The next day, after fhe had been prifoner 
 in the Receiver 24 hours, I began again to Pump, and 
 after feveral exfu&ions, her fides fwell’d pretty great, and 
 I perceived her open her mouth wide, and fomewhat like a 
 
ii4 £0tfceliani> ^bfetfcattons. 
 
 Bag endeavouring to come out, which furely hath been 
 fomeof her noble parts, ftrlving to dilate themfelves, the 
 body being freed of all Preffure from the ambient Air. 
 
 OBSERVATION XI- 
 
 T Ake a {lender chord, about 4 or 5 yards in length, 
 ana fatten the middle of it to the feiling of a Room 
 with a naiijfo that the two ends ofit may hang down equal* 
 ly. Take nest a piece of Wood, two or three foot long, 
 two inches broad, and one inch thick, and boring an hole 
 in each end of it, put through the two ends of the chord, 
 and fatten them with knots ? but i'o, that the piece of 
 Wood may ly Horizontal, and be in a manner a Pendulum 
 to fwing from the one end of the Chamber to the other. 
 Take next a Bullet of Lead or .Iron , about 20 or 24 
 ounces, and lay it upon the Laid piece of Woodbut be¬ 
 came it cannot well ly, without falling-off, therefore nail 
 upon the ends, and the fides of the Timber, lourp ; eces of 
 Sticks, oil each end one, and on each fide one, as 'Ledgets i 
 for keeping the Bullet from falling off. All things being 
 thus ordered, draw up the piece of Wood towards the one 
 fide of the Room, by which means lofing its horizontal 
 pofition, it will ly declining-wife, like the roof of an houfe, 
 lathis pofition, lay the Iron Bullet in the upmoft end of 
 it, and then let them both.pafs from your fingers, the one 
 end of the Wood going foremoft,and you will find it fwing 
 towards the other Tide of the houfe, and return again, as a 
 Pendulum. This motion, if the Wood be well guided in 
 its vibrations, will laft perpetually, becaufe in its moving 
 down, the Bullet is hurled from the one end of the Wood, 
 to the other, and hits it fo fmartly, that it begets in it, 
 
g piffcllang Obfettoatfott g, ny 
 
 an impulfe,. whereby it is carried farder up, than it would 
 be, without it. By this means, th t vibrations get not h': 
 berty to diminiih, but all of them are kept of the'fame ' 
 length. In the fecond vibration, the fame Bullet is hurl¬ 
 ed back again to the other end, and hiting it with all its 
 weight, creats a fecond impulfe, wherewith the Wood is 
 carried, as far up as the point it was firft demitted from. 
 
 Though this may Teem a pretty device ropleafethe 
 fancy, that’s many times deceived, while things are pre- 
 fented to it, by way of fpeculation, yet upon tryal and ex¬ 
 perience, there will be found, an unfpeakeable difficulty.* 
 and it’s fuch an one, that a man would not readily think 
 upon. I faid, that when the Wood was let go, and was 
 in paffing down, the Bullet in it, would hurl down, and 
 hitthe oppfite end, and beget an impulfe;, but there is 
 no fuch thing, for veiily, though the Bullet be laid upon 
 a very declining plain Board, whereupon no man could 
 imagine a round body could ly, yet all the time the Board 
 is in Twinging, from the one fide of the Chamber, to the 
 other, and confequently, fometimes under an horizontal, 
 and fomtimes under an declining pofition, the Bullet lies 
 dead in the place, where you firft placed it. This Obfer- 
 vation is not fo much for a perpetual motion , as for find¬ 
 ing out the reafon of this pretty Phenomenon , namely, 
 what’s the caufe, why the Bullet, that cannot lyupona 
 reclining Board, while it’s without motion, fhallnowly 
 upon it, while it’s under motion if What is more difficult, 
 and nice, to ly upon any thing, that declines from a levell, 
 than guide-filver-, yet lay never fo much of it upon this 
 Board, while it is Twinging, it fhall ly dead , and without 
 motion. But no fooner you flop the motion of the wood, 
 Ff but 
 
216 jgpfctuanp CWemtions* 
 
 but afioon, the Bullet, orth e gttick- fiber , isfinrle-d, 
 either this way, or that way. - 
 
 OBSERVATON XI !• 
 
 I Fitti it mentioned by fome learned perfons, that when 
 a Ship is under Sail, if a done be demitted from the top 
 of the Maft,lt will mtfve down in a line parallel with it, and 
 fall at the root. Some might think, it ought not to fall 
 dire&ly above the place it hang over, but rather fome 
 diftance behind, feing the Ship hath advanced fo much 
 bounds, in the time, wherein the done is coming down, 
 Likewife, while a Ship is under Sail, let a man throw up a 
 {tone never fo high,and never fo perpendicular, as to his ap- 
 prehenfion , yet it will fall down diredly upon his head 
 again, notwithftanding that the Ship hath run ( perhaps) 
 her own length in the time, while the done was afcending 
 and defcending. This experiment I find to hold true, 
 which may be eafily tryed, efpecially when a man is carri¬ 
 ed in a Boat upon fmooth Water, drawn by a horfe, as is 
 done in fome places abroad. Let him therefore throw up 
 a little Stone, or any heavy Body, and he will find it de- 
 fcend juft upon his head, notwithftanding that the Horfe 
 that draggs the Boat, be under a gallop, and by this means 
 hath advanced ten or twelve paces in the time. Or while 
 the Boat is thus running, let a man throw a ftone towards 
 the brink of the Water 5 in this cafe he (hall not hit the 
 place he aimed at, but fome other place more forwardj 
 This lets us fee, that when a Gun is fired in a Ship under 
 Sail, the Bullet cannot hit the place it was directed to. 
 Neither can a man riding with a full Career, andfhooting 
 a Piftol, hit the perfon he aims at, but muft furely mifs 
 
SBlfccllatip Dbfetbatfotis. ivf 
 
 him, notwithftanding, that though in the very inftant of 
 time wherein he fires, the mouth of the Piftolwas moft 
 juftly direded. For remedy whereof, allowance muft be 
 granted in the aiming at the mark. 
 
 While a man throws up a ftone in a Ship under Sail, it 
 muft receive two diftind impulfes, one from the hand, 
 whereby it is carried upward, the other from the Ship, 
 whereby it is carried forward. By this means, the ftone i(t 
 going up, and coming down, cannot defcribe a perpendi¬ 
 cular, but a crooked Line, either a Parabola, ora Line 
 very like unto it. Neither can it defcribe a perpendicular 
 Line, in coming down from the top of the Maft, thopgh 
 in appearance it feem to do fo, buc ,a crooked one, which 
 in effed muft be the half of that, which it defcribes ingo¬ 
 ing up,and coming down.For this fame caufe,aftone thrown 
 horizontally, or towards the brink of the Water, mujft 
 defcribe a crooked Line alfo. And a Fiflol Bullet fhot, 
 while a man is riding at a full Carreer, muft defcribe a Line 
 of the fame kind. Note,that a man walking from the Stern 
 of a Ship to the Head, walks a longer way, than in walk¬ 
 ing from the Head to the Stern. Secondly, a man ftijty 
 walk from the Head to the Stern, and yet nor change his 
 place. ’Tis obfervable, that a man under hoard , will not 
 perceive whether the Ship be failing, or not, and cannot 
 know when her Head goes about. And it is grange, that 
 when a man is inclofed in a Hegs-head, though he have 
 light with him; yet let him be never fo.oft whirled about, 
 hefhallnotknow, whether he be going .about, or not. 
 
 Ffa Op$£R* 
 
u8 ggifcc llanr €> afett>at (ons, 
 
 OBSERVATION XIII- 
 
 I " ^oundlm Philo fophicaltranfaBion lately Printed, that 
 Deccmh.13.1669, one Dofior Bed found the Mercury 
 in the Barofcope, never to be fo high, as it was then. That 
 {?m e very day, I found the hight of it 29 inches, and 
 nine ten parts,which I never obferved before. And though 
 the day here was dark, -and the Heavens covered with 
 Clouds, yet no rain for many dayes followed, but much 
 drynsfs, and fair weather. On Saturday night, CM Arch 
 ■26, 1670, I found the altitude no more than 27, and nine 
 ten parts. This night was exceeding windy, with a great 
 rain. On Febriury 1.1671. 1 found the altitude 30 inches, 
 and the Heavens moft clear. But in the moft part of May 
 following, I have found the hight but 27 inches, andfive 
 ten parts, in which time there was abundance of rain. 
 
 OBSERVATION XIV* 
 
 1 ^[Ovtmhr 7, 1670. I made exaft trial, with the 
 ]_\ Magnet ick Needle for knowing the variation, and I 
 found it vary from the North t three degrees and a half, to- 
 wards the Weft. Hevelitts writes from Dantzick to the 
 HoydSociety at London, $uly$. 1670, that it varies with 
 him feven degrees twenty minuts, weft. 
 
 OBSERVATION XV- 
 
 'T'VEcember. 17. 1669, I obferved with a largest-' 
 .1 M dr.ant , half 9 a dock at night, the formoft Guard-(lar, 
 when it was ia the Meridian 5 aadlowcft, to have 41 de¬ 
 grees 
 
g piftellanp iDbfc ttoatfotig. 229 
 
 grees 22 minuts of altitude. And on fpamary 7, 1670 at 
 7 a clock in the morning, I found it, when it was in the Me - 
 ridian, and higheft, to have 70 degrees, 27 minuts Hence 
 I conclude the elevation of the Foie here to be 5 5 degrees, 
 54 minuts, 30 feconds: and confequently as much at 
 Edinburgh ^ becaufe both the places are upon one and the 
 fame Parallel. 
 
 OBSERVATION XVI* 
 
 F Or finding the true Meridian , follow this method. In 
 fome convenient place fix two V.'yre firings with 
 weights at them, that they may hang perpendicular. Then 
 in the night time,obferve,when the fourth far of the Plough 
 begins to come near to the loweft part of the Meridian , at 
 which time you will find the Polar far Kigheft. T Ken, fo 
 order the two firings, by moving them hither, and thither, 
 till both of them cover both the faid Stars , then fhall they 
 in that pofition give you the true South and North, This 
 obfervation is the product of the fevenrh. 
 
 OBSERVATION XVII- 
 
 T Here fell out in Mid and Eaf-Lothian , on Thurfday 
 May 11, 1571, in the afternoon, a confiderable 
 fhour eAha.il, with thunder and rain. It came from the 
 South-weft, with a great blaft of wind, and ran alongs from 
 Piffs-land-bills North- eaft, towards the Sea- coaft. The 
 hail were big in feveral places,as Mufqut *■ Ball , and many of 
 them rather oval than round. Some perfons fuffered great 
 lofsof their young Peafe •, others of their Glafs windows. 
 Eight or ten days before, there was a confiderable heat. 
 
2$o gptfcclianp £>bfert)ations* 
 
 and dry Weather. For 20 dayes after , cold Eafterly 
 winds, with rain every day, but efpecially, in the end of 
 the Moneth, extraordinary rain and mift This is fo much- 
 the more to be obferved, becaufe in this Countrey, ftl- 
 domfuch extraordinary hail falls out. This year the Agues 
 and Trtmbi ng Fivers have beenmoft frequent, and to ma¬ 
 ny deadly. 
 
 OBSERVATION XVIII- 
 
 I Did hear lately of a curious Experiment in Germany, 
 made by a Perfon of note, which I (hall briefly in this 
 Obfervation, let zhe Reader underftand. And though I 
 have heard fince, that it is now publifhed in Print, yet I 
 hope it will not be impertinent to mention it here, efpeci¬ 
 ally for their caufe, who cannot conveniently come to the 
 knowledge of fuch things. And for this reafon alfo, that 
 I may explicat the Phenomena thereof, from the forego¬ 
 ing doftrine , and demonftrat particularly the true caufe of 
 that admirable effeft, that’s feen in it, which I defiderat in 
 the publifher. The Audior then takes two Feffels of 
 Brafs , each one of them in form of half a fphere, of a pretty 
 large fize. Nothing can more fitly reprefent them for 
 form and quantity, than two Bec-skeps. Only, each of 
 them, hath a ftrong Bing of Brafs upon the Center with¬ 
 out : and they are fo contrived by the Artifl, that their 
 orifices agree moft exactly, fo that when they are united, 
 they reprefent an intire Sphere almoft. In one of the fides, 
 there's a hole, and a Brafs Spigot in it, through which the 
 whole Air within, isexfufted, and drawn out, namely by 
 the help of the Air-pump. And, when by feveral exfudH- 
 ons the Feffels are made empty, the St.op-coci is turned 
 
 about. 
 
flptfccltanp iDbfetbattotis. m 
 
 about, by which means, no Air can come in. And, they 
 remaining empty, are taken from the Pump, and do cleave 
 fo faft together, that though a number of lu(ly ftUom , i z 
 on each fide, do pull vigorously, by help of ropes faftned 
 to the Rings , yet are they not able to pull them afunder. 
 And becaufe this will not do it, he yokes in 12 Coach 
 Horfes, fix on every fide,yet are they not fufficient, though 
 they pull contrariwife to other, to make a reparation. But 
 to let the Spectators lee, that they may bepulied afunder, 
 he yokes in p or 10 on every fide, and then after much 
 whipping, and fweating, they pull the one from the 
 other. 
 
 The caufe of this admirable effeft, is not the fear of va¬ 
 cuity, as fome do fancy, for if that were, all the Horfts in 
 Germany would not pull them afunder, no not the ftrength 
 of Angels, It muft then be fome extrinfick weight and 
 force, that keeps them together, which can be nothing 
 elfe, but the weight of the invironing Air, Becaufe, no 
 looner a force is applied, that’s moiepowerful, than the 
 weight of the Air , but aflfoon they come afunder. And 
 fo neither fix men, nor fix horfeson each fide are able to 
 do it: but nine or ten on each fide makes a feparation. For 
 underftanding the true caufe of this Phenomenon, we muft 
 confider that the Veffels are 18 inches in diameter. If this 
 be, then according to the laft Experiment, there are two 
 Pillars of v 4 />,each one of them as heavy as a Pillar of Mer¬ 
 cury 18 inches thick, and 2p inches long, by which they 
 are united. Or, each Pillar ol Air , is as heavy, as a Pillar 
 of Water 34 foot high, and 18 inches in diameter. For 
 finding the weight of it in pounds, and confequently, the 
 weight of each Pillar of Air, : by which the two rebels are 
 united, follow this method, Firft, multiply 9 the femi- 
 diameter 
 
iji cgifcet ianp Obfccbations ._ 
 
 diameter of the Pillar, by 54 the circumference, and this 
 elves you 48 6,the half whereof is the bounds of the Area, 
 namely 243. Andbecaufe 34 foot contains 408 inches, 
 
 I multiply 408 by 243,the product whereof is 99144 s fo 
 many fquare inches are in a Pillar of Water 34 foot high, 
 and 18 inches thick. Now king there are 1728 inches 
 in a cubical foot, I divide the number 99144, by this num¬ 
 ber, and I find 5 7 fquare foot of Water, and more. And 
 becaufe every fquare foot weighs 5 6 pound 7 Vw.r, I multi¬ 
 ply 56 by the number 57, and the produft is 3192 pound, 
 which is the juft weight of aPillarof Water 34 foot high, 
 and 18 inches in diameter, and which is the juft weight al- 
 fo of each Pillar of Air, by which the two Fejfels are kept 
 together, which will be more weight than [even Hogs¬ 
 heads full of Water, This is eafily known 5 - for feing a quart 
 of our meafure weighs feven pound, (or to fpeak ftridtly 
 fix pound fourteen ounces, feing the Standard-jug of Stri- 
 viltng contains three pound feven ounces of Water) a gal¬ 
 lon muft weigh 28 pound: but 16 times 28, is 448. A 
 Puncheon then full of Water, weighs 448 pound. If then 
 you divide 3192 by 448, you will find more than 7. The 
 9 horles then upon this fide have 3192 pound weight to 
 draw, or 199 ftone, or the weight of [even Hogs-heads 
 full of Water, The other 9 horfes upon the other fide,have 
 as much to pull. ’Tis no wonder then to fee fo much diffi¬ 
 culty and pains to make a feparation.lt.is obferved,that be¬ 
 fore the Air be exfu&ed and drawn out of the two Feflels, 
 one man is able to pull them afunder with h:s hands only. 
 Nay,which is more,if he but blow into them,as a man doth 
 into a Bladder, he will feparat them. The reafon is, be¬ 
 caufe the Air within, is of as great force, as the Air with¬ 
 out. 5 Tis obfervablenext, that the larger the Ve\fels be 
 
 in 
 
ipfcciianp g>Dfcrtatton& 
 
 in dimeter , the more ftrength is required tp pull the one 
 from the other' Upon fuppofition then, they were 4 foot 
 wide, I verily believe 30 yoke of oxen, upon every fide, 
 would hardly difjoyn them j becaufe the weight of each 
 pillar of Air, would be no lefs, than 221844 pound, which 
 would take 63 ftroog horfes to overcome the force of it. 
 To pull the one Veffel therefore from the other, theremuft 
 be 125 horfes, that is, 5 j on every fide. 
 
 OBSERVATION XIX- 
 
 T Hough thisObfervation may feem ufelefs,becaufe the 
 Propofals, that are mentioned in it, cannot be made 
 out,and brought to pafs, the Author having died, before he 
 had encouragment to profecute them : yetforthefe fol¬ 
 lowing reafons, I have adventured to infert it here. Pirft, 
 that others, may either be minded to find out f if poflible) 
 his inventions, or fet a work to find out fomethings, that 
 may be as ufeful. Next, becaufe, he was one of this fame 
 Nation , and a great Mafter of the Mathematicss , not only 
 in the Speculative , but in the fraciical part chiefly, and 
 admirable for invention. And for this caufe principally I 
 have prefumed to mention his defigns, and propofals,whiqk 
 were found among his , alter his.death , which are 
 here infert, as they were written with his own hand, and 
 offered to the publick , not only at home, butabrpad,tp 
 ftrangers. There have been men in all ages famous, for 
 fomeoneArt and Science beyond others, as Ape Lie; fpr 
 Painting, Hippocrates for Medicine, Bem-oftbenes- fowOrat. 
 try ., but who have been more famous in their time.thap 
 fome perfons for their profound .knowledge in Afimmy^ 
 Geometry find the (Other parts of the UatkmAtich . What 
 
134 ffiifceu anp & bfeEftations» 
 
 an admirable perfonwas Archimedes lor his divine know¬ 
 ledge, both in the speculative , and Pratfical part. Yet, 
 it was not his fpeculations (imply, though excellent, that 
 did fo much commend him , as his Inventions , and admi¬ 
 rable Engines i or peace and war,as is clear from the Romane 
 Hiftories, and others. I confefs the Students of thefe Arts, 
 are not fo much in requeft now, at lead amongft fome, and 
 that knowledge is not fo much efteemed 5 and the reafori 
 maybe 5 becaufe fome who profefs themfelves great Ma - 
 fiers, ftudy nothin? but the pureYpeculations,which fome- 
 times are to fmill pm pore,others before knowing the fame, 
 unlefs for perfecting oi the mind, and giving to a man fome 
 private fatisfadtion. But fuch things will never commend 
 a man fo much as the practical part, and new Invention will 
 do. Tis furely a fnnll bufinefs for one to do nothing, but 
 to nibble at fome petty Demonftration. But when fuch 
 fpeculations are joynedwith invention and practice, for the 
 profit, andufeofmen, among whom they live, then are 
 they far more to be commended. And if this be not, fuch 
 knowledge is of fmall advantage to themfelves or others. 
 Many of the Ancient, and late Aftronomers have been,and 
 are famous lor pra&ice, aswitnefsthe indefatigable pains 
 they have been at in making their Obfervations. What 
 hathfo highly commended :derchi(lon over all Europe , as 
 his inventions, efpecially his Logarithmes d And it all be 
 true, that’s reported (which I am apt to believe i he might 
 have been more renowned, for his many excellent Engines , 
 which though ufeful, yet becaufe hurtful to mankind, he 
 buried with hlmfelf. I am confident, if the Author of 
 thefepropofals had had time to have profecuted them, he 
 would have been celebrated in the Catalogue of the moft 
 famous Mathematicians ofhistime. But leaving this, I 
 ' ' ' Ml 
 
cptfceuatiy a)bf wtatftm s. a# 
 
 fhall give you them in his own words: but firft his Apo-j 
 logy. 
 
 Thefe bold piopofals will need perhaps an apology to 
 fuch, to whom the cauies, and circumftances are unknown. 
 Let it fuffice, that the Propofer finding himfelf between 
 twoextreams, either to leave unprotected this affair, for 
 fear of being miftaken by fome, as impudent, or to com* 
 mit himfelf openly to the charitable judgement of others, 1 
 who will fufpend their cenfure, till they have feen what his 
 endeavours will produce. He hath rather chofen this laft, 
 efpecially confidering, that his filence could not anfwer to 
 his duty, which he owes to his Countreys fervice, feing 
 the following Engines may be fo ufeful to it. A deduction 
 of the fabrick, caufes, and occafions of thefe new Engines, 
 that fet the Inventer a-work, would take a long time to 
 difcourfe upon. This Paper therefore is only deftined for 
 a fliort information of their ufe, the reft, which could not 
 here be infert without impertinency, maybe fupplied af- 
 terwards (if need be) either by a difcourfe, or by a parti¬ 
 cular demonftration. The Propofer then is of opinion, fif 
 felt-love of his own Inventions do not blind his Judge¬ 
 ment ) that thefe paradoxes may be truly affirmed. 
 
 That if itfhall pleafe His Majefty to arm with thefe new 
 Arms, and Engines, 5 oo Foot, or fewer, this fmall num¬ 
 ber fhall be Matters of theTields in France Germany ^Spain, 
 or where elfe it fhall pleafe His Majefty, however encoun¬ 
 tered by the moft powerful Army of Horfe or Foot, armed 
 with ordinary Arms, of Piftol, Carabine, Pike, Mufquet, 
 which Europe can bring ro the Fields. 
 
 Thecaufeof this admirable effedl, is in the quality of 
 thefe new Arms,by which, the whole Horfemen and Foot¬ 
 men of the enemy are rendred ufelefs, and onfervicable ^ 
 Gg 2 - neither 
 
2j6 £ 0 tfcettanp dPbfttDatians._ 
 
 neither can they do any offence to thefe, who are fo 
 armed. 
 
 The Mufquettcers, who can only ferve againfi: thefe Ma~ 
 clins, /hall be put to fuch difadvantage, as it is impoffible 
 they can/land, the leaft time, in the common way of fer- 
 v:ce With the Mujquet, it not being able to make one fliot 
 for twenty, which (hall be made from thefe new Engines. 
 
 Thefe nuv Arms, have this advantage likewife, that 
 thefe who are fo armed, can by no force of Horfe or Foot 
 be broken, or put to ciforder, TheSouldiers are alfoby 
 them put to a neceffity of keeping together, and fighting, 
 and by them, they are fo Baricadod . and ftrongly defen¬ 
 ded, that if they leave them not, tney cannot be expofed 
 to danger. This contributes much to good Difcipline, 
 when the Souldiers fhali by neceffity be tied to his duty, 
 and fear, which otherwife makes him run away, fhali here, 
 for his fafety make him ftand. 
 
 Thefe new Arms are ufeful, as well in Marching, as in’ 
 Combating, for with them, we may march feenrely two 
 in front, through the ftraiteft paflages, and be able to force 
 with them any advantage a ftrait paffage can give to an ene¬ 
 my. Befides, for a long hafty march, where Victuals can¬ 
 not be well carried, the Souldiers are ablewith thefe Arms 
 to carry their own provifion for eight dayes, with more fa¬ 
 cility, then they can now carry one dayesprovifion. 
 
 To lodge in the open fields, thefe Arms fhali need no 
 Intrenching, for they fufficiently both Arm and Bari cade 
 the Souldiers, 
 
 And as they are ufeful in Service,fo are they a great deal 
 cheaper than the ordinary ^Jrms, For although with 
 5 rhoufandmen fo armed, the fervice of iooooo armed 
 with common Arms may be done, yet the whole price of 
 
 them 
 
fiPif ceunng gW f tcu ations, 137 
 
 them will not amount to that which will be required for 
 arming 20500 Cor rapiers^ as maybe particularly deduced, 
 from the particular prices of the Arms, and Engines fitted 
 for the feivice of 5000 men. The Propofer doth offer to 
 fhevv, that thefeArms will not furmount 40000 pound 
 Sterling. The Artillery will amount to 4500,and the pay¬ 
 ments of this number of men foarmed, yearly to 70000 
 pound. Yet all thefe are taken in l'o large a latitude of 
 reckoning, as the turn of Arms. Artillery, and payments, 
 will not be much above 130000 pound Sterling. 
 
 The Arms from which thiseffed is promifed, are new 
 Engines, with which, one man is able to do the fervice of 
 a great many Mufauetteers, And thofe are of two forts, 
 either to be ufed upon a fmall Wagon for Footmen, or on 
 a greater for a Horle, with either of which, one hand is 
 able to make the fire of roo CMupuetteers , and fo much 
 better, by how much it is more regularly, and fitly done 
 for execution and offence. The new Cannon fhali have 
 the like advantage above the old, both for eafie carriage, 
 being lighter, and for greater execution, fhooting fix, nine, 
 or twelve Bullets for one. Thefe Arms give not only 
 this advantage at Land in the field, but alfo in Ships, and 
 places of defence, 
 
 Thefe nine following propofitions he likewife offered to 
 
 makegood, 
 
 Firft, With one foot of Carney to do the execution of 
 five foot of the fame Cmnm > in the common way' of Bat¬ 
 tery. 
 
 Secondly,to difable any Ship or Galley with one foot of 
 Cannon. 
 
 Thirdly, to fire any combuftible matter with the foot of 
 a Cannon , 
 
 Fourthly, 
 
ffitfcel lanp flto fettwttons. 
 
 Fourthly, to make an Uachin or Engine for tranfporting. 
 an Army, which may be carried without the incommodity 
 thereof. 
 
 Fifthly, to make a Sotting Fortrefs for defence of Ri¬ 
 vers, and prohibition of Paflages. 
 
 Sixthly, to make a OKcrtar that hath a directory Stell 
 upon the Carriage, 
 
 Seventhly, to make Vet Ards of divers forms, that fhall 
 be able to do twice as much execution, as thofe that con. 
 tain as much Powder. 
 
 Eighthly, to make fmall Petards of great effed. 
 
 Laftly, to make Bridges^ and Scaling Ladders of eafie 
 Carriage. 
 
 OBSERVATION XX- 
 
 T Hefe Obfervations being MifcelUnj , require not 2 
 formal connexion between themfelves, and there¬ 
 fore ’tis no matter what method I keep in fetting them 
 down. And though this may feem not fo pertinent, as 
 others, yetbecaufe the defignofit is only Philosophical, 
 and for advancing the Hiflorical part of Learning in order 
 to Sprits , upon which the Scientificd part doth fo much 
 depend, I have prefumed to infer t it here, confidering al- 
 fo that there are fome, who have adventured to deny their 
 exigence, and being; which from fuch a Hiftoiy as this, 
 may be more than probably evided. I find likevvife, that 
 feveral Writers have remarked fuch {frange accidents, and 
 have tranfmitted them to pofteiity , which may feive ior 
 good ufe. The fubjed-matter then of this Qbfervation, 
 is a true and fhort account of a remarkable trial, wherewith 
 the Family oi one Gilbert Compel, byProfeflion a Wea¬ 
 ver 
 
^tfcellanp £>Dfeti)atfcn& 239 
 
 ver in the old Paroch of Gltnluce in Gdllcmj , was exer- 
 cifed.Though the matter be well known to feveral perfons 
 at that time, and fince too •, yet there are others, eighteen 
 years interveening, to whom (perhaps) fuch a relation 
 will not be unacceptable, who have either not as yet heard 
 of it, or at leaft, have not gotten the true information, 
 which is here fet down, as it was Written, at the defire of 
 a fpecial Friend, by Gilbert Campbel’s own Son, who knew 
 exa&ly the matter, and all the circumftances, whofe words 
 are as follows. 
 
 It happened m ottober i #4, that after one Alexander 
 Agmv, a bold and fturdy Beggar, who afterwards was 
 hanged at Vumfreis for blafphemy, had threatned hurt to 
 the Family, becaufe he had not gotten fuch an alms as he 
 required: the faid Gilbert was oftentimes hindered in the 
 exercife of his Calling, all his Working-Inftruments be¬ 
 ing fome of them broken, fome of them cutted, and yet 
 could not know by what means this hurt was done; which 
 piece of trouble did continue, till about the middle of No¬ 
 vember, at which time the Devil came with new and ex¬ 
 traordinary affaults, by throwing of Stones in at Doors and 
 Windows, and down thorow the Chimney- head, which 
 were of great quantity, and thrown with great force, 
 yet by Gods good providence, there was not one perfonof 
 the Family hurt, or fuffered dammage thereby. This 
 piece of new and fore trouble, did neceflitat Mr. Cjmpbel 
 to reveal that to the Minifter of the Paroch, and to fome 
 other Neighbours and Friends, which hitherto he had en¬ 
 dured fecretly. Yet notWithftanding of this, his trouble 
 was enlarged; for not long after, he found oftentimes his 
 Warp and Threeds cut, as with a pair of Sizzers, and the 
 Reed broken.; and not only this, but their apparel cut af- 
 
2^.0 £jMceuanp ^bfet&attons* 
 
 ter the fame manner, even while they were wearing them, 
 their Coats, Bonnets, Hofe, Shooes, but could not dif- 
 cem how, or by what mean. Only it pleafed G«d to pre¬ 
 serve their perfons,that theleaft harm was not done. Yet, 
 in the nisht time, they wanted liberty to Sleep, fomething 
 coming,~and pulling their Bed-doaths and Linnings off 
 them,and leaving their bodies naked. Next, their Chefts, 
 and Trunks were opened, and all things in them ftrawed 
 here and there. Likewife, the parts of the YV orking In¬ 
 struments, that had efcaped, were carried away, and hid 
 in holes and bores of the houfe, where hardly they could 
 be found again. Nay, what-ever piece of Cloath, or 
 Houlhold-ftuff * was in any part of the houfe, it was carried 
 away, and fo cut and abufed, that the Good-man was ne- 
 ceffitaced with all hafte and fpeed, to remove, and to trans¬ 
 port the reft to a Neighbours houfe, and he himfelf com¬ 
 pelled to quite the exercife of his Calling, whereby only 
 he maintained his Family. Yet, he refolved to remain in 
 the houfe for a feafon. During which time, fome perfons 
 about, not very judicious, counfelled him to fend his chil¬ 
 dren out of the Family, here and there, to try whom the 
 trouble did moft follow, afTuriug him, that this trouble 
 was not againft all the Family, but againft fome one per- 
 fon, or other in it, whom he too willingly obeyed. Yet, 
 for the (pace of four or five dayes after, there were no re¬ 
 markable affaults, as before. The Minifter hearing there¬ 
 of, {hewed him the evil of fuch a courfe, and affured him, 
 that it he repented not, and called back his children, he 
 might not expect that his trouble would end in a right way. 
 The children that were nigh by, being called home, no 
 trouble followed, till one of his fans, called Thomas, that 
 was farrefi off", came home. Then did the Devil begin a- 
 
 5 r .ru 
 
gpifcetianp i>bfc tbat(on g, 141 
 
 frcfli 5 for upon the Lords Day following, in the after¬ 
 noon, the houfe was fet on fire, but by his providence, and 
 the help of fome people, going home from Sermon, the 
 fire was extinguifhed, and the houfe faved, not much lofs 
 being done. And the Monday after, being fpent in pri- 
 vat Prayer and Falling, the houfe was again fet on fire 
 upon the Tuefday about nine a Clock in the morning, yet 
 by providence, and the help of Neighbours, it was faved, 
 before any harm was done. 
 
 Mr, Camfbel, being thus wearied, and vexed, both in 
 the day, and in the night time, went to the Minifier, de¬ 
 filing him, to let his fon Thomas abide with him for a time, 
 who condefcended, but withal affined him, that he would 
 find h'mfelf deceived, and fo it came to pafs: for, notwith- 
 ftanding that the child was without the family, yet were 
 they, that remained in it, fore troubled both in the day 
 time, and in the night feafon, fo that they were forced to 
 wake till mid-night, and fometimes all the night over. 
 During which time, the perfons within the Family, fufibr¬ 
 ed many Ioffes, as the cutting of their Cloaths, the throw¬ 
 ing of Peits, the pulling down of TurfF, and Fed from the 
 Roof, and Walls of the Houfe, and the ftealfog of their 
 Apparel,and the pricking of their flefo and skin with Pins. 
 The Presbytery having conveened at the place,for a folemn 
 Humiliation, perfwaded Gilbert Camfbel to call back fiis 
 SanThomas, notwithftanding di whatfoever hazard plight 
 follow. The Boy returning home, affirmed that he heard 
 a voice fpeak to him, forbidding him to enter withiu the 
 houfe, or into any other place where his Fathers Calling 
 was exercifed. Yet he entered, ;buc was fore abufed, .till 
 he was forced to return to the Miniftcrs houfe again. 
 
 Upon Monday the 12 of February, there# of rhe Fatni- 
 
 Hh " ly 
 
H 2 ©ifcellanp DbfemttQns* 
 
 Jy begin to bear a voice fpeak to them, but could not well 
 know from whence it came. Yet, from evening till mid¬ 
 night, too much vain difcouife was kept op with the.Dc- 
 A and many idle and impertinent queftions propofed, 
 without that due fear of God, that fhould have been upon 
 their Spirits, under fo rare and extraordinary a trial. The 
 Minifter hearing of this, went to the houfe upon the Tuef- 
 di t , being accompanied with fome Gentle-men, who af¬ 
 ter Prayer was ended, heard a voice fpeaking out of the 
 ground, from under a bed, in the proper Countrey Dia¬ 
 led, faying, Would ye know the Witches 0/Glenluce? / 
 millted you.them ^ and fo related four or five perfons names, 
 that went under an evil report. The faid Gilbert informed 
 the company, That one of them ms dead long ago. The 
 Devil anfwered, and faid, It is true, jhe is dead long ago, 
 ’jet her [first is living with ns in the world. The Minifter 
 replied, faying, (though it was not convenient to fpeak 
 to fuch a perfGnj The Lord rebuke thee Satan, andputthee 
 to (Hence ; we are not to receive any information from thee, 
 nh.it[0ever fame any perfons go under. Thou art but feeking 
 to feduce this Family : for Satans Kingdom is not divided 
 again[l it [elf. After which all went to Prayer again,which 
 being ended (for during the time of Prayer no trouble was 
 made) the Devil with many threatnings boafted and ter¬ 
 rified the Lad Thomas , who had come back that day with 
 the Minifter, that if he did not depart out of the houfe , he 
 would fet all on fire. The Minifter anfwered,and faid, The 
 Lord willpreferve the Hou fe, and the Boy too, Jeing he is one 
 of the Family, and hath Gods war rand to tarry in it. The 
 Devil anfwered, He (hall not get liberty to ftay : he was once 
 put out already, and (hall not abide here, though 1 fhouldpur- 
 due him to the end of the world, The Minifter replied, The 
 
 . Lord 
 
figiTcdianp iDofecijattons. 24$ 
 
 Lord will (lop thy malice again ft him. And then they all 
 prayed again, which being ended, the Devil faid, Give 
 meet Spade and a Shovel, and depart from the houfefor fe- 
 ven dayes , and I Jhall make a grave, and ly down in it, and 
 jhall t> ouble you no mere, The Good'man anfwei ed , Not (o 
 much as a Straw Jhall be given thee, through Gods ajft fiance, 
 even though that would do it. The Minifter alio added, 
 God (hall remove thee indue time. The Dew/anfwered, j 
 will not remove for you, I have my Commijj ion from Chrift 
 to tarry, and vex this Family. The Minifter anfwered, 
 A permifion thou haft indeed,but God will flop it in due time. 
 The Devil replied, I have (Mes, John) a Commiftion, 
 that (perhaps) will la(l longer than your own. After which, 
 th e Minifter and the Gentlemen arofe, and went to the 
 place where the voice feemed to come horn, to try if they 
 could find any thing. And after diligent fearch, nothing 
 being found, the Gentlemen began to fay, We think this 
 voice [peaks out of the children, iorfome of them were in 
 their beds. The Devil anfwered, Toulie, God Jhall judge 
 you for your lyinand I and my Father will come and fetch 
 you to hell , with Warlock-theeves 5 and (o the Devil dif- 
 charged the Gentlemen to fpeak any, faying, Let him Jpeak 
 that"hath a Commifjion ( meaning rhe Minifter) for he is 
 the Servant of God, The Gentlemen returning back with 
 the Minifter, they fat down near to the place whence the 
 voice feemed to come from , and he opening his mouth, 
 fpaketothem, after this manner. The Lord will rebuke 
 this Spirit, in his own time, andcaftit out. The Devil 
 anfwerin®, faid, It is written in the $ a / 1 Mark, the Dif- 
 ciples could, not caflhim out. The cJMinifter replied, what 
 the D/fciples could not do, yet the Lord having hightned the 
 Parents faith, for his own glory did caft him out, and [0 fall 
 Hh 2 he 
 
144 ©tfceuanp £Dbftcfcfitt0n0* 
 
 he the:. The Devil replied, It is written in the 4 ef Lukej 
 And he departed, and left him for a feafon. The Mmifter 
 fa id, The Lord in the dayes of his humiliation, not only got 
 the victory over Satan, in that affaalt in the wilderness, but 
 when he came again, his faccefs was no better, for it is Writ¬ 
 ten, Joh. 14. Behold the Prince of this world someth, and 
 hath nothing in me 5 and being now in glory, he will fulfill 
 his promtfe, and Godfull bruife S at an under your feetfhort- 
 ly, Rom. 1 5 . The Devil anfwered) It is written , Mat. 
 2 >. There were ten Virgins, five wife, and fvefoolifh •, and 
 the Bridegroom cam:: The fodifh Virgins had no Oyl in their 
 Lamps, and they went unto the wife to feek 0 )'l $ and the wife 
 (aid, Go and buy for your [elves: and while they went, the 
 Bridegroom came, and entered in, and the door was (hut, and 
 ihefoolifh Virgins were fen: to hells fire, T he Minifies an¬ 
 fwered, The Lord knows the fmcerity of his fervants, and 
 though there be Jin and folly in us here, yet there is a fountain 
 opened to the honfe of David for fin and for mcleannefs, and 
 when he hath wajhed tss there, and pardoned all our fins, for 
 his Names fake, he will cafl the unclean fpirit out of the land . 
 The Devil anf wered and laid, Thai place of Scripture is 
 written in the 13 o/Zechimh, In that day I will caufe the 
 Prophets, and the unclean fpirit, pafs out of the land-, but 
 afterwards it is written, I will [mite the Shepherd, and the 
 Sheep (hall be fcattered. The Minifter anfwered and-faid. 
 Well are we, that our bleffed Shepherd was [mitten, and there¬ 
 by hah bruijed thy head and albeit in fhe hour of bis fuffer- 
 ings, his Difciplesfor(ookhim, Mac. 26. yet now having 
 afeended on high, he fits in glory, and is freferving, gather - 
 fig in, and turning his hand upon his little ones, and will 
 live his poor ones in this Family from thy malice. The Mi- 
 sifter returning back a little, and Sanding upon the floor, 
 
<pfceUanp jDbfccDatton^ 24? 
 
 the Devil faid, I knew notthefe Scriptures, till my Father 
 taught me them. J am an evil Spirit, and Satan is my Fa¬ 
 ther, and I am come to vex this houfe ; and prefently there 
 appeared a naked hand, and an arm, from the elbow down, 
 beating upon the floor, till the houfe did fhake again •, and 
 alfo the Devil uttered a moft fearful and loud cry, faying, 
 Come up Father, come up: I will fend my father among you. 
 See, there he is behind your backs. The CM ini(l cr faid, 
 jfaw indeed an hand, and an arm, when the fir oak was gi¬ 
 ven , and heard . The Devil faid to him, Saw you that ? 
 It was not my hand , it was my fathers ; my hand is more 
 Mack in the loof, Would you fee me 1 Fut out the candle 
 then, and ifhall ccme butt the houfe among you like fire-balls. 
 After which all went to Prayer, during which time, it did 
 no harm, neither at any other time when God was wor- 
 fhipped. When Prayer was ended, the Devil anfwered 
 and faid, Mes John, if the Good-mans fens prayers at the 
 Colledgtof Glafgow, did not prevail more with God, than 
 yours, my father and 1 had wrought a mifehief here ere now. 
 To which one of the Gentlemen replied, though a check 
 had been given him before, Well well, I fee you confefs 
 there is a God, and that prayer prevails with him, and there¬ 
 fore we mu(l pray to God, and will commit the event to him. 
 To which the Devil replied, Tea Sir , you jpeak of prayer, 
 with your bread lipped Hat ( for the Gentleman had lately 
 gotten anew Hat in thefafhion with broad lips) fIt bring 
 d pair of Shears from my father, that.full clip the lips of 
 it a link. 
 
 The night now being far fpent, it was thought fit every 
 one fhould withdraw to his own home. Then did the De¬ 
 vil cry out fearfully, Let not the Minifier go home, I fhall 
 hum the houfe if he go ; and many other wayes did he 
 threatea 
 
246 (pfceuanp sUMcr&ations* 
 
 threaten. And after the Minijter was gone forth, the 
 Good-nun being inftmt with him to tarry, whereupon he 
 returned, all the reft of the company going home. Then 
 £kid the Devil to the Mtnifler , Ton have done my bidding . 
 Not thine, anfwered he, but in obedience to God , have I 
 returned to bear this man company, whom thou doji afflift. 
 Then did the IUnifier call upon the Name ol God , and 
 when Prayer was ended, he difcharged Mr. Campbel, and 
 all the perfons of the Family, from opening their mouth, 
 in one word to the evil [pirit, andwhenitfpake, that they 
 fhould only kneel down, and fpeak to God. The Devil 
 then roared mightily, and cryed out, What i Will ye not 
 [peak to me ? I [ball burn the boufe, 1 fhall firike the bairns, 
 and do ad manner of mijebief. But after that time, no 
 anfwer was.made to it, and fo tor a long time no fpeech was 
 heard. After this, the faid Gilbert f uffered much lots, and 
 had many fad nights, not two nights in one week free 5 and 
 thus it continued till April. From April to $ttlf, he had 
 fomerel'pite, anaeafe. Butafter, he was molefted with 
 new aftaults: and even their Vnftuals were fo abufed, that 
 the Family was in hazard of ftarving ; and that which they 
 did eat, gave them not the ordinary fatisf aftion they were 
 wont to find. 
 
 In this fore and fad affli&ion, Mr. Campbel refolved to 
 • make his addrefs to the Synod of Presby ters , for advice and 
 couniei what to do, which was appointed to conveen in 
 Ocfober 1655, namely whether to forfakethe houfeand 
 place, or not? The S pod by their Committee, appoin¬ 
 ted to meet at Glenluce in Feb. thought fit, that a 
 
 folemn Humiliation lliould be kept thorow all the bounds 
 oi the Synod, and amongft other caufes, to requeft Godin 
 behalf of that poor affli&ed Family, which being carefully 
 
$)tfceuan]? €Merfra tiong» 24.7 
 
 done, the event was, through the Prayers of his People, 
 that his trouble grewlefs till Afrilfmd from April to Au- 
 gt he was altogether free. About which time, theDe- 
 <vil began with new aflaults, and taking the ready meat 
 thatwas in the houfe, did fometimes hide it in holes by the 
 door-pofts, and at other times did hide it under the beds, 
 and (ometimes among the Bed-cloaths, and under the Lin- 
 nings; andatlaft, did carry it quite away, till nothing 
 was left there, fave Bread and Water to live by. After 
 this, he exerciled his malice and,a uelty againft all the per- 
 lons of the Family, in wearying them in the night time, 
 with ftirring and moving thorow the houfe, fo that they 
 had no reft for noife, which continued all the moneth of 
 Augufl after this manner. After which time, the Devil 
 grew yet worfe, and began with terrible roarings, and ter¬ 
 rifying voices, fo that no perfon could fleep in the houfe, 
 in the night time, and fometimes did vex them with call¬ 
 ing of ftones, ftrikrng them with ftaves on their beds in 
 the night time: and upon the 18 of September, about mid¬ 
 night,he cried out with a loud voice, l jhaHbum the houfe ; 
 and about three or four nights after,he fet oneofthe beds on 
 fire $ which was foon extinguilhed, without any prejudice, 
 except the bedit felf: and fobe continued to vex them. 
 
 obser-; 
 
1 48 gptfceuanp $bfemtfons* 
 
 OBSERVATION XXL 
 
 I Need not make any apology for inferting this Obferva- 
 tion, eventhough it be well known upon the matter in 
 this place. But becaufe the thing is extraordinary, and 
 that there are many who have not fo much as heard of it, I 
 have therefore presumed to mention it here. The matter is 
 fhortly this. There’s a certain Woman, named Miftris 
 Lea, who had a real and true Horn, growing upon the 
 right fide of her Head, three inches above her right Ear. 
 The length of it is eleven inches, and two inches about. 
 The form is crooked fpirally. It is convex on the outer 
 fide, and fomewhat guttered in the inner fide. It is hard 
 and folid, and all very near of the fame greatnefs. It is 
 not hollow'within, as horns are ordinarily, but full, yet it 
 feems to be fpongious as a Cane. is. It was fcven years in 
 growing, 2nd was cut off in dUy 1671, by Mr.Temple ^ 
 an expert Chirurgeonhere at Edinburgh. 
 
 OBSERVATION XXII- 
 
 T His Obfervation is for finding the Primum vivens 
 in Animals. Albeit Idoubt not but the red Spirit, 
 or Bloody in moft Terre (trial Animals , is the firft product 
 of the Primigenial juice , and therefore not improperly 
 named the true Callidum Jnnatv.m of thefe Creatures, by 
 the Noble and Ingenious Harvey, in his Book de Genera- 
 tier:!. Neither do I fcruple to yeeld, that the Heart, and 
 appendent VefFels, are the firft iormed, and perfected parts 
 in the Totter kind of Animals: yet I am confident to af¬ 
 firm, that in many of the colder, and moifter kinds of 
 Anuatich, if not in all, neither the rednefs and heat of the 
 
gMcellanp DDfccbatfotis. 249 
 
 Vital Sprits, nor the formation of the Heart, Liver, &c. 
 arepievioufly requifite, to. the ftru&ure and exiftence of 
 the other parts feing the light of life, which at firft inha¬ 
 bited the clear and Criftalin radical moifture, before the 
 formation of any particular part, doth alwayes move in 
 every living creatuie, according to their particular exigen¬ 
 cy, without any abfolute dependency upon any one part, 
 or member (excepting fingular conditions, wnerein they 
 may be ftatedj as to its fubftance, light, and motion 
 there being in fome Animals a fimple undulation, in others 
 a flow creeping, but in the more perfeft, an impetuous 
 running, or rather flying of the vital Sprits, neceffarily 
 required for illumination and vivification of the whole. 
 
 For confirmation, I fhallgive you this fingular Experi¬ 
 ment. About the middle of March, the fpermof Frogs 
 (according to the number oi Prolific!: Eggs therein contain¬ 
 ed) fends forth a multitude of fmall round Creatures, co¬ 
 vered with a black, and moveable Frock', which about the 
 end of March, and beginning of Apil, by the Gyrations 
 of a Tail behind, like a Rudder, do flowly move their 
 bodies in the Water. At this time having opened feverals' 
 of them, I found nothing (apparent to the naked eye) 
 but a clear th n Membran, under the fore-named black 
 Frock, within which werecontained a clear Water, and 
 fome fmall Fibres like Inceftines, and in the fore-part a 
 fmall orifice like a mouth. About the middle 0 i Apil, 
 its motion is more vigorous, and the Trips within are 
 moft evident, lying in a very fine circular order, but as yet, 
 there is no Veftige of Heart, Blood, or Liver, &c. About 
 the middle of Maj, the feet formed like fmall threeds, ap¬ 
 pear thorow the black Coat : within the Breaft, the Heart 
 is then vifilale, of a white and Fibrous fubftance, the Liver 
 Ii is 
 
2fo £gtfceitenp ffi dfccsano ns. 
 
 is white,and the Gall therein eafilydifcerned. But (which 
 istheheadof this Experiment) the Vital Spirit, in form 
 of a dear and pure Water, is manifeftly received by the 
 Nervous Heart, and by the contradion thereof tranfmit' 
 ted to all the Body, thorow white tranfparent Veflfels, 
 which being full of this Liquor, do represent the Lymph a- 
 tick, rather than the Sanguiferous Veins, Laft of all do 
 the Pneumatic!: Vef.cles (which in this Amphibium fupp'ry 
 the place of the Lungs) arife in the Bread, after whofe 
 produdion, the Lympid and Cryftalin Liquor, while the 
 Heart is turgid therewith, feems to be red and fiery, but 
 in the other Veflfels, it is of a faint pale colour, until! 
 
 (about, or near the end of $une ) the Frock being caft off, 
 and a perfed Frog formed, the whole Veflfels are full of 
 Blood, or a red fubftance very thin, and clear: the Liver, 
 and Fneumatick Veficles , &c. become red, and Rofy s fo 
 that the Blood in this Amphibium (which in the more per¬ 
 fect Animals is firft compieat) feems to be the laft part in 
 attaining its perfection. 
 
 That Salmonds^ and great Fronts hive an aqueous liquor 
 which runs thorow their Arteries , and Veins , before their 
 Blood attain the true confiftency, and faturat tindure I am 
 certain: whether it hold in many others, I fufped, but dar 
 not affirm. Hence it may be (if mens obfervations, were 
 frequent in all kind of Anatomical infpetfions, in feveral 
 Embryo's of every fpecies) it would be found evident, that 
 the Blood in all thefe, called hath its immediat origi¬ 
 nal from a Ample homogeneous, and uniform liquor , and 
 doth by gradual and frequent influences of the vital ferment 
 of the heart, receive at length the full tindure,eftence, aud 
 fubfiftence reqaifi.ee for vivification, and illumination of 
 -the whole members. 
 
 Whether 
 
ffitf ctllatip g)b[eci)«t(ons, ist 
 
 Whether this Experiment dothnot fufficiently impugn 
 the univerfality of the hearts firft living, the original of the 
 Gall from the fervour, and ebullition of the Blood, the 
 production of the Blood by the Liver, and many other an¬ 
 cient errors, let any judge,who will but take pains to make 
 and compare Harveys trials demo, with this of the Por- 
 wigl or GyrinuS) abovo. 
 
 Yea, if the aqueous liquor, be not one with the vital 
 Spirit, and fubfequent Blood, then my eyes, and tafte are 
 altogether erroneous. 
 
 Moreover, it were to be wifhed, that PhjfitUns would 
 not Amply Hand upon the Galenic!: [uppofittons ofthefour 
 alledged Components of the Blood, nor any fuch, or equi¬ 
 valent fancies of the latter cbymifls 5 but that they would 
 ferioully examine the firft original, and rife thereof from 
 the Primigemaljuice y or liquamen, the progrefs,and perfec¬ 
 tion of its tinClures, how many renovations, or new tin&ures 
 it is capable of ^ the vaft difference between the Blood of 
 old and young Animals, (though, it may be, they are 
 both univocal fubftances, while in their integrity within 
 theVeffels) with the fpecifick difcriminations, not only 
 of that of anyone Aqutick, from any Volatile Terre (Irial, 
 but likewife of any one Species living in the fame Element, 
 with thefe that enjoy the fame Aliments, but ofa different 
 Species, And laftly, the variety of particular conftituti- 
 ons, and lingular properties of individual Animals, radi¬ 
 cated in the fountain of life, or firft original of the Blood. 
 If thefe things, and many more, were truly inquired af ter 
 (though the Cook be fometimes neceffitated to throw 
 away fome of the Broth with the Scum ) I doubt not but 
 the Neoterick Invention of Transfuficn of Blood, would 
 prove altogether ridiculous, and the ancient miftake of too 
 I i 2 much 
 
i5i ©tfcfllanp^bfecfcations* 
 
 muchProfitfion of this treafure by Phlebotomy might fuf- 
 fer fomereafonable checks from infallible Experience, and 
 found reafons, not here to be mentioned. There are truths 
 in Natural Philofophy, which (I doubt not; but found 
 reifon sad experience will convince the vain world of in 
 due time. 
 
 OBSERVATION XXIII- 
 
 T His Observation is concerning the aliment and growth 
 of Plants. The inquifitive wits of this, andthelaft 
 age, having rejeded the old opinion of the earths nourifh- 
 ing of Plants, or being converted into their aliment, have 
 made many laudable Experiments lor finding out the ma¬ 
 terials, and means of their growth, and vegetation, fuch 
 
 as Sir Francis Bacon's obferve of Germination, Belmonts of 
 ^Willow , and the Noble Mr, 'dojh of a Gourd , &c ; For 
 though a Tree be cut down, and the root thereof wax old 
 in the earth, and the frock die in the ground, yet through 
 the fentof Water, it will bud, as^fpeaketh, Chap, 
 14 - 7 ,8,9. I/hall add a foort remark of a Willow grow¬ 
 ing without earth. Upon the 13 of April 1662, I fet a 
 top branch ol the Peach-leaf d Willow in a Glafs-viol,among 
 12 ounces of pure Spring Water, with three fmall buds 
 upon the top thereof, fcarce yet difcernable. The firft 
 ten or twelve dayes, little white fpecks appeared upon the 
 fides of the Willow, like fmall drops of Quick-fiver^ or 
 like the firft Bubbles that arife upon the fermentation of 
 Ale or Wine, but no confumption of the Water all this 
 time. Indeed the Gemms , which flood three inches above 
 the Water,did vifibly /well about the twelfth day. About 
 the fifteenth day, I perceived fmall white roots within the 
 
 Water, 
 
£pf«iiatip SDofctbationg. 1*3 
 
 -Water, upon feveral places'of th e riant, and obferved the 
 Liquor grow fomewhat thick, and decay in bulk confide- 
 rably. Having perceived this, I took anothei Glafs of the 
 fame bignefs, with that wherein the Willow giew, and 
 having filled both top-lull with Spring Water, I obfer¬ 
 ved dearly the confumption of the Water wherein the 
 TLnt hood, to be fo great, that during a ay, $une, and 
 a great part of $ulj, eveiy week (at leaft) an ounce and 
 an half, or two ounces of it were infenfibly (pent: whereas 
 the other Water, (landing by in an open Vetfel of the fame 
 ■fize, made not wafte of one fpoonfulina whole moneth. 
 About the middle of Auguft, the Water turned veiy thick, 
 and green, like that whereon Duck-weed ufeth to grow, 
 and the fair white roots were all obfcured from the fight, 
 although the Veffel by the multitude of roots, was not ca¬ 
 pable of the third part of Water it received at fiift, At 
 this time the branches were advanced to half the bignefs, 
 and a much greater length, than the whole flock, at its 
 firft planting, and the leaves of as freih a verdure, as any 
 Willow in the fields, Thus, having obferved, that a tree 
 of four ounces weight, could in three moneths time, and 
 little more, confume infenfibly, feven or eight times its 
 own weight of pure Water, without the warm prefervati- 
 on of the earth, and by its own proper digeflion,to thicken 
 the remnant of the Water, that it might ferve for loricati- 
 on of the tender fibres of the roots, I took the Glafs, the 
 Tree, and all, and threw them over a Window, fuppofing 
 it needlefs to recruit the Water any more, and judging it 
 impoffible without the warm guard of the earth, that the 
 naked Tree could be preferved in Winter; yet it had the 
 good fortune to fall among fome thick Herbs in the corner 
 -•of a little Garden, where (after it had lien all Winter) it 
 
i5 4 ©tfceuanp ©bfesbattons* 
 
 was found, and brought back to me, the branches fairly 
 budding in April, the whole Tree frefh and green, yet ve¬ 
 ry little Water was left in the Glafs, by reafon, as I judg¬ 
 ed, it had fallen upon its fide. Then I endeavoured to 
 keep Water about it, but the Stock filling the neck of the 
 Viol, and the Roots the whole body thereof, theftarved 
 Plant died in tMay, after it had lived a whole year without 
 earth. From this it would feem, that this kind of Tree, 
 (andit m2y be, many moe) dothdifllpat infenfibly fix 
 times more Liquor, than it doth affimilat, and by confe- 
 quence, that a great quantity of moifture is necefiaiy for 
 maintainance of great Woods. Neither is there any way 
 fo aavantagious for draining raoift ground, where there are 
 no living Springs, as that of planting abundance of Tim¬ 
 ber, which wifi beft agree with that kind of foyl: for by 
 this means, what was formerly noifome, and fuperfluous, 
 is now converted partly into theufeful aliment oftheTim- 
 ber , and partly fent abroad in infenfible exhalations, 
 which (according to the nature of the emitting Plants ) 
 prove either very noifome,or wholfome to the Neighbour- 
 Inhabitants. Great care therefore would be had in the 
 choife of fuch Trees, as are to be planted in fuch moift 
 ground, as are near to mens dwellings, or places of con- 
 curfe. They are not fools, who prefer Firs, and Lime- 
 trees in their Avenues to Oak and Elm. Let the effedts- 
 of the Atomical exhalations of Alder and Oak upon fine 
 Linnen, and white Skins be more particularly noticed. 
 Having fpoken fomewhat of the aliment and growth of 
 Plants, I (hall in the next place give a fliort hint at the mo¬ 
 tion of their aliment, efpecially of Trees. That the ali¬ 
 mentary juice of Plants , is much thinner, than that of 
 Animals , no man. I fuppofe, will deny, feing that\% con¬ 
 veyed 
 
SpifceuanyWerbatfotw. m 
 
 veyed chorow the trunck, or body of the Plants, byiu-J 
 perceptible pores •, but this (for the moft pare) is fent 
 thorow all the members, through patent and manifeft Vef- 
 fels. But how the nourifhing, and vital juice in Plants 
 doth move, and by what paflages, hath not yet been made 
 known, by any that I have feen. I made once a few Ob- 
 feivations,for trying of the motion of the aliment of Trees, 
 which bred in me this conjeflure. The nutritive juice of 
 Trees is tranfmitted both to the roots and branches,through 
 the heait, or pitch, and woody pores of the Timber, and 
 when it is come to the extream parts, it returns again from 
 the tops of the roots and branches, between the bark and 
 timber, into thefe forenamed interior paflfages, and fo back 
 to the extremities again, and that continually, fo long as 
 the life remains. And becaufe the fubftance of that skin, 
 or bark, which invefts the fibres of the root, is more open 
 and porous, than that which is upon the outward branches: 
 therefore it feems,that fo much as is fuperadded to the flock 
 of the former aliment, from the earth, is conveyed to the 
 heart and pitch, by means of, and together with, that part 
 of the re trograd juice, which returns from nourifhing, and 
 enlivening the timber of the root-branches, ( for it is an 
 eafie Experiment, to make the top of any Tree become 
 root, by laying it down) and receives the impreflions of 
 the life of the Tree, common to the whole mafs of ali¬ 
 mentary juice, like the Ch)jl in Animals mixed with the 
 blood of the reni-cave , before it cometo the heart. 
 
 This motion is not to be thought alwayes alike fwifr, 
 or of equal celerity: for the vital juice of the Tree be¬ 
 comes fo thick and oleagenous in theWinter, that the mo¬ 
 tion thereof to the outward, is fcarce difcernable (though 
 the preparation of the Gemma ,both for leaves and flowers. 
 
2 56 ^ifceuanp ^Dfertjatsons* 
 
 are obferved by the curious, and can be diftinguiflied, even 
 in the coldeft feafons) and the returns inward are in fo 
 fmall quantities, that they are rather like vapours, than 
 liquid juice. Indeed, Come Trees, when their root-bran- 
 chesarecut (even in Winter) will yeeld no fmall quanti¬ 
 ty of an acid liquor, which by addition of the recent Lcf* 
 ■fas from the earth, fmells evidently of the Matrix, from 
 which it did proceed. Moreover, the paflages efpecially. 
 from the branches to the Trunk , are fo ftraitned and con¬ 
 tracted, that the barkcleavethtothe Timber, as every 
 Wood-man knows. But fo foon as the warm Spring hath 
 attenuated the ever- flowing juice in the whole Tree, then 
 doth it become turgid, and more aqueous over all: the 
 paflages, and channels both in the trunk ^ and among the 
 tunicles, and particular skinnes, are fo palpably filled with 
 this vital juice, that having no fufficient place to be com¬ 
 prehended in, itputteth foith netv growths both in the 
 top,and in the root, which may be eafily feen to have more 
 pitch than wood, and to be fealed on the extremity, with 
 the veftiges oi a future Gemrn; that by the former, ’ they 
 may the more freely receive the vital influences from with¬ 
 in,and by the latter, may be fecured from the depredation 
 of the external Air. 
 
 To prove the motion ad extra , or to the extremities 
 of the branches *, take the branch of any ordinary Tree, 
 about the bigntfs of a mans wrift; make it bare near the 
 bocy of the Tree of all bark, and fubjacent tunicles (for 
 every Tree according to its kind, hath moe or fewer skins, 
 which ferve for Veins, within the ftrong ourmofl Cortex) 
 at ieaft for the breadth of a fpan , or two hand-breadth. 
 
 Then tye up the pIace,fo excorticated with a ccmpoft,mde 
 of horfe-dung mixed with earth 5 let it ftand fo from May, 
 
spfceuanp sHMertoattons* 2*7 
 
 till November , Then cut off the branch, a little above 
 the Compojt, near the body of the Tree, and you fhall 
 find it living and frefh, like the reft of the branches: yea, 
 (mail roots fhall evidently appear to have come forth under 
 the Compoft near the bark, but not under the bared place. 
 This branch in many kind ofTrees being planted,will hold, 
 though not in all. I fay then, feing the forefaid bough is 
 nourdhed from CM ay till November , it is ntcefTary, that it 
 receive nutriment from the body of theTree, by the in¬ 
 ternal porofities thereof: for the bark being difcontinued 
 by cxcortic.ition, can fend nothing upward towards the top 
 of the bough 5 and if it received notlvng from the root, it 
 would wither in a few dayes, Yea, leave the difcovered 
 part naked, but tor a few dayes, and of neceffity the branch 
 dieth, the aliment thereof being exhaufted by the Air, be¬ 
 fore it can reach the extremities of the bough. 
 
 That the Vital Balfome of the Tree returns from the ex¬ 
 tremities by the internal bark, and inward fuperfice of the 
 external, together with the fmooth outward part of the 
 funck, although the neceffity of both timber and bark in 
 all Incifions , and Inoculations , might perfwade the judici¬ 
 ous, and the vifible courfe of the juice of the Sycamor in 
 February , and of the Birch in March, upon the cutting of 
 any final! branch , might convince any curious beholder ; 
 yet the knot or callus , that is made upon grafted Trees, will 
 better inform the ignorant: for this knot being alwayc-s 
 upon the (boulder, or root of the Graff, and never upon 
 the top of the Stock, doth evince clearly, that it is made 
 by re(lagnation, of the defending, and not of the amen¬ 
 ding juice: otherwife, why doth itnotfwell the top of 
 the Stock, as well as the root of the Graff i Or why doth 
 it not extuberat in any other place of the Graff? Thefe 
 K k are 
 
2*g ©ifceliany ^Dbferaatums* 
 
 are accidental varices, which can hardly be flnmned in Imp¬ 
 ing, feing the top of the Stock (except when it is very 
 young and fucculent) doth not receive fo kindly, as it 
 ought, theretrograd fap, although all that isfentout to 
 the Graff muff afcend thorow the pores of the Stock. 
 Hence many times a confiderable part of the Stock is mor¬ 
 tified, becaufe although abundance of aliment afcends to 
 the head or top thereof, yet no more of it goes to the 
 branches, but what is bellowed upon the Graff, a great 
 part of the reft being exhaled by the Air (efpecially in big 
 Stocks) and consequently, the place defrauded of its nou- 
 riihment: no other waves than when the motion of the 
 vital fap faileth, either in the whole, or in part, a total 
 decay or particular mortification of fome part neceffarily 
 follows, as in the Stemms of annual Planes, and mortified 
 tops of the Eclraplous branches (that I may fo call them) 
 of Widows, Plumbs, &c. we may obferve every Autumn . 
 
 / O B SEKV ATI ON XXIV. 
 
 / 5/V ’ 
 
 \ Was not a furprifed, at the receit of yours, when 
 \ (c i I had confidered your defire in it, being prtft with two 
 '“ difficulties, which'feemed equally hard to evite. The 
 one, to give you my judgement in a matter wherein I 
 “ have been fo little conversant my felf, and have had the 
 “ fteps of no other to follow, never one having hitherto 
 C: touched that fubjeft in watting ; I mean of Coals , and 
 “other Minerals of that nature, their Courfe, and other 
 cc things relating thereunto 5 the obfervation whereof (I 
 tc grant) wants not its own pleafure, and ufefulnefs, The 
 “ other, to refufe the defire of a friend, when importuned, 
 
©ffccUanp ^DbfcttoatfotiSu 
 
 te to whom I owe my felf, by many obligations. This laft 
 tC having prevailed, hath determined me to aflay the over- 
 “ coming of the firft, And though I am confident, what 
 “ account I can give you , fhall give but very little fatis- 
 “ faftion: yet I adventure to offer it, fuch as it is, vefy 
 “ freely in the following difcout fe, wherein you are not to 
 cc expeft, that I will meddle with fome questions, there- 
 “anent, which might be more curious, and pleafant, then 
 “ profitable, or fatisfying, fuch as, if Coal, and Free-fane, 
 “ which keep one courfe , and have the fame accidental 
 <c qualities, have been created in the beginning, in their 
 tc perfection, as wee now find them, and fince that time 
 <f only preferved, as they were created for the ufe of men, 
 “ to whom all fublunary things were made fubfervient? 
 “ Or, if they have been but produced gradually, as they 
 cc fpeak of Gold , and other CMinerds , by the influence of 
 “ the Sun, in the bowels of the Earth ? And if their pro- 
 “ duCtion be of that nature, out of what matter they are 
 <c formed' Thefe things being above my reach,I fhall leave 
 <c their inquiry, to thofe that are knowing in the fecretsof 
 “ Nature, and fhall therefore give you a narration, of 
 c ‘what either I have obferved of thefe things, which oc- 
 te curr in the winning of Cod in my own experience, or by 
 “ cbnvei fing with others of more experience than my felf, 
 “ in doing whereof, I fhall follow this Method. 
 
 Eirft,I fhall fpeak of thefe things that are common to all 
 Cod^ wherein they all agree,and which are*, as it wer e,effe»- 
 tialto all, and of there differences, which are but acciden¬ 
 tal, and gradual fometimeS, and yet are abundantly confpi- 
 ■cuous,andcaufeth different effe&s in the workings astheif 
 Ditfs and Rife , and Streek y for fo are they' termed. ' 
 
 Secondly,of fome things,which are but accidental to (W, 
 Kk z and 
 
260 spifcellanp DDferuations* 
 
 2nd yet fo ordinary, that fcarcely any is found without 
 them , in lefTer or greater degrees ; fuch are Gae's , and 
 Djkes,x\az alter the natural Courfe of the Met alls, very in¬ 
 cident to every Coal, though infomelefs frequent, con¬ 
 form to the nature ani kind of the ground, where the 
 Cod is. 
 
 Thirdly,! (hall fpeak fomething of Damps, and of their 
 d:ff;:ent caufes, ani effects: of Wild-fire, and other fuch 
 like things, which are met with in the working of Cod. 
 
 And Lilly, of the bed way for trying grounds to find 
 Cod , where never any hath been hitherto difcovered: of 
 carrying on o {Levels , for draining the water of Coal and 
 making it workable. 
 
 It is to be cofidered, that all Free-[lone , though of diffe¬ 
 rent natures, hath the fame courfe, with the Coal , that ly 
 either above them, or below them , except it be accident? 
 -ally, interrupted : therefore, whatfoever is fpoken of the 
 one, is applicable to the other. And fo we find in Dig¬ 
 ging or Sinkings hat after the clay is paft, which keeps no 
 courfe, all Metals, as Stone, and Tilles (which are Seems of 
 black Stone, and participat much of the nature of Coal ) ly 
 one above another, and keep a regular Courfe wherein the 
 three things mod remarkable are their Dipp, and Rife, and 
 their Streek, as it is termed. 
 
 The Dipp, and Rife, are nothing but a declining ofthe 
 •whole body of the dMetalls, And this general holds,that 
 all of them from their Center rifes, till they be at the very 
 furficeof the Earth-, fomsonly at a foot or two foot, 
 forne at an ells d dance from the furlace, which is here 
 termed a Crjpnn* : and whether Coal or Stone, the nearer 
 they come to the firface, the fofter they become, till at 
 
ggifc euanp ffWtrtoat fotis, -m 
 
 laft they are converted, if it be a Stone ^ to a very iW, and 
 if cW,to a D/v/lt,which wifi not burn. 
 
 This declining or Dipping , of the Coal , is fometimes 
 greater, and fenfible, fometimes letter, and almoft infen- 
 fible. There being fome, that if you confider the decli¬ 
 nation , it will not be found one foot in ten ; fome one 
 foot in twenty, or one in thirty, .Whereas n other's it will 
 be one foot in three , or one in five. And fometimes it 
 hath its C our ft from the Center of the Earth , -dmoft in a 
 perpendicular to the furface, it cu.v.nj t, nr- r-> a right 
 Angle, The firft fort, they term FU: -h-o.d in re¬ 
 gard of the plainnefs, and evennefs of r'Gu. The 
 next, they call Hinging-coal , The laft isct led Edge- 
 Cod. The (lift is the moft profitable , in regard, that 
 it’s long before the Coal-hewers can reach the Cnpp , and 
 confequently the more oi it is workable. Thefecond and 
 third fort, are fometimes of their own nature, more firm, 
 and fitter for burning, but lets of them can be reached in 
 working. The Courfe of all the three is moft perceptible 
 in the three following Schematifms. 
 
 • Figure 
 
i«i £@ifcellanp£>bfeirtsattons. 
 
 Ft pure I, 
 
 A B 
 
 C 
 
 A 3 B 
 
 C D 
 
 in all the three Figures, the point B is the Cropp of the 
 Cal, The Line BC is the body of the Coal declining 
 or the Dipp from the Cropp. AC is the perpendicular, 
 failing from the Horizontal Line, whereby the true decli¬ 
 nation or Dipp of the Coal is found. So that after you have 
 found your Coal at B, you muft fet down your sink at the 
 point A. In the Flat-bread-Coal, which we fuppofe only 
 to decline, three fathoms in Gxty-,the Sink, that anfwers 
 to the perpendicular AC, will be of deepnefs three fa¬ 
 thoms, 
 
03 tTfcliatiy £)bfett)atfon& 263 
 
 thorns. If the diftance B A, be fuppofed to be 120 fa¬ 
 thoms alongft the Gnfs, or furf'ace, then will the deep- 
 nefs of the Sink be fix fathom, and fo forth. In the fe- 
 cond, if the Cod be fuppofed to decline one fathom in 
 three, the Sink A C, being fet downat the fame diftance 
 from the Crcft B, with the former, it will prove thirty fa¬ 
 thom deep. If the faid diftance be doubled, it becomes 
 fixty fathom deep, and fo forth. In the third, keeping 
 that fame diftance alongft the furface,you fhall not encoun r 
 ter the Cod with a Perpendicular Sink, becaufe of its great 
 declination, and therefore through want of Air, and other 
 difficulties, you cannot dig fo deep, as is neceffary to that 
 effeift, except the Sink fhould be made to decline, as doth 
 the Line AD. All thefe Difts are to be feea in feveral 
 places of Lothian . The fiift is moft confpicuous in the 
 Earl of Wintons ground at Tranent, where thecW, and x 
 other Metals are extraordinary flat and even. The fe- 
 cond is within the faid Lordfhip of Tranent, in apiece of 
 ground, called Wefier- Fan fide. The third in Lonhead of 
 Lafmid, which pertains to Sir fohn tficolfon of Nicolfon : 
 and in many other places, one may fee very different de¬ 
 clinations, who is curious to obferve them. 
 
 From this general position of the Bin, and Cropp of all 
 free Metals , there is one confequenr, wnich is no uncouth 
 Obfervation, namely that thefe Metds rifing from their 
 Lift to a Croft , every one of them rifeth in their proper 
 courfe, ifnone of thefe things whereof we fhall treat here¬ 
 after interveen, and make an alteration, that is the Cod or 
 Stone, which is loweft, comes farreft out in its Croft'ng , 
 which is eafily underftood by the fubiequent Schematifm; 
 
 Wherein 
 
164 £@tfceUanp £>bfetfcat(on& 
 
 Figure 4, 
 
 A D F H K M 
 
 C E G I L 
 
 Wherein the Line AM reprefents the furface of the 
 Earth, CD, EF. G H. IK. L M, are fo many feve- 
 rai 'Metals, lying in courfe one above another. Suppofe 
 C D were a Stone , and the Roof of the Coal E F (tor fo 
 they term the Stone , immediatly next above the Coal) and 
 G H, IK 1 were other two Stones , interveening be¬ 
 tween the Coals E F, and L M, then if the Cropp of the 
 uppermoft Coal be found at F, the Crop of the Stone above 
 it, mud be found back, at the point D, and the Cropp oi 
 the Coal under it,which is L M, muft be found at M. And 
 this diftance of Crcpp is proportioned by the length of the 
 perpendicular between them, and the quantity of their de¬ 
 clination. For,, the more even and flat a Coal is in its 
 coirft, and other Metals , above and below, the farder 
 doth the Cropp of the lowed Coal advance before the Cropp , 
 of the uppermoft. For illuftration whereof, let usfup- 
 pofe in twofeveral grounds, twocW-r, between which, j 
 there is an equal diftance of perpendicular. And fuppofe | 
 the Metals in the one ground to decline at 13 to 24, the 
 other at 13 to 16, then will the diftance between the 
 Cropps in the two grounds be very confide: able, as may be! 
 reprefented by the two following Figures. 
 
 Figurt 
 
6 . - D '• 
 
 Suppofe then, that DI, is of equal length in both-TV*-’ 
 angles, which is the perpendicular, between thetwp Coals: 
 yet D F in the fifth Figure, is much longer, than D F in 
 the 6. And the reafon is evident, becaufe the'^/^/tf 
 DIF, in the 5, is greater then the Angle DIF in the 6: 
 and therefore the Ba'e D F, which is fubtended by the 
 greater Angle in the 5, muft be greater then the Safe D F, 
 which is(itbtendedby the lefler Angle in the 6 , which Eu- 
 clide proves in his 24 Proportion of his ftrfl Book, "&nd is 
 demonftrat by Prod us in the Scholium.XS> the 4 th Proporti¬ 
 on of the fame Book. 
 
 By this is made to appear theprpfitablenefs of a Flat- 
 Coal, beyond a Hinging-Coal , which Was touched before* 
 in regard that having the Sinks of equal deepnetsdn^Soth, 
 there is much more of the F later-Coal to be wrought, ..be¬ 
 fore it Crspp out, then of th tpinging y asthtfefta diffe¬ 
 rence between the lines DF in thefitf^ahd^^rttf fi 4 
 gfee: ''drf^wterithe'LineJ-IP^bVtlitMe^ * 
 
 LI If 
 
i66 SJBifcellanp iDDfetDattons* 
 
 If it be enquired, if in rifing grounds, Where there is a 
 considerable afcent above ground, the Coal keeps a propor¬ 
 tion m its Rifing and Difpingmxh the afcent and defcent of 
 the'ground above? Ianfwer, there is no certain and con- 
 Bant proportion kept, whatever fometimes may happen, 
 •Fori haveobferved fome Cods upon grounds of a confide* 
 rablesfcent, and their Dipf run quke-contraiy-to the de¬ 
 fcent of the Hill : and others have had a quite contrary 
 courfe to that, and have declined, or dipped with the de¬ 
 clination of the ground above But in the Stuck ( where* 
 of I (hall fp eak a little hereafterj there is more propor tion 
 ordinarily to be remarked. 
 
 There remains only one Queftion about the Difps, and 
 lifmgsoi Coals , which I fhall a lhtleconfider,having en¬ 
 countered different judgements .anent it, in converfing 
 with perfons, who had experience in Cod^ viz. whether 
 Coal and other Metals, after they have declined Tuch a 
 length from their Cupp, fuppofe from Weft to Eaf , take 
 another ceurfe , and rifeto the fame point, to which for- 
 ■Hjcriy they dipped 1 
 
 Figure ,7. 
 
 As if the Cm/ dipped from A, which is the Croppy to B, 
 which dhonld be the Ce/iter q{ that Body:, and after that 
 JitetQ C ? Or if it fhould continue its declination thorow 
 
gp<fona n!» £>bfttbation g, icy 
 
 B to D, which is Antipodes to us ? I fhall not offer to de* 
 cermine in a matter wherein there can be fo little certainty* 
 attained-, but thall give my opinion, which is founded 
 upon the experience I have had, and Obfervations I have 
 had occafion to make on that Head. And firft, I find in 
 allthefecWr, wherein no contrary Cropp or Rifing cm\& 
 be vifible,there are invincible obftru&ions 5 as either, they 
 have been near the Sea , and have dipped that way *, and fo 
 if they took any contrary courje , the cropping behoved to 
 be in the deeps , and fo no accefs to trace them. Or next, 
 they have dipped towards the foot of a Mountain, and fo 
 the ground above rifing the fame way which they declined; 
 their courfe could not be purfued, till a contrary rifing 
 flrouid be difeerned. Or thirdly, they have encountered' 
 fome Gae, or Dyke, which hath cut them off, before they 
 came to their full dipp , and thus their courfe was obftruft- 
 ed. Now, thofe that have been acquainted with no other 
 Coals but fuch, I think it not ftrange, if ic be hard to per* 
 fwade them of thofe things they have not feen. But be- 
 fides- all thofe kinds, I have feen others, whofecontrary 
 rifing and dipping have either been vifible to the eye, or 
 demonftrable by reafon. For example, I have entered 
 underground, as it were at the point C, at the very Grafs- 
 cropp, and have gone following the dipp of that Coal to the 
 point B, at which the courfe hath altered, and carried me 
 out at the Grafs at A, which are two contrary points of 
 the Compafs, And that alteration of courfe was not oc- 
 cafioned by any Gae, or trouble , which fometimes have 
 that effeft, the ground being very clean, and good i/e* 
 tals, keeping their courfe moft regularly, . 'j 
 T here are other inftaftces for confirming my experience, 
 in fields, which are fo large, that ’tis impoffible to.work' 
 LI i the 
 
268 cptfcelianp £)bfcttoattons, 
 
 the Cod fo far to the Dipp, it falling deep, and fo wants Le- 
 vdio: conveying water from it,or wants Air,for following 
 it to fuch a deepnefs, as to overtake its Center , where it 
 takes a contrary courfe , and yet the contrary Cropp hath 
 been wrought in feveral places, which is evident to be a 
 part of the fame body, with the other, both by the nature 
 of the Cod it fell, by the Mctds lying above it, and the 
 Cods below it, all which keeping the fame Courfe , except 
 when they encounter troubles , which are incident to fome 
 parcels of ground, more than to Others. T he greateft field 
 I know wherein this is conlpicuous, is in CM id- lot hi an 
 where is to be found, the cropping of a Cod of a confide- 
 rable thicknefs, which is termed theh great-(earn ^ or Md si- 
 cod, and the other Cods lying below it, which may be 
 traced in the order, following. At' Pref on-Grange thefe 
 Cods are found dipping to the N W, and rifing to the 
 SE, which have been wrought up to Wall:footd: fiorn 
 that along by the foot of Faufide Hill, the dipp lying in the 
 Linds of Innertsk^ which marches therewith on the North ; 
 From thence it runs through the ground otcarkrry, eve-' 
 ry one of thefe grounds from Prcjfofi-Grange, Giving Le- 
 <vsd to-another. From thence, through a part of the'Lands 
 of Smeaton , and next through a piece of ground belonging 
 to'the Family of Buccleugb , called Condon: and through 
 Wefi-boufes, whiclrbelongs to the Earl oi Lo'ihim, and at 
 Cockpen , and Stobhill , from thence runs through to Caring* 
 ton- M id 5 all which is a courfe^ which in Strsek lyes near 
 to S Wj- and N W, and will be in length about eight 
 miles. -From thence, the courfe of the Cod turns, and is 
 found in the Barony of Carington , l-Vhite-bill -Ramfay ^ Gil - 
 merton , and from thence taking its Dipp> quite contrary 
 'to whac it had before, the other Dipping N and N W, 
 
^tfccuat tp Dbfe rftatfong, 169 
 
 or N E, according to the turn of the Streep it Dipp f there 
 S, S E, &c. and trotn Gilmrton, it is found at Burnt (lone, 
 a piece of ground belonging to the Earl of Lauderdale: and 
 from thence at the Magdalen Pans, where the turn of the 
 cropp being within the Sea, is not feen, till it be found at 
 Prefton-Grange, where we began to remark its courje, The 
 parcel of ground, under which this great body of Coal lyes, 
 is of a confiderable extent, it being eight miles in length, 
 and five or fix in breadth ; in regard whereof many other 
 Coals are found lying above the greatfW,the cropps where¬ 
 of doth not come near the Cropp of it, by a confiderable 
 diftance. 
 
 Though this inftance alone, may fufficiently convince, 
 yet I (hall not be unwilling to give another. The parcel 
 of ground, In which this Coal is found, is not of fo great an 
 extent, as the other, and-therefore its.cottrfe may be the 
 more eafily traced. For the greateft-part,-it belongs to the 
 Earl of Winton, and lyes within th t Lordfhtp of Tranent^ 
 whole contrary Cropps, are moft confpicuous, This great 
 Coal, which is io,or i a foot thick (beginning at the head of 
 theTounof Tranent) where it hath been wrought, runs 
 S W towards the march of the Lands of Elphingfton , be¬ 
 longing to the Lord Regifler , dnd continues in that fame 
 courfe, till it come near to the houje, and for the moft part 
 dipping to the S E. And near the Iwtfe, the Cropp is turn¬ 
 ed downward towards the march between RlphingflonznA 
 Ormifton , where the dipp is contrary to the former. And 
 from Elphingfton-mains, it takes its courfe almoft round, 
 through theLands of Panfton , and returns to the Toun of 
 Tranent where it began , which b6dy of Cod will be in 
 length two miles,. .an^hbfopaeplaces,,^sjnifch in breadth. 
 Now,I leave it.t'o %p|eihf|i’t 4 A! 3 V-iftfe&e. 
 
^7° ©ifceuany £>iJf«toatuM£* 
 
 not more reafon toperfwade, that this fliouid Be the natu¬ 
 ral courts of where fuch pregnable inftan* 
 
 ces, to evince it, are found; then to conclude the contrary ' 
 from thefe Coals , the course whereof cannot be followed, 
 becaufe of the invincible impediments, I mentioned before. 
 However, I leave every one to be determined, by his own- 
 opinion, and (liall be fatisfied to injoy my own, till thefe of 
 more experience convince me of the contrary. 
 
 There are fome Other things farder to be remarked a- 
 bout the Bipp , and Rife oiCeds, which ( poffrbly } every 
 one hath notfeen, they being fo very rare , and therefore 
 are not fit here to be palled without being confidered. One 
 is, of a Coat, which having that contrary Bipp and Rijc, 
 
 (whereof I have been fpeaking) inoneofthec?v/>/>r, hath 
 not come out to the Grafs, and terminat ; but after it hath 
 rtftn a confiderable way in its contrary courfe, in Head of 
 Cropping out, hath taken a Dipp towards the fame point, 
 to which it dipped firft, and fo having dipped ro the Center 
 of its courfe, it hath rifen again, and cropped to the contrary- 
 point, as is-to be feen in this eight Figure. 
 
 Figure 8. 
 
 A F B 
 
 D C 
 
 Where A B is the furface oftfie‘-Ear tFr. The point B 
 is the Crepp of S Coaldippihgixom N W,to the S E. From 
 
 C it 
 
ipfauan p iDafct bations, 271 
 
 C iwakes its rife , and courfe to a contrary Croff, towards 
 •thepoint’F, where the deadCrop? ought tobefound. But 
 io (lead of going that length, it takes another courfe flora 
 the point E pipping S E towards D,from which it takes its 
 ri[ f, and continues it to the point A, where it terminals , 
 and where the dead Cropp is found, I grant, that it meets 
 with a trouble , or Gae\ at the point E, which feemstobe 
 the caufe, why its natural course is changed. Bur its very 
 extraordinary to fee fuch aa effetf. But of this afterwards, 
 in its own pi ice. 
 
 There is yet another thing toBe remarked, in th tdipps^ 
 and riftngs of Coals , which js this. In the moft part of 
 Coals,fhn have their courfe from dipp to cropp, without the 
 intervention of a djk; or gat, the declination is ftraight 
 down, from the horizontal line drawn from the point of the 
 croppy to the fardeft point of xhtdipp. That is, the Coal 
 dedining.from that point in a right line , .makes with the 
 horizontal line, a right lined angle , angulus reftilineus, 
 though in fome the angle is more acute , and in others lefs, 
 as is to be feen in the fii ft, and lecond figures, where A B 
 being the horizontal Line, and B the cropp y B C is .the 
 body of the Coal declining, which meeting with A'B in.the 
 -point'B, conftitutes a right linedangle,zni where ABC in 
 the fecond figure,is a greater angle, then A'B C in the firft. 
 Yet I have feen a Cod, the body whereof from ditdipp, or 
 fardeft point of decimation, had its rife towards the cropp 
 very infenfibly, it being Flatt, and then began to be.more 
 fenfible,.till at laft coming near to the furface of the Earth, 
 it takes in a fudden fuch a rife ;thzt from dedining one foot 
 of 12 or 14, itdeclinesnowone foot of three, as,may be 
 .made evident from this following Figure, 
 
zji £ 0 tCceUaup 3 DDfectoat(ons* 
 
 Figure 9. 
 
 Where AB is the Line drawn from the extream points 
 of the Crop?, right horizontal. The body of the Cod 
 rifing infenfibly, is D C. But afFoon as it comes to C, it 
 rifeth with a great afcent till it Cropp out at A, Here you 
 fee, that in ftead of one fide of a Triangle, which the courfe 
 of other Cods in their riftng,oi in their declination makes* 
 this Cod in rifing makes two fides,namely D C, and C A, 
 the Figure DBCA being quadrilateral. The Cod of 
 this courfe was really wroughr,and is yet vifible in its wafte, 
 where there is found no Gae or Dyke to make this alte¬ 
 ration. 
 
 Thefeare the chief things that I have thought worthy 
 of Observation in the Dipps , and Rifings of Cods, and 
 therefore I come now to touch a little the other part of 
 their courfe, which is commonly termed the Streek of a 
 Cod. To make intelligible to thofe, who are not expe* 
 rimentally. acquainted with Cod, this term, or what the 
 Streekls, wemuftlay this foundation, that the Cod is a 
 Rhpficd Body, and fo hath its three principal dimenfions, 
 which.doconftituteitfo, viz. Longitude, Latitude, and 
 Rrofimditj, Its Latttudef&d&l part contained .between its 
 streamlines,- which is meafurableby its furface, towhich 
 
<$MfceIlanp £>bfert>atfott& 2jy 
 
 its dipping and riftng, though alwayes incident, yet is but 
 accidental. Ics Profunditj is to be meafuredby the di Ranee, 
 between the two iurlaces, immediatly next to it, above and 
 below : which are termed in Co alien its Reef and Pave* 
 ment^ becaufe of the refemblance they have to the Roof^ 
 and Pavement of a houfe. T he Longitude is nothing elfe 
 but what is termed by the Coal-hewers , the Street, For 
 if you imagine a Line drawn along the extream points of 
 the Rife , or Cropp of the Cm/, t ^ at is properly the Street 
 of the Cm/„ 
 
 There are but few things to be remarked, as to this 
 part of Coal: only firft to find how it lyes, to what points 
 of the Compafs it moves. For knowing whereof, there 
 is this general Rule, that, having found your Dipp and 
 Rife , to what ever Points that C ourfe is dire&ed, the 
 Street is to the quite contrary. For fuppofing a Coal Dipp 
 SE, the two points* that refpeft the Dipp- and Rife, muft 
 be SB, andNW, being the points oppofite one to ano¬ 
 ther. Then it muft needs follow, that the Street muft 
 run S W, and N E, which two eourfes divides the Cora- 
 pafs, at right Angles. And therefore, where a Coal is 
 found to have contrary Dipps, and Riftngs, they declin¬ 
 ing fometimes to all the Points of the Compafs fwhereof 
 there hath been given two notable inftances before) it muft 
 needs follow, that there be alfo contrary Streeks* andfo 
 the Street of a Body ofC oal is fometimes found to deferibe 
 a round figure, though not perfe&Iy circular, and fomtimes 
 a multangular figure. For it cannot be fuppofed chat the 
 Street makes alwayes a right Line,between the two points, 
 from which it is reckoned. For example, between the 
 Laird of tref on-grange his houfe at Prefton■ pans , and the 
 Stob-hilfthere are the Streets of feveral Coals Jying one a- 
 M m bove 
 
274 30 ifceltanp ^Dfefecfcaaons* 
 
 bove another,which will be Of length, about feven or eight 
 miles, lying near upon S W, and N E 5 yet the Crtfpt of 
 the faid Ceils (their dipp, and rife, being N W, and S E) 
 are fometimesfarder advanced towards the S E, fotnetimeS 
 farder back towards the N W, by the difference of a mile, 
 and this generally occafioned by the encounter of a Dyke 
 or Gae, whereof hereafter. 
 
 The fame quefhon, that occurred in the C oils dipping 
 towards a Hill, or riftng above ground, comes to be in¬ 
 quired into here 5 viz. If a Coal encountering an alcent, 
 or Bra1 above giound in its Streek , rifes alfo with the 
 ground, and keeps itsafcent? I anfwer, I have found it 
 fo in all the C oils I h.:ve ever feen of that nature. GOD in 
 his providence, having fo ordered it, that thereby it may 
 be the more ufeful,m regard more thereof may be wrought 
 by one Level or Aquaducl, by which the Water is convey¬ 
 ed away, as afterwards will be obferved in fpeakingto Le¬ 
 vels. For confirmation whereof, I fhall bring inftances 
 both of Coals, that declines towards the Hill, and of others 
 that declines with the fame dipp , the Hill hath it felf. In 
 iheCw/f of Bonhard , Grange, Kinglaffy, and Kinnetl , 
 which keep all one general courfe, the afcent aboveground 
 is from the Sea, (which lyesNo: th^ towards the South, 
 or thereabout; the Coal dipps or declines towards the 
 N W, and fo confequently rifes to the S E. The Streek 
 of thefe Coals, is from the N E to S W,which flops alongs 
 t,he Hill, and comes Hp to the top thereof to the Wefr- 
 ward of the Houfe of Bonhard, Now, in finking in that 
 ground, if an equal proportion be kept, in all the Sinks 
 ■from the Cr/pp, and a juft allowance given for the different 
 B'.ftrg above ground, the Sir.ks will be near of an equal 
 deepaeisalong, all the Streek, So that a Sink upon the 
 
 fame 
 
^tfceliatip £H>rch)at(oti0, 27* 
 
 fame Coal near to the Sea, which is the N E point of the 
 Streek, at equal diftance from the C ropp, will be as deep as 
 a Sink upon the top of the Hill, being the S W point of 
 the Streek u the fame diftance from the Croppy allowing 
 alwayes the different rife above ground, and excepting 
 fome particular troubles falling in upon the Metals of orie 
 Sink, and not of another, and fo making them dipp more, 
 which will occafion a difference of the deepnefs. The fame 
 is alfo found in the Cedis of Djfart , and Weems . As alfo 
 in that great body of Coal before mentioned, between 
 Prefl on-grange and Stobhill , the declination whereof' is to 
 the N E, which is alfo the courfe of the defcent above 
 giound. 
 
 Another inftance is from the Coals within the Lordfhip 
 of Tranent , the dipp whereof is of another courfe , being 
 contrary to the defcent of the Hill, viz. the Coal dipping 
 to the SE, and confequently the Streektunning S Wj 
 and N E, where the fame is to be obferved that was feet| 
 in the other, anent the equality- of the deepnefs of-S/frfo 
 along the Streek, with the fame allowances, and exceptions 
 before mentioned. 
 
 Some have been of opinion that- St reeks ofCoat's lyge* 
 nerally South and North, or to fomeof the points near to 
 thefe two Cardinal ones, between South and S W, and 
 North and N E, as South and by Weft, and North and 
 by Eaft,- &c. To which general; Icannot agree-, in re* 
 gard of wharl have, before-made-evidently appear, 
 that fome. Coals have xhelxcroppbgs to wards ailthepointS 
 of the Compafs, and the Streeks being regulated by the 
 Crapp, they muft rieceflar ily be'judged to have their conrfes 
 proportioned to theirs / fo that ifa C odl dippxo the- true!: 
 Norths andri/tto the South, the street muft be Eaft, ancE 
 
 - Mm z Weft, 
 
*7 6 ^ifceuanp Dbfer&atiDtis* 
 
 Weft. -However, I acknowledge two things, for con- 
 arming that opinion. 
 
 Eirft, that of all the Cods I ever have feen, where thefe 
 contrary dipps and rifi.igs, could not be traced, and made 
 vifible,theSre«£ hath inclined to thofe points of South and 
 -North. Bur I muft alfo confefs, that they are but few I 
 have feen, in refpeft of what I have not feen, and fo if any 
 others experience, who have feen more, contradid mine, 1 
 iball willingly yeeld, and not be tenacious. 
 
 Next, in thefe Cods, which I infhnced,that have their 
 Crcpp to all the Points,and confequently their Streets,mi 
 in others of the fame nature,which I have feen, and not in¬ 
 stanced, I found that part of the Street, which lyes towards 
 thefe Cardind points, to be the greateft, being double, or 
 triple to the other Sreeks in length. So that when the 
 Sto ok, .that'Iyes-either alongthe one-C ropp, or the other, 
 towards the S W, and N B, will be feven miles in length, 
 that lying S E, and N W, will be but four, and fometimes 
 iefs. And this is all the account I can give, of that part of 
 Coal, -called the Street. 
 
 Thefecond-thing l promired to fpeak of, was of fome 
 things, which are but accidental to Cods, and yet fo or¬ 
 dinary, that hardly are any found without them in lefler, 
 or greater degree, fuch are G tie’s, and Djkes, which alters 
 their natural courfe, andthey being-theoccafion of fo much 
 Trouble, in the working of Cod, and following its courfe, 
 the Cod-hewers call them ordinarily by-that name7 "rouble. 
 This Trouble or Gae then,is a Body of Metd falling in upon 
 ! the coarfe of-the Cod, or Freerflone, obftru&ing, or al¬ 
 tering their-kindly and natural courfe, keeping no regular 
 mrfe it felf, and being of nature alwayes different from the 
 iMetal, -whole mrfe it interrupts. And thefe Goes dif- 
 
tiijiffciia np Dbfctaatlon s, 177 
 
 fer alfo among themfelves, in their nature, and in their 
 ■com ft they keep: or more properly in the way wherein 
 'they encounter other Metafs, and in their effects. In 
 ,their nature, for fome of them confifts of- an impregnable 
 Whin-Rcck y or Flirty-Stout, thorow which it is almoft 
 impoflible to work: and if there be a neceflity to cut them 
 thorow, it is done at a vaft expence, and taices a long time, 
 and muft be cut open to thefurfaceof the earth, it being 
 -impoflible to Mine it under ground. Some of them are 
 again of Store , -like a Free-(lore, but feems rather an abor¬ 
 tive of nature, they having no rule in their courfe,by which 
 a man can-follow them, norcantheirftonebeufeful. 
 
 In their encountering of Coals, or Free-(tore , fome- 
 times they encounter them in the Dip , and fometimes in 
 •the Strcek, and fometimes between tne two. Thefe that 
 are met with in following the Dipp of the Coal, ly along 
 ithe Streek thereof. For example, if the Coal Dipp SE, 
 the Gee lies N E, and S W. Thefe that are encountered 
 'in the Street,lyes to the Z)//>pand Rife .-.fo theC oal Streei- 
 ' ing N E, and S W, the Cat isfound to.ly S E, and N W. 
 •Others of them, lyes between Sireehnd Dipip, that is to 
 fome point between the two: as the Strttk being SW1, 
 and 'N E, and the Dipp and Rift S ; E, and N W, there 
 •may be a Cat found lying W S W, and E N E. Now, 
 fwhenl fpeak of a Gats lying to fuch Points of the Com- 
 pafs, this doth not contradict what was faid before, that 
 rthey had no regular, mr/e themfelves. My meaningbe- 
 ing, that though they have a certain length, lying between 
 -twopoints, and a thicknefs between two.Me/ 4 ///., yet by 
 -the Metal of the Gae it felf, it is impofltbleto know its 
 ■courfe, as it is in other Met alls of Coal or Fret-font )Ttfhofe 
 ■courfes are difcernable at the fir ft view, 
 
 Their. 
 
v7% q3tfcellanp Dbfcrbations. 
 
 .Their e.ffedls. are different, a? their nature, and ccurfe 
 are different: only they agree, in thefe two generals. Firft, 
 that all of them renders that part of the C od, that comes 
 neareft to them, unprofitable and ufelefs,though idmelefs, 
 and fome more, they being unfit for burning. And it is 
 remarked, that thefe Gaes that confifk of Whin-rock, ren¬ 
 ders the Cod next to it,, as if it were already burnt, being 
 fo dried, that it moulders in handling it. In others, the 
 Gw/is not altogether fo ill, and yet its nature is altered, 
 from what it is at a diftance from the Gat. The next ge¬ 
 neral is, that all of them alters the natural course of the 
 Cod in Iefs or more, fome of them making it Diff much 
 more then its ordinary ccurfe , which they call Down-gaes: 
 Some again making their rife much more than their coarfe, 
 which they call Up-gats. Others making an alteration as 
 to the Streek, caufing it go outbeyond its ordinary bounds, 
 as we obferved before in that great Streek of Cod between 
 Trepan-Grange and StobhiU. 
 
 Now it is to be confidered, that when in Working of a 
 CM/,whethertothe Vipp,oi Rife, or Streek, one. of thefe 
 Gats is encountered with, the Cod is quite cut offj and as 
 it were ttrminat : fo that you fee nothing where the. Cod 
 fhouldbe, but either a Stone, or clay, orrotten T///, or 
 fome ftrch thing. And the pradtique of C odlery is to trace 
 the coarfe of the Cm/ through that, till you overtake.it in 
 the other fide. And before.any thing be/aid, to. that,part, 
 you muft notice, that : fome Gaes are of greater, force than 
 b.thers, and tKeir influence upon the courfe of other Me- 
 tails greater, whence you /hall fee a threefold effedt. One 
 is r that by fome,great Gaes, which a Cod meets with, it 
 is quite cutoff,, fa that in the other fide thereof, there.is 
 not a veftige of that Cm/,, or of any other Metal that was 
 
 above 
 
{©tfcciiatip i0bfcct)attons f 179 
 
 aboveit', or below it, to be (een. And if there be ary 
 other Coal, as fometimes there are, they are quite diffe¬ 
 rent from them of the other fide. I faid by feme , becaufe 
 there is one inftaiice to the contrary, which is fomewhat 
 ftngular. In the Earl of Wintons ground at Cockeny, there 
 is found a cottrfe of Coals and Free-flone, tiffin? to the 
 S E in the Links *, and upon th tfull-fea-mark, there is a 
 traff or courfe of Whin-rocks lying E and W, underneath 
 which thefe Cm// and Stones comes thorow without alte¬ 
 ration of courfe, and are found within the Sea-mark, with 
 the (meDipp and Rife upon the North fide, they had 
 upon the South fide of the faid Rocks : 2 nd yet the Coal is ^ 
 encountered upon the South hand by a Gae under ground, 
 through which it paffeth, not without a confiderable alte¬ 
 ration. 
 
 The greateft of thefe Goes, that I know, is that which 
 takes its beginning, that we fee on Land, at the Harbour 
 of the fans , called Achifons-Havtn, which hathbeen cut 
 by Pre[Ion-Grange, to Level to his Coal , and goes from 
 that to Seton , which may be traced above ground, almoft 
 the whole way 5 and hathbeen cut at Seton , for feiving 
 the Level-oi that Coal now wrought at Tranent, FrOflJ 
 thence it paffeth through the fields Of Lon*-Niddrj,z place 
 pertaining to the Earl of Winton , and through the Coats, 
 which pertains to the Earl of Hadinpon , till it joyn with 
 fancrtck-hills, a trad ofRocky Mountains,"from whence 
 it is traceable to Liriton-bridges, where it is vrfible ift the' 
 Water, the Water -ol Ty» falling over it, and makings 
 Lin, which they call Linton-Lin-, from thence to the 
 Baft-fed. And it is known by Sea-men, that it keeps* 
 courfe thorow the Firth from Achifons+haven), fwheacb 
 we teokoned its beginning upon Land) towaidstheWeft. 
 
is© ©ifccitanp £>bfctfcattons* 
 
 2 aa N W, it being found to the Southward of Inch-keith, 
 2 ad before Leitb, where ftanda a Beacon, and fo can be 
 traced to the North Shore, 
 
 The fecond effeff of Gaes, is to cat off the C eal quite, 
 as to a part of the field, fo that in the other fide, having 
 pierced the ( 7 *?, you Ihall not find the Coal, and poflibly 
 not Within a quarter of a mile of the Gat, which cuts it off, 
 and at that place (hall only find the C repp and the Body 
 Dipping,zs it did before it was cut offhand it you (hall mea- 
 fure between that fide of the Gas, where you loft your Cm/ 
 (I fuppofe the Coal then being 24 fathom from the Grafs) 
 to the place where the Coal in the other fide of the Gae 
 Ihall be found at the fame deepnefs, it will be near 500 
 paces. For making this more intelligible, let us fuppofe 
 a Coal Dipping SR, and in working to the Dipp, there is 
 a Gas encountered with (This was really done in a piece 
 of ground I know,and fo ic is no meer fuppoficion)at which 
 Gae the Coal is cut off ; for finding whereof the Gac is pier¬ 
 ced, and nothing found in the other fide, viz. in the 
 SB fide of the Gae, but at more than 100 paces diftant, 
 the Crop of a Coal , which lyes under the Coal, chat was 
 loft, was found, after which it was eafie to find the other. 
 Now, that it was the fame C eal, thatwasloft, upon the 
 North fide of the Gae, is not only evident, by the kind of 
 Coal, and ail the Metals above, and below keeping the 
 fame cmrfe, but by this, that the Gae wearing out towards 
 the Weft, the two parts of the Coal that was feparated by 
 it, joynes themfdves again, and continues in one body, 
 as they were before reparation. 
 
 , The laft effeft of the 'Gae is, that it doth not quite cut 
 off the Coal from the other fide of it, but makes an altera¬ 
 tion m the courfe, either in the Dipp, or in the Rife, or 
 
 Street, 
 
SMccUanp CWemttons, 281 
 
 Streek, as was before noted: fo that in meeting vvith: one 
 'of thefe Gats, having confidered its nature,and pierced it, 
 the Coal will be found in the other fide,immediatiy touch¬ 
 ing the Gae, but with an alteration of courfe. Now, in 
 thefe two laft effects, fince the C gal is not totally cut off, 
 it will be worth the inquiry, to find the fureft way of re¬ 
 covering the Coal after it is loft. Therefore, where the 
 Coal is not cut off, by a confiderable diftance, and having 
 pierced the Cat, it is not to be found in the other fide, ‘ 
 you are to confiderwell the nature of the Metals you find 
 approach to the tar,and if they be fuch,whether Stoat, or 
 Coal, as you know to ly under the Coal that you have loft, 
 then you may be fure the Coal is to be found above in its 
 cottrfe, which is to be traced by the Dipp of the Metals 
 you find. Asfometimes I havefeen, when a Coal hath 
 been cut off by a Gae, happly there is another Coal under 
 it 12 fathom, after the Gae hath been pierced, and the loft 
 Coal not coming near to it in the other fide, that hath been 
 found there, by which it was certainly concluded, that the 
 uppermoft Coal behoved to be there alfo, though a little 
 back, conform to its courje. But, if the Metals or Coals , 
 
 • under the loft Coal , hath not been known, then you are 
 to take notice of the Dipp and Rife of thefe Metals , you 
 find on the other fide of the Gae , which you have pierced, 
 and making that your rule, range back over the Metals, con¬ 
 form to the direction to be given afterwards,, and you (hall 
 find the Cropp of the Coal you want, and . after which you 
 were inquiring. 
 
 Where the Coal is not quite cut off by the ,but hath , 
 its cottrfe only altered, you are to confider, in learching for , 
 it, belore you pierce your Gae , that which the Coal-hcw - j 
 vs term the Vt[e , or fome of them the Wejft of the Gae, ; 
 
 N n which : 
 
i8i ffiiftcuanp ffiblttbati ons, 
 
 Which in effea is nothing eHe, but a dark veftige of the 
 Dipp or Rife, that the body which now conftitutes the 
 'Cde, fhould have hadnatmally, if it had been perfe&ed- 
 which when it tends downward, then mud the Gae be put 
 over that way,and in the other fide (hall the C oal be found, 
 and Xfonw, a s they term it •, that is, the Dipp which it had 
 fiaturally, augmented. And, if th tvife be Up , the fame 
 Way nraft be taken for piercing the Gae, and the Coal will 
 be found Wp, that is, its Rife augmented. But thefe things 
 cannot be made fo intelligible, as by feeing, there being 
 many things in the alteration of the cotirfe of Metals very 
 curious, and worthy of Obfervation .• as when a Cod is 
 eaft down out of its natural courfe by a Gae , and fo made 
 fometlmes under-Lev el, it rifeth as much to another hand, 
 and the Cropps go fo much farder out, which (till makes the 
 Level afeful, the ufe whereof would have been judged loft 
 by the doan-cafling, Sometimes a Coal made to havedour 
 contrary courfcz, as is evident from the eighth Figure, 
 where there being a Gae at E, makes it take fuch another 
 mrfe , in Head of coming out to the grafs, Sometimes, 
 before the Metals overtake the Gae, they are made to ly 
 like a Rom-, one inftance whereof is vifible above ground 
 in fome Metals lying between Bruntiland and Kinghurn, at 
 a place called the iMiln-ftone, where there is a fmall Coal 
 with Free-flow above it, all Dipping to the S E, and Ri- 
 fingi o the N W. Upon the Rife they meet with a gae, 
 which is a great whin-rock. In their courfe to th t grafs, 
 before they touch the faid Rock , they tike a contrary 
 courfe, and cliffs into it, and are there-quite cut off. The 
 manner whereof is to be feen in this tenth Figure follow¬ 
 ing 
 
aptfcetlatip aDblettmtlons. iSj 
 
 figure ip. 
 
 A D 
 
 J* ■■ ' - 
 
 Where A B. is the Reek ; E F the Coal: G D the -ireOik 
 fiene. Now, whereas they fhould have rifen towards A, 
 they turn at D, and diffs into the Rock, which any may 
 obferve in palling that way. Many other fuch motions 
 are obfervable, which I pafs, and leaves them to the obser¬ 
 vation of the curious. ' 
 
 The third thing I promifed to fpeak of, was of Damp', 
 and as they are termed by the Coal-heivers, Iff Air, Thefe 
 dodeferve a more accurat inquiry into their kinds, their 
 taufes, and effetfs-, then I am capable to make, there-be¬ 
 ing many things in them very confiderable, and ^worthy of 
 u narrow fearch: therefore following the courfe I hate 
 hitherto obferved,Ifhall fhewrhy own Observations there¬ 
 of, and leave the more curious fearch to the fpirits fitted for 
 thatpurpofe. > ’ - ■' 1 r 
 
 T his Damf then makes an obfitruflioii of refpiration in 
 Men,, or other living Creatures, ‘in Subterraneous fpaces, 
 as Caves', Coal rooms, Levels , Sinks, and fuck like 5 
 which obftrudion proceeds principally from two.caofes, 
 both which goes under the name of iff Air, among the vul¬ 
 gar. The -firft is the corruption , or putrefa&ion bfthe 
 Air, whereof there are two forts 5 one is in placeswhere 
 Nn 2 hath 
 
184 ®rtcel lanpa?ttfcmtions. 
 
 hath been fre kindled,which burns the Coal under ground, 
 the fmoke whereof, being full of Sulphur, and other Bi¬ 
 tuminous matter, and not having free paffage to come a- 
 bove ground, filleth all the wafte Rooms under ground, and 
 infers the Air fo, that the fmellofit, even at a difhnce, 
 is intolerable, and amongft it no living Creature is able to 
 breath. Of this there are examples in Djfert in Fife, and 
 Fiufde in Eaft- Lothian . This was kindled ondefign by a 
 Fellbtv, who for his pains was hanged in the place, and 
 hath burnt thefe 50 years, and more, the /fre whereof is 
 ibmetimesfeen near the grafs, with abundance of fmoke, 
 5S it runs from one place to another. The fecond, where 
 the Air is corrupted without the mixture of fmoke, orany 
 other grofs corrupting body, which is the moft confide- 
 jable-of z\\ Damps, and hath the ftrangeft effefts, in kil¬ 
 ling Animals in an inftant, and fo hath been alwayes moft 
 .prejudicial in the works, where it is found, many perfons 
 having thereby loft their lives, without accefs to cry but 
 •once Gods mercy , to fome inftances whereof I have been 
 witnefs. I fhill not offer to determine about the caufe of 
 this Damp, but (ball give an account of fomethings I have 
 ebferved about it, which when duely pondered, may hap* 
 ly lay a foundation, at lead of a probable conje&ure, 
 whence it may proceed* 
 
 This kind of Damp then, and ill Air , is never found in 
 Coal, or other Metals, where there is Water to be found-, 
 I mean., whence the Water hath not been drawn away by 
 a L'vel, or Aqua-duel : as in Coals, where th€fe is a ne- 
 oefiicy to lave the Water from place to place, or to pump 
 .. it atar^the atcent or rife of the Coal , to the bottom of the 
 Sink, f r om which k is drawn out above ground, this ill 
 ■dir is so; found. Nor is found frequently, if at all, in 
 
ipfcelianp iUMctbattans. igV 
 
 thefe Coals where the Water is drawn from the Coal by 
 a Level , or Aqu&-dutt under groundsill it come of its own 
 accord to the bottom of a Sink, which is in place of a Ci- 
 fiern, out of which it is forced alfo aboveground, and dif¬ 
 fers only from the other, that the Water* runs here of 
 its own accord by a defeent to the Sink , which is termed a 
 drawing Sink : in the other it muft be forced by the Rife of 
 the Coal-, becaufe happly, a Sink upon the nipp would be 
 of fuch a dtcpntfs, that no force could draw it up in a per¬ 
 pendicular. 
 
 Buc this kind of Damp is found ordinarily in thefe Coals 
 from which the Water is drawn by a Level, the begin¬ 
 ning or mouth whereof is above ground, and carried along 
 by a right Line under ground, till it overtake the Coal , 
 which it is to dry: fo that the Water which comes from 
 theCW, runs without being forced, and is fometimes fo 
 confiderable, that it makes Mills go, without any other 
 addition, as is to be feen in the Earl of Wintons Lands of 
 Seton, where four <Mitis goes with the Water that comes 
 from under ground, out of the C tal$ which kind of Le¬ 
 vels are only found where the Coal lyes in a Field, which 
 Lath a confiderable Rife, or afeent above ground $ there 
 being a neceffity to makeafeof the other two wayes fpo- 
 • ken of, for drying the Coal, when the Field in which it 
 lyes is a Plain. 
 
 Further, of thefe Coals, which aredryed by the Free- 
 level (for fo they term the Level that runs unforced )i 
 there are fome to which this kind of Damp is mo: e incident, 
 than to others. The caufe of which difference is found to 
 be, the folidity and clofsnefs of the Metals , whether of 
 Coal or Stone, wherein fome exceeds another. There be¬ 
 ing fome, that are full of rifts, or empty fpaces (I mean 
 
 empty 
 
286 ^tfceitanp sDDfctDattons; 
 
 empty of any part of the fame body where they are) which 
 will lomecimes ferve, to convey, a confiderable quantity of 
 Water in place of an aqua-dull or level 5 which jpaces are 
 termed by the vulgar. Cutters , which fometimts prove* 
 very profitable in the ground where they are found, both 
 in regard of the ufe they ferve for, in ftead of Level , and for 
 rendring the Metals wherein" they are found, more eafie to . 
 work, ia making them yeeld eafily to the force of the 
 mdge and leaver. Other Metals there are, .wherein few 
 of thefe Cutters are to be found, and if water be to be con¬ 
 veyed through them, there is anectflity of cutting a paf- 
 fage through them for that efkft. How, this Damp, 
 whereof we fpeak is found moft frequently, and moft vio¬ 
 lent in the fi. ft fort of cMetals, viz, in thefe which are 
 full of Cutters or Rifts , which gives fome ground to this 
 conjetture of its caufe. Thefe Spaces which are found in 
 Coal , or other Metals , as Stone or TV//, before the Coal 
 begin to be dryed by a Level, are full of water, which is 
 ftifi in motion, as are all Subterraneous firings, whereof 
 fome are more violent, fome more flow', conform to the 
 pafTage they have to the fountains aboveground, where 
 they difcharge themfcives. Now, for drying thefe Coals, 
 and readring them workable, there is aneceflityto cut a 
 paffage, thorow which that water difcharges it felf quick¬ 
 ly, it being large, and admitting a great quantity at once, 
 by vertue whereof $ a great field is drained at once, and 
 the Sourfe not being able to fornifh fo much water, as the 
 Conduit is able to convey, thefe Spaces in the body of the 
 Metals, being emptied of Water, muff needs be filled with 
 Air-, which Air -having little contatt and commerce. With 
 the great body-of Air aboveground, and fo hath little or 
 ao motion, corrupts in thefe places, and thereby becomes 
 poij enable 
 
flgtfrcHanp £>bfcrtiattoiis. 187 
 
 pi[andble a fo that when any Animal is neceifitat tQ draw 
 it, a'nd retire by it, itchoaks them on a hidden, juft #s 
 ftanding Water, which being withoutmotion corrupts, 
 .and becomes poifonable, though haply not' in fo great a 
 degree as the Air : the Air, being a body much ,finer and 
 purer, than Water, that holding good m it, corruftio 
 tytim pesfma. This is much confirmed by what is before 
 nfferted, that in the cW*,whence the Water is drawn, and 
 they drained, but not by frte-courfe, but by Force, as 
 Tumping, and drawing by buckets, thefe Damps are feldom 
 or never found: becaufe the paffage of the Water being 
 forced, it does-noc fo fuddenly dry the the other, 
 
 whereby there is alwayes left in thefe Spaces fome Water, 
 which being it felf in motion, keeps the ^Air alfo in mo¬ 
 tion with it, and thereby the Mr is kept from corruption, 
 at leaft in fuch a degree, as it is in the other. Hence we 
 find, that in thefe kinds of Coals , the Rooms under-ground 
 are alwayes wet, or for the moft part they are fo: -whereas 
 in the other, there will be no Water found .to vvafli a mans 
 hands:. and fomerimes the Coal through want of Water, 
 becomes fo dry, that it cannot be wrought,in great pieces, 
 as others, but crufhes in the very working, and .when 
 wrought, is rendered ufelefs, and will not at all burn. 
 This pats me in mind of a very pleafant conception of a 
 worthy and learned Perfon, Dodtor George Hepburn of 
 Monk-ridgepwlth whom! had occafion oneday todifeourfe 
 on this Subjeft, 1 He is of opinion that the Water is the 
 Mother of the cW, whereby it is preferved frefb, and in- 
 corrupted, and that whentne Water is drawnoff, and this 
 Damp follows,. it is not the Air, which..fuccpeds in place 
 of the Water, and is corrupted for want of motion, that oc* 
 ■cafions it, But as we fee, when the corruption of a Li- 
 . quor 
 
is s Sgnfcettanp Dbfettoattons* 
 
 quo: within a Veffel, when the Mother is gone, corrupts 
 the Veffel it felf, and occafions an ill lavour or tafte in the 
 Veffel; fo that the Coal being corrupted by the want of 
 its Mother , the Water - corrupts the Air in the fubterrane- 
 ons St/aces, as in Coal-Mines, Sinks, Caves , and other fuch 
 like. He had likewife another pieafant conception about 
 the generation of Coal , judging it to be formed gradually 
 out of another Metal, as of Till, by the help of Water, of 
 which he himfelf may perhaps give an account,And though 
 I be not of his opinion in that matter, yet I muff acknow¬ 
 ledge, I was taken with it, and (hall be glad to fee a more 
 full account of it from him, than he had accefs to do in the 
 (hort conference we had. 
 
 The effefts of this Vamp are fuff, it hinders the burning 
 of all combuftible matter, as Candle , Coal , Pitch, Sul¬ 
 phur, &c. fo that if you take a Torch lighted, and let it 
 down to a Sink , where the III Air is prevalent in the time, 
 it (hall flraightway extinguifh it. Or take a Coal , which is 
 burning, and let it down, it (hall no: only extinguifh the 
 Flame , but (hall make the Coal in an inftant dead, and as 
 cold as never heat had been in it. But the mod dangerous 
 effect is, its killing of living Creatures, avhereby many 
 perfons have been fuddenly killed. Some in going down 
 to a Sink, where it hath been powerful, have fallen out of 
 the Rope, and perilhed. Others have been choaked, and 
 yet have gotten out by the help of others in a fudden, and 
 have remained a confiderable time without the lead ap¬ 
 pearance ol life, but yet have at laft recovered. Yet it 
 hath been obferved, that fome of thefe perfons that have 
 been fo (truck with the Vamp , and recovered, have had 
 slwayesfome lightnefs of Brain thereafter, and never fo 
 ' fettled as formerly. This I know to have happened to one, 
 whom I have feen fo, many times thereafter. What 
 
^ifceiianp Obfctfcatfons. 289 
 
 What hath been itseffeds on fome Animals, whereof 
 you have made Experiment,. Heave to the account you 
 have given, One thing I ftiall only mention, which to me 
 Teems fomewhat ftrange,rhat notwithftanding thefe Damps 
 are fo effedual, and caufeth fo fuddenly the death of Ani- 
 mats, yet the Ratts, which are in Tome of thefe places, 
 where the Damps are moft violent, are not reached by 
 them, Forfomecimes, when they are To powerful, that 
 nothing that lives can enter under ground, withoutfudden 
 death, yet they continue there, and are notiound to ditni- 
 nifh, even where they have no accefs to cfcape, by com-> 
 ing above ground. Or if it fhould be imagined, they re¬ 
 moved to fome other place of the ground,where the Damp 
 is not, how is it, they are not as quickly choaked with 
 it, as Dogs are, and other Animals y . which at the firft en¬ 
 counter are killed * 
 
 If it be inquired*, how comes it to pafs, that in thefe 
 Fields of Coals , which are dryed fully (aswasfaid) and 
 to which thefe Damps are incident, baeaufe of corrupted 
 Air that remains within the Body of the Cod , or other 
 UHetals y how comes it to pafs fl fayj that they are but 
 fometiraes incident, and are not alwayes found f For clear, 
 ing this, it is certain, that even in the grounds, where 
 thefe Damps are moft frequent, for the reafons above* men¬ 
 tioned, yet they are only powerful when, the Wind blows 
 from fuch a certain as fome Chimneys, that do only 
 fmoke, when the Wind is in.fuch an Airth. This is foge- 
 nerally, and well known;, that the Work-men obferve it, 
 and when they find the Wind itvfuch a Point, whence they 
 fear the Damp , they will not enter under ground, till tri¬ 
 al be made of the Air, which they do in Sinks } by firft let- 
 Qo ting 
 
290 £ptfceUanp£>bfet&ae!ons, 
 
 ting down a lighted Candle, or fome burning coals : which 
 if they do not burn, then there is no accefs to enter. 
 
 Secondly,the wind in which this III Air is moft noxious, 
 and hurtful, blows from that Point, where the Field of 
 Coal lyes, that’s not yet wrought, which feems fomewhat 
 flrange, and yet when duely confidered, it will appear a- 
 bundanrly confonant to reafon. An example of this is to 
 be found in the Cod of Tranent and Elpbingflon, the Streek 
 whereof goes to the rife of the Hill aboveground, from 
 N E to S W> as hath been formerly obferved. So that 
 the beginningof'their is at the NE point of the 
 
 Streep from which t he Cod hath been wrought up along 
 the Streek towards the S W, the IVajles lying all towards 
 . the N E. Yet when the Wind blows from N E, or N, 
 or ahnoft from any other Point of the Compafs,-they are 
 not troubled with this Damp. But if it blow from S W, 
 and blow hard, they are in hazard to encounter it/ And 
 though the Damp is not alwayes found when that Wind 
 blows fwhereof<here may be fome particular caufej yet 
 it is neve: oblerved in another Wind, whether it blow left 
 or mo‘e: the reafon whereof may probably be, that the 
 'Wind blow.ng from other Points, as from N, or N E,' 
 hath more accefs to enter the Wajtes under ground, and 
 move the Air that is in them, towards the face of the un* 
 wrought Cod) whence is fuppofed to proceed the corrup* 
 ted Air, that lurks in the Rifts and Cutters thereof, (from 
 wh : ch the W r ater is drawn away,) and occafions the Damp, 
 Now this Air being moved by the force of the Wind, 
 keeps the corrupt Air from coming out, it being ftronger 
 theaxhe other. Whereas, upon the contrary, while rhe 
 -Wind blows from S W, it entering the empty Rooms, 
 drives the Air under ground from the face of the un- 
 "Wioughc 
 
aSPifcelia np i&Metfration g, m 
 
 wrought Coal, down towards the old wa(lcs, which have 
 their coitrfe from the beginning of the Level, By which 
 
 means, the Air, that is corrupted within the bowels (to 
 
 (peak fo) of the Coal, comes out to the Wafles, without 
 refiftance,. it being certain, that Fluid Bodies, as Water, 
 and Air , inclines to move towards that place, where they 
 meet with the leaft refiftance. Hence is it, that the more 
 diredl the Wind be, in blowing againft the face of the un* 
 wrought Coal , as is the Wind bom N E, the/# ,*/> is 
 the more repelled and driven back, but the more oblique 
 it be, as are the Winds from thefe Points, that are neareft: 
 to S W, the l Air is not fo good and free: which difference 
 is known by the burning oi Candles, they burning with 
 greater difficulty in thefe Winds, than in others, which 
 blow from thefe Points neareft to N, and N E. Some 
 are of opinion, this III Air (in thofe places we have been 
 fpeaking of) comes from the great Wajks, that Iy above 
 the un-wrought Coal , and by ftrong S W Winds is driven 
 thorow the Cutters thereof. Or the Wind blowing from 
 that Point, and coming thorow thefe Cutters, brings the 
 corrupted Air alongs with it, even as,, after a ftiowr of 
 Rain, a fpait of Water comes, and carries alongs with it, 
 both the foul Water and the clean,it meetS; with. Though 
 this may be probable, which feems to be your ownopini. 
 on, yet the other feems to be more probable. 
 
 The other fort of Damp, is that which they call want of 
 Air 5 and though the term be not altogether proper (there 
 being no fpace without fome Air) yet there is a want of 
 Air, which is fufficient for refpiration of Animals, or for • 
 the burning of fire. This is ordinarily found in the run¬ 
 ning of Mines under ground, for conveying of Water from 
 Coal, or other Metals,or in the wafirRooms of Coals, where 
 Oo 2 the 
 
i91 ^tfcelianp £>bfectmt(ons, 
 
 thi'Sinh are very deep, and to evite the charge thereof, 
 there is fome necefficv to work as founder ground for win¬ 
 ning of Cm/, as ispoflible, without new Sinks. The caufe 
 feems to be, that the Air under ground, in fuch cafes, 
 wants communication with the Air above ground, becaufe 
 it is found, that by giving more communication, the evil 
 is cured. Whence comes the neceflity o {-^Air-holes in 
 Levels , which are fo many Sinks fet down, for no other 
 ufe, but for giving Air to the Workers. Some are of opi¬ 
 nion, that this deTe& might be fupplied by the blowing of 
 Bellows, from above ground, thiough a Stroop of Lea¬ 
 ther, or offome other thing, which muft run along to the 
 end of the Level Jor keeping the Air there in motion. But 
 I have-not yet heard, that it hath been made practicable. 
 
 The effeds of this L'amp are not fo dangerous, as thefe 
 of the other, 'Tis true, it will kill Animals, and extin- 
 guifh burning Coals and Candles , but not fo fuddenly as the 
 former 5 and fo people are not fo readily furprized by it. 
 The other feemsto kill by feme poifonous quality: in this 
 Animals dies "for want of fufficient Air for refptration. 
 Therefore in advancing in a Cod Roomer Zew/wherethis 
 is, you fhall fee the flame of the Candle grow lefs and'lefs 
 by degrees, till at laft it be totally extinguiflied, and the 
 perion entering, fhall find the difficulty of breathing grow 
 greater, as he advanceth forward, till at laft he cannot 
 breath at all. Hence it is, that few or none are killed by 
 this kind of DamK and all its prejudice is, that it rendeis 
 the work more chargeable, when there is a neceflity to 
 remove it. 
 
 •For that, which they call Wild-fire, it being a thing not 
 incident, but to very few Coals, is lefs known, than any 
 $fohe reft of the-accideats that follows Cods. The.ac- 
 
 £ounc 
 
ifiiccilanp Obfetbatfotts. 19 j 
 
 count T’have beard of it, is, that in fome Coals, which 
 naturally are full of oil, and that are (as they call them ) 
 fatt Cods, there is a certain Fire, which is as a Meteor and 
 i judge, that from its refemblance to Ignis fatuus, which 
 the Vulgar termeth wild fire, it'hath the fame name. It 
 feems to be compofed of fome fatt oily vapour, that goeth 
 outofthe Cod, the Pores thereof being once opened,which 
 is kindled after the fame manner,as thofe J fires above Ground 
 are, which are moft ordinarily found in fatt, and marnfli 
 ground.Of this fire it isreported,that in theday time while 
 the Work men,are working in the Cod-roomes,\ t comes to no 
 height, though it be fometimes feen inlittleholesof the 
 'Cod-mil, flrining like kindled fulphure,but without force: 
 butwhen the Work-men are ©nee removed, and have flayed 
 out all night, it gathers to fuch a ftrength, that at its firft 
 encountering with fire, which the Cod-hewers are neceffi. 
 ■tare to have., by taking in of light, it breaks out with 
 fuch a violence, that it kills any perfon, it finds in its way. 
 The reafon, why it is without this force, while the Work¬ 
 men are in the place, feems to be this, -that they- working 
 With fuch violence, and motion.as they do, do certainly 
 move the Air confiderably, it being contained in fo narrow 
 a place, as a Coal-room. And this Air being violented by 
 motion, moves that oily vapour, whereof the fire is formed 
 fo that it gets nor liberty to unit irfelf, being diflipaced 
 by the motion of the Air. But fo foon, as the Air is ftill 
 and quiet, after the Work-menare gpne home, it unift it 
 felf, and ga the! s force, and therefore, fo foon, as it meets 
 with-fire, which is more forcible, than-the'flame that is 
 kindled'in it, it rarifieth-, the fulphurious parts being kind¬ 
 led, andforceth it felf out, as powder out of a Gun. For 
 at hath kenobfervedj that if any perfon % in the Cod- 
 
i9+ ©tfceuanp ©ofectattons. 
 
 fink while it breaks within the Coal-room, they are in dan¬ 
 ger of being killed. T he ordinary way by which the hurt 
 of it is prevented, is by aperfon that enters, before the 
 Work-m:n, who being covered with wet jack-cloath, when 
 he comes near the Cod-wall, where the Fire is feared, he 
 creepeth on his belly, with a long Poll before him, with a 
 lighted candle on the end thereof, with whofe flame the 
 Wild-fro meeting, breaketh with violence, and' running 
 alongs them/, goeth out with anoife, at the mouth of 
 the 'sink, the perfon that gave fire, having efcaped, by 
 creeping on the ground, and keeping his faceclofe to it, 
 till it be over-paffed, which is in a moment. 
 
 The place, where this was moft known, was in a Coal 
 be-w eft Leith, in a piece of Land called ffWy, which for 
 want of Level , and the violence oi that Fire , the Owners 
 were forced to abandon. 
 
 I come now to the laft part, which I promifed to fpeak 
 of namely of the beft way for trying of grounds, to find 
 Cod, where never any hath hitherto been aifeovered, and 
 of carrying on of Levels , for draining the Water of Cods 
 and making it workable. As to the fir ft part, there are 
 but three wayes, Firft by finking, which is moft charge¬ 
 able, in regard, that in fuch grounds, where the Metals 
 are all intire, Water abounds, and this doth not only bring 
 the Mafier under a neceflityof great expence for drawing 
 the Water, but alfo rendereth it impoflible to get finked 
 toanydeepnefs, which may fuffice, for giving an account 
 of all the Metds to be found, within the field, that may 
 be rendred workable. There was afecondway invented 
 to fupply this defed, which is by boaring, with an inftru- 
 ment made of feveral Rods of Iron, which boareth thorow 
 the Metals, and tryes them. This way in my opinion, is 
 
 worfe 
 
^ifceiump ^Dbfetfcations. 19$ 
 
 worfe then the former. For firft, if the Coal Iy deep, in 
 the place where you try by boaring, it becomes almoft as 
 tedious, and expenfive, as Jinking , the drawing of the 
 Rodes, confomingfo much time, in regard it muft be fre* 
 quently done. Next, In haring, fuppofethe nature of 
 the Metals , be found, yet thereby their conrfe cat! never 
 be known, till they be finked, which is one of the things 
 moftconfiderableirtchefearchof aC pal, becaufe thereby 
 is known, whether it be workable, with advantage or hot, 
 .and whether it be poflibleto draw Water from it by a Level, 
 or otherwife. Laftly, this way leaves the Mafler at an 
 uncertainty (notwithftanding the Coal had been found ) 
 of its goodnefs , as to its nature, and as to its thicknefs, As 
 to its goodnefs, becaufe all that is found of the Coal, by 
 this haring inftrumnt, is fome fmall drofs, which remains 
 after the wafhing of the thing that’s brought up in the., 
 n fumble, by which none can judgeof its goodnefs, or bad* 
 nefs. As to its thicknefs, becaufe it is impoflible to difcertt 
 exactly, when the boaring-infrumenthuh pafTed the Coal.: 
 all the rule for trying thereof, being the kind of Metalthit 
 is brought up in th emmble. Now, I have known in my 
 experience a Coal hared, which the Roarer by that rule 
 hath judged four foot in thicknefs, yet when it came to be 
 finked, hath not proven one. Thereafon whereof, is ob¬ 
 vious, becaufe the haring-ims, being long, and weigh* 
 ty in lifting them up, and down, they break the Cm/, 
 already pierced *. and this falling down among the Metals^ 
 they are piercing, and being found in the mmble With 
 them (efpecially when the Metal under the Coal, is a black 
 till) gives ground to imagine, that all that time, they 
 have been peircing a Coal, and foCOflfcquendy, the Coal 
 muft be offucha thicknefs. 
 
296 spfccUanp £>&fert>atton0* 
 
 Thelaft, and beft way of trial, is that which is termed 
 an Tanging over the Metals, For doing whereof, this me¬ 
 thod, is to be obferved. Suppofe there be any place with¬ 
 in the ground to be fearched, where the courfe of Metals 
 can be feen, as in the banks of a River , or Rivalet , .or Sea- 
 banks, when the place is near the Sea, then confideration 
 muft-be had how far the loweft of thefe Metals, can go be¬ 
 fore they Crop out to the Grafs, which will be known by 
 obfervingthe Dipp or declination of the Metals, and the 
 Rijeoi the ground above, whereof a juft allowance muft 
 be given, and having digged before the faid Crop , you- 
 fhali certainly find, the Metal, that is next under it, and 
 if that prove not Cod, keeping the former proportion, 
 you rauft advance, and digg before its Crop , and fo fliali 
 you find, thenext Metal under it, and fo ftill, till you 
 have tried your ground, and found the Crop of all your 
 Metals within it. But if there be no Water-banks, or fuck 
 like, to give you the firft view, of the courfe of your Me¬ 
 tals, then muft you fink firft at random,- and having once 
 paft the C lap, you will readily overtake fome eJMetals,. 
 whereby you will know the courfe of the reft, and having 
 once found the Dipp and Rife, you muft follow the me¬ 
 thod of rangingil^iy preferred,except the ground fo to 
 be tried contains notwithin it felf the Crops of the Metals, 
 the body whereof lies in it, whether of Coal, or Stone, in 
 that cafe, there is no way to try, but by finking, or boar¬ 
 ing. The way of ranging is confpicuous m the following 
 figure. 
 
 figure 
 
SPifcellattp jDbfctbations. 197 
 
 figure 1i, 
 
 P 0 K L M N 
 
 F G H J I 
 
 The piece of ground to be tried, is P N, where there 
 are (evera\ Seams oi Metals, that Crepps out at the Points 
 K L M N. Suppofe the loweft to be the Cm/, viz, IN* 
 for which you are to make trial. You Bigg firft at K, 
 without the Crop? of the Seam FK, and you ^/g- till you 
 find the other Seam of Stone G L, at the Point C. Fol¬ 
 lowing the Rule before given, yon.advance.before! ts croppy 
 znddiggs at L, and-findsthe other Seam oi Stone -H M, at 
 the. point .D .• from which you alfo advance, and diggs be¬ 
 fore its crop? , at the point M, and finds your Coal at the 
 point E. But, if by advancing over the croPps ofthefe 
 . Metals^ which comes out from under one another, you 
 find no Cm/; then you are to range backward, for the 
 crepps of Metals lying above thefe, wherehaply the Coat 
 maybe, as at 0, and.P, This in my opinion, is themoft 
 certain and exaft way of trying Fields for Coalgox any other 
 Metal of that nature, and leaft chargeable of all others. 
 
 The fecond of this laft part, I promifed to fpeak of, 
 was in order to Levels, or Cod- Mine s^ which are nothing 
 ;«1fe, but Conduits or Gutters made under ground, for con¬ 
 veying of the Water from the Coal, and fo rendering it 
 1 : Pp ' work- 
 
298 SgifceUattp ©bftrfcatfcms, 
 
 workable. It Teems that a very little time before this, 
 that way of Minting under ground hath not been fallen 
 upon. For thdre are T to be found Coals tvafted in their 
 Cropps onlyJ 5 fpr conveying the Water whereof,they have 
 made aC onduit, ''in Level, which, hath been open to the 
 Surface , like a great pitch r fame whereof have been ten 
 or twelve fathom in'their deepnefs. 
 
 The beginning of th e Level (to keep the term ufed) 
 muTt alwayesbeat theloweft part of the Field, where the 
 Cod lyes to be dryed. Some whereof, by the rifing of the 
 ground, and the Streek of the Cod rifing that way ( as we 
 fhew before) gives the advantage of a Free ZfW, that is, 
 when the Water comes above ground of its own accord, 
 without being forced by drawing. In others; there is a 
 neceifity of Engines to draw the Water from the loweft 
 part of the Level, and bring it above ground $ which En¬ 
 gines are of feveral Torts, As when mtn draw with ordi¬ 
 nary Buckets, or when there is a ho*fe-work,QX water-work, 
 and that either by a Chain with Plates , and a Pump, or 
 with a Chain and Buckets ; all which are very common, 
 efpecrally thoTe we have mScotland 3 they being capable to 
 draw but a very Tmall draught, making only uTe of one Sink 
 for that effeft. But there are to be Teen in the.North of 
 England, in BifibpYick, Water-works, by which Water is 
 drawn above 40 fathom in perpendicular, but not all in one 
 Sink, The manner whereof is thus, there being a Sink 
 from the end of their Level, to the furface of the earth, 
 ■where their Works are going, 49 fathom deep, whichrnuft 
 dry the <Zod-Sfnks at 60 or 70,’ which ly above the Banks 
 of the Elver 3 where the Water-works are feituated, there 
 is firft one 40'fathom deep from the Grafs,, Another in a 
 right Line from that,of 34/ Another of xaj upon all which 
 
 •- - • rhprfi 
 
$)(fceuanp ^bfetbattons. 199 
 
 there are Water-works. In the firft Sink the Water is drawn 
 from the bottom 1 2 fathom, and thence conveyed into a 
 Level or Mine, which carries it away to the fecond Sink, 
 By the fecond If ork, the Water is drawn out of the fecond 
 Sink 14 fathom, from the bottom, and fet in by a Level 
 to the third Sink, which being only .ra fathom deep, the 
 Water-work fets it above ground. The form of. the Engine 
 is after this manner. In the fiift Sink there is an Outter- 
 wheel moved, as other Milns are, by the Water of the 
 River: upon the end of the Axle-tree of which Wheel, there 
 is a Ragg-wheel, turning vertically fradoth the Outer-wheel, 
 This Ragg-whed by a Nutt, or Trinle turns another, which 
 moves horizontally, the Axle-tree whereof goes right down 
 in the Sink , and may be is 8 or 10 fathom 5 at the end 
 whereof there is another Ragg, which by a Nutt turns ano<- 
 ther 'Wheel^ which goes 1 vertically as the firft Ragg, and 
 caiifeth another Wheel with a long Axle-tree turn as the 
 firft, and fo down till it come to the Wheel, which turns the 
 Axk-tre f, by which the Chain is drawn. The fecond 
 Sink , hath fuch another Engine, but not fo many Wheels^ 
 In' regard it is not fo deep. The third, hath only omjihgle 
 Wheel, Whereby the Water is drawn above ground. 
 
 The moft curious of thefe Engines, that are to be feenj 
 are at Ravenfworth near to Nemafllt , which belongs to 
 Sir Thomas Liddd , a moft ingenious Gentleman, who, for 
 procuring a Fall of Water,whichway ferve the Wheels of 
 all the three Sinks , hath ere&ed the firft work upon Pil¬ 
 lars like a Wind-Mill , pretty high above ground, from 
 which the Water falling, makes the fecond go clofs above 
 ground. And to make the Water fall to the third, the 
 whole Wheel is made go within the furface of- the ground, 
 which teminats at a River under the Works, which Mint 
 Pp z is 
 
^tfceuanp saDbfertmtious* 
 
 is of a confiderable length. Where Water cannot be had 
 to make fuch Works go, they ufe Norfe-works, but not With 
 fo good fuccefs, being more chargeable, and not having 
 fo much force and power, as the Water-works. But I am 
 of opinion, that Wind-works might fei ve well,where Wa¬ 
 ter cannot be had % and when no Wind fhould happen co¬ 
 blow, the fame Works might be fupplied by Horfe: and 
 that the Wind, when it blows but ordinarily, hath as much 
 force, as fo much Water, which is made ufe of for turning 
 fuch Wheels, is to me unqueftionable. For I have feen in 
 Holland,z Wind-Mill, that by the motion of the 0 utter- 
 vohttl, can fe d feven pair of Mill-(tones to go at once, be- 
 Cues another motion for bringing the Victual from the 
 ground, four or five Stories high, to be Grund. And fe- 
 verai Saw-Mids, which befides fix or feven great Saws, 
 they caufed go, did by another motion bring up from the 
 Water great Trees UkeShip-Mafls, to be fawen, and placed 
 them right againft the Saw • all which could not be but of 
 greater weight, than ioor r 2 fathom of Chain with Buc¬ 
 kets. or Plates for drawing of Water. - ■ 
 
 But to return, for the right making of a Level , the true 
 hight of the ground, where the Coal lyes muft be firft ta¬ 
 ken, that it may be known, how much of the field can be 
 drained by it •, which muft be done,either with a Quadrant, 
 or with an Inftrument made exprefs. Then care muft be 
 taken, to take the loweft part for the mouth of the Level, 
 that the field can afford, andfrorq*that it muft be carried 
 in a ftraight line towards that part of the field, where the 
 C cal is thought to be encountered by the Mine. In work¬ 
 ing whereof, two things are in a fpecial manner to be re¬ 
 guarded. Firft, that the Level be wrought without afcent j 
 or decent : the beft. way for trying this-, being by the fur- 
 
flptftrtia np Pbfetbatfon g, w 
 
 face of the Water palling through it, which ought fo^beaS 
 lit tie moving, as can be: for the lots of one toot of Levtl % 
 which the ground gives, is alofsof a confiderab’e parcel 
 of Coal to be digged, efpecially if it be (late. If there occur 
 any JWefa/jy which are impregnable, in the eourje of the 
 Levels fo that it is impoflible,to follow fo ftraight a line,in 
 regard the (Mine muft be wrought over the top Qf that 
 ftone, which is unworkable, in that cafe, there is but one 
 of two to ferve the lofs of Level y cither the Cm/ rife* id' 
 Streek towards which the Mine is carried, and if that be, 
 then after that (lone is paft, the Level muft be carried, as 
 low, as it was before it encountered the fame, and’ the 
 courfc of the Water fhall not be obftrufted, becaufe the 
 fourfe , viz. the Coal from whence the Water comes,riling 
 higher than the Stone , the Water fhall eafily pafs over that 
 highr. Hence it is, that we fee in fome Coals, that have 
 been wrought, at the loweft point of their Streek by 2 
 drawing-(ink) and the Streek riling from that point, the 
 Water that hath come off the Coal, being in its Sourfe 
 higher, than the mouth of that drawing-jink, hath made 
 it to over-run, and ferve to difcharge all the Water, that 
 comes therefrom. But, if the Mine be run to a Cm/, that 
 after it hath overtaken it, rifes no higher in Streek, than 
 the Mmitfelf, the Water that comes from it, will not 
 pafs over any hight in its way, but will be unqueftionably 
 Hopped. Therefore, in cafe fuch an impediment could 
 not be removed, as many times fuch Metals will fall in, 
 which are unworkable in adir°ft line, theule of a Siphon 
 might be tried, which would unqueftionably fupply the 
 lo(s of about 32 foot of Level) this being the hight in Per¬ 
 pendicular, to which the Prepare of the Air ,is able to raife 
 Water up thorow a Siphon, 
 
 The 
 
jot ffitfct llanp O bfctbatlons, 
 
 : The no thing to be obferved in carrying on of Levels^ 
 are tbeMr-holes, ■ for which there is aneceffity indifpenf-, 
 able. In fetting down whereof, care muft be had, that • 
 they be uotdire&Iy upon the Mine, left mbbifn falling tho- 
 row from aboveground, Ihould flop ,.and obftrudl the 
 feme, and fo obftrud th ecourfe of the Water ; and there¬ 
 fore it’s better they be fet down at a fid e, their only ufe 
 being to communicate frelh Air to the Work-men , which if 
 it could be otherwife fupplied ( as I think it not utterly 
 jmpoffible) would render the charge of the Coal-mrha, 
 great deal more eafy; - * 
 
 Other things might be fpoken to of Levels , as that. 
 fome ran with the courfe of Metals ^ they pafs thorow • and 
 that fome run againft that courfe •, and of bringing Level 
 from-the K/p of an uf>f>er-Cod 3 which hath a Level o{ its 
 own, to dry a Coal lying under it, which cannot be other- 
 wife done. But theie things being common and obvious to 
 any, who have but the fmallefi skill and experience, I 
 -Ml forbear. 
 
 This confufed account, your importunity hath drawen 
 from me, for which if your Book fuffer cenfure, which I 
 grant it may do, as to this part, of it, you are to blame your 
 fell, audio I reft and am, &c, 
 
 F I N I S. 
 
 legate 
 
 
POSTSCRIPT. 
 
 Reader , 
 
 T Hat thou mayeft know the rife, and occafion of this Poft- 
 fcript, which I have fubjoyned, I (hall give thee this fhort 
 account. When this Book was firft committed to the 
 Prefs, I Cent an intimation thereof to (everal perfons, whom I judg¬ 
 ed would encourage It, yet to none, buttofueh, in whofe kina- 
 nefs I had confidence, and whoml judged my real friends . Among 
 others, I Cent over to Saint Andrews one of my Edicts, to one 
 or two there, in whom I trufted, but in (lead of a kindly return 
 from them, to whom I had written moff affetfionatly, they wrot 
 back a Letter, wherein they fuperciliouftycondemnthe purpofes 
 "of this Book, before ever they had feen them, which is as follows. 
 
 Sir, 
 
 T Received purs on Saturday lafi,and having occafion the fame night 
 1 to he in company with many of the -JM afters of tbtUmvtrfity, / 
 made known your reflation to them, jhewing them your Edicl , and de¬ 
 firing their Contributions : fame were notpleafed, that ye call the Do* 
 etrine concerning the weight and prefure of the Water in its own Ele¬ 
 ment, new, feing Archimedes hath affirmed, and demonfirated in 
 his Books de infidentibus humido the fame Geometrically 200,0 years 
 ago •, others affirmedthat it was fo farfrom being new,that they would 
 undertake to demon frat the event of an) of all yonr Experiments a 
 pnoxtfrom Archimedes his grounds, yea, in general of any Hydro.- 
 flatted Experiment, feing they look upon it, as a Science long ago 
 perleded. Some faid, as to Diving, that they imagined any me* 
 t hod better then that of Melgims, which is now vulgar, to be impof- 
 fible. As to the obfervation of the Sun, or Moons motion in a [econd 
 
 QdJ '/ 
 
of time, yea, or muchlefs, it can be done mof exactly byaTeleJcope, 
 andtfendnlum^ but fcrvesto no piirpofe, jling that fame motion can : 
 bi had inf nit ly mere exact by preport ion , from obf?rv at ions of a con- 
 [titrable interval $ for fo the Astronomers colldt all the middle mo¬ 
 tions of the Planets. As for the Obfervatiens of Coal-finks, lati¬ 
 tude 0/Edinburgh, and its variation of the Needle, the) may ajftt - 
 real) increafe the Historical part of Learning • jet many of the Mu¬ 
 ffs here imagine themselves concerned in credit not to promote the 
 publication of any thing , which feemeth to declare ottr Nation igno¬ 
 rant {by calling them new, and unheard of ) of theje things known 
 oyer all the World the [? many years among really Learned Men , albe¬ 
 it they be debated amongft ridiculous Monkifi Philosophers. I con¬ 
 ceive, ye would do be'jlto undeceive this liniverfity, by Sending us 
 feme of your mo SI abflrufe Theorems, and Surprizing Experiments-, 
 which if -they be not evidently and clearly deduceablefrom Archime- 
 ces, orStevinus, who did write long ago, or rather, ifthey be not the 
 famewith theirs ye way affure your [elf that this Univerfty willtake 
 sway at leaf all the obligations ye have fent here ; otherwayes, I am 
 afraid , I fall not be able to prevail with them. 1 hope-ye wiR par¬ 
 don this my freedom l uSt with you. and return an anlwerwith the 
 frfi cccafon, to 
 
 St, Andrews, De- Sir, 
 
 cemb. 27. i6jt. Your moft humble Servant, 
 
 After the receit of this, being unwilling to make it a ground of 
 'debate, I returned a moft difereet anfwer,thinking to conquer their 
 humour with civility, and kindnefs,but not long after, hearing of 
 their clamour againft the Intimation , and of their difiwading 
 others, who would willingly (I fuppofej have condefcended, I 
 wts neceiTitated to fend this return,for a joynt anfvver to them both, 
 fo: befides this, another of the feme kind camealfo, ol which here¬ 
 after. 
 
Sir, 
 
 I Received your s, of the Date of December 27 . l6yi. and though 
 it was a little unp leaf ant,yet I took it very kindly from you,asfrm 
 a p erf on Ijudged ingenuous, at my return of January 9.16J2, can 
 witnefs, wherein 1 did not in the leafl refent any thing you wrot-, nei¬ 
 ther would I ever have done, if you, and feme others efpmaUf with 
 you, had not proclaimed publickly , what you and they had written to 
 meprivatly, the not[e whereof ', / have heard here, by f everalperfons 
 who came from the place, Therefore, Sir, you mufl pardon me, if 
 now at lafi , after [0 much filence , I return you this anfwer, for no 0- 
 ther end, hut for my own vindication, tn what I have lately Printed , 
 and am about to Print. 1 am very much then furprized with the an¬ 
 fwer, that you and they have returned, juch a rank fmed of prejudice 
 and envy, I find in it. Jam rewarded evil for good j for l minded 
 nothing hut good-will 5 elje, you and they jhould never have been 
 troubled with my propofal. if they had ajfefted the reputation of 
 Learning, there was another way to it, then the courfe they have ta¬ 
 ken, namely to condemn with Juch a deal of fupercilioufnefs, as dero¬ 
 gatory to the credit of the Nation, forfooth, the labours of one , that 
 hath done more for the credit thereof, then they have dene as yet. 
 They might have minded the faying of the grave Hiflorian, Nam 
 famam atque gloriam, Bonus atque ignavus aeque fibr exoptant: 
 ille verd via nititur, huic, quia Bonce artesdefunt, doles atque fal¬ 
 lacies contendit. And for undeceiving of the Univerfity, as I am 
 very far from counting ]uch per Jons the Univerfity, fo have 1 more 
 refietifor it, and all Learned Perfons in it, then to account their deed, 
 the deed of the Univerfity. As for what they can do, forpromitting 
 the work I have now at the Profs, I value it not at the rate of (hewing 
 them fo much as one of my Theorems : for, if they have (narled fo 
 much , mbutatonemrd, inthe intimation of the work-, what Would 
 they, do, if they had more of it ( which pt'mufi'fiandfirm', urshfs 
 they (for y tis 4 matter of fail, and cannot, be contradUled wtth$Q- 
 pJiiftry and Non-fenfe) overthrow it, which! Us tie fear,- asC ice* 
 1 a did VerreS) Tabulis& Teftibuxad fingnta indicia prolatis. i\^^ 
 then will thmimaginatim tb it? for thatcannotmaki fe&sftrinf'e- 
 Q^q z rtum 
 
( 3P8 > 
 
 dam. It feemeth to be a great weight, that they lay upon the force of 
 their imagination, ftnce they are fe confident, as to fay, they imagine 
 any method of Diving better then that c/Melgims,?# be impoffiblc, 
 aaeo familiare eft hominibus fupra vires humanas credere,qaicquid 
 {bora illorura captum fit. As forthefe others, that would demon- 
 flrat a priori, the event of all my Experiments from the grounds of 
 Archimedes, as I doubt not, but they would, if they could, fo in this 
 then bewray their want of skill: for Archimedes wanted a neceffary 
 requifite, which I go upon for my deduBions, And though it were 
 true (which they jay) that all my Theorems were demon(Irable a 
 ■priori from the grounds of Archimedes,ycf this doth not hinder them 
 to be both new, and un-heard-of,as if new,and un-heard-of conchfi- 
 . ens, mi<rht not be deduced from old principles. In this they are fo 
 
 ■much the better, andnottheworfe. And whereas they fay, they look 
 sipon the Hydroftaticks, as a Science long ftnce perfected, in this 
 ■they do yet more -difcover their weaknefs : for what one Science hath 
 yet-come-to its perfection ? Nay, hath not this Pedantick humour 
 been the great bane of good Learning, that Sciences were already per- 
 ■fectedi So that Seneca [aid truly, Putomulcos pervenire potuifle 
 "ad fapiaitiam, nifi putaifent fe pervenifle, As for thereprefenting 
 cfibcSnn or Moonsmotion to the eye (for that foould purely have 
 teen taken in) that you fay, ferveth to nopurpofe, to me is a little 
 ■uncouth, -xonfdering-how much it conduceth to the accuracy ofAftro- 
 TtOmiul Obfervations, beyond what the former Ages could attain to. 
 i^d-nd-whereas you fay, it can be had'infinitly more exaBly by Obfer- 
 svatim -of a confiderable interval, as Afironomers collect all the 
 middle-mitions of the Planets, but I fay, even tbofe intervals -fhould 
 have-been -far better known, tf they had by this mean, and the Ofcil- 
 htor-y Clock been obferved $ (o whatever arguing by t'he rule of pro¬ 
 portion, •may-do for fhewing the Suns motion in feconds, and thirds, 
 it reach;(th not the(e accuracies, that are reached by'this invfhtion, fo 
 long ns the Senie ‘-cannot deprebend, andfx them. As for the oh- 
 •ftruations-ofCod-fiinks, &c. which you fay, may affuredly increafe 
 the Bif cried part-of Learnings are they not for this the more ufe- 
 fuL, fimc 'hcScitntifcalpart of Learning dependeth Jo much on the 
 -Bifloricilpsrt, and which conduceth mere thereto , then all the pre- 
 - - carious 
 
carious principles o/Cartefius, Epicures, 4 ndtheUk?$, who ipfiiht 
 of giving m An account.of theWorld that Go dr^ude /have given ut 
 imaginary ones of their own making: fo thatfuch a Hifory, is Na¬ 
 tural P'hdofophy requires, is rvijelyaccour-tedampng •</&< de fidera ta 
 in Learning by all (bundihilofophers to this day. So mush in a»\ 
 fiver to yours, andlreft . . D'... :: , • ' 
 
 Edinburgh, peb. 22, 
 1672. 
 
 Your Servant. 
 
 * 1 N anfwei to this left, there came to my hands from Sti Andrews 
 J a Letter unfubferibed by any Matter, full ol barbarous railings, 
 patting all bounds or civility, againft my felf, friends, and works, 
 which, it the Contrivers had not been more gall’d with reafpn, then 
 injuries, I fuppofe they would have ferborn, And thinking this 
 not fufficient, they would needs aggravate tire wrong, by one cir- 
 cumftance more, which they either did-out of difdain, ox fear, 
 not daring to own what they had contrived, in making the Bedale 
 of the Llniveifiry fubferibe it. And togive a further proof of their, 
 infatiable malice, they muff needs diftrihute copies thereof, as glo¬ 
 ry ingin their flume, one whereof was Lent over to Edinburgh un¬ 
 fubferibed alfo. Now, let any indifferent-perfon judge, whether 
 or not, I have nor reafon to do-what I have done. They have 
 been thefirtt proclaimed, though in ncLwdeftinev/zy, and why 
 not I next, in this way.. But left, they think, they have marred 
 as much the tranquillity ol my mind therewith, as they have their 
 own, I fhall anfwer in the words of the Moralitt, Eleganter Deme - 
 trins nofler folet dicere, eodem loco ftbi e(je voces mperitorum, quo 
 ventre, redditos crepitus . Quid tnim inquit, mea refert, furfum 
 ifi, five d.orfum fonent. And let thisftand, for the railing part 
 Of the letter. 
 
 But fir ft, whereas he fhould have fpokento the contents of this 
 Book, he falleth foul upon my laftPeice,. intituled, Arsmva,& 
 magna, gravitatis, & levitatis, fnarling eight or nine times, at the 
 bare title, like a Cur at the horfc heels, when he cannoc.xeachthe 
 rider. T his lay not in his way, doing herein like Fejento the blind 
 
 Courtier 
 
- 
 
 Cfcurtietof ^nhethbulcfhave turned his face to 
 
 the right-hand,- where-the Sturgeon lay, tarried it to the-Ietr. 
 
 - - . — Rawflnrimti dixit' 
 
 -In bgvm-cenfatrffs' tiitttdtxtn focebt 
 
 So that concerning all thefe invectives, limy-lay, fed quid h*c 
 &d Rhombum . But what other can be expe&ed, ubi furor arma mi - 
 niftrat.. Butfciog his Letter fliews, howlick he is of the plague 
 of malice, and envy, I am fo far from ftorming at him, that I pity 
 him, though he may be a Matter, and teacher of others, and wifti 
 him to teach himfelf. =. —— Servitium acre 
 
 Te nihil imfellit ? me quicquam extrinfecus intrat 
 £hodnerves agitet t Sed fnntus &jecore agro 
 Nafanturdpmini,-quttirmpunitiorexu 
 
 ■ Atque hie, quemadftrigiles (cat fa & nut us egit htrilis\ 
 
 * That I do not interpret this ( Reader ) excule me, for I am 
 {peaking ( I fuppofe ) to a Matter of anUniverfity, and a gentle¬ 
 man too-, of very high pretences, as to learning. And yet I can¬ 
 not bat think ftrange-of two things. - Firtt, that he returneth not 
 the Ieaft Ratine fentencem-anfwer to mine, no not fo much as per¬ 
 tinent language in his Mother--tongue. What? AnUniverfity- 
 man, and no return in Latins to thefe fayings,of fo grave Authors, 
 or at leaft in pertinent Bnglifh. Theother, that he no more un- 
 derttands, thefe-words, as Cicero aid Ferres,tdulis &teftibusad 
 ^ftnvnl* indicia prolatis , than the Curat did the tModicum bonum 
 " that he was defi ed to prepare for the Bilhops dinner. For, whereas 
 he'faith, as for pur Lathte fntencts, where ar cur dolt,and fallacia, 
 tabular & tejies, fapientia adqaam put'musms perventfe. To pafs 
 the fi ft and laftqueftioit, of which anone, the fecondwas moft 
 improper for him to ask at me, who did put him to it, to over¬ 
 throw the title of my Experiments, to wit Kew, not by Sophi- 
 (fry,- and Nm-jenfe, bur as Cicerodid Ferres, tabulis & teftibus t 
 "By proof and-W rtnettes-/this he ftiould ; not have asked, but an- 
 fwered. I am confident ' aBoyituhe. fecond Glafs, could, better: 
 have underftood- thefe words, than this man. And for the firff 
 queftion, where art our Whyflioul'dhe ask it, 
 
( 3M ) 
 
 feing the ddiga of his Letter may be evidently feen y .to pHtltyW 
 Societies , and Untoerfities between him and me, in the fnont,whom 
 I have not made my party, but to whom I owe all duerefpftft, 
 and finch a poor pitiful feliow ast'he BesUle inthe Rear, incaufiog 
 him fubfcribe his letter thus, 
 
 . T , ■■ iWr. PatrickMather-s, Arebrh.eddk 
 
 mrchH.-ten. . 
 
 Is not this to do, as th e-Rutehey did, : who fought,his;kaife, when 
 it was flicking in his teeth;. If the.Unfv^fify orderedsius- fubfafo- 
 tion,,it would have been, (aid, at the command .of, ■ th&Uvhferfiiy, 
 If not, itcannotbe purged.fiom a falfeinfinuation: and the liffi- 
 veiTity may juftly refent it, that their publick fervant, hath been 
 foabufed, If the fear of a. counterblow hath made him afraid, to 
 put his hand to it, he hath done as th$ ^did,*that#ruft the Cats 
 foot into the fire, becaufe he durft 1 not do it himfelf, andgivena 
 -palpable difcovery of the diffidence he had of his caufe. If he hath 
 done it, to put indignity on his adverfary, he hath miffed his mark, 
 for as a certain Wriser faith wiH, Inf my. is as it is received .. If 
 •thojth Mtidimll it-will\{lhk': if- ^arbU-it mil rebound-: if-if/ott 
 flow at it^ it is thine: if thou defpife it (as I do this) itisbis. 
 J 3 ut befides this, he endeavoureth to put Mr, fames Gregory be- 
 tvveen him and me alfo, ; and bringeth him infpeaking of my writ¬ 
 ings, with filch a deal of difdain and faucinefs, ut nihil jnpra, What? 
 was Mr. ^ tames Gregory fuch.an eminent perfon, that-he could not 
 .fpeak his thoughts himfelf, butneedethyouSir, foraPr^j, and 
 Chancellour to fpeak for him. If Mr. fames Gregory will fpeak to 
 ,me,- what you have fpoken in his name, he fhall have an anfwer. 
 But.I have no mind to gratify fo far,your doli+md fallacia^tetf) 
 fall on any man upon your word, having, fo little confidence of 
 your common honefty. This were perverfamgrdtiam gratijtcari . 
 Wherefore pa.ffing his impertinent railings, I come to anfwer, what 
 he hath returned to my purpofes in my laft. Andthathe may get 
 no wrong, I fhall fet down the very words of his Letter,^; ; m 
 ■ to what pu write concerning the imperfections pf Sciences : the Sci - 
 htificdpairt ofGeographie isfe perfe 0 ed i that there isnethingw- 
 
 quirei 
 
. ( 3 'u) [! 
 
 quire d-for the prelection, defcription, and ft nation of if lace, which 
 cannot he done, and demcnfirat . The truth is they have overfhot j 
 themfelves in this, though they be afhamed to acknowledge fo j 
 much; for what a pitiful fliift is it, to bring Geography for an inftance i 
 of a perfected Science, when fo much of the Earth remains to this ; 
 cay unknown altogether, as the Uuivcrfal Mapps teftify. Of the 
 inown parts,how little is there to this day fufficiently deferibed by ; 
 theexadleft Mapps, that time,, and labours of men have yet produ¬ 
 ced. And now to retort your own qneft ion upon your felf, di eft 
 fapientia ad quant putalis vos pervettiffe t O but faith the Author, 
 it is perfected as to its Identified part . But I pray you Sir, what is 
 this, though you may be a teacher of Logick of no fmall efteem 
 with you: felf, and difdain of others, but to play che Sophifier, by j 
 the Fallacy a ditto fecundnm quid, ad dictum fimpliciter : Geogra- I 
 pb'j is perfected as- te its (cientificalfart, therefore it may he called j 
 ' a perfected Science, when It ; is fo defective as to the Htfiorical part. 
 IxAftronomy to thisday.be a Science not perte&ed, through want of 
 its Hi(lexicalpart, {hall not Geography be fo likewife. But furder 
 Sir 2 for the Scientifc-alpart of Geography, which you alledge to 
 beperfe&ed, in this aifo you argue againft' the rules-of Logick, in 
 committing that fame Fallacy over again, for giving and not grant- ■. 
 ing what you fay, that the Scientifcalfart of Geography were per¬ 
 fected, as to the projection, defeription, and fitnatien o f & place, is 
 it for this perfected as to the Scientifcal part fimpliciter, which you 
 are obliged to prove, elfeyou fay nothing to the purpofe. And 
 what I pray you, is that poor alleadgence you make, in compari- 
 fen of thefe things, wherein Geography is defeftive, even as to the 
 Scientifcal part * W ho hath fpoken yet fufficiently to the Jurface, 
 and hight of the Sea above the Earth, the Eight of the Hills, and 
 -Mountains, Longitude of places, nay the circumference of the Earth 
 it felf * Anfwer this queftion, if you can, Had then perceived the 
 breadth of the earth, declare if thouknorvef it all t Job. 38. 18. 
 And now Sir, I muft put you to-it again, ubi eft fapientia ad qmm 
 putatisves perverifie, ; - .... - 
 
 His next anfwer runneth thaspT&e Scientific alp art of theOpticks 
 isfo perfected, that nothing can be required for the perfectjon of the 
 
 fight, 
 
fight, which is not demonfir at, albeit mem hands cannot reach it . 
 And thefe being the objects, oftheforefaid Sciences ( you fhould Sir, 
 have faid, the whole objefts of the forefaid Sciences, elfeyou ftill 
 play the Sophifter ) your authority [hall not per (wade him, or us, that 
 it is altogether imp refer to call them perfect . But mark Reader, 
 how the force of reafon maketh thefe Authors to fuccumb: for 
 whereas they fhould have faid, that it is not improper to call them 
 per fell, they qualify it thus, it is not altogether improper. And 
 again, your authority [hall not ptrfwade us , that it is altogether im- 
 proper. But ( my Uttefiers) I do not crave that my authority 
 may pcrfwade you, but reafon. Wherefore to return : the Scien- 
 tifical part of the Opticks (fay they ) is fo per felled, that nothing 
 can be required for the perfection of the fight, which is not demon fir at, 
 albeit mens hands cannot reach it. But where Sir, and by what 
 perfon is this done i Shew me the man, (if you can) that hath done 
 it. But though all this were true, were therefore, either the op- 
 ticks, Dioptricks , or Catoptricks perfected Sciences? Who hath 
 yet fufRciently explained the manner how we fee M lefs how Birds, 
 and Fifhes, Beafis , and InfeCts fee ? How the Eagle mounting aloft 
 fpyeth her prey from a far. Who hath fpoken fufficiently to the 
 nature of colours 1 Forthefealfo belong to the opticks, or of light, 
 and of the infraction, and refiaCHon thereof. The learned Lord 
 Verulam was not of your mind Sir, when he wrot thus, Do forma 
 lucis, quod non debit a »o»-fatta fuerit inquifitio ( prafertim cum in 
 FerfpeCliva firenuc tlabormt homines) fiupenda quadam negligen - 
 tia cenferi po(jit, Etenim, nec in pcrfpeltiva , nec alias, aliquid de 
 luce, quod valent, inquifitum eft. 
 
 If Mr, Newton had been of this Authors mind,he fhould not have 
 attempted the late invention of his Span-long Dioptrical-catcptrical 
 \ FrofpeCt, whereby fiupiter his Satellites, and Venus horned are to 
 befeen. And if Mr, Hook, had been of his mind, he fhould not 
 ! have made his late Propofal of Eelefcopes, Microfcopes, Scoto [copes, 
 
 ! by figures as eafily made, as thofe that are plain and fpherical, 
 whereby the light, and Magnitude of objects, may be prodigioufly 
 I increafed, and whatfoever elfe hath hitherto been attempted, or 
 j almoft defired in Dioptricks, may be accoroplifhed, Wnere ob- 
 1 Rr ‘ ferve 
 
( 3*4 ) 
 
 ferve (Reader) how that ingenuous perfon, is fo far from the »//*- 
 dy language of this Author, that he doth not fay, whatever cm 
 be required for the perfection of fight is demonfirat, or any thing like 
 it, but whatsoever hath been nitherto attempted, or almofl defired. 
 
 For who can tell, what /hall be found out hereafter, even in thefe 
 things. To them we may borrow the words of the Poet, 
 Prudensfuturi temp or if exitum 
 Caliginofa nocte premit Deus, 
 
 So, Sir, I ftill put you to that queftion, llbi eftfapientia adqum 
 
 put at is vos pa vewffe ? 
 
 In the next place he falleth upon the Hydroftaiicks, which for¬ 
 merly he looked upon as a Science perfected long ago. But bec'aufe 
 in his anfwer, he in effeX yeelds thecaufe, I purfue him no further. 
 Eahemtts conftcntem ream, while he exprefly grants, there are ma¬ 
 ts) things jet (faith he) relating to the proportion and acceleration of 
 the motion of Fluids , which are jet unknown. As for his reflexi¬ 
 ons upon what I have written in my Ars Nova, concerning a per¬ 
 petual motion, which I never intended to demonftrat, I leave them 
 as indicia tgri & impotentis rmimi, I proceed to anfwer him in 
 v, hat he adeeth thus. Only we cannot but admire jour fmplicitj in 
 this , Aflronomy feeketh ah ayes to have the greateft intervalls be - 
 to: ix ebfervitions , and ye take that ye will give an excellent way for 
 cbferving the Sun or Moons motion fora [econdof time, that if to fay , 
 as if it wer a great matter, that there is but a fecond ofiym betwix 
 your obfervatiens. I wonder yew fay the eye Jhuld be. added, for the 
 invention had been much greater had that been away. But what is 
 this Sir, but ftill to play the Sophifieri Is not this the. Sophifm, 
 ab ignorattone Elenchi i for it doth not contradiX my condufion,- 
 which is, thatAftronomicaiObfervations, by this mean, and the 
 Oicillatory Clock, may be made to a fecond of time, which is of 
 fo great importance in Aflronomy . But mark the Non-fen fe. (Rea* 
 cerj the invention ( faith he ) had been much greater; if the eye 
 hadbeen away : that is, the invention of this Obfervation had beeff 
 much greater, ihhee/f, that is, the obfervation had been away. 
 Ia this they have outfkoi themfelves alfoj aadwhat they fpoke 
 ~ ~~ ~ unadvifedly 
 
( 3 J 5 ) 
 
 , unadvifedly before, they will now fpeak aeliberatly, and defend 
 it mhetby Sephi/lry and Non-[enfe, then yeeld to the truth. 
 
 Has Mies oft at a exegit gloria fee Has, ' 
 
 The Author addeth, None wit denay but that anguid hi fiery of 
 nature is abfolutelie the mo ft neceffary requisite thing for learning, yet 
 it is not like , that yow are fit for that purpoje, who Jo femelie believes 
 the myrakles of the Vefi, as to put them in Trent, and recordeth the 
 femple Meridian Altitudes of Comets, and that only to halfs of de¬ 
 grees, or little maire, as worthy noticing. If it were needful, I 
 could produce the paffages of fome-of the moft Learned Writers, 
 ,of chefe laft times, that have recorded the like. Were they there¬ 
 fore unfit to write Hiftory < A perfon ol this Authors reading and 
 learning,will foon find them out. It he do it not,let him know,that 
 I keep them for a referue. To fpeak nothing of Arifiotle, who 
 wrot a Book ««*<**** a*.^*™*, extant to this day: was he 
 therefore unfit to write his Natural Hifiories < Prodigious relations, 
 when the memory of them may be found credible, and maintain¬ 
 able, fuch as mine are, ought not to be excluded from a Natural 
 Hlfiory, or die the Learned Lord Verulam is much miftaken in the 
 third Aphorifm of his preparatory to Natural and Experimental Hi~ 
 fiery. Nor had he reafon to carp at my Obfervations of the Co¬ 
 mets, as long as he made none, himfelf. But they will fpeak for 
 themfelves to any that read them. Neither need they him for a 
 Common Cryer, either to>commend them, or difeotnmend them? 
 who, when I was at thefe Obfervations, he poffibly hath not been 
 fo well exercifed. 
 
 He fubioyneth, However if yow dor this laft part concerning Col- 
 finks weiil, and all the reft be but an Ars Magna & Nova.- ye may 
 come to gaine the repute of being more fit to be an Collier, than a 
 Skollar. I muft tell this Pedant , that a Coal-hewer is a more hfe- 
 ful perfon in his own ftation, to the Countrey, than he is and 
 that the Science of Coal , and other Minerals, is far beyond any 
 knowledge this man hath, or can teachi But, m f Lords and 
 Gentlemen, who are Coal-Mafters, mark this;.if yeftandt : tQ the . 
 judgement of this Pedant, though ye had never fo much skilhifi 
 thefe things,ye may come to gain the repute of being more fit to be 
 Rr z foal- 
 
• (3io; 
 
 Coal hewers, than Schollars 5 as if the knowledge of inch things 
 were not a part of Natural philojephy, It feems he hath either for- I 
 gotten the common definition, or elfe hath never known it, that 
 Phyfca 4 Scicntia Corf oris Natural, 
 
 He fuhjoyneth, Te might have let alone the precarious principles, 
 and imaginary Worlds o/Defcartes, till yom new inventions had 
 made them fo : for it man he telledyow Deforces, valuedthe Hi {lo¬ 
 ry cf Nature, as much as any experimental Philofop her ever did, and 
 ferfccled it more with judicious Experiments, than ye would do by ad 
 appearance in ten ages , But I pray you, Sir, did Des-cartes, and 
 Epicurus, and the like, found their Philofcphy on NaturalHiflory, 
 and not rather upon their own precarious principles : and therefore 
 havequite miffed the mark, and method, that was requifite for the 
 advancement of Learning, and have been fo far from grafting Na¬ 
 ture, that it hath j?«rw out from among their hands. As for what 
 he talketh of Des-cartes, perfecting Natural Hi (lory by Experi¬ 
 ments, if he had done it, as the Poet faith in another fenfe. 
 
 Non mihi res , fed me relus comfonere Conor . 
 
 he had done right. But when he took pains on thefe,to force them 
 to a compliance with his own fancies, was not this to ftudy Natu¬ 
 ral Hiflory, as Here ticks do the Scripture, and to be a Fanatick 
 Philofopher , and a fit Mafterfor the like of you. The Proteus of 
 Nature, muff be bound with ftronger Chains, then the fantafiick 
 Nuga of Des-cartes, before he will tell his fecrets. The vanity of 
 whofe method may be feen in the Epicureans, who having laid 
 down this precarious principle, that the fenfe cannot erre, do turn 
 themfelves into fo many drapes, to proved the Sun is no bigger 
 4 han a blew Bonnet, . 
 
 In end, after he hath given a Fling at my labours m Chjgow Col - 
 ItM, about UmvtrfaU, and Ensratienis, which I am not afraid 
 telhall come the length of in hafte, for ought I can learn, hefal- 
 ieth foul upon the two Lines I cited out of fuvenal , in the dofe 
 ^f^y.anfwer to a paffage in a Philofophical Ironfall ton : the Lines 
 
' __ (Wl " 
 
 ———Cuius (apienud MHftrdt _ 
 
 Summospoffe vim, magnaque txempla datum "'■/ 
 Vervecum in patria craffoque fub acre nafci. 
 
 Of thefe Lines, he writeth thus, of which (faith he) thefenfe 
 it net under flood, except jemake jour (elf the <ummas vir, undue 
 nil Verveces. I fuppofe this maj be the greet credit , thnt je faj, je 
 have laboured to gain to jour Nation, viz. to get us all the honourable 
 Title of Weathers, But (.Reader) had thefe Learned Clerks been 
 as skilful in Rhetorical Compofttion , and Refolution , as in Algebrai¬ 
 cal they would not have made fuch an Inference : for the Argu¬ 
 ment is « minori ad maj us. Nor was it ever intended for another 
 end. As for the honourable Title of Wedders , which they alledge 
 I have gained to them, I cannot indeed affirm it *, for if I fhould, 
 fome fin ely would judge me to have wronged them as much in this, 
 as I have done them right all alongs. 
 
 But, that thou mayeft know (Reader) fomething more of the 
 temper of thofe perfons I have to do with in this matter, take but 
 the following words of one of them, as they are tranfcribed out of 
 a Letter written with his own hand to me, after I had written to 
 him a friendly Letter for obtaining the concurrance ofhisacquain- 
 tance for advancing my Book, Andthej promife (to wit the Ma¬ 
 kers promife) yefball not wantlheir concurrence, whereof ye may be 
 lure, ^ effect ally having here your friend Mr. Gregory, jour Couftn, 
 and me here to put them in mind. This is all at prefent , fiom, Sir , 
 •our real friend and fervant. 
 
 Now, what fhall be thought of one, who will (peak fo fair to 
 youi face, and yet cut you with fo many inveftives behind backs, 
 let any man judge. , 
 
 Aflutam vapidofervatJub pettore vulpem 
 - Hie ntgtr eft, hunc tu Roman " caveto. 
 
 Buttogivea further difeovery of him, intheyear i 66 t, acer- 
 tain ingenious Gentleman, that had not been bred a Schollar, by 
 his own induftry advanced fo tar in the athmaticks , that he was 
 able to fi t forth an Almanack, for which, ingenuous and ingenious 
 men (hould have commended him. But this Author, with another, 
 tho'U’h he had never injured them, and without adwrtifement, fdl 
 " ° . .. 
 
CsiS; 
 
 Bpon him like a couple of -Mafttyes, upon a harmlefs PafTenger, as 
 if they would-havc worried him in his reputation, in a Pr^gnoflioa- 
 tion they fet forth/ rateing and abufing him out of meafure: all 
 the caufe being fome alledged miflakes,they thought they found in 
 fome of his.calcillations, and in a Table in the end of the Almanack , 
 which he calleth perpetual, and which they-fay, though falfly, 
 that it will not hold. What had that righteous man deferved at 
 their hands,to be fo abufed in Print by them i But that the defiga 
 is palpable, the raifmg of reputation to themfelves , upon the ruins of 
 tne names of others ? And yet one of them many years after, was 
 neceflitat, for fear of bodily harm, to crave him pardon, with humble 
 offer to his knee. In the Rrognoplication , he would needs play the 
 Feet in his chronology , which the perfon whom he wronged, might 
 have found more fault with, with better reafon, than he could do 
 with him, for his Calculations. What a ftranger he is to the more 
 poliihed part of Learning, for all his high pretences, thefe Verfes 
 will abundantly teftify, fome whereof follow, that thou mayeft 
 know the reft, Ean^uam ex ungue leonem. 
 
 Since that the fulian period firft began. 
 
 Since that of nought the Lord created man. 
 
 He fhould have faid, 
 
 Since that of duft the Lord created man. 
 
 He addeth, 
 
 Since ifrael from Egypt Land did flee. 
 
 Since in Canaan , he made Hams fons to die. 
 
 Since Romulus did build his ftacely Roma, 
 
 Since Nabsnaffar , hence is that ancient nr a. 
 
 Since Gregory helped the Calendar forlorn, &c. 
 
 Mark Reader: thefe Verfes are of five feet,at leaft they lhould be 
 fo: but how far he is from obferving the Precept of that great 
 Matter of Poets, 
 
 Rrimum nt medio,. medium nt diferepei imo. 
 
 Will appear Lorn his dofe, 
 
 Since'fair Lueina fulfilled the Golden Number. 
 
 Since glittering Rhebut augmented Sundays Letter. 
 
 Rugt Roeta, 
 
 It 
 
( 3 * 9 ) ' • * ^ 
 
 It may be he will fay, every man is not born to be a Poet. I an- 
 -fwer, If the Gentleman, whom he reviled, failed in a calculation, 
 he ought to have been born with, and encouraged: for there are 
 many things that even a mediocrity is commendable in j but 
 Poefie is none of thefe. - 
 
 - Mediocribui e[fe Poet is 
 
 NonDii , non homines, non conceffere Column*. 
 
 However, for this, he may allure himfelf, that 
 Perque Pat arum nunqum celebrabere faftos. 
 
 But I leave him to the Satjrifls of the time, Quo illujlrius vd- 
 fulet , for his never being feen farder in Print, than by a railing Al¬ 
 manack^ and ridiculous Ferfes , the better whereof, might have 
 been made by the Laird of Djfert. 
 
 ’Tis like this Antagonift, will fet his Plumbeous Cerebroftty a 
 work to rifle fome of my Writings, and (hake his head, when he 
 is put to a demur, as everamandid abode for Sack but though 
 he fhould , and I have nothing of his, but an old Pr 0^0 [beats on 
 oftheYear, 1661, toripeup, yet whoknowes, butimaymeet 
 with fome of his Bajan-notes, or tome oi his wonders about Ens Ra- 
 tionis , and Genus Logics, that he is now fweating at. I airr in¬ 
 deed at fome difadvantage, while he only letteth a flisk at me, from 
 under deck. Though I have been a little fnell in this reply, yet 
 ’tis no wonder, considering what a barbarous, and uncivil Pifle I 
 met with, which I (lull keep for areferve. I defire to live peace¬ 
 ably with all men, Neither (hall Ibefoon provocked, folong as 
 they keep within the bounds 0! civility. If that beobferved, I 
 fhall thank them, for any miftake they fhall let me fee in my writ* 
 ings, if done with reafon, and without railing. 
 
 ■ # 
 
 FINIS.