'^■^m^' 
 
 
 DUKE UNIVERSITY 
 
 DIVINITY SCHOOL 
 LIBRARY 
 
 GIFT OF 
 
 .Lo.ui.a...C....-.K^rp.ins3^i. 
 
 iS^^ 
 
w 
 
 i 
 
THE 
 
 PREFACE. 
 
 I Am far from being fond of their 
 Pradice, that arfeft to give 
 pompous and promifing Titles 
 to their Books; in fb much that; 
 ny Friends have feveral times re- 
 )roached me with inclining too 
 quch to the oppofite Extream. But 
 'et I ^m not averfe from prefixing 
 Q the enfuing Paper, the Title of 
 [Jedic/m Hydrofiafica ; not only 
 or the Conveniency of Cirations, 
 u'hich ^re ufually troublelbme to 
 pake in Trafts that have long Ti- 
 les;; butbecaufe toQ I am Invited, 
 f not Authorized to do it, by the 
 ;.xample of the famous and judici- 
 ms Sa/^clorius'^ who fcrupled not to 
 )re6x the Name of Me^h^a Sutka^ 
 A J to 
 
*lhe PREFACE. 
 
 to a Writing almoft as Small, as *tis 
 
 Ingenious, Which applys the Bal- 
 
 lance to Some Ufes relating to the^ 
 
 Medicinal Art, perhaps- ^o^ JMkre, 
 
 than will be here found propofed 
 
 pf the famf Inftrument, improved 
 
 by fpme Additions. And 'tis (carce 
 
 to be doubted, but that in this In* 
 
 quifitive Age, th^ Sagacity of the 
 
 furious will make, both of what he 
 
 has difcovered, and of what Ihave 
 
 delivered, uleful Applications, that- 
 
 neither He, nor I, ever thought of. 
 
 If the chief thing, I aimed atin^ 
 
 Writing, had been to gain Applaufe, 
 
 I would have taken a more likely 
 
 way to obtain it, than by treating 
 
 of a Subjeft, wherein few will think 
 
 themfelves concerned, (^thp* many in 
 
 rcallity be fp, and whoft Importaqce 
 
 does not at firft view appear.^ ^nd 
 
 ^his Subjeft too, the Nature of it has 
 
 obliged me, to treat of in fuch 4 
 
 way^ that it will be almoft as un- 
 
 pleaCant to the Reader to p^rule fo 
 
 unadorned a piece, as it was trou- 
 
 biefome to the Author to, write io 
 
 ' ^ ' ^ Toilefomo 
 
the PRiFAcE. 
 
 Toilefome an One. And In^htd 
 whdn ICame to take notice of the 
 Number of Farticulars, tha-t I had 
 brought together imo this Ijctle 
 Book ; I did my felf fofi^'ewhat won- 
 der, how I can^ to be prevailed with 
 to lay out fo much Pains upon fbun* 
 inviting a Subjeft. But KrK)wkc^e 
 and Health are tvvot fucb valuable 
 things, that \ durft m)t refufe four?- 
 dergo,evena toiiefbrHie Task ^ whilft 
 1 was encouraged by the Hope, that 
 was given me. that this kind of La- 
 bour may conduce fomewhat to 
 thafe defirable Ends ; if not other- 
 vays, yet at leaft by exciting the 
 more curious among Phyficians, 
 Chymifts, and Others , to inlarge 
 their Inquiries,and by helping them 
 to remark divers things relating to 
 Medicinal Bodies, that they are wont 
 to overlook. 
 
 I had pjfoVably better confulted 
 my Reputation, as well as my Ea(e, 
 if, having contented my (elfwith 
 thofe few uncommon No: ions, and 
 Qbftrvations, tl^^t the relV of the 
 
 Book 
 
The PRE FA C JB. 
 
 Book was built upon ; I had left the 
 Applications made of them to par- 
 ticular Bodies, to the induftry of 
 Others. I fhall not folicitoufly ex- 
 cufe my felf, for not having beftow- 
 e^: more Ornaments upon the fol- 
 Igwing Effay ; fince the Nature of 
 the Subjed and Drift of the Writer, 
 are fulTicient to juftifie the Plainnefs 
 of my.Style to the Judicious. I may 
 have fomevvhat more caufe to Apo- 
 logize for this ; That I have not caft 
 ^Treatife about a Subjefl; wherein 
 f/lecbanicks are fo much imployed, 
 intoilie Form of Propofitions ; and 
 given it a more Mathematical Drefs. 
 But. I was iinvvilliDgby that meaos 
 ta^ifcourage thofemany , who,u'heri 
 they .meet with a Book, or Writ-* 
 iiig, ^j.'herein the.l'itles of Thcortmc^ 
 fYQhJ^/pe^ and .other Terms of Art, 
 sre confbicuouUy placed, ufe^.to be 
 frighted at tqem; and thinking them 
 to bQ written on'yforMaihcaiatica I 
 Readers, defpair cf ur4deriranding 
 \t\ ap^ therefore. lay it afide, as not 
 ixicari: for the ufe of fuch, a3 they, 
 
 But 
 
The PREF4CE. 
 
 ^ut there is another thing, upon 
 whole Icore, I confefs, I ought to 
 wifh for indulgent Readers. For the 
 Paperscompiled into this EfTay, ha- 
 ving been written in loofe Sheets, 
 and aft*" fuch diftant times, that di- 
 vers Accidents intervene between 
 them 5 the lofs of fome of thofe 
 Papers, as well as others of diffe- 
 rent Natures, and my want of 
 Health, and Leifbre, obliged me to 
 change more than Once my propo- 
 fed defign , and to imploy fome- 
 times theStyle of a private Letter, 
 and fometimes again, that of a 
 bifcouiTe intend^ for the Pub- 
 lick ; By whicn," noeans fome 
 Things, and fome Lxpreffions, that 
 were fuitable to the Defign I had, 
 when Iconimitted them to Paper, 
 became incQpgruous,v.'hen the Scope 
 and Scheme 6P rrt^^fcourfe were 
 altered, efpecially ^pe parts of the 
 Copy being* out cfT^'hands,when 
 IfhbuM have a'djufted the Others to 
 them. But tho' thefe Irregularities 
 may keep the >/2ft^ts[' of this Effay, 
 
The PREPUCE. 
 
 frov^ being fb coherent as they 
 fliould be ; ye^ they will not prove 
 very prejudicial to an intelligent 
 Jleader 5 who, finding the Matters 
 of Faft, and |he Notions, to b^^true, 
 may, notwithftanding the want of 
 an uniform Contexture, make gpod 
 pfe of them. 
 
 Tho* divers little Memoirs and! 0- 
 ther things, that occurred to. me 
 from time to time,whilft I was bring- 
 4ng together the following Papers, 
 have infenfibly fwelled them into a 
 Book ; yet the Eflay it felf was iq 
 my firft intention, but a large 
 fragment of a greater work : where- 
 of an Account is given in the Letter 
 to a Friend, (thai is premised to a 
 P^per annexed to the following Ef^ 
 fay,) which {'LetterJ haviag been 
 intended for a kind of rPreface to the 
 laft Scheme of the wUole larg^er 
 work; if ^he Reader pleafc to p^- 
 ufe it, he will there find the Rife, 
 and Scope of this little Traft, as well; 
 as of the other parts of that defign- 
 ^d Book ; *ndi iQj;i;^e pth^r thiogv 
 
The PR^FJCS. 
 
 that may mal^e it needled tp lengthen^ 
 thisPrean^bleby any thing more than 
 two Advertifemcnts. Qfthefe, One 
 is, ihat, being reduced by divers un- 
 expected, and unwelcome Accident$ 
 to forego my firft defign,and give on-*, 
 ly ty^o or three Specimens of what 
 was intended, and ixiore than be- 
 gun ; I made 9hoice of the Title of 
 the Chymical Changes of Bodies by 
 CoIorati,on,as a Sample of theChymi- 
 cal part pf the Treatife ; and Ipitcht 
 ppon the Subje£b of this prefent Ef- 
 fay, as a6'/>fr/«if« of the Mechanical 
 part of the fame Treatife ; The^?* 
 thtr Advertifement, isjthat the Rea- 
 der need dot be tfenled, tp find (pmc 
 Jjule Variations of Specifick Gravity, 
 among feme of the Memoirs \^\A to- 
 gether in ^his filTay, becaufe he wil^ 
 in due plac^ betold, why fuch things see the 
 ought to b^ expeCled. And in the^^^'F^^' 
 mtan time, it may, I hope, fuffice 
 to fay, that ftich Variations are nei- 
 ther new,nor eafily a vcidable things, 
 in making f/y^ro/j/Zr^/Experiments 
 or others of Affinity to them. For 
 
 Proof 
 
The PREtACE. 
 
 Proof of whichjto Readers, that, for 
 want of having made Tryals them- ^ 
 (elves, may diftruft what we have , 
 laid, I fhall produce a Couple of' 
 notable Teftimonies. The firft i^ 
 given by fb induftrious and dili- ' 
 gent a Mathematician, as Mtrfenms 
 himfelf. For he candidly ackncfw-;, 
 lodges, when he has occafion to*^ 
 Varietai mention fpmeTryals of the learned 
 ^dt\qu£% Ghetaldus^ and of the accurate French 
 fius in EngineeriVI>:?-^y?e«rPe/^^5&:of hisown; 
 Grtffs^"^ that the Variety of weighing, which ' 
 contvigit, often happens to amount to fome ' 
 fimiiis eft Grains, is but like the Variety of Af- 
 Aftrom- ftronomical Obfervations ; which dp 
 micArum almoft always difter in (bme iViinutes 
 ohfeyvati- Or fomc Seconds. To which he foon 
 fcmperfe- after adds an Intimation, that (hews, 
 Ycqiiibuf that he expefted not an exaO: uni- 
 'nmu% formity between the ^Obfervations 
 vzi^mnis.oi GhetdLi/u^^c. already made, and 
 jiveSecfw^ the Tryals of an Experimenter,' that 
 mnt.^tx. would examine them, hy malting the 
 fennusin like again, 
 
 Sd^u" ^"^ ^''^' firft Teftimony we fiiall Tub- 
 Veil. j oyn the Second, whkh is^ that our 
 
 • ' iamous 
 
The PRBF ACB. 
 
 famous Experimenter, the Lord Fi^ 
 rnUm himfelf, writing of a Sub)eft, 
 that in feveral things has much Affi- 
 nity with ours, confeffes, that 'tis 
 not to be doubted, but that many 
 of the Bodies, which he has fet 
 down in his Table of their Di- ui^jg^jp^ 
 menfions, and Weights differ in ^{(arit.?. 
 the lame Species ox Denomination ; ^v'^'- 
 ibme being heavier than others, and unTrLn: 
 that therefore there is fbme Contin- m q^avo. 
 gency in this Affair, fb that 'tis not 
 neceflary, that the Individuals he 
 made his Tryais with fhould be 
 exaft Standards of the Nature of their 
 refpeftive Species^ or fhould, (which 
 makes directly to my prefent pur- 
 pole J agree altogether to a Title 
 with Experiments of other Men. 
 
 But this fcarce evitable Imperfe- 
 ction of fl^i^rc)/?4^if^/ and the like 
 Experiments does not hinder, but 
 that by their help we may make good 
 Eftimates of the Weights^and Bulks, 
 of very many Bodies ; and among 
 them of not a few that belong to 
 two forts of the three, that our II- 
 
 luftrious 
 
 /- 
 
The PREFACE. 
 luftribus Authbr acknowledges to lt)C 
 reducible tb hi s Way^jof Menfura- 
 tioii. And thcle Bftifnates wIlF Tfif 
 I miftake not) befound^notonly pre- 
 ferable to thofe thatcaB be made of 
 the fame Bodies by Gedmetrical In* 
 ftruinents; but (which is mbrej confi- 
 derable for the Reader J^ accurate 
 enough to be very tifeful on a great 
 Kutnber and Variety of Occafidns. 
 Which laft Claufe, Ipurpofely add 
 to infinuate, that the Hydroftatical 
 Way of Menfuration may be ulefiil- 
 ly applyM to feveral Bodies and Ca- 
 fes,that do not at all feem to relate to 
 the Materia Misdica , as would ap* 
 pear by inferting httt what is deli- 
 vered ahftt m trical^ and about Bx^ 
 florstor^ Expurments and Obfervaiu 
 onsy in other Papers ; if that were not 
 too foreign totheenfuihg Eiray,asnoi 
 belonging to the SubjcQ, or to th4 
 Pefigaofit. 
 
 Medicf/rg 
 
■ifiii 
 
 . J^ie^jt^^ Hydroftatic4^ 
 
 The CONTENTS. 
 
 Oiap- t nrH^t Boles and kfsva- 
 
 \. Ititd Stents may havt 
 
 d$s great Mtatcal Ptrtues^ as Gemmsi 
 
 tint quality p/jfy^ viz; the Sfecifick_gra^ 
 
 ifity ef FoffileSy difcovered by this way 
 
 nffexploriijg them: That Rock-Chrj- 
 
 fial^ hiing the mofi pure and Homogt^ 
 
 fi^om kind of Stone ^ is pifcheA upcn as 
 
 ibtStandard^rvhichin rpeightis-by com* 
 
 put at I cn^ to dear IVaftr nftqsal bnlk^ 
 
 4s two and an half to one. One Vft 
 
 tof thif way of Hipftghiug fiony fuhfiarjcts^ 
 
 viz. how fat they partake of a Mstal- 
 
 li0t Naturt^ at that of fome other 
 
 MimrM, From p. i . to ^; 
 
The Contents. 
 Chap. II. The may of weighing 
 fmki/igRodies i» Wat^. How^t^ dtf- 
 €Over practically the proportion in 
 rvtighty between the Solid and the Li- 
 qurn^ Froni P.7.W21. 
 
 Chap. III. An account of fever al 
 Solid Bodies thus examind^ viz^ La- 
 pis Haematites, Lapis Lazuli, and 
 Lapis Calaminaris. A Note^ That 
 the greater or lejjer weight of fuch bo" 
 diesy does not neceffarily imply greater 
 or lejjer Medical Vertms^ or Noxious 
 Qualities in them. From p. 21. to 2S. 
 
 Chap. IV. Aficokd ufe of this Hy* 
 drofiatical way of Inquiry^ viz. To find 
 out ^whether a Mineral Body propounded^ 
 as likely to be ajione^ or of a jlonyNa^ 
 ture^ he jo indeed. This iryed in Cotaly 
 Pearly Calculus humanus andBezoar. 
 Fromp.28 to 3 J. 
 
 Chap. V. J Third VfcyVizt^o 
 
 d'tfcover^ the fefemblance^ or the diffe* 
 fence between bodies of the fame deno^ 
 mination. From p. J J • to 3 5 . 
 
 Chap. 
 
The Contents; 
 
 Chap. VI. J Fof^rthVfey viz. to 
 difcern genuin Stones^ whether Animal 
 or Mineral^ from Counterfeit ones. 
 
 Fromp.35.to39. 
 
 Chap. VII. A Fifth Vfe, VIZ. to 
 m^kefrobAhle Eflimates of the genuine* 
 nefsy or the degree offurity of fever d 
 bodies^ thxt are^ or mxy^ ^tfefnlly he em- 
 flayed in Phyfick^ though they be not 
 Stones or Minerals^ provided they bt 
 heavy enough to fink in Water, An^ 
 Advert ifement to "Jewellers^ and Phy^ 
 ficians , what Gems are to be tnoji 
 efleemed of by either. An experiment 
 of fufing Zaphora rvith Venice Glafs, 
 as alfo a Granate. From p.39. to 44. 
 
 Chap. Vlir. How to make Hydro-- 
 fiatical Inquiries into Liquids ; for in" 
 fiance^ Mercury. From p. 44. to 54^ 
 
 Chap. IX. The way of weighing 
 Hydrojlatically the Pouders of finking 
 bodies J fmall fands^ or the fragments 
 of greater bodies: An Advert if eme0t 
 for the more exaH weighing of theft and 
 ether thihgi. From p. ^4. to6i. 
 
The Contents. 
 
 Chap. X. The Wdj of ^XAmining 
 
 HydroftaticaEy a body that rvilldiffolve 
 in IVater^ or eajily mingle mth it^ 
 viz. to weigh it in Oleous Liquors Qn 
 Oil of Turpentine, /i?r infiame^ x»hich 
 jptH not diffolve it. From p.6i. 1067. 
 
 Chap. XI. Horv to find out by the 
 Hydrojlaticksy the gravity of fluid bo* 
 dies, viz. by weighing fame one folid 
 body in as many of them^ as you pleafe. 
 E.G. Amber in the lighter fort of hi* 
 quors 5 a Globular Glafs Hermetically 
 fealed with ^ickjlher in //•, or Rock'^ 
 Chryjlaly in either lighter or heavier. 
 The Vfss of examining Liquors by an 
 Hydrojlatical Solid. From p.fij.to 85. 
 
 Chap. XII. Several ways to ^md out 
 the weight of Liquids in Water j and 
 other Liquors. From p. 85. to 93. 
 
 Chap. XIII. Of what ufe this Hy* 
 droflatical Examination of Liquids one 
 inanother^ maybe to Phyficians. 
 
 From p. 94. to 99. 
 Chap. 
 
 ^^ ^ 
 
The Contents. 
 
 Chap. XIV. Two Reajoni why y in 
 many Cafes '*tis not necejjary the Scales 
 employed in HydrofiaticalExftriments 
 jbonld he extraordiuary good. An Oh» 
 je^iion agatn(l this Method of finding 
 out the weight of finking bodies in Wa^ 
 ter^ from the different weight of the 
 Water that may be mxde ufe^ anfivered. 
 From p. 99. to 10 j. 
 
 Chap. XV- Hydrofiratical Stereo^ 
 metry appUed to the Materia Medica. 
 Seft. L How to find the weight of a 
 Cubical Inch of Water \ and how by 
 means of this being found out^ to find 
 the dime n (ions of a Solid heavier in 
 fp^cic than Water. Seft. II. How to 
 miafure by the fame means the f olid 
 Contents of a Body lighter in Specie 
 than water y whether it be of that fort 
 of Floating Bodies that are of a cloftr 
 texture^ than eafily to be invaded by 
 water ; or ofThaty that fo abounds with 
 pares^ as to be diffofed to imbibe the 
 water too much^ while the B^xperim-'nt 
 is Of making. The fame Experiment'^ j. 
 to be made in Oil of Turpentine, of 
 b Z Bodies 
 
The Contents. 
 Bodies that are apt to dijfolve in rvdy 
 ter^ From p. loy . to 130. 
 
 Chap. XVI. Two Sl^eflions an- 
 fw^red. The Firfi^ Whether I have 
 fropofed the befi ways that can he 
 thought ofy to examine Bodies Hydro^ 
 flat ic ally 'i The Second^ What credit 
 may he given to the Efiimates of the 
 weighty and prof ort ions of Bodies^ ob^ 
 taind by Hydrojlaticd Tryals ? 
 
 From p. 130. to 143. 
 
 A Pre- 
 
A Previous HydroUatical 
 If^ay of Estimating ORES. 
 
 The CONTENTS. 
 
 Std^- 1. /^OntAining a, fundamental 
 \^ Ohftrvation necejjitry^ in 
 order to make thu^ previous Examen, 
 viz. the finding out the Sped fck gravity 
 cf a pure Stone {y,g, Chryfial^^c. ) 
 hy the Hydroflatical way of Tryal^ de- 
 livertd above in the Medicina Hydro- 
 ftatica. From p. i 5 1 . to 1 54. 
 
 Se£t. II. A more general Vfe of the 
 aforefaidObfervAtiony viz. to find out ^ 
 whether a Fof/ile have much^ or little^ 
 or nothings of a Metalline, nature in ity 
 by compariyjg its rveight this tt>ay^ vp th 
 That of a pare Stone, Three FoJJiks 
 
 ' ■ thns 
 
The Contents. 
 
 tht^s exAminedj viz. the Magnet, E- 
 meri and Lapis Hematites. 
 
 From p 154. to 1 59. 
 Sea. III. and IV. Five Remarks 
 
 to illufirate the former Obfervation^ 
 and make it more di^inB* 
 
 From p. iS9i to 167. 
 SeQ:. V. A more particular notice taken 
 <?/*Marchafites, which by their Jhining 
 fireaks or other gliftering farts^ and 
 their ponder oufnefs^are aft to delude the 
 Vnskilful. From p. 167* to 172. 
 
 Sed. VI. An Advertifement toEx* 
 Aminers ejfO R E S, concerning Flux* 
 fowders. From p. 1 7 j . to 1 7 5 , 
 
 Sea. VII. and VIII. Some Obfer- 
 'vaticns about Native Gold^ and the 
 Hy dramatical Ex amen of Gold and its 
 Ore. From p. 175. to 185. 
 
 Sea. IX. The Hydroflatical way of 
 exploring Sand^Gold, 
 
 From p. 1 8 5. to 189. 
 
 Sea. X» Two or Three Chymical 
 ways of Examining Sand-Go/d. 
 
 From p. 189. to 194. 
 
 Seft. XL An Advice to thofe 
 who are given fa the fearch of 
 
 J^ines^ 
 
The Contents. 
 Mines^ to take notice of any Vnknown 
 or Vnommon Foffiles^ they meet withj 
 and to Examine them Hydroftaticallyi 
 How to examine Ores^ or Wombs^ of 
 Metals^ which may he found difguisd in 
 the form of Earth or Mud^ in an Hydro-' 
 fiatical Bucket » From p.194. to 200, 
 
 Se£t.XII.r^4/ this lafi way of ex amen 
 may heofufe in divers Cafes,p, 20 1*202 
 
 Seft. XIII. The mofi frofitable ufe of 
 the Hydroflatical Bucket^ is^ to ufe it in 
 weighing variety of colour'* d Sands and 
 Gravels. Fromp.202. to 207. 
 
 Seft.Xl V. That there isfuch a thing 
 
 as Volatile Gold ; And that corpufeles 
 
 of a Golden Nature may be in Foffiles^ 
 
 wherein they have not been fufft&ed. 
 
 From p. 207. to 209. 
 
 Seft. XV. An advice to thofe who 
 will apply the Hydrojlaticks to FoJJiksy 
 that they procure Samples of Ores of the 
 fame Species out of different Mines ; and 
 find out what proportion of Metal they 
 contain. From p. 209. to 215, 
 
 An Advertifem^nt concerning the 
 Table annexed* p. 2 1 6 . 2 1 /• 
 
ERRATA. 
 
 PAge 189. 1. 5. r. Tryal of fuch 
 Wares. 1. 4. dele, fuch Wares. 
 p. 193. 1. J. r. or both. p. 195. 1. icf. 
 jr.poife. p. 199* 1. 4. dele, And. p. 
 20 j. 1. 1, r. But therefore, p. 20/. 
 1. 3. r. the Operation. 
 
MLedicina .Hydro^aticaia 
 
 E'-g 
 
 o:i,3l vf*,?M'-^ ;?3:ncr J.-^^d 
 
 - rt ^-n 
 
 70 ;V^-'^^qQ ^^ tik:n.ir^ 
 ,. ,C HA .Pfii^loa 
 
 IhayCj ifi a former Traft, endea^ 
 vour'diCandjas I ani tojd in Prin?, 
 and Gtherwife, nof^^kogethqr 
 unf^ccersfully)to naake it proba- 
 ble^thatdiyers, if not mod, of tlie 
 real Virtues (for many fabulous Ones 
 have been afcrib'd to theni) of Gems 
 or precious Stones, may in great 
 part proceed from the Qualities of Me- 
 talline and Mineral Subftances, That , 
 whilft the Matter was either fluid 
 or (oft, were (moreprlefs plentiful- 
 ly) incorporated with th^ ftony Mat- 
 B ter, 
 
Medicma Hydrofiatica: 
 
 ter, which hardned afterwards into 
 a Gem. The fame PhasnomtnA and 
 Refleftions, that led me to the Opi- 
 nion newly recited, induced me to 
 think it alfo very probable, that di- 
 vers Boles, Clayes, and other Earths, 
 and,muchmore,that{everalMinerals; 
 which, tho* not looked upon as Me- 
 talline Oars,and feveral Sfones or fto- 
 oy Subftances, that,by rcafbn of their 
 Bignefs or Opacity, or perhaps un- 
 j)lea(antCoburs,havebeen judged un- 
 worthy to be numbred among Gems 
 or precious Stones,may yec be indow- 
 ed withconfiderable Medical Virtues^ 
 & perhaps with greater than the finer 
 Gems themleives, becaufe in thefe 
 defpifed Stones and Minerals, there 
 is often found a greater ftore of Me- 
 tallick and Mineral parts, which, 
 while they were in folutis Princi^ 
 fiis^ as Chymifts fpcak, might with 
 eale plentifully infinuate themfelves 
 into thefe more open Bodies, where 
 being fetled they were not lockt up 
 fb faft and ftrongly, as in the nobler 
 Gems; fuch as Diamonds, Rubies, 
 
 Saphirs, 
 
: An ESSAY. i 
 
 Saphirs, {!rc. which are of Co Com- 
 paft, and as 'twere Glafs-Iike, a Na- 
 ture, that divers Corrofive Liquors, 
 and Ajua Fortis it felf, are unable to 
 penetrate and diffolve them 5 tho\ as 
 hereafter will appear, thefe infe- 
 riour Medical Stones, and other Mi- 
 nerals, may be opened by the like 
 Menftruums^ 
 
 Upon thefe Grounds, I thought it 
 might be a thing of ufe to Phyfici- 
 ans, as well as to divers Mineralifts 
 and Mine-workers; if I imparted to 
 them a Way of Exploring many Fof- 
 fils, that I do not remember I had 
 met with, either among Phyficianj 
 or Chymifts : And tho' this Way of 
 Exploration pretends not to difco- 
 ver direftly more than one Quality 
 of the Body examined by it 5 yet 
 that Quality, being its fpecifick Gra- 
 vity, is fb radical and confiderable a 
 one, that it may lead a Sagacious 
 Enquirer further than at firft fight 
 one would think, 
 
 I confidered then, that the moft 
 
 pure and hpmogeneous kind of Stones 
 
 B 2 thai 
 
4^ " Medichu Hydroli-dtica : 
 
 we know of, and that ieenis the freeft 
 from all adventitious Mixtulres, and 
 mnaares ^ven *TR's. isRock-Chryftal ; And 
 therefore I pitched upon Thfe, as the 
 Standard I would imploy, to make 
 Eftimatesof the greater or lefler re- 
 cefs from Simplicity or Homogeneity 
 of the Stones, or other Stone-like 
 Subftances, whole fpecifick Gravity 
 I fliDuld examine. 
 
 We took then Ibme Pieces of na- 
 tive Chryftal,clear and colour lefs, and 
 having carefully weighed them firft 
 in the Air, and then in Wat^r, we 
 found, by Computation, that pure 
 -^hryftal was to clear Water of the 
 lame Bulk, as Two and an half, or 
 thereabouts, are to One : So that, to 
 clear the Matter by aninftance, if we 
 fuppole an hollow Cube, of Brals or 
 other Metal, to be filled as carefully 
 as may be, (for the upper Surface 
 will fcarce be exaftly LeveU with 
 %j. of Water, and if afterwards the 
 Cavity of the empty'd Veffel beex- 
 aftly filled with a Cubical piece of 
 Rock Chryftal ; this Stone will 
 . ' - - weigh 
 
". t.v 
 
 An ESSAY. 
 
 weigh §ij and about an half. Some 
 of hiy Trykis indeed, mad^ with ten- 
 ■der Balances, reprelented the Pro- 
 :j)ortion of thefe twa Bodies, with 
 4bme pefty Variation. But befides^ 
 that *tis not improbable, that diiFe- 
 ring pieces of Rock Chryftal it felf, 
 «tho' of etjual Bulk, may not be pre- 
 cifely equal in Ponderofity 5 befides 
 this, I fay, the Variation I found from 
 the newly affigned Proportion was 
 fb fmall, that having juft intimated, 
 that for the moft part it rdther fa- 
 voured a little the fpecifick Gravity 
 of the Chryftalv than fell ftiort of it ; 
 we may negleft it without any pre- 
 judice, worth taking notiqe of, to 
 the life that is to be made of this Pro- 
 portion in this Paper. And for as 
 iniich as there may be fome Scruple, 
 tho* groundlefs, made about the 
 Origin and Nature of Chryftal : I 
 fiall add, by way of Confirmation 
 of what, has been delivered, that I 
 procured fome ftrong Icicles, that 
 had been fafteny to Vaults, &c. as Bo- 
 dies that would be acknowledged to 
 B 3 be 
 
j5 Medicina HydrofiaticA : 
 
 be true Stones, and yet to have been 
 in a Liqfuid Form 5 and having Hy- 
 droftatically examined thefe Concre- 
 tions^ the fpecifick Gravity, tho' not 
 cxaftly the fame in all, appeared to 
 be little differing from that of Chry- 
 ftal; the folid Body exceeding the 
 Weight of the fluid water, it Was 
 Weighed in, about two times and an 
 half, Ca little more or lefs.^ 
 Ufe L ^^ apply ^his Fundamental Obfer- 
 vation to the Ufes defigned in it, 
 when I had a mind to make a proba* 
 ble Difcovery/for by this Way Ipre- 
 ^ tend to no more) whether in a Stone, 
 or Stone^like Body propounded, the 
 merely ftony Matter were more or 
 left commixt with fome adventiti- 
 ous Subftance of a Metalline Na- 
 ture, or that of fbme other Mineral 
 more ponderous than Chryftal,! care- 
 fully weighed it : Firft ia the Air, 
 and then in the Water, according to 
 the Method formerly declared, and 
 if by Virtue pf its fpecifick Gravity, 
 its Proportion to Water of the fame 
 Pulk, exceeded the Proportion of five 
 
 ?9 
 
An ESSAY. 
 
 to two(^wl?ich to avoidFra£Hons,may 
 be commodioufly fubftituted to that 
 oftea already mentioned of 2 1 toone^ 
 I concluded it probable^ that the 
 Concretion had in it a. Portion of 
 adventitious Matte:r;:, heavier in 
 Specie than Chryftal or, mere Stone, 
 by how much more 01^ left the {olid 
 Body exceeded the Weight of ^ater 
 equal to it in Bulk, by fomuch grea- 
 ter or lefflpir ?a Portion pfrMeterogerf 
 neous Matter was gueft to be com- 
 mixed witli the ftony in the pro- 
 pounded Concrete. This may be 
 illuftratcd, -,as well as proved, by the 
 Examples tfiat fhould prcfently fol- 
 low, but that it will be fit, before I 
 dcfcend to Particulars, to premife a 
 Paper that concerns the whole Dc* 
 fign of this Tra£t, 
 
 
 CHAP. II, 
 
 T 
 
 HOl^ the Way of weighing So- 
 lids in Water hath been deli- 
 B 4 verej 
 
J Medhim Hydtoftafica : 
 
 jJlffSi by ^ife ingenious MtrinH'/GM' 
 M-dns^'k^^y bat' of hiih, 'by Ibfe ffew 
 bther Amhbi^?- and tho^ thfcfrrfore 
 I might^e^ey&ily dHJ)efi&'itiy fel| 
 ^m 'deliVerifig it diftirtdlj^ t Tei^ 
 fihce their "BooJiS are -fcrfcB,' knd tfie 
 know Jed^* * of this W^ jr * i^ almoft 
 ^ery V^'h(*^e^ fijppoTed ii^-ih'efc )?^^ 
 per$/ill6M^fe^^ery fit^ tfef itfht)tflcl 
 once be propbfed in thi^- J'raft, not 
 OnJy^Wft^ ReSfon, bW^^rT^)trd 
 otfet^^ ' ^«(?;?hft ;a dexWMfe' W^ay of 
 fittdiri^ bift'the'V\^tight! 6F'Bbc|ie$^ftt 
 LiquorSj My be of ©r^rtfofe, uft 
 thain M^ {feeffi to ^e'y6|:'k^ire4:)j^ 
 beia g ca{5able iof b6ing -'tti^d^J %y^ it 
 little Varfatibn and Inipfovemtrrt^^Qf 
 good life to Nat uralifts, ^ndeycii?^ 
 GJiymifts; ' Wii'^tOt^K^ thatp^^ 
 haps you will finti canfe io^ftfrik, 
 that Experience and Refledions on it 
 mtiyteve-furnilht (TidTviditSme ^w 
 Expedients and Cautions for the bet- 
 ter Pvaftice of this Arr, and for the 
 avoiding of fotne Errors., |hat .may 
 be very eafi{y,afid perhapsligve been, 
 run intO) for want of the Cautions 
 Jieregiven? T!4e 
 
An ESSAY. • ^ ^^ 
 
 -'in tVafer. j^' *" ^^ ' '-'^^ 
 
 tH?^lid1$da>, 'i^h^'th be exa- 
 mfned; is to be t^'Ukbdut with ati 
 fiorie-hair of a toinpc tent length, 
 which^fifair at i^S^otfi^ tfl'd istb b^e 
 fafterted^ to b^ ' t)f . the Stai^i^f a 
 tehder iad exaQ:ly ecjiiiKbrated^pit 
 lanctf, ^tfiair, the|^^ Body^b^ 
 ing exaftly we j'^ted , in the Air, ahd 
 then in^rri^rfed 1A nGlafs ot other 
 fit Veffel, almoftrfdll of fair Watet\ 
 rn^yhartg fteel^^^bit tiquor, S^^t 
 irig' ont;Vtty fide ertccioiyaited by it; 
 This done, Vou triiiift' , p»t irito tfife 
 oppbiitd Scale aj? ihany Weights, as 
 lerve to Hring Oie !Bbdy hanging in 
 the Wat^t, jo '^in-m£i u£^iiiJjh'^um 
 With the Countefpo?±e, and cbiife; 
 quently the Beafti of the BalkhCbm . 
 an Horizant^l;Scii;uation. Thentate 
 out the Weighty' newly imploye'd, 
 which give yOU the Weight of the 
 Body m the Water, and dedufl;ing it 
 from the Weight rof merly taken of 
 
 the 
 
|0 Medioim BfdroJlAticA : 
 
 the fame Body in the Air, and by the 
 remainder, which will be the^diflfe- 
 rcnce of theie two, divide the whole 
 Weight of the given Body in the Air, 
 and the Qaot^nt (whether confid- 
 ing of whole f^^ibers, or aFraftion, 
 or bothj will fliew the Proportion, 
 in^fpecifick Gravity, between the 
 pxamined Solid, and as much Water 
 asVis juft equal to it in Bulk. To 
 make this more eafily intelligible by 
 an Example ; We took a fine piece 
 of u^hite Marble, fthat Stone kern- 
 ing the moft pure, and moft free 
 from Mineral Tinftures of any com- 
 niori opacous Stones) this being put 
 ifi^o; a good Ballance, whofe Scales 
 wei;e, well equilibrated, was found 
 to weigh in the Air, 5ij 5iij 9i. 
 Grains XX. which, for Conveniency 
 of Supputation, we reduce to 1169 
 Grrains, then an Horfe-hair was tyM 
 about this piece of Marble, and the 
 other end of the fame Hair was fa- 
 ftened to one of the Scales, under 
 which, at a convenient diftance, was 
 plac'd a fbmewhat deep Glafs, almoft 
 
 full 
 
An ESSAY. if 
 
 full of fair Water, in this Liquor the 
 Stone Was made to hang freely, be- 
 neath the Surface, and in the oppo- 
 fite Scale, there were put Weights 
 enough to bring it to an jEqmltbrium 
 with the other, thefe Weights were 
 iFdund, being reduced to the former 
 Denqmination, to amount to 738, 
 Crains, which gave us the Weight of 
 the Marble in Water, fwhich was 
 much lefs Weight than the for- 
 mer, becaufe the Stone was partly 
 fuftained by the Water^ this being 
 fubftrafted from the Weight of the 
 lame Scone in the Air, there remai- 
 ned 451. Grains, which gave us the; 
 Weight of as much as was equal to 
 the Stone in Bulk. By this remainder 
 the Weight of the Marble in the Air, 
 'viz,. 1169 being dividedjthe Quotient 
 was found to be 2 & TTo,or near enough 
 Jv for the Proportion in fpecifick Gra- 
 vity of White Marble to water* The 
 Demonftration of thisPraftice is foun- 
 ded on what I have elfewhere given, ^^''^^^; 
 and it may, in another way, be found radoxu.' 
 in Jom6 of the Commentators on 
 
 Jrchif 
 
Archimedtl , di- I»fidentihfis Bumid^^ 
 ■r For underftandtag of the Summa« 
 fyTOrcftion newly givetij it mdybc 
 tifeful to fubjoyn the following 
 Notes : Fir ft, ;**isl ^manifeft by the 
 N^cufeof thfe'thiA^, that the Body, 
 propofed to be weighed, ought .ca^b6 
 heayy enough to firik in Water, finti 
 tytlferw'il^ its Weight ift that Liquor 
 being none at all, cannot be-fienifii- 
 cantl]^ deduftefd^ft^ its Weight in 
 tbd/^r; bur^if there be occafion to 
 Wdigh ' in^vy at6r/ 4 Body lighter i« 
 Sj:fecie ttfatt it/ t^ B^e^wax , apiece 
 of Pitf'wood, '^V. ^ -It may b(J done^ 
 ttt^^Wof Without 'fomc't^ 
 joyriing'td It' a'' Body, heavy enough 
 fd'|na]^e the Wak fink with it, but 
 tHs, <?af6 ^beforig^ nt)tto t his plaice, i • 
 \^ An Horfe-hair is made chdiceof, 
 for Hydroftatica^ Operations ,: be- 
 caufe its ftid to be Equiponderant to 
 fo tniicli Watei--; and tho' I have nor 
 found that to'beftriftfy true, yet an 
 Horfe hair is fitter to be imployed in 
 thele Tryals, than any other ftring, 
 I know of; andits fpecifick Weight 
 
 ufually 
 
An ESS A Y. ij 
 
 ufiially differs fb little from That of 
 Water, that tlie Difference may be 
 (afely enough neglefted ; and if the 
 Solid propofed be too lieavy to be 
 fuftained by a finglcHOrle-hair, one 
 may twift two, (or,if need be} more 
 of them, to make the ftring ftrong 
 enough to fuftain the Solid. 
 
 3. I Ihall add, that I have met 
 with Bodies, about which, by Rea- 
 fbo of their Roundnefs, as in Bullets, 
 or of fbme other inconvenient Figure, 
 we could not wellfaften an Hair, or 
 other ftring, wherewith to tye it to 
 theBallance. Now,on fiich occafions, 
 Icauled ibme Hairs to be (b contex'd, 
 as to make a kind of a little Hoop- 
 net, whole Mealhes were not great 
 enough to let the Body flip through 
 them. In this fmall Veffel, whether 
 you call it aNet or a Basket, which 
 was ty'd by an Horfe-hair (fingleor 
 twifteci)jto one of the Scales, we pi^ 
 the folid Body to be weighed, and 
 proceeded in the Operation, as if the 
 "Body were tyed but with a firing. 
 
 A. But 
 
t4 Medici fia Hydrofiatiu : 
 
 4. But here it muft be carefully 
 noted once for all, that whenfoever 
 any Hydroftatical Tryal is made with 
 an Horfe-hair ; there muft be put in- 
 to the Scale that holds the Counter- 
 poize, as much of the fame Hair, as 
 can be gueft to be of the fame Weight 
 with that part of the ftring that fu- 
 ftains the Body in the Water, which 
 appears to be above the Surface of 
 the Water ; for this Liquor takes off 
 the Weight only of as much of the 
 Hair as is immersM in it, fb that the 
 unimmers'd part of the ftring adds 
 to the Weight of the Solid hanging in 
 Water ; and therefore, ought to be 
 compenfated by an equal Weight put 
 into the oppofite Scale. 
 
 5. When I kept a Ballance, only 
 or chiefly, for Hydroftatical Tryals^ 
 I found it expedient, on divers occa- 
 fions, to take off one of the Scales 
 with the ftrings belonging to it, and 
 fubftitute in its room a piece of Lead, 
 or other Metal of a Conical , or 
 (bm other convenient, fhape, exaftly 
 Equiponderant to the oppofite Scale, 
 
 and 
 
An ESSAY. i$ 
 
 and at the fame end of the ftring, to 
 faftert one end of the Horfe-hair that 
 tyed the Body to be weighed in Wa- 
 ter. And Ibmetifies alio, when I 
 did not take off one of the Scales, I 
 caufed it to be perforated in the 
 middle, (yet, without leflening its 
 Wcightj that fb the Body, to be im- 
 merft, might hang very Perpendi- 
 cularly from the midft of the Scale. 
 TheMotiveSjthat induced me to thefe 
 Praftices, cannot be fo well ftt down 
 in few words ; and therefore fball 
 be now left unmentioned, efpecially 
 becaule the Pradices themfelves, tho' 
 on fbme occafions convenient, are 
 not necelTary. 
 
 6. There remain yet a couple of 
 Remarks, which muft left than any 
 be pretermitted, if Men would avoid 
 fome Errors, that are but too often 
 flipt into, by the Makers of Hydrc- 
 ftaticalTryals. We are then (Firft,) 
 to take notice, that the Body, to be 
 examined, hang freely in the Water, 
 lb that no part of it any where touch 
 the bottom or the fides of the Veflel, 
 
 or 
 
li Medicinf Hj/drofiatica: 
 
 or. reach above tl^e upper S^iiacQ of 
 the Water contamed in it ; for,,if any 
 of thefe Circumflances be pot f^ken 
 care of, (as it happens, when we are 
 not heedful enpuglQ the true Wf^ight 
 of the Solid is fomewhat altered ^and 
 if aqy 'Corner, or pther part of the 
 Body, (and thq J^kqma^y.be faid.of the 
 Hor fe-hair, 'tis tyccj, with) tho'but^ 
 fmall one, appear "^|)Qve the Surface 
 of the Water .• That extant Portion, 
 b^ing not at all fultained by tlie Li- 
 quor, adds (more or left) to the 
 Weight,that the imoierft Body fliould 
 have. Care alfb muft be had^, th,a|:> 
 as nothing but the Water dp. touf;li 
 the hanging Body, fb, no part of the 
 Water may touch the Scale whence 
 it hangs. Ihav^feveral times obfer- 
 yed, that immerft Bodies liave been 
 concluded to weigh more in the Wa- 
 ter than really they did 5 becaufe, 
 through Rich a want ofHeedfuInefi, 
 as is not uncommon, the Experi- 
 menters did not take notice, that if 
 the ftring were too fhort , or the 
 VeiTcl too full ^ the vibrating Moti- 
 ons 
 
An E S S A Y. tj 
 
 6ns of the Ballance, would, at one 
 time or other,carry do\Vn the Scale, 
 the fuQjended Body was tyM to, to 
 low, as to make one part or other of 
 it touch the Surface of the Water: 
 femei^ Drops of which Liquoj: would 
 ^cadil3^ftiqk to it, arid^ bccaule they 
 adher'd^^b the nether pirt of it, 
 would lye i^oncealed from art Eye 
 that was not prying, and by confe- 
 quence wy)uld icnfibly add to the 
 Weight of the ^cale^ and make the 
 Bodyl)e thought heavier than indeed 
 it was ; which Over-figfit muft needs 
 be very prejudicial, when one makes 
 Experitnetits that require Exaft- 
 riefi. 
 
 7. But the mbft ufual Gaufc of 
 Miftakes in Hydroftatical Tryals , 
 (elpecidlly fuch , as are made on fmall 
 Bodies) wherein a little Error may 
 be greatly cohfiderable, is this ; that 
 Men are wbnt to think it lufficienr, 
 fin thele Tryals) that the Body to be 
 examined, be totally inimerft in the 
 Water; whereas it does not only 
 often, but moft commonly happen^ 
 e that 
 
8 Medrcm^ Bj^oftiUlca : 
 
 that the giveii SoJi^, and rt^^ing^ 
 that is tyed about it, cajrx^ 4owq 
 with .the.m divers Partij5i^^.o|]rAir 3 
 and perhaps %Q9^, it niay i^LpcJ^ ^ad ex- 
 tricate other:S,;that lay cqncq^l^d 4a 
 the Pores of thp l^iq^or it felfj, ^y hff h 
 Atrial Particles [iaften then^leives to 
 the hctle^ A^erities, tl^at tHey meet 
 with on the Swrface of the immerft, 
 BodieSjin the form of Bpbyps^^which, > 
 lifce io many Jtole Blacid^rs full of, 
 Airj endeavour to buoy up^^hp (Body 
 they adhere ,to; and on th^it: account 
 dOjinPropprtiqi. p tl^eii; Niimber and 
 Bignefs,leiren.t?ij9 Weij^u^AVflif^^'^^ 
 immerft Body would oth^i[i^^fe have 
 in Water. And therefore, great care^ 
 is to be had, efpecially in: nice Expe- 
 riments ; thatj, bjy, flia king the ftring, 
 and warily l^aocking the Body a-^ 
 gainft the fides qf the Glafs, the ad- 
 beriiig Bubbles^ may be difplaced,- 
 and emerge to -the to,p of tb^ WaterJ^ 
 And I fliall add a defire^ that on Ibme. 
 occafions this : Caution^ bf^ ..laade^ 
 life of mote than on|qe) ra...th(3/^ 
 fan>e Try^l^. j, fe^qauife I 'tiayj^^iey^eral 
 ':^:n ' i) "' "' times | 
 
:* An ESSAY. 19 
 
 times ob{ei-'ved,that now & then after 
 the immerft Body was freed from the 
 firft Bubbles that appeared about it, 0- 
 thers did fiTcceed, before an end wais 
 made of weighing the Body 5 out of 
 fbme of whole unp^rceived Cavities, 
 orPoreSi(whetherfuperficialorlying 
 deeper) perhaps the latent Air could 
 noteafilyon afudden be driven by 
 the Water. I have been the more 
 Circumftantial in explaining thi 
 fummarily propofed Method of 
 WeighihgjBodies in Water J becaufe 
 Experience hath fhewn, that 'tis not 
 near fo eafie,as,upon the flrft reading 
 of it, one would prefume ; to be ex-^^ 
 aft in the Praftice of it. 
 
 Having obtained th^- Weight of a 
 Body propofed 5 Firft,in the Air, and 
 then in Water, according to the Me- 
 thod plainly delivered ; '*twill nor be 
 diflScult to difcover Praffically the 
 Proportion in Weight, between the 
 Solid and the Liquor. I fay Pracfical- 
 ly^ becaufe the Rule is eafie enough, 
 tho' the Demonftration is not fo rea- 
 dily t^.be underftood by them, that 
 C 2 are 
 
ip Aledicha Hydro/iatica : 
 
 are not acquainted with the Prin- 
 ciples of the Hydroftaticks. The 
 J hear em y upon which our Praftice is 
 grounded, was firft,that we know of, 
 delivered by the moft fagacious Jr- 
 chimedes'-y whole Commentators have 
 bufied themfelves in demonftrating 
 it in a Mathematical way, as I have 
 fince endeavoured to do in a Phyfi- 
 cal way, and more eafie to Natura- 
 lifts in the Hydroftatical Paradoxes. 
 Jychimedes^sVropoCition is this, That 
 d Bodj/y heavier than Wafer y weighs lefs 
 in W^ter than inthe Air yhy the Weight 
 ef as much Water as is equal to ipinBulk 
 or Magnitude: Whence 'tis not diffi- 
 cult to deduce a Rule fuflScing for our 
 prefent purpofe. Forifyoufubftrafl: 
 the Weight of the Body propoled , 
 whilft it isevery way environed with 
 Water ; from the Weight of the I&me 
 Body, which it was found to have in 
 the Air;the refidualNuniber or Diffe- 
 rence gives you the Weight (taken, 
 in the Air^ of as much Water as is 
 equal in Magnitude to the Solid pro- 
 
 pofedy 
 
An ESSAY. 21 
 
 pofed ; fb that, having now two Bo^ 
 dies, one Firm, and the other Liquid, 
 together with the Weight of each of 
 them apart ; to find their Proportion, 
 you need but divide the greater by th^ 
 lefler $ and the Quotient compared to 
 One, that is, to an Unite, will be the 
 Antecedent the of the Proportion de- 
 fjred between the fblid Body and the 
 Water ; which is mentioned , but, as 
 it is the Liquor that is generally im- 
 ployed in thefe Experiments, for 
 otherwile the Rule will hold^ wutatis 
 mutandis^ in other Liquors, as well as 
 inWatcr.-^'^^^^^^-^'-^"'^':"' 
 
 ■H . I I ! -^ '■ '■ ■ — ■> 
 
 C H A P. III. 
 
 ■ ^::t)M ill'- ' ■ ■lijrCJ''* • 
 
 ANd iK$W Havibg optfemiftd thefe 
 Remarks, and thereby made 
 way for the clearer llnderftanding of 
 the fubfcquent part of this Paper ; 
 we fhall proceed to the Examples, 
 that this not unneceffary Digreffion 
 has diverted us from propounding. 
 
 C I There 
 
J 2 Mtdicim iHjdroJliitica : 
 
 There is a deeply Red and Op*" 
 cous Mineral, .pbat commonly paflcs 
 in the Shops Ujnder the Na^ne pf La- 
 pis H^m/itttes^ tho' it feen>s to have 
 more Affinity to that which divert 
 Authors call Schy^os.. But whatever 
 be the mofl: proper Naiiae-jtfeat be- 
 longs tait, it is anhard Foffile^whieh, 
 tl^o' little ufed by our Englifh Phy fici- 
 ansjis in ft veral Pi'aces abroad in great 
 Requeft ;& that not without caufe, as 
 far as lean judgejby what I yet know 
 of it; and efpecially, for that Somni-s 
 ferous Quality,, that may be oblerved 
 in fbme of its Preparations. But 'tis 
 not here, tho' 'tis elfewherc^my Pur- 
 pofe to deliver its Medicinal Virtues; 
 but only to examine, whether, accor- 
 ding to our Method, it otj^ht to be 
 concluded to abound with Metallick 
 Particles,(perhapsbutEnibryGaated,) 
 to whole Intermixture femolof its 
 Virtues may probably be.aftrib'd. 
 Therefore, m a very goodBatlance, 
 having weigh^d a piece of Englifh. 
 fiamatites^ that chanced to amount 
 to about W}lh\ ^ ,. Firft, ia the Air, 
 
 and 
 
and th^gil-iriWateF; we found its Pro- 
 portion to this Liquor, as 41^ tot. 
 AtwhidhFonderofityj if I had not 
 fbrnaefly" made the like Experiments, 
 I fhould have been (urprized ; as you 
 ?prohab'[^^wi!t be, wheb you confider, 
 tfiac thi^ Metalline Stone did not very 
 much W^Af' of almoli twice the 
 Weight J^f a f^er^Stone of the fame 
 Bulk. This great Weight much con- 
 -firm^^'fttein the CoH)e£lure I had 
 *%iade; «tii^t in this Lurrvp was coa- 
 '^fainM' tt good deal of 'Mfet^line Sub- 
 "ftance. And this induced me (to 
 4ddifeat^|^dri the byjfto eKamine my 
 Guefsjfey-fubliming it, Nrhen finely 
 powdered, '^jid diligently^mixc wdth 
 fl^n equ^^:6f double, Weight ofSa/ar-. 
 •^ffhiac} i(^ tfien having rafted, with 
 tie iip i^f ^y Tongue^of thisSafro?^^ 
 coloured Sublimate 5 I found it 5 as I 
 expe£ted| very Aftringent' or Styp- 
 Itek^ as' aij^ers Preparationsof Mays 
 are worif tb be; and,for fui*ther Proof, 
 having p«t fefs than a Grain of it in- 
 to a fpooftful or two of gdod Infu* 
 fion of G^lls J there W'fts insttjfediate* 
 
 C4 ly 
 
34 Medicine HydrofijLticA : 
 
 ly produced a Black, and as i( 'twere 
 Inky, Mixture. ^ 
 
 La^fts Lazuli is fbmetinies made 
 ufe of by European Phyficians, but 
 more frequently by ArAbun and o- 
 ther Eajlern Ones,for divers purpofes, 
 but efpecially to niakeEvacuations by 
 (Vomit, This Emetick Faculty feem- 
 cd, likely enough, to belong to it up? 
 on the Score of a Metalline Ingre- 
 dient; and accordingly, having e)^- 
 amined Hydroftatically, 4 piece that 
 was judged moderately rich, wc 
 found the Proportion of it to an e- 
 qua! Bulk of Water, to be as 3. to \, 
 which argues,That,notwithftanding 
 its brisknefs in Operation , it con- 
 tained a much leffer Proportion of 
 Metalline Subftance, thsin Lapis H^^ 
 matites^ or divers lels Operative Mi- 
 iierals. 
 Sf^S" ^ elfewhere fiiew, that the Load- 
 The LW- ftone may be applyed to Medicinal 
 ftone\, as Ufcs, and that it emits Effluvia^ that 
 nnl^''^^^ not Magnetical, and may have 
 ' fenfible Operations upon the Body of 
 Man^ On which accpunt , it was not 
 
 improper 
 
An ESSAY. 25 
 
 improper to examine it Hydroftati- 
 cally ; by which means I found, that 
 the Weight of a Lump of Loadftone, 
 that I judged to be either Engli{hoT 
 Norwegia^'j, was in Prpportion to Wa- 
 ter of the fame Magnitude, as ij^» 
 to I. But of the fpccifiqk Gravities 
 of Loadftpnes, much more may be 
 met with in another Paper. 
 
 l,apis CaUminaris is often enough 
 uled in Phyfick, efpecially by Chy- 
 miils^todry 3 and to imbibe Acidities. 
 For which llfes, I prefer it before di- 
 vers morp famous Drugs : But,tho' 'tis 
 wont to be imployed, only as an ex- 
 ternal Remedy ; yet fome things, 
 that I found in fome uncommon Chy- 
 mical Preparations of it, made me 
 think, it may deferve to he further 
 examined and tryed, A famous and 
 not unlearned Empyrick, to whom 
 I willingly communicated Ibme Pro- 
 cefTes, that he defiredofme; when 
 I asked him about a Medicine, whofe 
 Succefs brought him a great number 
 of Patients, for griping Fluxes, and 
 (pme Dylenterical ones; candidly 
 
 difco- 
 
t6 Medici rf a Hyiroflatica : 
 
 difcovered his Medicine to meV artd 
 fblemnly aflured me, it was iiothing, 
 but pure and well-ground L^pls CaU- 
 minariSyk^i^ondbXy given in a juftDole^ 
 as in a fitter place I have more fully 
 declared. This made it obvibtis for 
 for me to conjefture, that L-apisCaU^ 
 minaris participates of a IVTet^llick 
 Nature, as may be argued froni its 
 Operation upon Copper, which is 
 thereby turned into Brafi. Wherefore 
 weighing a piece of this Foffile^firft in 
 Air, and then in Water, it appeared 
 to be to this Liquor as 4I'? to i. 
 
 If I had not among other 'Papers 
 loft Some , wherein I had R^egiftred 
 a good Number of Tryals or this 
 kind made upbn/difFering Foffile^s 
 ^twould be eafit for me to add- to the 
 four already recited, others rnani- 
 feftly conducing tc the fame Purpbfe. 
 But prefuming, that thofe alreafdy 
 delivered may-ttprefent fifffice^ I 
 fhall now fubjoynia few Obfervatr- 
 ons, whereof thq /r/? may bewme 
 the Candor and; tepartiality ch :a 
 Lover of Trutft^ -and tlie reft inti*- 
 
 mate 
 
An E S S A Y, %^ 
 
 mate fbmc further Ufes of the Hy^ 
 droftatical Way of exploring hard 
 and ponderous Concretions, hitherto 
 treated of - ^^^^^^ 
 
 I muft not therefore forbear toad-- 
 monilhyou, that, Mo' when an hard 
 Foflile propounded, is found to be 
 much heavier than Chryftal of the 
 fame Bulk ; 'tis a very probable To- 
 ken, that- in the Solid Concrctiorrr 
 rhere is a notable Portion, greater or 
 JelTer, of ibme Metalline or other 
 ponderous Mineral Body, vi'hence its 
 good or evil Qualities, in reference 
 to human Bodies, may probably be 
 deduced ; Te?, this hinders not, but 
 that i'ris very podible, for a Foflile 
 to be endowed with Medicinal Vir-- 
 rues, or to have noxious Qualities,- 
 on the account of a Portion of ex-^^ 
 traneous Matter ; tho' its fpecifick[ 
 Gravity doth but little exceed thatof^ 
 Chryftal, or the advantage feem but ' 
 inconfiderable. For, (to pafs byo^: 
 !ther Refleftions) a very fmall PrO^ 
 portion of Adventitious, Metaitine, 
 or Mineral, Subftan.ce, if it be orali-' 
 •^ Opera- 
 
^9 MedicinA Hj/droftaticA : 
 
 OpcrativeNature,may,in{bme Cafes, 
 fuffice, to diffufe its lelf through the 
 reft of the Mafs, and impregnate it 
 with aftive Qualities. Which may^e 
 partly lUuftrated, and partly Proved, 
 py fome Experiments that will be 
 hereafter met with, in one of the 
 Chapters. 
 
 CHAP. IV. 
 
 - - nr^O hint fomewhat about the fur- 
 Ule II. J^ therUtility of our Hydroftatical 
 Way of Inquiry;! fhall take notice in 
 the firft place, that it may aflift us to 
 guefs, with probability, whether a 
 Mineral Body propounded, as likely 
 to be a Stone, or of a ftqny Nature, be 
 fo indeed. Thus Coral, for inftance, 
 is by fome thought to be a Plant, by 
 others ^ Lytho-dendron^ but, by the 
 greater Number, 'tis reckoned a* 
 mong Precious Stones. In this Dil* 
 fent of Opinions, the fpecifick Gra- 
 vity may be of confiderable life. 
 
 Where* 
 
An E S S A Y. 29 
 
 Wherefore, we thought fit to weigh 
 a piece of choice and well colour* 
 edred Coral; firft, in the Air, and 
 then in the Water, and found its 
 Proportion to the Weight of as much 
 of that Liquor, to be as 2 ^V to i. 
 So that its fpecifick Gravity much 
 favours their Opinion, who take it 
 to be a Stone, fince it not only e* 
 quals that of Chryftal, but fbme- 
 what exceeds it. 
 
 There are Some, that will have 
 PearlSjbecaufe of their Hardnefs, and 
 their being treated of by Jewelers, 
 and others that write of Gems, to be 
 of a ftony Nature. Wherefore I 
 thought fit examine their Pondero- 
 fity alfo.But not having now with me 
 any Tryal of that kind ; Ifhall fub- 
 ftitutc One that I made upon a mon- 
 ftrous Pearl, that was prefented me 
 by a Pcrfon that took it out of the 
 Oyfter. I call it Monftrous, becaufe 
 tho' it be well enough coloured, yet 
 its Shape is irregular, and its Bignels 
 extraordinary 5 as is alfb its Weight, 
 amounting to full 206 Grains* This 
 
 being 
 
5© Medicifia Hydrofiatica : 
 
 being weigh'd in Water, its Propor- 
 tion in Gravity to an equal Bulk of 
 the Liquor was found to be as ali? 
 tQ 1. So that its fpecifick Weight 
 was much about the fame, with that 
 of Chryftal. 
 
 There are Many , that take the 
 Stones formed in Mens Bladders, for 
 as true and genuine Stones, as Thofe 
 tliat Nature forms in the greater 
 ^Vorld ; and fpeak much, and fbme- 
 tiraes not without ground, of the 
 great Hardnefs of divers of them. But, 
 tho^ I deny not, that, in a laxer Senfe, 
 they may well enough pafs for Stones; 
 yet I fhould rather call them J^smal 
 Sfo^es^th^n fimply Sto/^es ; this Name 
 having been conftantly and generally 
 ufed, to fignifie Mineral or Foffile 
 Stones: which,by ourWay of Explora- 
 tion, may be eafily diftinguiflied fromt 
 human C^/^«///i's, and other like hard 
 Concretions, found in the Bodies of 
 Ibme Animals. For, having examined 
 a good Number of thefe Stones, I 
 found, that not only the Chymical 
 Andjifes^ I made of them, of which 
 
An E.S SAY. 31 
 
 lelfewheregive an Account, mani- 
 fefted them, how hard foever they 
 were, to be Concretions belonging 
 to the Animal Kingdom, not the Mi- 
 neral : But, by an Hydroftatical jEjc^- 
 «rf/zof divers of them, I found them 
 to differ much, in fpecifick Gravity, 
 from true Foflile Stones. Of this 
 you will,in its proper place,meet with 
 feveral Inftances ; 10 that it may 
 herc{iiffice to memioiiTwo,thatnow 
 chance to come to hand. Namely, 
 that 2iCaIculus humajms weighing a- 
 bove 5vj(s was found to be in Propor- 
 tion to an equal Bulk of Water, as 
 I fjv to I. And anotlier, that 
 weighed ^iv and above an half, in 
 the Air, being alio weighed in Wa- 
 ter, appeared to be tp this Liquor, 
 
 as I ro^ to I 
 
 I mention thefe Scones as belonging 
 to the Materia Medka, tho' they are 
 lookt upon rather as Difeales , of 
 whichjindeed, they are very fad Pro- 
 djLidions, becaufe a famous and ex- 
 perienced Phyfician, that Pracliled 
 long in' the £A^-./W//?i, and had abet- 
 ter 
 
52 MedicinA Hydhjiaticai 
 
 ter Opportunity than almoft any £//- 
 rdpaau had before hitn , to try the 
 Virtues of Bezoar^ does either equal 
 or prefer the Calculi^ we are fpeaking 
 o^ evert to Oriental jBe2id?4r. 
 
 And to fhcw, that Men are not 
 the only Animals, wherein Stone-like 
 Concretions differ in fpecifick Gra« 
 vity,(and fo may bediftinguifhed,by 
 that difference,) from Chryftal and 
 fuch like true Stones ; we fhall fub- 
 joyn Two or Three Experiments , 
 niade upon choice Bezodr Stones, not 
 eicceedirig a middle Size, fuch being 
 the likelieft not to be adulterated. 
 The firft of thefe weighing in the 
 Air 5iij, and odd Grains, was found 
 to be irt Proportion to Water of the 
 fame Bulk, as i rJ? to i. Another 
 weighing Ibmewhat lefs than 
 5;iij, was to the Weight of an equal 
 Bulk of Water, as i Ho to 1. 1 might 
 add divers other Inftances of the 
 like Import ; and tho I think them 
 not neceflary,yet I fhall fubjoyn One 
 more, becaufe 'tis afforded by a Be- 
 z^oAr (tone, taken out of another of 
 
 the 
 
An ESSAY. 3? 
 
 the fame kind : This Kernel- ftone, if 
 I may fb call it, being Weighed in 
 the Air wanted Nine Grains of ^iij, 
 and its Proportion to Water of the 
 fame Magnitude, was found to be as 
 that of I Kt to I. In all which In- 
 ftanees, we may oblerve, that thcfe 
 Animal Stones not amounting to 
 twice the Weight of Water equal to 
 them in Bulk, have lefs of fpccifick 
 Gravity, by above a Fifth part, than 
 a true Foflile Stone(ruch as Chry ftal) 
 is wont to be endowed with. 
 
 v;i.;rf 
 
 li-iiiv:)^ 
 
 C H A P. V. 
 
 THE life lately propofed of our' ,p j,^ 
 Hydroftaticar Way of Ex-^^^^^^' 
 ploration, fuggefts to me Another, 
 which may be deduced from it, as a 
 kind of Corollary. ' '^ f ^^\. -''^ 
 
 This comprehends two,' fbmewtiat^ 
 diflPering, Ways of applying the Ob- 
 ftrvations, we have lately tiicntioned. , 
 For firft, we may by the Hydrofta-' 
 
54 Medicim UydrofiiHica: 
 
 ticks be affifted to difcoyer , withij 
 Probability, the referablance, or the j 
 difference that may be between Bo-'j 
 dies of the lime Denomip^tion, Ior 
 that fbme fiibordinate <S^£fie^ of 
 them, may perhaps be diftinguiihed, 
 as well as feveral IfidividuALs of the 
 f^me, orjowermoft, S/w^^ iSince, 
 for Inftance^ we have found ^ nota- 
 ble differpgce between the fpecifick 
 Weights of feveral Loadftpnes, that 
 were dug tip in feveral Gauntries or 
 Mines ; if greater Number and Va- 
 riety of Experiments, of this kind 
 were made, we (liould poifihly find>. 
 tl>at, Ceteris pAnbus, the Loadltones 
 of one Country, or of one Mine, are 
 confiderably heavier tnan Thofe of 
 anotherj.^3, if I miftak^yrot^^Iufu- 
 ' ally oblervedv the N,omf^^W^ cirid 
 the Ea?^///?'. Loadstones r\^pQ^!^div\tt 
 /^cS/^er/fyth^q^^hofe tU^ ^reftid to 
 come out of a warmer ^^giWi^^p'^hy 
 wlioie Ifland of Elba, a{>q^nds:with 
 Mines, wh94*epF: I fav/ ooejptire Mafs,^ 
 that Ijudg^ to weigh agreatmanyV 
 hundfedoll^otihds.Andthi>$cliSerence: 
 
An ESSAY. 3 J 
 
 of Weight between Foffiles of the 
 fame kind(, when Yis confiderable, 
 may be of good ufe to help us to di- 
 ftinguifh between the Stones of the 
 lame lo^yefb Sp€€iej, that are pro- 
 per to diflering Countries or Mines. 
 But, in Cafe the unequal Weight 
 proceeds, as it often ctoes, from an 
 Adventitious Matter, that infinuated 
 it felf into the more genuine Matter 
 of the Foflile, whilft 'twas Fluid or 
 Soft, it may much aflift us to guefs 
 at thegreater or leffer Purity of Ho- 
 mogeneoufneft of the Foffile propo,- 
 fed ; which Difeovery may, on dir 
 vers occafions, be of no fmall ufe to 
 the Phyfician, the Jeweller^ or tlie 
 Naturalift. 
 
 "^^ ^ ' ' }] .. f ^:; -- 
 
 C H A P- VL 
 
 BUT the Second thing compri- .^ ^y. 
 ted in our Cor/oUrj, may in^^^^^* 
 divers Cafes be of much greater Uci« 
 lity and Importance, as being very 
 D 3f P^op^^ 
 
j6 MedkirtA Hydroflatica : 
 
 proper to help us todifeern genuine 
 Stones, whether Animal or Mineral, 
 from counterfeit Ones 5 which too 
 often pafs for true, to the great pre- 
 judice of PhyficiansandPatientSjand 
 the great Lofs of Lapidarie\'aind their 
 Cuftomers.For as there are few Qua- 
 lities appertaining to ponderable Bo- 
 dies here below, that are ib radi» 
 catedj, (if I may Co fpeak) as their 
 Ponderofiry is. So there is fcarce 
 any Quality, wherein 'tis fb difficult 
 for Impofiorsy to make a notable Al- 
 teration unperceivedly, asthefpeci- 
 fick Gravity. I laid, for Impojlors ; 
 becaufe,fAf?' in feveral Cafes, 'tis not 
 fb very difficult, to alter the fpeci- 
 fick Weight belonging to this or 
 that, kind of Bodies ; yet in thofc ve- 
 ry Cafes, it may be exceeding diffi- 
 cult, and perhaps impraQible, to 
 , make a confiderable Change in that 
 Quality, but by fuch Additions, or 
 Operations, as will make a fenfible 
 Change in Tome other Qiialities too, 
 and thereby expofe the Fallacy to be 
 .difcovered. And this will efj:>ecially. 
 
 prove 
 
An E S S A Y. 37 
 
 prove difficult in many Cafes to vul- 
 gar Cheats, and Counterfeiters, or 
 Adulterators of Gems, and other var 
 luable Minerals ; becaufe the little 
 knowledge they have of the Nume*- 
 roufnefs, and Variety, of Natural and 
 Artificial Produftipns, confines them 
 to a fmall Number and Diverficy of 
 Means, to aceomplifh their fradulent 
 Defigns. And whilft they are in- 
 tent, but upon counterfeiting th^ 
 more obvious Qualities of tfengs ; 
 and perhaps of eluding the known 
 and vulgar Tryals Men are wont to 
 acquiefee in ; rhey are not like to take 
 Care to maintain the fpecifick Gra- 
 vity, and fecure their adulterated 
 Wares,againfl:an Hydrofliatical Way 
 of Examen^ which, probably, they 
 never fo much as heard of. By this 
 means, feveral Peris, for Inftance^ 
 may be difcovered to be Counter^ 
 terfeit, without, in the leaft, injuring 
 them. And I remember^ That fome 
 faftitious Corals, that, for Divertife- 
 ment , I made, to fiiew what mighe 
 hp done in that kind ; were^ notwith- 
 P 3 itandin^ 
 
g^ Mtdicina Hydrofiatica, : 
 
 Ending their fine Colour, Shape, 
 and Gloffineft, eafily difcovBtfable , 
 by their having a fpecifick Weigh? 
 toanifeftly exceeding That,which be- 
 longs to natural Corals. 
 
 Before I knew better Ways, I have 
 fometimesjfor Recreation,by the help 
 'of Mimum made Paftes, or faftitious 
 Gems, which, tho' tranfparent, and 
 finely enough coloured, yet, becaufe 
 they contained Ibme vitrified Lead, 
 added to the other Ingredients to pro- 
 mote the Fufion,were liable to be de-- 
 tefted by an eafie HydroftaticalTryal 
 of their Ponderofity. I have likewife 
 it^n 2ii2iiT ^ezoar Stone, that (b re- 
 fembled a genuine Stone, That a 
 great Price -was fet upon it. But be- 
 ing brought, me to be judged of, I 
 made little doubt of its being Coun- 
 terfeit, by rea(bn of its appearing to 
 me as heavy ^s a Mineral Stone of 
 that Bulk;tho' the PoffelTor being loth 
 to expo!^ it to an uncommon Tryal,! 
 could not (b cogently evince, that I 
 had a clear Reafbn to difadvile the 
 purchafe of it,' 
 M'^ ' CHAP. 
 
MESS AY. tf 
 
 CHAP. VII. 
 
 AFter thelelnftances, (which are 
 not the only, that might be al- ^^ ^* 
 ledged of this kind) the affinity of 
 the Subje£is invites me to take notice 
 • of another Life, orj at leaft, a Varia- 
 tion of the former, which may be 
 made of our Hydroftatical Way of 
 examining Solids. For it may, on di- 
 vers occafions, affift us, to make pro- 
 bable Eftimates of the Genuinenefs, 
 or the degree of Purity of feveral Bo- 
 dies, that are, or may, ufefully be 
 imployed in Phyfick; tho' they be 
 not Stones or Minerals, provided they 
 be heavy enough to fink in Water, 
 For when we have once found the 
 fpecifick Gravity of a Concretion of 
 this fort, that we know to be Ge- 
 nuine, and well-conditioned in its 
 kind ; this degree of Ponderoufnefs 
 may ferve us for a kind of Standard, 
 P 4 where,. 
 
-<4^ Medicind H/drpflatica : 
 
 whereby to judge of others, of the 
 fame Denominarion, or that are faid 
 to be of a Hke Nature. 
 
 To illuftrate a Remark, tfcat has 
 no more of Difficulty in it than This, 
 fewer Inftances will fuffice, (if any 
 be neceffary^ than you will meet 
 with in the following Part of this 
 Traft, wherein they will opportune- 
 ly occur. And therefore, inftead of 
 , letting them down in this place^ I 
 choofe to give you an Ad vertifetnent, 
 that would furprize you, if I had not 
 formerly hinted ibmewhat, ^pplia- 
 ble to the fame purpole, by no great 
 Variation. For that which I am a- 
 bout to obferve ;o you, is, That, I 
 think, there Iheuld be made a great 
 difference between the Eftimate, that 
 Men make of feme Stones, to which 
 the Shops give the Name of Gems, 
 according as the Eftimate is to be 
 made by Jewellers and Goldfmiths, 
 or by Phyfjcians and Chymifts. For 
 the Tradefinen, who dfiially aim but 
 at the Beauty and Luftre of the Gems 
 they would Sell, may juftly efteem 
 
 thofe 
 
An ESS AY. 41 
 
 thofe C£teru pAribus the beft, tliat 
 are in Speck the lighted, becaufe fuch 
 are generally more uniform as to 
 Senfe , and more Tranfparent ; and 
 alfo, receive their Colour from Pig- 
 ments of finer Parts. Button the con- 
 trary ,thofe, that in Gems feek main- 
 ly, if not only, for the Medicinal Vir- 
 tues ; may juftly value Thofe moft, 
 that are moft Ponderous : as having 
 more plentiful Portions of the Me- 
 tallick , or Mineral, Subftances, 
 whence the greateft part of their 
 Virtues i% as has been formerly no- 
 ted,in Probability,to be derived.And 
 this difference in fpecifick Weight, 
 in Stones that have the fame Name 
 given them, I foretimes found to be 
 far greater, than one that has not 
 try'd it would imagine, as may ap- 
 pear by Ibme Inftances, applicable to 
 this Argument, that will hereafter be 
 met with. But yet, I would not 
 hence infer, that even (uch Stones, 
 whether tranfparent or not, as ap- 
 pear fine, and are but light in their 
 kind, muft be devoid of Particle^, 
 
 whether 
 
42 Medkisa Hydrofiatica : 
 
 wheriier Metalline, or of kinto them, 
 whence they may be endowed with 
 confiderable Medicinal Virtues* > For 
 there are Mineral Pigments of fo fub- 
 tle a Nature, that folmall a Quantity 
 asw^ill fcarce make them feafibly 
 "heavier than Gems that are lefs, or 
 perhaps not at all coloured, may be 
 diffufed through the whole Matter ; 
 and,at leaft,impregnate every fenfible 
 part of it : This I fhall Illuftrate by 
 the following Experiment, devifed 
 for that purpofe. 
 
 Five Grains of powdered Zjpbora^ 
 being mixed with |j xfi of finely 
 powdered Venice Glafs, and kept a 
 full liourinFufion in a Furnace, that 
 gives an exceeding violent Fire, af^ 
 forded a tranfparent Mafs, that was 
 throughout of a fine blew Colour, 
 and that deep enough ; fo that one 
 part of the Pigment (ufficed to tinge, 
 by Fufion, above an hundred parts of 
 the Glafs : And when for Curioficy, 
 we made the Proportion of the ^- 
 fhora. a little greater, taking Eight 
 Grains of the Pigment tq |j of Glafs, 
 
An ESSAY. 43 
 
 that is, One to fixty ; the Mixture ha- 
 ving b^en kept for the like time in 
 ftrongFufion, the Mafs was fo dee-ply 
 poloured, that the Proportion of the 
 Tinging ftuffe to the reft of the Wa- 
 ter, appeared too great to make a 
 handfome Gem, 
 
 And further to manifeft, that a 
 Quantity of Metalline Matter, tho' 
 it be but very fmall, may luffice to 
 give a Tinfture, and fo to impart a 
 Virtue to a Glafly Body, and even to 
 Gems ; Ifhall addanExperiment,that 
 perhaps you will think fbmewhat 
 ftrange. I had long conjeftur'd, that 
 there was in Granats , efpecially in 
 fbme that were deeply coloured, pret- 
 ty ftore of Metalline Corpufcles of a 
 Martial Nature, and that thofe Cor- 
 fnfcles are more than fufficient for the 
 Grahate it felf, into whole Compofi- 
 tion they enter, tho' not vifibly, be- 
 caufe of their exrream Minutenels.Up- 
 on this fuppofition, I took a Bohemia,xi^ 
 or rather German fir anate^^ioxln^vot 
 faw any Bohemian fb large) that I 
 had kept by me for a Rarity, becaufe 
 
 9i 
 
44 Mediciti4 Hj/droftaticA : 
 
 of its Bigncfs and deep Colour, tho 
 it was not a fine Stone to look on, 
 notwithftahding its being tranfpa- 
 rent in thofe Edges that were thin. 
 This being reduced to very fine Pow- 
 der (but not in an Irofl Mortar, left 
 fhould take fbmthing from the Metal) 
 we exaQly mixt Eight Grains with an 
 Ounce of finely pulverized Chryftai- 
 line Glafs s afterwards the Mixture 
 was kept two hours in a Furnace, that 
 gives a ftronger Fire than ordinary 
 Wind- Furnaces, by which means we 
 obtained, as lexpefted, a pretty uni- 
 form Mafs tinged of a fuflBciently 
 green Colour, fuch as prepared Iron, 
 or Steel, gives to pure Glafs. 
 
 CHAP. YIII. 
 
 T 71 7Hat has been hitherto deli- 
 V \ vered, may ferve to fhew, 
 in fbme meafurc, the Ufes of our 
 Hydroftatical Way of examining 
 Drugs, upon a Suppofirion that they 
 are Solid,and neither very minute,nor 
 too light to fink in Water. But I 
 muft not forbear to cpnfefs,and even 
 
 givQ 
 
An E S S A Y. 45 
 
 giVe Nbtice , that there are many 
 Simples, and other ponderable Sub- 
 ftancesjthat may , upon good Grounds, 
 be laid to belong to the Materia Me- 
 diea ; which yet want One, or More, 
 of the newly exprefled Conditions. 
 Wherefore I muft not conceal, that 
 there are Three things, which, tho* 
 not neceflfary to the Underftanding 
 of the Uiefulnefs of the foregoing 
 Partof this Difcourfe; may, if they 
 can be performed, miich conduce to 
 Facilitate ffor I dare not fay,to Com- 
 pleat) the Hydroftatical Way of exa- 
 mining Bodies, heavier //? Specie i\\2in 
 Water. And therefore, tho' I con- 
 fefi it noeafie Task to Iiirmount the 
 Difficulties to be met with in this 
 Attempt; yet I fhall endeavour to 
 leffen them as much as lean, by offer- 
 ing to you the Expedients, that I was 
 w^ont formerly to make ule of in the 
 1 hree C^fes, I a,m about to mention : 
 Namely, F/>/?, When the Body to be 
 examined was Liquid, and conft- 
 quently, I could not be immediately 
 taken hold of by an Horfe hair, or 
 
 any 
 
ifi Medicina, Hydrqfiatka : 
 
 any other flender String. Secondly^ 
 When the Body propbfed was. either 
 in the Form of Powder, or confifted 
 of Fragments that were fo finally that 
 it *twas not poflible , or, at leaft, not 
 fit, to fatten each of them to an Hair \ 
 and fiifpend it after the manner of 
 a Body of a greater Bulk. And^ 
 Ihirdly, When the Solid to be Hy* 
 droftatically examined, though great 
 enough in Bulk tobe tyed about, was 
 diflbluble in Water; and confequent 
 ly unfit to be weighed in that Medi- 
 um: Since therein its Gravity muft 
 continually decreafe, whilft the Ope- 
 ration was performing. 
 
 As to the Eirft of the Three Diffi- 
 culties ; lately mentioned, Ifuppole, 
 I need not fblicitoufly premife, that 
 the Liquid Subffance, to be Hydro* 
 ftatically examin'd , ought to be 
 heavier in Sptcie^ th^n the Water^ 
 or other Fluid, 'tis to be weighed in ; 
 and of fuch a Nature, as not to be 
 apt(at leaftjfpeedilyy' to mingle it felf 
 with it: fince, otherwife, the pro- 
 pofed Liquor will either emerge in 
 
 that 
 
An ESSAY. 47 
 
 that it fhould be weighed in, or elfe,;, 
 be confounded with it^ and fo tct' - 
 tain no diftinft Maft, or Gravity. 
 
 Suppofing then, that the Liquor, 
 to be examined, has belonging to it 
 the Two newly recited Conditions, 
 we made ufc of this Expedient to » 
 explore its fpedfick Weighr. We 
 took a fmall Jar, or wide-mouthed 
 GiafSjCapable of containing an Ounce 
 or two of common Water,and weigh- 
 ing in the Air about. Three or four 
 Drams (more or left, as occafion re^^y 
 quires*) This Glafs, which, forBre* 
 vities fake, we ar-e woqt to call Hy- 
 dro&atical, or elle Glals-Buckec ; we 
 weigh very carefuMy once for all, 
 firftin theAir, and then in the Wa- 
 ter,, , and by the difference of ' the 
 Weights we find^ according to. the 
 knowA Hydroftagcal Method, a 
 Weigbf eqjuivalentitp- That of the 
 Subfence of the Gkls in Water ; (b 
 that fijch a Weight; being put into 
 the oppofite Scale of the Ballance, 
 the VefTel hanging under the Sur-^ 
 face of the Water, may. be conftr.' 
 
 dered 
 
4S MediciWa Hydrsftattu: 
 
 dered as having no Weight at all, 
 that is, no Praeponderancy. And con- 
 fequently, the Weight of a Body 
 contained in this Bucket may be 
 looked upon, as That of the Body it 
 felf in Water, without being increa-» 
 fed by that of the Veffel ; fo that, in 
 our Inftance , . the Bucket makes a 
 Mafs of Qijick-filver, tho' Fluid, as 
 ponderable as if 'twere coagulated 
 into a Solid Body. 
 
 The Glafs-Bucket being thus pro- 
 vided once for all, weputthepropo- 
 fed Mercury into it, and weigh them 
 together in the Air 5 whence dedu- 
 cing the already known Weight of 
 the Veffel it felf in the Air, the Re- 
 fidue gives the Weight of the 
 Quick-filver alone in tht Air. Th's 
 done, by the help of an Horfe- 
 hair, we tye the Bucket to one of; 
 the Scales, (or to cither end of the" 
 Beam,)and letting it,with the Quick- 
 filver in it, flowly fink intoaGlals, 
 or other Veffel, competently full of 
 fair Water, and hang lb, that the 
 Bucket may not any where touch, 
 -' either 
 
An E S S A V. 4^ 
 
 either the bottom, or the fides of the 
 larger Veflel ; we reduce by Weights, 
 put into the oppofite Scale, and ad- 
 ded to the formerly mentioned Coun- 
 terpoife of the Bucket in the Water, 
 the Ballance to an exa£t jEquilibriumy 
 without raifing the Bucket quite to 
 the Surface of the Water ; this new- 
 ly obtained Weight, of the immerft 
 Qyick-filver , being deduced from 
 its Weight in the Air, 'tis eafie, by 
 the known Hydroftatical Method, to 
 obtain the Proportion in Gravity, be- 
 tween the given Mercurj , and an 
 equal Bulk of Water. 
 
 To expedite this Operation ^ it 
 may be convenient to have in rea- 
 dinefs (as I was wont to do,)a couple 
 of Weights, of Lead, or Tin; the 
 greater exaftly equal to the Weighn 
 of the Glafs-Bucket in the Air, and 
 the other equal to the Weight of the 
 fame Bucket in Water. For,by keep- 
 ing thefe two Weights conftantly in 
 rcadinefs, One has at hand a Coun- 
 terpoile of the Veffel, in which foe- 
 ver of the two Medium^ 'tis employ 'd 
 E ins 
 
■JO Medkmt Hydroftatica : 
 
 in 5 which favesthem, that have fre- 
 quent occafion to ufe the Ballance, 
 much of the time that muft other- 
 wife be fpent to adjuft it. 
 
 This Advertifement being premi- 
 ftd^ the lately propounded Operation 
 will-be beft underftood by an Exam- 
 ple ; w^e took a fmall Glafs-Jar capa- 
 ble of holding about ?fs of Water, 
 and put it into one Scale of a ten- 
 der Ballance 5 whofe other Scale we 
 fiirnifhc with a Counterpoile 5 or 
 Weight, equal to the Glafs. Into 
 this little Veifel, we then put §1, 
 that is, Four hundred and eighty 
 Grains of Mtrcury (afRrm'd to be 
 Spa?^tjh^\v\\\Qh is counted thericheft) 
 and the Glafs with this Mercury in it, 
 was, by sn Hor(e-hair,made to hang 
 from one of the Scales, into a deep 
 Giafs Veifel of Water. Whillt it was 
 in that ftate, there ^was in the op- 
 pofire Scale a Counterpoile to the 
 Glafs it felf in the Water, fo that 
 the Drams and Grains^ that 'twas re- 
 q-uifite to add, gave us the Weight 
 6fthe Qgick-filveronly, the Weight 
 
 of 
 
An ESSAY. 51 
 
 of the Clafs, being already accoun- 
 ted for. But Care was firft taken, 
 that the open-mouth'd Veffel ihould 
 be every where environed with Wa- 
 ter, and diligently freed from adhe- 
 rent Bubbles ; and that a piece of 
 Horfe-hair fhould be added to the 
 Counterpoife , to compenfate thac 
 part of the String or Hair eyed a- 
 bout the Bucket, that was in the 
 Air, intercepted between the Scale, 
 it was fattened to, and the Surface 
 of the Water. By this means, we 
 found the Weight of theQuick-filver 
 in that Liquor, to amount to 446 
 Grains , which being fubftrafted 
 from the Weight of the Quick-filver 
 in the Air, the diflFerence was 54 
 Grains, by which the greater Num- 
 ber being divided, the Quotient was 
 14 and about T,-. So that the Mer* 
 cury, imploy'd in this Operation, ap- 
 peared to be in Gravity to Water of 
 the fame Bulk^ as 14 v«o to i . I fa id, 
 iht Mercury imployed in this Opera- 
 tion, becaufe, in former Tryals, I 
 Icarce found common Quick-lilver, 
 E 2 tliar 
 
52 Medkha Hydrofldtiaii 
 
 that was bought in Shops, to weigh 
 full Fourteen times, and Ibmetimes 
 fearce i j and \ as much as a Bulk of 
 Water equal to it ; whether the 
 Ponderoufhefs of our laft uled Mer- 
 cury proceeded from hence ; thsity as 
 (brae Chymifts extol Spanijh Mercu- 
 ry, as participating more than o- 
 thers of a Golden Nature, (which O- 
 pinion, a Tryal , that I purpofely 
 made of That imploy'd about the 
 late Experiment, did not disfavour '-,) 
 So, there M^as in this of Ours fbme- 
 thing of jLinfixt Gold, that fome- 
 what increafed its Weight 5 I leave 
 to further Enquiry. 
 
 If you can command, as lean- 
 not, the Learned Ghetaldmh Archie 
 medts Promotiis \ Since, as lam in- 
 formed, I-k there fets down the in- 
 tenfive Weight of Qaick-filver Hy- 
 droftatically found ; it may be worth 
 your while to confulc that fearce 
 Bookj and compare the things you ■ 
 may meet with there, relating to 
 Qiiick-filver, with what I have now 
 delivered. To which I fliall add^ 
 
 That' 
 
 I 
 
An ESSAY, ^j 
 
 That this I may here give you No- 
 tice of in general ; That, having on 
 Chymical and other Accounts, had" 
 more occafion than mod Men, to 
 make Tryals of this fort, I did not 
 find all running Mercuries; tho' they 
 did not appear adulterated, to be pre- 
 cifely of the lame Weight.: Nay, 
 even deftilled Mercuries, if once 
 combiri'd with Metalline Bodies, and 
 particularly, if they were animated, 
 and drawn from fine Gold ; I found 
 to differ more from common Mercu- 
 ries fold in Shops, than Thefe did 
 from one another ; and even between 
 common Mercuries , notwithftand- 
 ing their having been Deftilled, we 
 found a notable Difparity. But to 
 inlarge on this Subjeft, were impro- 
 per in this Place, where I mentioned 
 the Weight of Mercury : But to give 
 focIear(tho' butfingle)anlnftance of 
 the Way of nicafuring the Weight of 
 ponderous Liquid Bodies in Water, as 
 may warrant me to Oiy; That, by 
 this Method;tho' not always w^ith the 
 fame eafe, we may explore the fpe- 
 E 3 cificic 
 
j^ Mtdicina Hydrofiatica, : 
 
 cifick Weight of other Liquors, that 
 are in equal Bulk heavier than Water, 
 
 , and yet are indifpofed to mingle with 
 it ^ fuch as are the Chymical Oyls of 
 Ginnamonj Clow ^%^Gua]acumjUc, But 
 
 , the chief.thing, that has made me the 
 the more Circumftantial in deliver- 
 ing the foregoing Experiment, was, 
 that this prafbical Direction, for 
 weighing one Liquor in another, 
 will hereafter appear to be applia- 
 ble to ufeful Purpofes, efpecially 
 when w^e come to mention, in the 
 following Chapters, feveral Cafes, 
 wherein Liquors of a Nature very 
 different from Water,may be fubftitu- 
 ted in its ftead. 
 
 CHAP. IX. 
 
 AS for the Way of Examining 
 Hydroftatieally the Powders of 
 finking Bodies, fuch as Minium^ Put' 
 tie^ &c, or fuch fmali Solids, or Frag- 
 ments of greater Ones, as by reafon 
 
 of 
 
An E S S A Y. yj 
 
 of their Littlenefs or inconvenient 
 Sliape,are/-^^/y unfit to be tyed with 
 an Horle-hair totheBallance ; as the 
 Fragments of Rubies, and other pre- 
 cious Stones, wont to be fold by 
 Weight at the Drugfters or Apothe- 
 caries Shops : the Way of difcovering 
 the Weight of thefe in Water, dif- 
 fers not' much from That lately de- 
 livered of weighing Qiiick-filver in 
 that Liquor. For on thefe occafions 
 alio, we imploy fuch aGIafs-Bucket^ 
 as was lately defcribed ; and having 
 made it very dry, as well within, as 
 without; We put into it the Metal- 
 line Calx^ or other heavy Powder, or 
 •a convenient Qi^iantity of the Frag- 
 ments of Gems , or a competent 
 Number of fmall, tho' intire, Bodies, 
 as Pieces of Native Cinnabar^ Seed- 
 p^^arl^ &c. and proceed with thefe, as 
 we did with Quick filver. Oaly 
 this Caution is to be hee^dfully takea 
 along, that we warily, and little by 
 little, put into the Bucket,^vhilft 'tis 
 yet kept in the Air, and hath the 
 already weighed Powder, or Frag- 
 E 4 me Its 
 
5 5 Medicine HydroJlaticA : 
 
 ments in it, a convenient Quantity'of 
 the fame Water, 'tis to be weighed 
 in ; that the Liquor naay have time 
 to infinuate it felf between the dry 
 Bodies, andeven theC^^'^^yr/e/of the 
 Powders, and expel thence the Air, 
 that was harbored in the Intervals 
 betwixt them 5 which little Aerial 
 Portions, if not thus feafonably ex- 
 pelled,would, upon the immerfion of 
 the Veffel, produce in the Water ftore 
 of Bubbles, that would buoy up, or 
 faften themfel ves to the Fragments,or 
 other fmall Bodies, and make the Ex- 
 , periment uncertain,or fallacious. And 
 if it be a Powder^ that is to be 
 weighed ; unlefs it be before hand 
 throughly wetted, and thereby freed 
 from Jerul Particles, and reduced to 
 a kind of Mud ^ there rs Danger, that 
 fome dry Coypufcles of the Powder, 
 will , when the Veffel is under Wa- 
 ter, be buoyM up, and get out of it, 
 and, floating on the Surface of the 
 incumbent Water, take off from the 
 true Weight, that the immerft Pow- 
 der (hould have in that Liquor. i 
 
 If 
 
AnESSAY. ^7 
 
 If this Way of examining Bodies 
 be carefully imployed by a dextrous 
 Man, furnifhed with a tender Bal- 
 lance, it may be of confiderable ule, 
 not only to Phyficians, Druggifts, 
 and Apothecaries, that are conver- 
 fant with the more precious Kinds, 
 of finking Bodies, that belong to the 
 Materia Medica ; but alfo to Lapida- 
 ries, and Gold- finiths, whom it much 
 concerns not to be impofed upon by 
 counterfeit Gems, or by other Stones 
 of price, that are not duly conditi- 
 oned, in their kind. Thus the Frag- 
 ments of the Five frecious Stones, 
 That (upon what grounds, I now 
 inquire not,) are made Ingredients 
 of feme Noble Compofitipns, asCt?;/- 
 feci to Hyacinthi^ &c. thefe Fragments, 
 I fay, may each fort of them apart 
 be ufefuUy examined by their Weight 
 in Water, by him that knows the 
 true fpecifick Gravity of a parcel of 
 the fined:, or elfe of fuch as he jud- 
 ges to be fitteft for his purpofe. And, 
 to add That upon the By, whereas 
 Gradates are reckoned among the 
 
 Five 
 
J 8 Medici m HydroJlaticA : 
 
 Five Medicinal precious Stones, and 
 in fbme Pharmacopcea^s are preferrM 
 to the Firft place,as the beft ; I have 
 found fo great a difference, in point 
 of Ponderofity, between European 
 Gradates and American Ones, whereof 
 fbme were fent me as a Prefent from 
 New Eitgland^ and others, I my felf 
 pickt plentifully enough out of an 
 odd American Mineral, that I fufpe- 
 fted to contain them;that it was very 
 obvious to think, their Virtues might 
 be very different, if not as to K/W, 
 yet,at leafl:,asto Degrees: knd not only 
 luch fadlitious Pearls as have delu- 
 ded many, and Ibmetimes even fa- 
 mous, JewelIers,(asoneofthemlelves, 
 that was Lapidary to a great Mo- 
 narch, confefled to me) may often- 
 times by this Expedient be difco- 
 vered, efpecially if Mercury (tho' 
 difguis'd) be imployM in making 
 them ; hut^wt may probably by the 
 fame Method difcriminate the natu- 
 ral Pearls of feveral Countries and 
 Sorcs,whereof I have feen a far grea- 
 ter difference than one would cxpeft ; 
 
 and 
 
An E S S A Y. 59 
 
 and I have fbmewhere yet by me na- 
 tural Pearlsoffuch various Coloursjas 
 well as Shapes^ as have fbmewhat 
 furprizcd even the Curious, But 
 becaufe it more concerns Phyficians 
 and Patients, to be able to make Efti- 
 mates of Seed Pearl, that are on ma- 
 ny occafions of good ufe to healthy 
 than to know the Genuinenels of 
 thofe bigger Ones, that are feldom 
 made ufe of, but for Ornament ; I 
 fhall here mention the refult of an 
 Experiment, which I find among my 
 old Notes, to have been made by me, 
 when I was furnifhed with very fine 
 Oriental Seed-Pearls. For having 
 examined thefe by the Way, we are 
 now difcourfing of, as judging them 
 Orient enough to be fit to be Pat- 
 terns, wherewith to compare Others ; 
 we found thefe to Water of the 
 fame Bulk, 2 U^ (L e. |J to i. 
 
 But in This, and in thofe other 
 Tryals, whofe Difficulty, or Impor- 
 tanee, require, that we make them 
 as exaftly, as we are able. I muft 
 advertife you, that'tisnotfittotrufl 
 
 to 
 
6o Medicha Hjdroftatka : 
 
 to the Steddinefs of your hand, in 
 holding the Ballance, but that you 
 make ufe of a Gibber, (as they call 
 it,) or fome other ftable Proptofup- 
 port it. For the Hand often fhakes, 
 and makes the Inftrument that it 
 holds, to do fb : and oftner grows 
 weary before the Scales have had tinte 
 to play up and down, and at, length 
 fettle in a determinate Scituation ; 
 wherein if you mils of atrueyfig^a/- 
 lihrium^ the Hand muft undergo a 
 new Pennance : Whereas, when the 
 Ballance hangs on a ftable Fulcrum ^ 
 you have both your Hands to help 
 you, and need not be tempted by 
 Wearinefs to defift, before the Bal- 
 lance be brought to reft in a per- 
 fe£t JEqutlihrmm. The Neglefl or 
 Omiffion of this Praftice, I take to 
 be one main Reafon, (for the want 
 of good Ballances, or of Skill to ufe 
 them, is oftentimes Another) why fo 
 many of the Experiments, that re- 
 quire weighing, are Er/oneous"; as 
 tliey that cautioufly examine them 
 (as I have fometimes had occafion to 
 
 do) 
 
♦ An ESSAY. 6t 
 
 do) may eafily find. And therefore, 
 (to add That, upon the By,) I hope, 
 you will not make hafte to cenfure 
 the Accounts I give of Hydroftatical 
 Tryals, becaufe they do not always 
 agree withThofe of other Mensifince 
 perhaps they did not imploy, either 
 more Diligence , or better Inftru- 
 ments, thanl. 
 
 C H A P. X. 
 
 THe laft of tlie Three Cafes, for- 
 merly mentioned: Namely, 
 What is to be done^ tvhm the Body to 
 be Hydrofiatically examined^ will dif~ 
 folve in Water, or eajily mingle with it <* 
 Imports a Queftion,difficult and trou- 
 blefome enough to be refolved. Nqt 
 can this Examen be performed by a 
 fingie Operation, which yet fufficed 
 in each of the Two foregoing Cafes. 
 And having leriouQy oonfidered the 
 Matter, the beft Expedient I could 
 then think of was, That, which di- 
 vers 
 
6 2 Medicina Hydrojlaticaf 
 
 vers years ago, I propounded in an 
 Affembly of the Royal Society, and 
 grounded on this Refleftion, That 
 tho' the Body propofed could not be 
 immediately weighed in Water, yet 
 we may fubftitute another Liquor 
 that will not diffolve it, and there- 
 by inveftigate the fpecifick Gravity, 
 in reference to that Medium ; and 
 then, by comparing the difference of 
 thofe Two Liquors in point of Gra- 
 vity, One may come to difcover, 
 . What the Body propofed would have 
 weighed in Water, in cafe it could 
 have been kept there a competent 
 time, without having any part of it 
 diffolved. Confidering then, that, 
 except Quick-filver, the vifible Fluids 
 we can command, are either of an 
 Jqaecu^f or of an Oily^ Nature ; and 
 that moft Bodies, whereof we can 
 make Solutions in Liquors of the for- 
 mer, will not (atleaftjfenfibly) fuf- 
 fer themfelves to be diffolved by 
 thofe of the later. Kind, whilfl: a pro- 
 pofed Solid is weighing in them : We 
 prefum'd that the moft Saline Bodies, 
 
 fucU 
 
An ESSAY. 6^ 
 
 fuch as AUum^ Vitriol^ SalGtm, to 
 which may be added, Borax ^ SM'u 
 mate, &c. might be commodioufly 
 weighed in 0/e^^ Liquors. Among • 
 theft I made choice of Oil of Tur^ 
 ^mtine^ rather than Oil-O/z-z/e, or 
 any Chymical Eflential Oil: Partly^ 
 becaufe, being of common ufe, 'tis to 
 be procured in fufficient Quantity, 
 and, being very cheap, is (eldom a- 
 dulterated) as Chymical Oils are too 
 often found to be ; and, partly^ be- 
 caufe being a diftilled Body, it may 
 be prefumed to be free from Ag^ucoh^s 
 Parts , of v/hich Experience has 
 fhewn me, that common exprelTed 
 Oil is far from being deftitute : 
 But becaufe Two Liquors, that are 
 indeed both of them Oils, are wont 
 to have diftinfl: Names given them 
 in the Shops ; I fliall here intimate, 
 that I do not , when I have my 
 Choice, make ufe of that which 
 many call the 0/7 of Turfentim^ but 
 of That which firft comes over,which 
 thofe that diftinguifli them, call the 
 Sfir'n of Turpentine : I prefer This, 
 
6^ McdicwA HydrofiaticAi 
 
 (I fay,) becaule 'tis clear, almofl: like 
 fair Water 5 whereas, That which is 
 called theO/7,befides that 'tis lefsFluid, 
 is commonly of a Yellow Colour, ^ 
 which does leflen its Tranfparency, 
 and may be compounded with fome 
 of the coloured Bodies to be weighed 
 in it. 
 
 There are many Perfbns, that 
 would find it very dijficult^ and to 
 whom, on moft occafions, 'twill not 
 be necejfary ^to know the determinate 
 Proportion in Gravity, between Oil 
 of Turpentine^ and the Solid that is 
 weighed in it ; and to difcoverjby the 
 help of that Gravity, what the Bo-- 
 dy propofed would weigh in Water, 
 in cafe it could be kept for a com- 
 petent time in that Medium^ with- 
 out having any part of it diffolved 
 therein. And therefore, T/^^', if you 
 defire it, I fhall, God permitting, an- 
 nex the Method of performing this 
 Task (which, you know, requires 
 more Calculation, than every com- 
 mon Reader is able to go thorow, 
 with) to the ead of this f raft: Tet^\ 
 
 for J 
 
An E S S A Y- 6 j 
 
 for the prefent it may perhap^be fuffi- 
 cient, as well as fit, that I give you 
 notice, that thofe, that have not Skill 
 enough to determine, by the Hydro-, 
 ftaticks, the Proportion between fink- 
 ing Solids, and the Liquor they are 
 weighed in 5 may yet be aflifted by 
 what we have delivered about 0;/ 
 of Turpentine^ to make a not, unufe- 
 ful Eftimate, What is the fpecifick 
 Gravity of divers BodieSj in reference 
 to others of the fame, or a differing. 
 Species y and by that means, to make 
 a probable Guefs, Whether or no it 
 be rightly Conditioned 5 if he be but 
 provided with one piece of the Body, 
 wliich he knows to be Genuine or 
 well qualified. For This may ferve 
 him as a Standard, whereby to exa- 
 mine other Bodies of the (arae De- 
 nomination, that he may have occa- 
 fion to Purcha(c, or to Sell, or to 
 Imploy. As, fuppofe a Trades-aian be 
 to buy a parcel of Sublimate, he may 
 take an Ounce, for infl:ance,or halfan 
 Ounce of fbme of That he knows to be 
 goodorright^ made: Then having 
 F ' c-arefully 
 
6S Medicim Hjdrojfdtica : 
 
 carefullyiweighed it in OiloiTurpen^ 
 twe^ and fee down how much it- 
 weighs therein; if he' takes an^* 
 Ounce, or half an Ounce of the Sub-' 
 limate, he would make Tryal of, he 
 may weigh that, as he did the other, 
 in the fame Liquor, whereVn if it' 
 give the fame Weight with the 
 Standard, ^is a good Sign ; but if it 
 weighs not To much, *tis a Sign that' 
 it has not its full or due Proportion 
 oiMercHry^'dindi too great a Proportion 
 of Salts, whence its comparative 
 Lightnefs proceeds. The fame 
 Way of trying may be madeufe of, 
 for the Examen of Mercurius DnlciSj 
 and divers other Bodies, totally or 
 partlyjdiffoluble in Water,as o^Allurn^ 
 which is often Sophifticated with 
 fbmebafer Salt, and oi Roman Vitriol^ 
 which is fprnetimes either counter* 
 feited, or adulterated by the help of 
 Roch Allum^ and a Tinflure of Copper. 
 And according as the Weight inOyI 
 of the Body p.ropofed, recedes more 
 orlefs from the Weight of the Stan- 
 dard, fo the Adulteration may be 
 probabfy conc'uJed to be lefleror 
 greater. CHAP* 
 
An ESSAY. ^j 
 
 CHAP. XI. 
 
 Bpfore I gooff from thisSubje£t, 
 ! 'tis fit that I give you notice, 
 that the Hydroftaticks may fupply 
 us with another Way of Eftimating 
 the intenfive Gravity of Bodies, Solid 
 or Fluidy that may on Ibme occafi- 
 ons be of good ufe. The Way I 
 mean is this; we take a folid Body 
 more than heavy enough to fink iri 
 Water^ and carefully obferve, once 
 for all, its Weight in the Air; then 
 we weigh the felf farhe ^olid, firfl: 
 in One of the Liquors we would 
 examine, and then in another ; and 
 fo onwards, if there be more than 
 two : And having noted the diffe- 
 rence between the Solid, and each 
 of the Liquors, 'tiseafie to find, ac- 
 cording to the PraSice elfewhcre 
 delivered, the fpecifick Weight of 
 each; and' ttfi. Proportions betwixt 
 Fa thento 
 
68 MedlclnA HydroftaticAi 
 
 them. And in regard 'tis but OncJ 
 and the fame Solid, that iscompar'd 
 to the differing Liquors ; whatfo- 
 ever their Number be, it will not 
 be difficult, to compare the fpeci- 
 fick Gravities of thofe Liquors be- 
 twixt themfelves, and to difcover 
 by the Weight of the f />/, That of 
 any of the Others that Onepleafes. 
 
 The proposM Way having beea 
 but Summarily delivered, it will 
 not be amifs to fubjoyn Ibme Re- 
 marks relating to it. 
 
 And Firft^ If you intend to im* 
 ploy but One Solid in your Examen 
 of Liquors, 'twill be neceffary you 
 make Choice of fuch an one, ai hatha 
 much greater fpecifick Gravity, than 
 is neceffary to make it fink in WV 
 ter. For there are fome Liquors 
 that are far, perhaps twice, more 
 ponderous than This newly named* 
 Sicordly^ The Body ought to be hea- 
 vy enough to fink in all Liquors but 
 Qyick-filver, (for inThat^none but 
 Gold is ponderous enough to fink.) 
 But if your Tryals are to be made 
 
 upon 
 
An E S S A Y. 69 
 
 ]upon Liquors that belong to ihe Ve- 
 getable, or Animal, Kingdom , the 
 Body you imploy need not be near 
 lb ponderous ; tho' it ought to be 
 more fb than Water, becaule ( as 
 I found by Tryals purpofely made) 
 ibme Liquors, that are very Spiri* 
 tous and Volatile, are yet much Hea- 
 vier m Speck ^ than Water. Tis 
 not very eafie to pitch upon fuch a 
 fingle Solid, as may have all the 
 QuaHties in reference to our Purpo- 
 fes, that may be defired in it, if it be 
 to be made ufe of for a long time. For 
 Thirdly^ Befides that, it ought not 
 to lofe of ks Weight, (and confe- 
 quently to change it,j by the inien- 
 fible A volar ion pf Effluvia^ and that 
 it rniift be, as was frefhly noted, of 
 a confiderable fpecifick Gravity. 
 Fourthly, It ought not to be toobig, 
 or too intenfely heavy, left it be too 
 heavy for a tender Bailance, or re- 
 quire too much Liquor to inviron it. 
 Fifthly, It ought to be of fuch a Tex- 
 ture as not to be diflb] ved,or corroded 
 by any of the feveral Liquors, fome 
 
jit> Medicina 'Hydrofiatica : 
 
 of which may., be ftiarp and ,pierc* 
 ing MenftruuniS^ihdX 'tis to be weight 
 inland thofe tooof differing l^atures. 
 Sixthly^ Itfliouldalfo be. oflfuch ^ 
 Make, as is not eafily lyabje to be 
 broken, or other wife fpoil'd,;tJ^t,it 
 may laft, till all the defigq'(^ %W^' 
 riments, tho' many, be riiade with 
 it. Se^tnthly^ and laftly, 'tis. defira- 
 ble, that it,fhould be of a natural 
 and uniform, as to Senfe, ^and prq* 
 curable Subftance ; th^t the£xperir 
 ments, made with it, may- be eafily 
 enough communicated toOthers,and, 
 if they think fit, tryed over again by 
 them ; and that, if any be judged 
 worthy, they may be tranfcpitt^d to 
 Pofterity. ' jq/a " 
 
 , Several Bodies there are, that I 
 looked upon as more fit than moft 
 Others to be imploy'd about the 
 Tryals, we are treating of The chief 
 of thefe \vtrt'^^rtm(tom,Ha,rdWax^ 
 Ivory, and White Marble, But tho' 
 each of thefe , efpecially if fitly 
 fhaped, may be of ufeon fomepartir 
 cuiar occafions ; yet every one wan- 
 ted 
 
An E S S A Y, , 71 
 
 ted fome of the defirable Qualifi- 
 cations lately mentioned. And there- 
 fore, I made much more ufe of Three 
 other Bodies, not becaufe they were 
 fuch 'as I could Wifh ; but becaufe 
 they were the leaft remote from be- 
 ing fuch, among thofe I could Pro- 
 Cure. The frji of thefe was a piece 
 q[ Jmkr betw;een Three and Four 
 Drams in Weight, of an high Yellow 
 Colour, but very Tranfparent, and 
 of an uniform Texture and conve- 
 nient Shape. This was judged fit 
 to be imployed, when we were toexa- 
 fnine the lighter lor ts of Liquors, fuch 
 as common Water, Rain-water, d^c 
 #ine,Brandy,i:eftified Spirit of Wine- 
 Vinegar, and .the Liquors drawfi 
 from it, Cydar, Beer, Ale, Urine, 
 rriany Waters and Spirits deftilled 
 from. Bodies belonging to the Vege- 
 table, and to the Animal, Kingdom?. 
 But 'tis not proper for the more pon- 
 derous kind of Liquors ; fince'twili 
 not fink to the Bottom, but float at 
 the Top, not only of Ibme Liquors 
 of the Mineral Kingdom, (as will 
 F 4 ere 
 
j2 Medicine Hydrofiatica : 
 
 ere long appear;) but in feyeral 
 Liquors aflTorded us by the Salinq 
 parts of Bodies belonging to th^' 
 Vegetable Kingdom ; ^s you will 
 find within a few Pages. 
 
 The Secoqd Body^ I imployed, was 
 a Qlobular Glafs, which I caufed to 
 be blown at a Lamp, and to be Her- 
 itietically fealed at the Neck, which 
 vyas purpofely made very fhort, af^ 
 ter there had been Lodged in it as 
 much Quick-filver, and np more, a^ 
 we guefled would ferve to fink it in^ 
 any Liquor, except Quick-fih^erj 
 This, by reafbn of its great Bulk, ia 
 reference to its Weight, was fit to 
 ^ifcover Differences in Weight, mi- 
 nute enough between the Liquor? 
 'twas weighed in ; and 'twas opt of 
 Danger of being corroded, even by 
 ^\2ivpMeNjlrui4ms\ and therefore, oq 
 divers occafipns, I preferred this In- 
 fi:rumcnt to apy of j the other Two; 
 but 'tis difadvaritagM by thefe In- 
 conveniencies, that -tis difficult xq 
 be made, or procured, that 'cis harcf 
 to be prefe'rved, being very eafie to 
 
An ESSAY. 75 
 
 t^e broken, and that partly on this 
 /Account, and partly on Others, it 
 can fcarce be a fit Standard in refe- 
 renQe to fucb Obrervatioris, as are 
 to be communicated to Others, and 
 tranfmitted to Poftprity. 
 
 Wherefore for Experiments that arc 
 to be imparted & recorded^, I m|de ufe 
 of a Solid, which //>(?' heavier in Spe- 
 cie than was neceflary to inable one to 
 compare together the lighter forts of 
 Liquors, and to dilcpvprtheir minu- 
 ter Difparities in point of Weight, is 
 yet a natural Standard not fubje£l 
 to be broken without grofi Negli-? 
 genge, nor to be diffolved, or cor^ 
 roded by the Liquors, 'fw^s to bQ 
 immerfl: in , however of various 
 Rinds, and very (harp, and ponde- 
 rous enough to fink iq all of theni, 
 except Quick-filvef, qnd yet not 
 near fb ponderous , as the lighteft 
 Metals, or many Metalline Bodies; 
 this Solid I fpeak of is Rock Chryftal, 
 which I formerly reprefenCed, as for 
 its Purity, Homogeneity, &c. fi? 
 to afford a Meafure, to which other 
 
 Bodies 
 
74 Medicma, Hydrojlatica : 
 
 Bodies may be compar'd in Weight, 
 and by that means' among them- 
 lelves. And of this pure Concrete,we 
 imployed an almoft compleat Globe, 
 (weighing in the Air §ij 3/ Grains 
 5,) fave that it' had in one part o\ 
 it twoTmall Holes near one another^ 
 apd eafily ftopt up with hard Wax^ 
 aft^r there had been put througli 
 them an Horie-hair, by whofe means 
 the Ball was eafily fattened to the 
 Scale from whence 'twas to hang in 
 the Water. The bignefs of this Gld- 
 huUr Body made it the more fittodif^ 
 cover the lefler Differences between 
 Liquors in point of iritenfive Gravity. 
 But becaufe we may have oftentimes 
 occafidn to know the Weight of Li- 
 quors, of which, by reafbn of their 
 Preciotifnefs, or Rarity, we can com- 
 mand but fmall Quantities , as it 
 frequently happens, if. \ve be to try 
 the W^ght of Chymical Oyls, Tia- 
 £tures, Slfences, &c. We thought 
 fitV'fdrVluch Liquors, to provide a 
 piece of Chryftal, fuch as Nature 
 h^^.^5p|ed it, viz. '^lu Hexagonal 
 
.An ESSAY. 7S 
 
 Pr/fmey^y/ith a kind of Pyramide at 
 the qqd^ which is oppofite to the 
 e;}^treai;ii, at which 'twas broken oft' 
 frooi tijie Body, it grew on. For this 
 clear and finely fhaped Chryftal, (or, 
 what Is very near of kin to it, 
 whitQ j^methj'ft^ by reafbn of its ob- 
 long Figure, might be commodioufly 
 weigh'd in lb flender a Cylindrical 
 Glafs, as required but a fmall Quan- 
 tity of Liquor to cover and furround 
 a conveniently fhap'd Body , that 
 weighed, in the Air, but half an 
 Ounce and fixteen Grains. And to ren- 
 der the Obfervacions,made with thefe 
 two Bodies of Medicinal and other Li- 
 quors, (for there are feveral of thefe 
 Tryals, that belong not to this Trafl:) 
 thq more ufeful to Experimenters, I 
 fliall here defire you to take notice 
 once for all, that the Ball of Chry- 
 ftal wa5 to Water of the fame Bulk, 
 as 2 T%v to I or thereabouts ; and the 
 Prifmatical Oblong piece of Chry- 
 ftal was to a Quantity of the fame 
 Liquor, equal to it in Magnitude, 
 as 2U0 to I. 
 
7^ MedicifiA HydroflaticA : 
 
 I have the more particul^f ly deli- 
 vered the Way or explorirtg the 
 Gravity of feveral Liquors with one 
 Solid, becaufe there may be made of 
 it a couple of Applications, that may^ 
 on feveral occafions, be of ufe, not 
 only to Chymifts, Phyficians and 
 Apothecaries, but to divers other 
 Experimenters, that are not of either 
 of their Profeflions. 
 
 Thefe Applications do, I confefs, 
 belong to another Paper , (viz. an 
 Eflay about fomeUles of Chymiftry 
 improved) that was written divers 
 years ago. But fincc, by reafbn of 
 the lofs of divers Leaves of it, I 
 know not whether^ much left wlreif^ 
 'twill come abroad, I fhall at prefent 
 borrow fomefew things of it toacr 
 commodate my prefent Defign. 
 
 Firft then, the piece of clear Am- 
 her formerly mentioned, or fome 
 fuch convenient Body, th^t is not too 
 little, nor in Specie^ too heavy, may 
 ferve the Chymift, Apothecary, and 
 others, to make probable GuelTes of 
 (he Degree of Spirit uofity, or pf Thin- 
 
An E S a A Y. 77 
 
 neft, that is to be found in rnany 
 Liquors belonging to the Vegetable, 
 ortheAnimaljKingdom ; which may 
 be done with far lefs Error by this 
 Way, than by thofe uncertain Signs, 
 on which the comnwn Ways of 
 gueffing are wont to be grounded. 
 For having onfce provided a Liquor, 
 by Comparifbn whereto One may 
 fafely make Eftimates of Others of 
 the fame Kind , or Denomination, 
 'twin be eafie, by obferving the 
 differing Weiglits of the Amber in 
 (everai Liquors to judge oftheFine- 
 nefs of any of them in its Kind ; for, 
 Qjittrk-^aribkis, That is the thinaeft, 
 or abounds moft in Spirituous parts, 
 where the Solid weighs more , thaa 
 in the Other, as for inftance, The 
 Amber we imployed, that in Water 
 weighed 6 \ Grains, in common Red 
 French Wine weighed 8^ Grains, in 
 common^ Brandy of a pretty good 
 fort, fuch as that oi Nant^Zt 17 | 
 Grains, and in vinous Spirits highly 
 reftified 34 r Grains. The fime 
 Way one may imploy, to judge of 
 
 the 
 
78 Medicina Hydrofiaticd : 
 
 the Strength of Spirits of Vinegar^ 
 Acttum Ra,dicatum^ &c. but with a 
 great difFerenee in the Application. 
 For it may pafs for a general Rule, 
 That, 'tis probable, that, of Liquors 
 deftilled from Wine, Gydar, Ale, and 
 other fermented Liquors, the Hydro- 
 ftatical Body (if I may fb call it) 
 weighs more or lefs , according as 
 the Liquor 'tis weighed in, is more 
 br left Spirituous ; but , on the con- 
 trary, in Acid Spirits and Liquors, 
 the lefs the Solid weighs, the ftron- 
 ger One may repute that Liquor to 
 be : That greater Decrement of 
 Weight proceeding ufually from the 
 greater Proportion , it contains, of 
 'Salts that are not Volatile. 
 Imuft not here pretermit oneConve- 
 nience of the Way newly propofed, 
 that may, in tfa£t of time, fave you 
 fome Money, and, at leaft, will ena- 
 -bk yoii to Husband better, than in 
 the vulgar Method you can. Li- 
 quors that you may have but final 1 
 Quantities of, or that are worthy to 
 be preferved. For, you know, 'tis 
 
 ufuai 
 
An ESSAY. 79 
 
 ufual with many Chymifts, andefpe- 
 cially thofe that are more circum- 
 fpeft than ethers, to try the Good- 
 nefsof their Spirit of Wine, or Bran- 
 dy, or other Spirits drawn from fer- 
 mented Liquors, by letting Fire to 
 a fpoonful of the Spirit to be examinM, 
 in order to lee, how much of it is 
 totally inflammable, and how great, 
 or little, a Portion of Phlegm will 
 be left behind But, not here to 
 mention the Scruples Ipropofe in 
 another Paper, about this Way of 
 trying Ardent Spirits, I fhali now 
 only take notice, that, by the new- 
 ly recited Way, you lofe or fpoil 
 all that you try, and the better the 
 Spirit is, the greater is your Lofs, 
 whereas by the Hydroftatical Way, 
 the Liquor is examined without be- 
 ing deftroyed. 
 
 Tis now fit to add, that, by the 
 help of the foregoing Obfervations, 
 One may alfo make Eftimates of Li* 
 qtwrs of the fame kind not deft Hied ^ 
 whether fermented or not fermented ; 
 as feveral Sorts of Beer,or of AIe,orof 
 
 Cydar, 
 
So Medid/ta Hydrojldticdt 
 
 Cydar, or of Juices of Apples, or of 
 Pears, newly preft out. And the fame 
 Hydroftatical Solid may beimployed, 
 to compare with one another, in 
 point of intenfive Weight, Liquors 
 of differing kinds, as Wine, Bser^ 
 Ale, Mead, Cydar, Perry, Verjuice, 
 expreft Oyls, Effential Oyls of diffe- 
 ring Bodies, &c. 
 
 But, in cafe the Liquors to be im- 
 ployea be very ponderous, Ambet^ 
 will not be a fit Solid to be examined 
 about them; for I have found by 
 Tryal, (what one would fcarcefuf 
 peft) not only that it would fwim 
 or float, in divers Liquors made by 
 Solution of Salts, whether in the 
 moift i\ir, or even in Water, fuch as 
 Oil of tartar per De//^////^/», Soluti- 
 on of Salt of Tartar in as little Wa- 
 ter as may be, and Solution of the 
 Salt of Pot-afhes, &c. But fome 
 deftilled Liquors would not fuffer 
 my pelluq[d Amber to fink to the Bot- 
 ' torn, as Ifound by Tryal made with 
 Oil of Vitrjol^ with Spirit of Nitre^ 
 and even with good Spirit of 
 Salt^ " Befides 
 
An ESSAY. 8t 
 
 Befides, there may be another U(k 
 madeofourHydroftatiGalSolidjwhich 
 may, on divers occafions, be as Ser-- 
 viceable to Experimenters in gene- 
 ral, by affifting them to proportion, 
 to their purpofes, the Strength of 
 the Me^/lruuMs, and other Liquors, 
 they are to imploy ; as the former " 
 u(e is toDeftillers and Apothecaries, 
 for difcovering the Strength of the 
 already prepared Liquors^Itliat they 
 would examine. For there are di- 
 vers Experiments, that either do 
 not fucceed, or, at ieaft, do not fuc- 
 ceed fo well, unlefs the Me^firmmi^ 
 or other Liquors, imployed in ma- 
 king them, be of a determinate De- 
 free of Strength, (which is ufLiallT 
 nowable by a certain Degree ot 
 intenfive Weight.) This will be 
 the more eafily granted, if (as 1 
 have elfewhere fhewnj the Strength 
 and Spirituofity even of feme Li- 
 quors, whofe chief Virtue and Ulh 
 is to be good Solvents, may yet be 
 imfic to diflblve, as well bccaivie 
 their Strength exceeds a certain Mba- 
 G ill re 
 
82 MedicinA HyirofiAttU : 
 
 fure, as becaufe, by their Weaknefi, 
 they fall fhort bf it. Of this, Ire- 
 member, I gave an Inftance irt AquA 
 lortis^ whofe ftrength, as it's Name 
 intimates, is rcckonM the beft Qua- 
 Ht'^itcan have; for I found, that if 
 it were reSified lb much as to make 
 it as ftrong, as we could, or but 
 ibmewhat lefs ftrong than that, it 
 would not diffolve Silver, But re- 
 quired to be weakened by an Addi- 
 tion of Water ; and Ifdund, that the 
 Mpj^firtmm^ iho* it were hot much 
 reftified , would not near fb vi'ell 
 dilfolve the Filings or Ralpings of 
 crude Le^dy^^wtoen 'twas moderately 
 ftrong and fit- to difTolve Silver, as 
 when 'twas allayed with a confidera- 
 ble Quantity of Water, efpecially if - 
 aflForded by Raih, or by Deftillation. 
 I fhall add; that, in making Extra- 
 ftionsfrom many vegetable Subftan- 
 ces, for Medicinal Ules , Chymifts 
 themlelves 'may fall into a Miftake, 
 :when they affeft to employ their 
 rnoft reftified Spirit of Wine , as 
 the beft Mt^Jlruumior their purpofe: 
 ^^ For 
 
AnKSSA^i 8} 
 
 For the Medicinal Virtue of not 
 a few filth Bodies does not refidc 
 only in what Chymifts call their 
 Sulphur , and might perhaps more 
 properly be called the Refinous Part, 
 which indeed isbeft difTolved by fucH 
 Spirit of Wine, as is carefully de- 
 phlegm'd ; but alfbifi k more Gum- 
 mous, and, partly perhaps, almoft 
 Mucilaginous Subftance, for whofe 
 ''Extraction a moderately Phlegtiia- 
 tick Spirit is more proper; be-- 
 caufe of the Aqueous Portion, that 
 is mingled with the inflammable 
 One $ lincewe fee, that (bme Giim- 
 mous Bodies, as Gt/m Jrdh/ck^ Gum 
 Tragacanth^ &c, are not difpoled to 
 be diffolved by the belt re&ifiedi 
 Spirit of Wine, as they are by A- 
 queous Liquors, as Water, weak 
 Spirit of Winei, &c.. and fbme, tho' 
 diflbluble in both kinds of Mcnflru* 
 ums^ are yet lefs eafily foin ftrpng 
 Spirit of Wine , than in waterifh 
 Mtnftruums ; as may be oblerved 
 43articularly in Myrrh ; for other In- 
 ftanccs applicable to thefc Adver- 
 G 2 tifements 
 
MedicinA Bydroftatica: 
 
 tifements .belong to another Paper. 
 And what has been now faidjinay 
 ferve to perfuade you, that it may 
 b€ of good ufe , on divers Occali- 
 ons, to take Notice of the Degree 
 of Strength of the Me^Jtrmmy or 
 other Liquor, we employ about this 
 or that nice Experiment ; that when 
 we have occafion to reiterate it to 
 the fame Purpofe only, we may be 
 able to bring the Liquor we make 
 ufe of to the fame Degree of 
 Strength with That, which we for- 
 merly emyloyed, and by which tlie 
 defign*d Eifetb was produced. But, 
 in Experiments that (hould b» very 
 Critically made, 'twill not be amils 
 to bear in mind this Caution, that if 
 the Liquor be very ponderous /;;tS)>e. 
 cky as 0/7 of Vitriol^ or Oil of Tar- 
 tar per ^e/'gr/^///w, 'tvvill be fit to put 
 fomething into the Scale, from which 
 the Solid hangs, to make Compen- 
 iation for that part of the Hair that 
 is immeried, fince Horfe-hair not 
 being of the fame Specifick Gravity 
 with this Lir]ucr, (tho' it be pre- 
 
 fumed 
 
An E S S A Y. 85 
 
 fumed to be fo with common Wa- 
 ter) is to be confidered, as a tbme- 
 what lighter Body, capable of buoy- 
 ing up the Solid a little; and therefore 
 its Comparative Levity ftiould be 
 cpmpenfated. 
 
 CHAP. XIL 
 
 -. r . 
 
 X2 Efides the Way, we come from 
 Ij dilcourfing of, there is indeed 
 another Way, which, we have, on 
 divers Occafions, found uleful, to 
 compare different Liquors, that^rc 
 of the fame Magnitude, in poinPof 
 Weight* This is done by fucceflive- 
 ly filling a Vial greater, or fmaller, 
 furniflied with a pretty long and 
 llender Cylindrical Stem, to a cer- 
 tain ftable Mark mad^ near the Top, 
 with the feveral Liquors to be com- 
 pared together in point of Gravity. 
 . But this Way Imuft here do no 
 more than,, name, not fb much be^ 
 cau^e Ifpeak pf it in a convenient 
 G } place 
 
Medicim H)'dr'o^atica : 
 
 place of another Paper, as becaufe" 
 'tis not Hydroftatical, But there is 
 alfo another Way to difcover, Whe* 
 theror no. Two, or more, Liquors 
 propofed differ in Specifick Weight, 
 and to make fome, not groundlels, 
 Eftimate of their Differences. This 
 is done by a hollow Cylinder of Brafs, 
 or other Metal, made fbmewhat hea* 
 vy at the bottom to dsilce 'it fwim 
 upright, that finks more, or lefs in 
 feveral Liquors, as they are- lighle^ 
 or heavier, one than another: But 
 the diVigent Merfenms himCel?^ "who 
 propofes this Way, coxifefTes it to 
 ,be\j|ery diiRcult to make fure Obfer- 
 vatRns by' it. To which, I fhali 
 therefore add but this, that, being a 
 Metal, it may be corroded by 
 Acid Me?7ftruHms , and if it be of 
 Brafs, or Copper, it may be wrought 
 upon or injur'd by Urinous Men^ 
 firunmsy too. 
 
 What Merftn^^s faid of this In- 
 flrument, may be applied to ano- 
 ther, tho' differing from it, both in 
 Shape and Matter, Fqr 'tis; made of 
 
 tWQ 
 
An ESSAY- 87 
 
 two Glafs Bubbles, and a very flen- 
 der Stem , which is Hermetically 
 Scaled with aBallaftin the lower- 
 moftofQuick-filver, tokeep it ftea- 
 dy, when partly immerft in Liquors, 
 in which this Inftrumentj like the 
 Metalline Cylinder, links deeper in 
 lighter- Liquors, than in heavier, in 
 ameafure fbmewhat anfwerable to 
 their Differences in Gravity. But, 
 tho- 1 have, on feveral occahons,em- 
 ployed thefe Inftruments, and found 
 them not unufefuli when I did not 
 confine my ielf to One, or Two, but 
 made ufeof feveralof different Sizes, 
 according to the various Liquors, 
 I was to examine; yet what you 
 may elfewhere find about., this In* 
 ftrument , difpenfes me from fay- 
 ing any more of it in this place, than 
 that, for fbme of the -ends aimed at 
 in this Chapter, it is inferior to the 
 Way of examining Liquors by the 
 help of the Ballance. 
 * There is alfo another Way, that 
 is Hydroflatical, propofed by Mer* 
 ff^nmSy of weighing of Liquors in 
 G 4 Water, 
 
S8 Midicifid tiydrojtdtka : 
 
 Water, and it is This; He bids you 
 take aGIafs Vial^to which,being hrft 
 weighed in Air^ and then in Water, 
 you are to adjaft a Stopple of Wax, 
 or Cork, that will fit it exaftly. 
 This done, you are to fill the Vial 
 with the Liquor you would exa- 
 mine, fb that no Air be left be- 
 tween it , and the Stopple, The 
 Veflel thus filled , you are to 
 weigh in Water, and fubftraft from i| 
 its Weight there^ the formerly noted 
 Weight of the Glafs it felf in Wa- 
 ter, and alfb That of the Stopple 5 
 which done, the remains will give 
 the Weight of the Liquor propofed 
 in Water. This Method I lately 
 chanced to find propounded by (the 
 Writer newly nam'd) the indullri- 
 ous MerfcHfius in his Hydranlicks ; 
 hut, 1 rcmeriiber not, that he affirms 
 himfelf to have made ufe of it ; 
 And tho' it may be ferviceable on 
 J bine occafions, yet, I fear, it will be 
 troublefome in Praftice. For, (to 
 omit Ibme inconvenient Circum- 
 itances) ordinary Vials, capable of 
 
 cpntaining 
 
An ESSAY. ^9 
 
 containing a competent Quantity of 
 Liquor, are, ufually, too heavy to 
 be imployed with tender Ballances ; 
 and common Stopples f fiich as Afer- 
 ftnnus may be well fuppofed to have 
 imployed) will be fubjed to divers 
 inconvenienciesj as, that they may 
 be penetrated by fbme Liquors, and 
 corroded by others, and if they be 
 made of Cork, or of common Wax, 
 or any other Subftance lighter, in 
 5/>et/e,than Water, 'twill notbeeafie 
 to find its fpecifick Gravity ; efpe- 
 cially fince Evaporation, and other 
 Accidents make this it felf vary ; and 
 whatever Matter, Vegetable or Ani- 
 mal, it be made of, the Veflel will 
 coft you two Operations, One to diP 
 cover the Weight of the VeJJtl'm Wa- 
 ter, and the Other that of the stopple^ 
 (at that time) which is troublefome. 
 Wherefore, when I met with this 
 Way in the ingenious Merfennus^ it 
 leemed to me more inconvenient, 
 than One, that, I remember, I had 
 formerly thought of, and which I 
 have (bmetimes put in Praftice, by 
 
 ghufing 
 
JO Medicina HydroJlaticAx 
 
 chufing a Vial not too large, and of 
 a round FigurCy that being the mod 
 capacious under fuch a Superficies, 
 a»J, inftead of other Stopples, fit- 
 ting it with one of (the like) Glafs, 
 carefully ground to the Neck of it. 
 For, by this means, the inconvenien- 
 cies of a Stopple lighter than Water 
 were avoided, nor would the Stop- 
 ple alter its fpecifick Gravity, either 
 by Imbibition, or Evaporation, nor 
 would it be penetrated by the moft 
 fubtil Spirits, nor corroded by the 
 moft fretting Ones. To which may 
 be added, becaufe, in fome Gales, it 
 may be confiderable, that a Glafs- 
 ftopple, as it will not be wrought 
 on by the Liquor contained in the 
 Vial; fo it will not communicate any 
 TiniSture, or extraneous Quality, to 
 the Liquor, which cannot be affirm- 
 ed of a Stopple of Cork or Wax, in 
 reference to fome Subtil and very 
 Corrofive,or otherwife very penetra- 
 ting Liquors, this Hydroftatical Bot- 
 tel (as for diftinftion fake I call it) 
 being together with its Stopple care^ 
 
 fully 
 
An ESSAY, 91, 
 
 fylly weighedjFirft in Air, and then 
 in Water, (that the Gravity of the 
 whole Inftrument in that Liquor 
 may be fetled once for allj wefili'd 
 it exactly with the Liquor to be exa- 
 mined, aiid fb proceeded,as we if were 
 to weigh Quck-filver according to the 
 Manner formerly declaredin theEigth 
 Chapter. The Weight of the give n 
 Liquor irt Water being thus obtai- 
 ned , its Proportion m Weight to 
 Water of the fame Bulk may be 
 eafily difcovered by the Way for^ 
 met ly^delivered in'die Second Chap- 
 ter (or the Tenth Chapter.) This 
 way 'df examining Liquors may, on 
 fome dccafipns, do good Service, and 
 I did the rather, now and then, makq 
 ufe of it, becaufe 'tis applicable to 
 all kind of Liquors, whetner heavier 
 /> Specie than Water, or lighten = 
 
 It yon ?lay afide the Stopple, the 
 roiind Ball it felf may be; made, 
 life ol; on feveral Occafions, inftead 
 of that Hydroftatical Bucket, for- 
 merly mentioned 5 for thq weighing 
 
 of 
 
^2 McdiciHA Hydrojluticd : 
 
 of Quck-filver , and divers heavy 
 Powders ; efpecially if they be Courfe 
 Ones. But if the Inftrument he fit- 
 ly fhaped, and not too heavy, there 
 may belong to it a greater Gonve- 
 niency than This. For when you 
 have, and arc willing to fpare, Li- 
 quor enough to inviron the little 
 Bottle, it may be ufefully fubftitu- 
 ted to the Hydroftatical Bubble, with 
 Quick-filver inclofed, that I former- 
 ly recommended. For,by reafon of 
 its exaft Stopple, it has no need of 
 an Hermetick Seal,(which is not eafic 
 to be be made or procured 5) and 'tis 
 far left Subjeft to be broken, than a 
 Bubble. And yet that which Imoft 
 made ufe of,/and which weighed a- 
 bout ?i^iii/. Grains xix, or 709 
 Grains) being well ftopt with only 
 Air in it , would fink by its own 
 Weight in Water^ and in Liquors 
 lighter than This, as WinCr Brandy, 
 &c. And if it were to be imployed 
 in Liquors much more Ponderous 
 than Water, as Ajfia Fortis^ Oil of 
 Tartar perdeliquifftn^ &C. 'twas eafie 
 
 to 
 
An ESSAY. 93 
 
 to make it fit to be weighed in 
 them alfb ; by putting into it a 
 Quantity of Qtiick-filver (or fbme 
 other fit Body) of a determinate 
 Weight, as two,three or four Drams, 
 before we flopped it: Which Ba- 
 laft, when the Operation is over, 
 may, if it be Quick-filver, be eafily 
 taken totally out, and kept apart 
 for th^ like Ules .• and the empty 
 Bottle, and Stopple, may thereby 
 become fit again, to be weighed in 
 Water and lighter Liquors. 
 
 But notwithftanding all this, be- 
 caufe Glaffes, for fize, fhape, and 
 weight , fit for Ballances , tender 
 enough, and furniftit with Glafs 
 Stopples exaftly fitted to them, are 
 very difficult to procure; and the 
 Way it felf is fubjed to fbme of the 
 Incon veil iencies, that we imputed to 
 other Ways^not long fince mentioned; 
 it (eems, that, generally fpcaking, 
 this VVay of finding the Weight of See the 
 Liqugrs in Water, is Inferiour for ^^^t/'^*''"' 
 common, ufe, to thofe more fimple 
 Ones, that we formerly recommenc^- 
 ed. CHAP. 
 
94 Medicifja Hydroflatiu : 
 
 C HAP. XIII. 
 
 life VI. TTAving now laid down thtf Me- 
 Jl X ^'^^^ ^^ i^eighing one Liquor 
 in another, 'tis allowable, and may 
 be fit, that we fubjoyri fome Applr- 
 cation of it : Efpecially, becaiafe it 
 will become rhe to make good, in 
 fome meafure, what, I remember, jl 
 formerly hinted to you, ^'/^. that, in 
 the fubfequent part of this Paper, 
 there would be delivered a further 
 life, which may be counted the 
 Vlth. of the Hydroftaticks in exa- 
 mining Medicinal Bodies. And tho^ 
 by the Inftances we lately had oc- 
 cafion to propofe in Ibnie ofthe 
 Chapters preceding This, divers 
 things referable to this Ufe , are 
 fet down already 5 Ttt Ifhould not 
 content my Self, (as 1 now muFt do) 
 to point at the chief Heads or Kinds 
 of things referable to it ; if, on a Sub- 
 jeft that'is more fertile; than it feem^, 
 ' want 
 
An E S S A Y. 95 
 
 want of leifurc did not reftrain tnc 
 frotti defcending to treat of the par- 
 ticular Inftances, that belong to 
 them. 
 
 Among the Services then, that the 
 Hydroftaticks may do a fagacious 
 Phyficiari, Imuftnot omit One, tho' 
 it has not hitherto, that I know of, 
 been propounded by any Author. 
 Andj Ihope, you will not think it 
 improper to be takenjiotice of here, 
 tho' it do not regard only tbo Mate^ 
 ria Medica, but is applicable fas I 
 may elfewhere relate that I made it) 
 to divers ^ubjefts, that are refera- 
 ble to other Parts of Phyfiology : 
 Since divers Bodies, that feem not lb 
 direftly to regard tliQ Materia Medica^ 
 as 'tis ufualty repofited in the Shops 
 of Drugfters, have been, in fame 
 times dnd' places y and may defer vedly 
 be ^^ii' made to afford Matter for 
 Remediesj to a free and ingenious 
 Phyfidikn. 
 
 I confider thea, 'that there are ma- 
 ny Liquors, whofe fpecifick Gravity 
 it may be ufeful to know, not only, 
 
 as 
 
^i MeJui^a Hfdroftatica : 
 
 it may help to diftinguifli Genuine^ 
 or well conditioned Ones,from Them 
 that are not fb, but for other good 
 Purpoles too. 
 
 Inftances of this kind may be 
 afForded by the Juices of Herbs and 
 Fruits ; where (according to the Di- 
 reftion given in thelaft Chapter) we 
 firft weigh a determinate Quantity, 
 as an Ounce, or lb many Drams, in 
 our Hydroftatical Jar , or Bucket ; 
 and putting fome Oil of Turptntine 
 on it, we fink it warily into that 
 Liquor ; whole (pecifick Gravity in 
 reference to refined Silver, clear 
 Rock Chryftal, (or fbme other Body, 
 if we know it to be as pure) has been 
 carefully found out and regiftred: For, 
 by this means, (as we have lately 
 manifefted) fubftituting this Oil for 
 common Water, we may difcover 
 the fpecifick Gravity of Liquors, not 
 to be weighed in Water, becaufe 
 they mingle with it. And thus we 
 may find, not only the difference in 
 Ponderofity between the Juices of 
 
 Plants 
 
An essay/ 97 
 
 Plants of differing kinds, as of 
 Wormwood arid Rdfes, and fome- 
 times of th© fubordinate Species of 
 the fame Gemis^ ^s of Ahfynthium 
 VulgAre , Pont hum , Romdnam^ &c« 
 and RbfesPFA/>e, 2fe^, Damask^ Tel- 
 low, &rc. but we may on fome oc- 
 cafions dbferve, whether, and, if at 
 all, how far, the keeping of a Juice 
 for fbme time, more or lefs, or the 
 Fefmentatrbn of it, or the Putrefa* 
 ftion, will alter itsfpecifick Gravity. 
 There are alfo other Liquids us'd 
 by Phyficians^ and riot ponderable 
 in Water, that may be by this Way 
 examined, as Honey, Vinegar, Ver- 
 juice, &c. And by the fame V/ay 
 may be alfo difcoVered and compa- 
 red, the rpecifidk Weight of the 
 Juices of Fruits of different kinds, 
 as of Grapes, Apples, Pears, Quin- 
 ces, &c. and of fubbrdinate Spectes 
 belonging to the fame Gtnus:, as 
 the newly expreffed Juices, that 
 fnake Sacks, French- wines, Rhenifli- 
 wines, 6^c, and thofQ Liquors, thar 
 are prelTed out of feveral forrs of 
 H Apples, 
 
M^dicw^ Hy draft dtica, : 
 
 Apples, as Pippins, Peatr'tnains^ 
 John-Apples,^ Queen-Appies , &c. 
 And in divers pf thefe, a Perlbn that 
 is curioas enough, may probably, by 
 the Method we have been propofing^ 
 beenabledtj:\ take. Not ice of the Dif- 
 ferences pr^uced. in the fpecifick 
 Gra«^ity Cwjiofe Changes are ufu- 
 ally acconipa,nied withthpfe of Con- 
 fiftence, &c \miAyt fevier;*! fucceP 
 five. States, ^he>rein the Liquors 
 may be foLijpt^ a^tixJiffer^nt times > as 
 (not to mengjap;,thp Juice of unripe 
 Grapes, 'z//^.-,4fx^i/^Ve), thejuice of 
 ripe Grapes is in y^ry differing States^ 
 rvh£n 'tis ne\yly prqflfed out ; whn it 
 begins tofermencrj ivhe;^ 'cis yet but 
 New Wine ; xvhe'/i/M has attained its 
 full Maturity and Perfeftion; whtn 
 it begins to degenerate into Ropy, 
 prickM WinQ, &t, mA when 'tis ab- 
 foiutely changed into Vinegar, or 
 el ft into Fappa. 
 
 But here ir ou^ht not to be con^ 
 cealed from you, That in this kind 
 of Experiments, to make ufe fuc- 
 cefsfaily ofthe Hydroftaticai Bucket 
 
 IS 
 
An ESSAYi; 99 
 
 is a task difficult enough, for Rea- 
 ibns that a few Tryals will eafily dif- 
 cover. Arid therefore, the' I would 
 )iot difcpurage the Skyful, yet fcMr 
 thofe that do not find themfelves 
 „dextrou$ at making Experiments, I 
 think it .^dvifeablb id imploy, in- 
 stead of the Bucket, Ariibei", or fbme 
 Other convenient Hydroftatical So- 
 lid, or rather (which is better^ a 
 GUfs-bdttle and Stopple, fuch as 
 We foriiierly delcribed 5 but as large, 
 as may well be implby'd without 
 Qver-Ioading , 6r iri)uting,the Bal« 
 lance. :^^itiJi: 
 '^ ::Jii:> rnoiT n« 
 . '■■'•^rv7^fjr.-;i^ — -^ 
 
 C H A P XIV. 
 
 AS I tfioUght 'twas'flrt&f give the 
 foregoing Advertifctnenr, by 
 way of GaUti6n,in the Gafes that 6c- 
 tafioned it ; fo having confidered 
 the Nature and Scope of theHydr6» 
 ftatical Experiments in General, that 
 belong to this Bff^f ; lihiM venture 
 H i to 
 
tbo MednitiA liydroftafica: 
 
 to add for the Encouragement of 
 thofe, that are better furnifbed with 
 ^inquifitive Minds,than with nice Bal^ 
 larlces; th&tt ho* in divers Tryals, 
 efpecially Thofe that are made about 
 precious things, , as Gold, Pearls, 
 Diamonds and other Gems ;there is no 
 relying upon any, but very Good 
 and tender Ballances;2i^, on many 
 -other occafiorlis; , 'tis not neceffary, 
 tho' it bedefirable, that the Scales, 
 we employ, ihould be extraordinary 
 Good. And this for twoReafons: 
 Ffrfl, bccaiife many: Hydroftatical 
 Experiments are lucb, that a little 
 Variation from the exaft Proportion 
 of the Solid xo the Liquor, or be- 
 tween Bodies of the lame Denomi- 
 nation, Cm lead us into no confide- 
 rable Error 5 or, at leaft, not defeat 
 t>ri:ie Exp^imeaters mainDefign; as, 
 \y\ith a Ballance that is, not niqe, 
 -:Qne may fufficientiy diftingujfhb^- 
 
 ' :tween an human Calculi^s^^nd a Peb- 
 
 -.ble,or otiier ordinary S^one 3 and be» 
 
 tween Courfe and Firie, native Ci;^. 
 
 tiWhri .Arid teiwcen atrUvGuine^, 
 r . i ' ^ or 
 
or o^her pie.ce of coyned .Gold, that 
 is not y^ry fniall, a.i?4 4 counter- 
 feit One, of Brafs, or ^nyTuch miK- 
 ture, the' never fp findy guilt. 
 
 And Secondly ^ Becaiife, as there 
 arefew^I^hyGc3lExperirnents,where- 
 in Mathematical Precireriefs is ne- 
 QefTary* and fewer vvheitin 'cis to be 
 eijpcSt^d ; ^^i' in Wany Hydroftati^ 
 pal Jryals^ ^tis very probable, that 
 the diffehePiieof Bodies 9^ fama 
 kind , or; petomination, ' flowing 
 frojn t!ieir Cpiiippfit idn^^^ a.nd inter- 
 gat TexturesV will riialce a difcer- 
 nable, t}hi>'..t>ut ftnajL idi^^ in 
 
 their fpectfick' Gra\7ity : As , in 
 Rpcfc-Chryftpji it fclf, \ye liave found 
 |biije piece?! to "b^ to"VV^t.er,;as 2 Jy, 
 or a litttei^'prp, to;0ipe^ and others, 
 jto bC'to' tjie tlanie IJi^iipr, as Two 
 and Si)^^, Qi;: between Six and Seven 
 Texjtlis, ^9* 04^;, And therefore, hov/ 
 exafit {ot^^kx^^^^^ Ballanc^ be, there, 
 muft be,ipme i\'ilpvva;ice ma'de foj: the 
 diV)ferIicyi tli^^/.may' befoond in tha 
 Bodies f h'qmlelves, that' -a^re exami- 
 Gedj vy-feich jfiverfity fii^y perhaps 
 '■ ' '^ H J " ^ ^' 'produce 
 
ipz Medicim ^ydroftaticax 
 
 produce, at leaft, as great a Diflfe 
 rerlce iri tlie jProportipns we Teelf 
 for, as needs; to be expefteifrdm t 
 ftiall Difference of tendernels, in thd 
 Ballances we.imploy. And indeed^^ 
 neither One of thofe Diflferences, noiJ 
 the Other, CrP^ perhaps Roth toge- 
 iiier,) is wont to be fo confiderawe* 
 as to challenge much regard in Phj^- 
 fifal Experimehts ; oratteaft, as to 
 hinder if to Be'^lrue,that,'pn moft occ^ 
 fipjns, the H^dfpftktica^t Waypf ti^ 
 mining |;hVifpecifick Weight of B6- 
 ^ies, is preferable by far to any ci- 
 ther VVay p^ doing it,: diat has beef/ 
 
 * Before.! pcocee^ to p^ r^'^alttj'ng 
 part pi tllfs'^ffay, it win wortn 
 while tp Qbyiaie ari Objeftiorr, that 
 i forefee :^i^y/ bVmade Critical 
 t^^tyralifts,^ again ft dtp^iyiethod 'hir^ 
 thertb dejiy er^id, pf findings the Pro- 
 portion in/Weig!it,:bj6t\^ fink- 
 ip^ febdy^^ao^ .Warei^ oif^ the fame 
 gulkV Fci:^'i.tr, (peci6u% q5.^y> and; 
 probably^vyiir, b.e objefli'ed^' tjiat, by" 
 this Methpcl,' we' ckrindt difcover 
 
An ESSAY. loj 
 
 the Proportion bet wedn a Solid Bo- 
 dy, arid Water in General J but only 
 betwixt jthe propofcd Body, and the 
 particular Water 'tfe weighed in ; 
 beiaVife ih^er'Q may fc^'^aM-eap Difpa- 
 rity between Liquor^^' that are cal- 
 led, 'a.i^d tfiat deiStVedlj^, common 
 Water. ' AM foiWe ' 1:'rav4lers 't^U 
 us from the Kefs, th^t'Mte Water 
 of ^ri.'g4ftern Rivei^y Which, if Irni- 
 R2kQ\)r^^h^ Fifth 
 
 jiart ligfiter than our Water. 
 
 But to this pla6fit)!e ObjeftiQii, ;l 
 have Tw^ things. tiB fflfwcr. 
 
 ral' ofccaflorts, the (Opportunity, as 
 ^ell^-^'Cti'riofity, :tp, examine the 
 Weight of divers .Waters , fome of 
 them t^ken li^ in iPlafc^s'^ery diftant 
 froA one another ; rfobnd the diffe- 
 rence between their fpecifick Gra- 
 vities far lefs, thanatrnoft any Body 
 'would expeft. And if I be not much 
 deceived by my Mem6ry, (whicn 
 Imiift have reCouffe to, becaufe I 
 have not by me tht Notes I took^of 
 thofe Tryals) the difFei-encfe between 
 jH 4 Waters, 
 
I04 Midkim H/drofiatica .' 
 
 Waters, wjbtere On^,\?4a^W.^pe£fc 
 ^notable Pifp^rity 5 \8f^s b\it ;about 
 the Thoufandth par;: f anc} Ibme- 
 times perchance very far lefs) of the 
 yVeigbt of either. Nor did I find 
 aiiy DiflFerpnce cbnfiderable, in refe- 
 jrence tp our Quefiion, between the 
 VVeight of divers Waters of diffe- 
 ring kinds, as Springe water, River- 
 %yaier, Rain- water, and Snow-water, 
 tho' this laft wer^ fpniewhat lighter, 
 than any of the reft. And having 
 had the Curiofity to procure fomc 
 Water brought into E?igUnd^ if I 
 piiuch miC-retpember not, frpm the 
 River Qarfges it felf *, I found it very 
 ' little, if ^tall lighter, thanfbme of 
 pur common VVaters. 
 ' And noy/ I fhafl reprefibnt in the 
 Second place, that J do not pretend, 
 j^and indeed -tis not neceffary^ that 
 the Proportiofi , obtainable by our 
 Method, fhould have a Mathema- 
 pil Pr^jcifenefs. For in Experiments 
 where we are .to deal with gro(s 
 ^Matter, and to imploy about it ma- 
 terial JnJJruments *, 'tis fuffieient tp 
 
 have 
 
Aa ESSAY. 105 
 
 have a PhyGcal, and almofl: impof- 
 fible to obtain (unlefs fbmetimes 
 by Accident) a Mathematical Exaft- 
 nefss as they will fcarce deny, that 
 have, as I havedone,confidered, and 
 made Tryal of the Difficulties, that 
 oppofe the Attainment of fuch a 
 Precifenefi. 
 
 CHAR 
 
t%6 MtdicwA Hydrofiaticd, 
 
 HydroJlatkdP Stereometry , 
 
 Applyed to the 
 MATERIA MEDICA. 
 
 SECT. I. 
 
 ^inHere is an life of Hydroft'a- 
 JL ticks, which tho' it do not di- 
 rtily tend to the Examen of Drugs, 
 or Simples received into the Materia 
 Medica^ yet may be Serviceable both 
 to the Phyfician and the Naturalifts, 
 in delivering their Defcriptions ; and 
 fb it may indirtSly conduce to the 
 fcnd^fedge of them ; and help, on 
 fome occafions , to diftinguifh be- 
 tween Genuine Simples (efpecially 
 Fruits) and thofe that are not fb ; 
 
 Tis 
 
An E S S A Y. 107 
 
 ^^Tis ienown, that the Writers of thq 
 Materu Medica are wont to let 
 ddwn the BigncFs of the Bodips they 
 iftlcribp, tiy very uncertain Oueffes; 
 and thpfe that, to bis more accuratej^ 
 aflign them determinate MjpafureSj 
 atetwont to do'it, by faying, that 
 iixth kWuiti of other Body, is, for 
 E^iarnple, an Inch, pr two Inches, ot 
 h^M^ ^f opt Idqg ; and half n Inch, 
 6t 4 U^hoie Intdh, or two Ineheif and 
 ^f h^fi ih bre^ife ' But Wbbvi- 
 Ws^ tdl!M)fe that aif b ndt great Stran- 
 ^Cr^s ^o^^ne Mathematicks, that, ae* 
 coMiii^'^tO this Wiay of defer ibing 
 ]B()dibisi,''thetemay be, by reafbn of 
 the great Variety t)f Figures, efpe* 
 Ci^'IfV irregaiar Qhes-, they arecapa- 
 Bfeior^^a very great Difparity of 
 rif^^nfttidc, or Sulk, ih Bodies, to 
 t^Ch bf jWhich, the lame Length ^nc| 
 Breadth' [tnay ,belpng or be ap- 
 
 •^iflidujd hefeie able to prefent 
 you arfHydroftatrcal Way of deter- 
 iijinhig the Bulk of Bodies, both 
 mtrth hearer the Trtith, than that 
 ^^^^^5''" ' newly . 
 
108 Mcdmm iJHydflofiatica : 
 
 neMfly recited, aad grpunderi ^s wi?H 
 p;^ Experiments a: MathematicJcs ^if 
 ampng other Papier?,; 1 had not uHr 
 fortunately loft Oqe, that I wroj}^ 
 -maoy years ago,^ ftbout the .^^ajtirr 
 ing of Solids^ by- the help of Liquors* 
 But tho* I cannotjOut of my Msiporf^ 
 recover the Thepre^ticalp^n ^oi xh^t 
 V^riting, (whofe fLofs I regret, fc 
 carafe it had beep exainined vbif QfXQ 
 iof theexaaeft,aswcil asfamoufel^^ 
 Mathematicians of f our Age^ ^;^9?9 
 I invited to be pre^nt at tlip^,5: hj^ 
 Experiments ) y^ , I thin^, Vl ,Q%n 
 call to rnind ^smucfi oftl)e|P?f^//:^ 
 Applications ofitji^ may fufti^^i^,^ 
 xny prefent purppl^. . \..-.^ ,,.:^ 
 
 ,:The ground of |he \^ay,Yliarg 
 abo).it to propose ,to you j \^ijl Jp^ 
 (ear%,qndevftoo|l.*fe^ the /alj|^wiogij 
 fW but fh0ri;^^CQi^nf, .;} caufcd to 
 ^car^^ully ix^e^by!jskilffu^l^^ 
 c6rs feveral CSl^es, bdth dfdifeenl; 
 Sizes ant^ difFerent M^teri^.^^^^s^r- 
 ble and Mctih;; w^^^^^ 
 ^ch of them,' as lipar as ttie.. ArUft 
 could xnake theqir-/eitli^r afl"" exaOt 
 Incia^ or precifely' more Inches than 
 
 One, 
 
An ESSAY. . 109 
 
 Oney aeeording to our E/jglifk mea- 
 fure; which is laid to differ very 
 Iktie from the correfpondent Oae of 
 the ©Id Romans. Thefe Cubes were 
 carefully weighed in trufty Ballan- 
 ces : Firft, in the Air, and then in 
 common Water. And tbo' I found 
 fbme little (and but little) difference^ 
 between the Produds of theTryals ; 
 yet that Difference being no mor* 
 than might reafonably be expefted 
 from-i the ilcarce avoidable Imper- 
 fcftion, even of good Artifts and 
 their Tools ^ We concluded, that 
 One might, without any confidera- 
 ble. Error, take a Mtdium (as they 
 fpeak,) between thefe Produfts, and 
 allow even to this Mednip^^ a Lati- 
 tude of fome Crains, fince that La- 
 titude :will not amount to the Sixtieth 
 part of the Weight of a Cubical Inch 
 of Water. Since therefore fome of 
 our^Tryals inciin'd us to judge, that 
 ,about Two hundred and fixty 5 and 
 fome others to think, that ,^bput 
 Twa hundred fifty twO;;vand o- 
 -tberslagain; thatabouB Two hun-* 
 noij; dred 
 
1 lb MedicinA Hjfdrop;AticA : 
 
 drcd fifty fix, came neareftL tt 
 the true Weight of a Cubical Inch 
 of Water ; we thought our felves at 
 liberty to make ule of that Num* 
 ber, that fhould appear moft com- 
 mbdioiis for Praftice, by reafon of 
 its Divifions aind Subdivifions mioA- 
 lfqHofel?2Lns; Efpeciaily if the. Bo* 
 dy to be examined \vfere not great ; 
 finccj in that Cafe , Two or three 
 Grains more or lefs would not be 
 tonfiderable, efpeciaily in a Pbyfi- 
 cal Experiment, where Geometrical 
 exafltnef s is not to be expefted, nor 
 indeed required; and a far lefs ac- 
 curate Eftimate will be lefs unac- 
 ciirate, than can with any certainty 
 be made by th6 formerly mentioned 
 Way of judging , by the Length , 
 Breadth, and Depth (or Thicknels) of 
 the Body pfopofed. 
 
 I made the lefs Scruple to pitch 
 upon the la:ft of the Three foremen^ 
 tionedNcfmbers of Grains, notonfyy 
 becaufe it affords many -^//^«^/-e parts 
 for a Number that is no greater, 
 fince barely by a fucceflive Biparii- 
 
 tzoit 
 
Art ESSAY. m 
 
 tiort, it affords Seven fuch Parts, 
 viz. 128. 64, 32. 16. 8. 4. and 2 ; 
 B«/, becaufe I was incourag^d by 
 an Experiment differing from thofe 
 already mentioned* For, having cailA 
 fed to be purpofely made by agoodf 
 Artift,an hollow Cube of Brafs,whofe 
 GaVity was fitted to contain a juft 
 Cubical Inch of Matter;(either Solid 
 or Liquid, ) we' put it into one Scale 
 of a tender Ballance , with a juft 
 Counterpoize in the other, and pla- 
 ced it there, as Horizontally as we 
 could. Then we warily put into it, 
 little by little, as much common Wa- 
 ter, as it would contain, without ei- 
 ther overflowing, or having its Sur- 
 face, manifeftly turgid ; putting alfb 
 from time to cime in the oppofite 
 Scale, fmall Weights to keep it from 
 fwerving too much at once from an 
 jEquUtbrmm. And tho' it is ex- 
 tremely difficult in Practice, 'to dif- 
 cern with certainty, when the Veffcl 
 is fo e)Caaiy filled, that a Drop, or 
 even Two,, or Three drops, more er 
 lei's, cannot be added, or taken a«^ 
 
 way^ 
 
H 2 Medicim Hj/drofiatka : ' 
 
 way, without being obfervable by 
 the Eye ; Tef, for this very Rcafbn^ 
 we thought our Experiment agreea- 
 ble enough to our Suppofition, when 
 we found, that by fo light an Alte- 
 ration, the Weight of the Water, 
 when the Scales were heedfully 
 Counterpoized, amounted to near 
 about Two hundred fifty fix 
 Grains , which Number we fhall 
 therefore hereafter imploy, as expreP- 
 fing the Weight of a Cubical Inch 
 of Water. 
 
 And now to apply the pad Dip 
 courfe to our prefcnt Purpofe. 
 
 Suppole^for Example, that a Solid,- 
 heavier m Specie than Water, ha- 
 ving been weighed firft in the Air, 
 be found to lofe of its Weight in 
 the Water |yf Sixteen Grains, that 
 is, Two hundred fifty fix Grains, 
 i fay, that the Dimenfions of this 
 Solid, if it were of a Cubical Qiape^ 
 would make it equal to a Cubical 
 Inch : So that, (to exprefs the thing 
 yet more clearly,) if the given Body 
 h% fuppofed to be an eafily fufible 
 
 MetaL 
 
All ESSAYnU^ Wf 
 
 Metal, as Tiri, or Lead ; aikl hesit 
 idg meked to be warily poUred in-K 
 to the hollow Cube formerly men<i 
 tiorted, and fuffcred tQ-eOpl i it 
 \;rould juft fill it and nd niore ; add 
 confequently be a Cubeipf Metal^ 
 whofeLengthjBreadthandDepth are 
 equal to one anotherji and each of 
 them to an Inch. For^as 'tis aFtin* 
 damental Theorem Iq Hydroftatick^j 
 demonftrated Mathematically by -4r* 
 chimedeSf and elfe where Phyfically 
 by me ; that a finkmg Solid weighi 
 lejfe in Water than in Ait ^ by the 
 Weight of ar niuch Water as is equal 
 to the Solid in Bulk ; and fince wc 
 have lately (hewn by Experi- 
 ments, that a Cubical Inch of Wa- 
 ter weighs §/. 16. Grains, that is, 
 ^56 Grains ; it will follow^ that 
 when the Decrement of a Bodies 
 weight in Water is found to be 256 
 Grains, the Solid content of that 
 Body is a Cubical Inch : Since an 
 Aqueous Body weighing 256 Grains 
 is equal in Magnicmde^ as well to 
 
 J ilia 
 
1%^ Mediihi- MySc^)iicx : 
 
 the SoM fi?apouftda^' as; to a Ccf 
 bkk ^I^isak pt; W^ter. ^Aod^ bere ir 
 may^^pjidv^nx' a Scriifrtc^' to ob^ 
 ferve, ^th^t^-tt) mailce Bodies equal in 
 Magnk^i 'ic is not at all necefla^ 
 jy^, that th^ (hould be of th^ fame 
 Wti^^^^^'x^^ as 
 
 isevident to Bullets of Copper, Tin 
 and ' Golid,<<S&ft*' fepaf ately and dek- 
 trouOy in 4ll^ fame Mould For thd^ 
 they beiy(?|«^WnfBulk, y^&tr' ibe BulJd: 
 of Copper ^ will' be rai5th heavier 
 than tha^ of Tin ; and-the Bullet of 
 pure Gol# wiil be more' than twice 
 afs heavyj^s'TJ^at of Copper. When^ 
 ioever tfierdfore you meet with a So- 
 lid^ ponderous! eriough to fink ici 
 Water, tfi^t'beirtg weighed in -that 
 Liquor k)(d^Q56Gi»ain5;*6fcfeWeight 
 ■^thad ^ri t{i»^'Air;y<>^i itiay Gonclade. 
 *the MagnKtfidr<)FBLltfe'6f thiat Body 
 to be 6<jikti'^ a^ Cubical' inch ; of 
 *^bate\^e?- Nia^t^r it Gon«(ifts, or of 
 w ItQ't S^^.a'pd' fde vJer^ h^tnifer' or irre- 
 ^gular^ iaiBe.v Aiid kVd^Jifc the Solid 
 pr6rk)ted«lQ-'l^ilts- it'^ill Very often 
 ^ ^ A happen 
 
A An ESSAYi.^ tt% 
 
 happen^ Ibfe of; its Weight in the 
 Water lefs than ? ^6 Grains; yoti 
 may conclude its Bulk to be propor- 
 tionahly iels than a Cubical Inch. 
 And filch is the Gonreniency of the 
 Number We have pitch'd upoa^which 
 abounds in AHqnote parts ; that eve- 
 ry 32 Grains, that th^ Solid lofes 
 of its Weight in the Water, anfwers 
 to an Eighth (that is, half a Quar- 
 ter; of an Inch in the Bulk of the 
 Body: as, if the Decrement be 128 
 Grains, the Solid Will be half a Cu- 
 bick Inch 5 and if it be but 64 Grains, 
 'twitrbe but a quarter of a Cubick 
 Inch; and fo if it be 160 Graifts^'twiH 
 be |j that is, half and half a quarter of 
 an Inch Cube : and on the other 
 •fide, if the Decrement of the given 
 Body exceed the Starldard, i//Zr.'2 56 
 Grains, twice, thrice ^ &c. then 
 that Decrement b^ing reduced to 
 Grains, as fiippofe it weigh fi + 
 Grains 3 2Camounting to j 1 2GrainS;) 
 or |i ^ ^1- Grains 48 jfamounting to 
 76S GFains)^ the Body will be equal 
 I 5^ to 
 
tld Medicina Hydrofidtica: 
 
 to two or three (fingle) Cubical 
 Inches. And if, after the Divifion 
 there remains a Fradiion, 'twill not 
 be difficult to eftimate it, to him 
 that Gonfiders what has been newly 
 delivered. 
 
 SECT. IL 
 
 "^ I O difcover Hydroftatically the 
 \ Solid Contents of a Body hea- 
 vier in Specie than' Water 3 to him 
 that knows bow to^nake ufe of the 
 Method newly delivered , 'twill not 
 not be very difficult, but to m«a- 
 fure,by the help of Water, the Soli- 
 dity of a Body lighter tn SptciCy th^ti 
 that Liquor y is a work not fbeafily 
 performed. It may fbmewhat lelTen 
 the Difficulty, to prenaife , that 
 there arc two forts of Bodies, that 
 will naturally not fink in Water. For 
 /vme are of a clofer Texture, and 
 
 will 
 
An ESSAY. iif 
 
 M/ill not be eafily invaded by that 
 L'lquor ; at leaft, in fo fhort a time^as 
 they are of neceffity to be kept in it : 
 SLnd others Sihonnd with Pores, that 
 difpofe them to imbibe the Water, 
 they muft be kept immerf^d in, till 
 the Experiment be di(patched^ 
 
 To begin with the Firft fort of 
 Bodies : 'Tis known to Hydroftatici- 
 ans, that^ according to z Theorem o( 
 Archimedes^ the weight of a Body 
 belonging to that kind, may be ga- 
 thered froiTi the weight of the Water, 
 that is equal, in Magnitude, to that 
 part of the Body, that is immerft in 
 that Liquor , when the Solid Moats 
 freely upon it ; as, if a Parakltprpt^ 
 cLon^ or zCylindtr^ of Wood, 12 In- 
 ches long, being placed upon Water, 
 fbould r^ft there, when a 12th part 
 gf it lyes beneath the Surface of the 
 Liquors in this cafe, the Weight of 
 tJie Water, equal in Bulk to that im- 
 merft 1 2Ch part,would be equal to rhe 
 weight of the whole woodenBody .But 
 bjecaufe the Bodies, wbofe Bulk Phyii- 
 ians ajid Chymifts may have occa^ 
 I 3 fioa 
 
fion toExaminc^will vef j7 feldomliap^ 
 pen to have Shapes fo near thofe of 
 regular Ones; *twiltfcarcebewoirth 
 our while toinlarge upon this Way 
 of Eftimating light Bodies 3 which 
 'twill be fo trpubldlbme to make fit 
 for moft Mens Praftice^that, unlds it 
 be defired, I fhall not trouble yoi^ 
 with it ; but forthwith proceed to 
 what will conduce far more to our 
 prefent Defign , which being. To 
 tneafiire the Solid Can tents of Bodies^ 
 not fo heavy (intenftvdy) as Wdter^ 
 ' and for the mofi part irregnUrly 
 fhafd 5 It will be neceflary, that we 
 imploy a Method differing from what 
 we have hitherto made ufe of. In 
 theFirft ftep of this, tho' not in the 
 Second, we may be helped by the 
 induftrious Mfr/e;?;;^^: Who proba- 
 bly borrowed his Way of QhetaU 
 df^i from whofe Promot us Jr chime* 
 dts, he profeiTcdly borrows many 
 things. 
 
 But becaufe, that ,on this occafion, 
 Mtrf^nnm^ aftefling Brevity, hath 
 made himfelf obfcurc, fo that what 
 
 he 
 
^ - 
 
 3>e writes can fc^'rce bfe- tilKJerWobS, 
 tut by Mathematieal Peruferis ; 'I 
 #iall, for the fake of another fort oT 
 ^Readers , deliver the' propounded 
 •Method, tho* not in Co few words, 
 yet m<3redearlj^, and orderly : F/rfi 
 then, you fhal] weigh in the Air, the 
 Body, (lighter than Water) to be 
 examined : 'Smmdlv^ you fhall taire 
 a Plate of Lead capable bfinaking 
 this Body fink with its felf in Water, 
 and of Ibme Weight not mcumbri/d 
 with Frafibions, as juft aDram, half 
 an Ounce, an Ounce, &c. Thirdly^ 
 you muft weigh this Plate in Water, 
 and • by^'tubftrafting .its- Weight iq 
 this Liquor, from what it weigh'd 
 in the Air, you muft obrain a Dif- 
 ference, which will give the weight 
 of as much Water, as is equal iii 
 Bulk to the immerfed Lead. This, 
 for diflinftionsfake, may be called, 
 The fpecijick Weight of the Ledd in 
 Wa^er. 'Fourthly^ you rniift tye to^ 
 gether (which you may'beftdo by 
 One or more Horfe-hairs,) the Plate 
 of Lead^ and the lighter Body, and 
 I 4- ' pore 
 
f ^ Mtdicina Hydrojlatica : 
 
 note the Weight of the Aggregate j 
 which, as you know, is nothing but 
 the Slim of the refpeftive Weights 
 of th^ lighter, and of the heavier, 
 Body, Fifthly, you muft weigh this 
 Aggregate in the Water, and fub- 
 ftrafl: its Weight in that Liquor , 
 from the Weight that the lame Ag- 
 gregate had in the Air; and thp 
 pifffercnce will be the Specifick 
 Weight of the feid Aggregate in 
 Water, Sixthly, From this Diffe- 
 rence 3 fubftrad the formerly found 
 §pepifi(k Weight of the Plate alone i» 
 Water, and the Jlemajns will give 
 you the Weight of the lighter Body 
 in the fame Liquqr^ 
 
 Thqs far our Author 5 without 
 whofe help, we may eafily difpatch 
 J the reft qf our Work, by the Mer 
 tbcd implpyed already of meafuring 
 Solids heavier than Water. For the 
 lately obtained Weight of the light 
 Body i^ Wat<2r, being, (accorduig 
 to the Method formerly propofedj 
 divided by ^^56 Grains, will giy^ 
 yoy the Solid content of that nati|- 
 yglly floating Bpdy, PUt 
 
An ESSAY. Ui 
 
 Butbecaufe a Method, that is dif* 
 ficiilt enough to be put in Praftice 
 by tbofe that are not nwre than on 
 cJinarily well vcrled in Hydrofta. 
 jicks, requires to be illuftrated by an 
 Example ; I fhall fubjoyn an Expe- 
 riment, that may ferve, not only to 
 clbar upthisPraftice,but,in good mea- 
 fure,to confirm it too ; We took then 
 a piece of Oa-k conveniently fhaped, 
 and that weighed in Air, 193^ Grains. 
 To this we tyed with an Horfe-hair, 
 a Plate of Lead weighing juft half 
 an Ounce, /. e. 240 Grains. But 
 before we tyed them together, the 
 Lead was weighed in Water, where 
 it loft of its former Weight 20 
 prains, which, being deduced out 
 of the 240 Grains lately mentioned, 
 left a Difference or refidue of 20 
 Grains, for the Specifick Weight of 
 this piece of Lead, (For I have fel- 
 dom found Lead quite ib heavy) in 
 the Water. Then the Aggregate of 
 the Wood and Lead was weighed ; 
 Firft, in the Air, and found to be 
 45 3 Grainy and an half, and Then in 
 
 Water., 
 
4S^2 Medici/fa Hfdrofiatica : 
 
 Water, where it amounted 'but^ to 
 i62Gtams; which being fobftri^- 
 flted from the Aggregate or the fkm^ 
 Bodies m the Air, the Refidtmil^iif 
 Difference, was found to be 271 add 
 4 Grains: From which Difference^ 
 the other Difference of 20 Grai'BS 
 •^wjiich had been lately found) of the 
 ie4den Plate alone in the Water^ be- 
 ing -dedufted 5 there remained 251 
 Grains and % for the Weight of Water 
 equal in Bulk to the given piece of 
 Wood. If thisnumber had amotHi- 
 ted to 256 Grains , of which it fell 
 fliortbut 41 Grains, we might have 
 concluded the Solidity df it to' be a 
 Cubick Inch ; fince 256 Grains of 
 Water , which we formerly foiind 
 equal to a Bulk of Water of a Cu- 
 bick Inch, was alfo now found equal 
 to the Bulk of the given piece of 
 Wood. And indeed, intending (as I 
 formerly intimated) to give an'Ex- 
 afnple,that fhouldnor oniy Illufbr^te, 
 but Confirm, the propofed Pra&ice ; 
 I caufed the Wood I imployed to be 
 formed intp as exaSt a Cube of an 
 
 Inch 
 
An ESSAY. 125 
 
 Inch everyway, as I could procure 
 from a Joyner, that bragged of the 
 Pains he had taken about it ; So th^t 
 the Difference of its Weight in Wa- 
 ter from 256 Grains, the Weight of 
 a full Cubick Inch of that Liquor , 
 may probably be imputed to fome 
 little Imperfeftion in the Figure of 
 the Wood, or fbme other light Cir- 
 cumftanccj not confiderable tflough 
 to be much regarded, 
 
 Of this Experiment one of my Notes 
 gives the following Account. 
 
 I. The Oaken Cube in Air) , 
 weighs f^iii Grains xin ;.) \ 95*- 
 
 II. The Weight of the tead") 240. 
 in Air, ^iv.) j < * 
 
 III. The Weight of the Lead^ 
 
 in Water (^iiif5 Grains xj/220. 
 which, being fubftrafted from > 
 its Weight in Air, leaves forvs^^o, 
 its iSpecifick Weight in Water ^ 
 
 IV. The Aggregate of thel , 
 Two in Air is j'455.- 
 
 V. The 
 
1^4 Mediciaa Hydrojtatica : 
 
 V. The weight of both ) 
 
 together ia Water, is C162. 
 
 Which being fubftrafted fromf 
 its Weight in Air , gives the ) 
 Difference of both the Ag-? 
 gregates, ^*7n- 
 
 VI. The Difference be- 
 tween theweight of Lead a- 
 Ipne in Air, and in Water, ori 
 which is all one, theSpecifick 
 weight of the Pla4:e alone,i//-2;.^c20. 
 being fiibftraSbed from theDif-/ 
 ference of the weights of thersji'. 
 Aggregates in Ajr, aqd in Wa-\ • 
 ter, gives [for theweight of . 
 the Cube propose,] 
 
 The Way of meafuring Bodies, 
 that has been hitherto delivered, is 
 appropriated to fuch, as will not at 
 all, or, at leaft, will not readily , be 
 dilfolved in Water. But becaufc 
 there are divers other Solids, a§ 
 Lumps of Sah^ Jlume, Vitriol^ 6V/- 
 gar^ &:c. whofe Magnitudes it may 
 be fit for inquifitive Men, of more 
 Profeffions than On^^ to know, and 
 Xp compare ; I fhall to what has been 
 
 already 
 
An ESSAY. i^j 
 
 already faid, fubjoyn this Adver- 
 tifement ; That the fame Way may 
 be applyed to meafure the Magni- 
 tudes of Solids diffoluble in Water, 
 if,infl:ead of this Liquor, we fubfti- 
 tute Oil of Turpentine ; whole Pro- 
 portion, and Specifick Gravity to 
 Water, we have found , or is other- 
 wife known to us. When I firft 
 made this Reflcftion, I had not fuch 
 Conveniencies, as when I found the 
 weight of a Cubick Inch of Water^ 
 to determine the weight of a Cubick 
 Inch of Oil of Turpentine. But^ 
 having yet lying by me the hollow 
 Veflel of Brals, whofe Cavity was 
 an exaft Inch, that I imploy'd to 
 find out the weight of a Cubick Inch 
 of Water ; I made ufe of it on this 
 occafiontoo: and found that, when 
 it was carefully filled with fuch Oil 
 of Turpentine, as we were wont to 
 impjoy about Hydroflatical Experi- 
 ments 5 the contained Liquor a* 
 mounted but to 22I Grains, and an 
 Eighth (part of a Grain 5) by which 
 number the DifFerence of the weight 
 
 of 
 
I26i MediciftA HydrofiaticAi 
 
 of a Solid in the Air, and in that Oil, 
 being divided > the Quotient will 
 give you the Solid Contents of the 
 examined Body. 
 
 ^ After fo cireumftaiitial an Ac- 
 count, as we have given,of the Way 
 q£ Hydroftatically examining fuch 
 floating Solids^ as, hke the Wood 
 we imploy'd, are of a Texture at 
 leaft moderauly clofe ; it may be fea- 
 'fonable, to proceed to the mention 
 of the Second fort of floating Bo- 
 dies, that 1 formerly told you, might 
 be propofed to be weighed in Wa- 
 ter: Namely, fuch as, by their Po^ 
 tofity or Luxemfs of Texture, are 
 fubjeft to imbibe too much of that 
 Liqaior$ even ia as little time as is 
 .neceffary for the difpatch of the Ex- 
 periment. 
 - j^. I'X -Merfenmts (more briefly than 
 Phje'no- fCJearly) propofes an Expedient in 
 mcna Hy- j-fjij ^afe, wWch is to cover over the 
 talllX Body to be weighed in Water with 
 Wax, iPitch, orfome other Gluten, 
 as he calls it,whofe Speciikl? Weight 
 in Water muft be firft knawHr Bur, 
 
 I 
 
An E S S A Y. 127 
 
 1 taEeoBees-wax to be much prefe- 
 iable< to the other Two, For Pitch 
 k>%:apt to ftick to Ones Hands or 
 Gloathes, that 'tis troublefome to 
 apply it, and verydifBoilt togetilj 
 iff 5 And as for Glues, moftofthem, 
 elp^^ciaHy the more common, arc-difi 
 fblUble in Water, and therefore not 
 fo&tfot the purpofe: as Bees-wax^ 
 (fep'That, I prefuf^e, lie means by 
 Wa$C4')v^^bich has this Gonveniency 
 kpn\titkti its Proportion to Wa^ 
 tet bd^fig ttfualiy conftant enough, 
 artdb tke'Gravicy of thofe two Biodies 
 ditJerti^g 'but' lUi\cy one may. orore 
 eaiily d]fpiatch,a good part of .the 
 Experiment ; i\Xthk:h is tims ta be 
 performed Take the Solid' lighter 
 tJhaPuWa^ter , ttiartj!iyou woiijd -exa- 
 fWi^>lMydroftat3eailiy , and Waving 
 w0^f)'d''it in the^ Air , ov:er4^y ic 
 ckrmiWy with* ^thih Goat ofiBees- 
 li'ffKf ■ f^' that no) pa^e' of it may t6- 
 •mm uncovered,'' waccertible to the 
 Lfquor^ Then take 'alfo in the Air 
 the Weight of the Wax you ha ve 
 ^ift^tpy'A, and^faften to the Body 
 '""'<' thus 
 
^j8 Medicma HyArofidticai 
 
 thus coated, a Plate of Lead, or TitiJ 
 heavy enough to make it fmk, and 
 oblervc the weight of the Aggre- 
 gate in Water. This done, fub- 
 ftrafl: the weight of as much Water, 
 as is equal In Bulk to the Wax, and 
 proceed with the reft, as is before 
 taught* Mtrftnnus declares this 
 Prafticeby this Inftance,ifthe Wax: 
 that invefts the propofcd Body be of 
 |xxi j in the Air,the Bulk of Water e* 
 qual to it will be |xxi ; and therefore a 
 Quantity of Water of^xxi, muft be 
 firft taken away, or fubftrafted, that 
 the remaining Bulk, equal to the 
 (immerft)Body,may,by itsGravity^ 
 fhew the Gravity of the Body (prof- 
 pofed,) as has before been faid. : . 
 But, becaufe the Way, above deli- 
 vered, can help us but to the know- 
 ledge of the Weight of the propo- 
 fed Body in Water; we muftj to 
 difcover the SolU Content of it, pro- 
 ceed further than our Merfennus ^nxr 
 bles us to goe; and therefore we 
 muft divide the Weight of the^o- 
 lid in Water, already found, by 256 
 
 Crains^ 
 
An ESSAY. *2^ 
 
 Grains, that by the help of the Quo-, 
 tient we qiay obtain the Solid Con^ 
 ients of ihe prdpofed Body. 
 
 I have (biiietimeS ^to add That 
 iipdri the Byj) tKoiighc o£,and try'd; 
 another Expedient, to hinder fmailer 
 Solids, whether Hghter or heavier 
 //^.Siberie than Water, from imbibing 
 the Ambient Liquor. In ordet id 
 tills, Ip/l found the Weight of at 
 Cubickinch of QuickGlver, ^whicK 
 is not/difficult to difcoyer by its Pro-^ 
 portion to Water of the fameBuIk.J 
 And tlkh 'WQ brought the Body to. 
 be liiedfured, into a Veffeli whole! 
 Solid Contents were known before ; 
 and Thirdfy, all that was not pdT- 
 lefled by the firm Body, being filled 
 with Quickfilver, 'twas eafle ^^ 
 hough t0 know by the Ditference 
 in Weight of That Quickfilver, iroih 
 the Weight of the Quickfilver, re*- 
 tjuiiite to fill the whole Veffel, to 
 how iliuth Quickfilver the environed 
 fcody w^as equal. Ana by this mean?^ 
 and the knowledge before gained of 
 the Weight of a Cubical Inch of 
 K Mercury^ 
 
i^o Me die w A H)/dro(lAtica : 
 
 Mercury, the Solid Contents of the 
 Body propofed was not difficult to 
 be obtained. But I forbear to give 
 more than this Intimation of an fix« 
 pedient, which, befides that it be* 
 longs properly to another Eflay, is 
 rather Mechanical than Hydroftati- 
 caK And for the fame reaibn, I for- 
 bear to fetdown one Way of mea* 
 furing the Contents of Irregular So- 
 lids, delivered in fome Books of Pra- 
 ftital Geometry ; and another, but 
 yet unpublifhed, Way, differing e- 
 nough from the Former, that tends 
 to the lame purpole. 
 
 CHAP. XVI. 
 
 BiJIt, I perceive, that *tis now 
 ) more than time, ttiat I fhould 
 put an end to a Labour, that has, 
 I fear, tyrM you , becaule, I am 
 fure, it has tyr'd me. ' And yet I 
 dare not conclude this Traft with- 
 out briefly anfwering a couple of 
 ' Queftions, 
 
An £SSAYi i^r 
 
 Queftions, that, I forefee, may juftly 
 enough be asked me by ^ Perufer df 
 the foregoing Eflay. 
 
 And )&y?, I prefume irmay be de* 
 marided, Whethtr I have propofed 
 the hefl fVdys thM can be thought of^ 
 to examine Bodies Hydi^ojlatitdlly } To 
 which Queftion I anfwer^ that, upon 
 divers Confiderations, fbme of which 
 have been mentioned here and there 
 in theBody of the foregoingEfTayJdid 
 not think my felf obliged folicitolifly 
 tb InventjOrptopoundjriew Inftru- 
 inentsfor the- Hydroftatical Bxdtnen 
 of Bodies. -P©T tho laili not Igno* 
 rant, that diWrs mord curious and 
 Artificial ways of finding out their 
 Weight in Water, or their Solid 
 Contents by it, may be deviled by 
 Perfons inore skilful and fagacious 
 than L And tho* alio I think it not 
 Unlikely, that, when the Utility of 
 fuch Praftices coiiles to be taken no- 
 tice of, Artificial Inftruments will 
 be found but to Facilitate, or other- 
 wife Improve them : Ttt^ I thought 
 it became me at firft to propound 
 K 2 only 
 
IJ2 Medicina HyJroJiAtica : 
 
 only themore fimple V^fe'ys of Opera* 
 ting, as the moft likely to invite the 
 Generality of thofe, -for .whole fake 
 this Effay-is; made publi^k ; and to 
 require, for the. main parr of our Ex* 
 periments, only the life of the Bil* 
 lance, as an Inftrun:}6nt eafily pro- 
 curable, and already,' for other pur- 
 pofe, in moftMeos hands, without 
 mentioning, at thisti^Tie^ any more 
 f Artificial Inftruments; iithoMomQ of 
 them are fueh, as I have long fince 
 not. Only had thoughts of, but, for 
 
 riny.ownLlfes, praftifcd;;* which Itir 
 timatioa may be CA'*"itejnanced, if 
 it wereineedMi by-jE^ife cnention of 
 that littlsf Inflirum^qfev; for diftin- 
 guifliing between, trvieand counter- 
 feit Guineas- or th^ lik^ Pieees bf 
 coyn'd.Gold,- by the help^pf Water; 
 
 : which vvasjfcveral ^^Mt^ ago pub- 
 
 • ii filed i^jtbe-; Phil0fophi<?al T;-;anfiai. 
 ons, and Jia3 fincc (wichoiit flay- 
 ing for i. my; Improvement^ of itj 
 been made Ufe of by Som^, and 
 ufiirpM! by rOthers* ;.Buc,:pf fuch 
 thing.s> no more in this place. 
 
 i . ,. Having 
 
: An ESSAY. 133 
 
 Havirtg anfwiered the' Firft Que- 
 ftion, it remains , that I confider 
 the Second, wherein tho* I Jfhall aim 
 jat Brevity as much, as in the for- 
 mer, yet I fear, I (hall not bq able 
 todifcufs it in as few Mnes, as I 
 did That. I prefymc then, it willbe 
 asked, fVhat Qredit may be given to 
 the EJtimates of the Weighty and 
 Proportions of Bodies ^obtained by Hy* 
 drojlatical Tryds f Since,we lee^ that 
 tho* Mathematicians, not knowing, 
 or not applying, our Obfervationa- 
 tout the Specifick Gravity pf Rock- 
 Chryftal, and the Nature of OiU 
 efpecially that of Turpentine, have 
 given us but the Proportions of Me- 
 tals, and fpme very few other Fa- 
 miliar Bodies, as the Loadftpne , 
 Wax, Hony , Oiland VVine; yet 
 thole few that have not tranfcrib'd 
 from one another, differ ir> the Ta? 
 bles, they have left us, of theComr 
 parative Weight of ;hofe few Bor 
 ^ies. V : "- 
 
 This Queftion is (b con^prehea- 
 
 fjvg, that, t chink, it cannot wqII r^r 
 
 K 3 ceiv.^ 
 
I j4 Mqdmm HydroJiaticA : 
 
 e^ive a fingle Anfwer ; and therefore, 
 I (hall offer Two things to be confi- 
 d^red about it. 
 
 And firfi, I freely acknowledge , 
 that there i§ no exaft Uniformity in 
 the Obfervations deHvered about the 
 weight of Metals, and the other Bo- 
 dies newly nam'd, among the few 
 Authors that have written of this 
 Subjeft ; and there would proba- 
 bly have beeii yet more Difference 
 in their Accounts , if feme, even 
 of thofe Writers, had not avowedly 
 made ufe, to their purpofts, of as 
 much as they thought fit of the Ta- 
 bles of Ghetaldus, 
 
 Nay, Ifhall not think it very 
 ftrange , if I find, that the Experi-* 
 Hients of the fame Man, made at dif 
 itant times, and in other differing 
 Circumftances, fhould not ^11 of them 
 exaftly agree. For I have already 
 noted, and, I think, in more places 
 i;han One, that there will fcarce be 
 found fo greap an Uniformity in 
 -Qu^liiies, and particularly in Spe, 
 ari(jk weisht, among Bodies of th^ 
 
. An ESSAY. 135 
 
 fame Kind or Denomination, as there 
 is generally prefum'd to be. There 
 may bt alfo fome Difference , tho' 
 but little, .betwixt the Waters Men 
 employ, efpecially if the Air beat 
 One tinae (asin jf///y^ intenfelyhot, 
 and at Another (as in January) ex- 
 ceeding Cold* The Difference alfb 
 of Degrees of Goodnefs of the Bal- 
 lances, Men employ about nice Exr. 
 periments, is nor altogether incon*^'^^-^ 
 fiderable. But there is a thing of 
 greater Moment than this, towards 
 the hindering Hydroftatical Expert 
 ments, and even Statical Ones them- 
 felves, from being fo accurate, as 
 thofe, that are not verfed in fuch 
 Matters, may require. The thir^g 
 J mean, is, the Difficulty of finding 
 an exafl Uniformity in Weights of 
 the iarae Denomination, which, for 
 that Reafon, are vulgarly fuppofed 
 to be exaGIy equal ; But, to know 
 how far this Suppofition is to beTe- 
 ly'don, it may at prefent fuftlce to 
 (etdown fomePaffages of a Math?- 
 matician juftly famous for his dili- 
 K 4 gence, 
 
ji$ Medicine HydrofiAtica ? 
 
 gence, and who has made it his par- 
 ticular Work to examine thefe Mat- 
 ters fcrupuoiufly. 1 he firft Paffage,| 
 
 ^ Ihali allege put bf his Writings, ftiall 
 be the fhort Account he gives of ma- 
 
 ^ ny Tryals he mad^ of natural Grains, 
 
 whence all forts of weights have 
 
 In Pr^fa. tg^^ dcduced. Ciim (faith he) om- 
 
 tionc ad ^.^ - I r ■ • /■ 
 
 Librum ^^a grana^ vel/emwa^ fu reper^ri/O" 
 
 de Menfft- k/jf in atfUs vemltbus Lutetia , ad 
 [l^'P°^^^''^/4rer4w €xpepdiffem\^ vix^que granum 
 numrtii?. ullum ipter ejufdcmfpeciei gram gtano 
 ulttrt exaOe refpondtffet ^ in incertis 
 ludtrt nolui. The fame Author in- 
 forms us, that the Rontan Grains dif- 
 \fer ixomiht French Grains; fince, 
 as, he pbferves, 688 Grains of the 
 former fort, are E<^uipond^rant but 
 to 576 Grains of the later fort. And 
 he f ubjoyns,thar, whilfl he was wri^ 
 ting thelethings,there was found by 
 the more pxaft weights of the Mint, 
 in Error in the forpner Eftimate, of 
 at leaft half aGrairi in 56 Grains. 
 
 And elfewhere he gives notice, 
 
 ihatjby two Relations, fent him from 
 
 J^opi^y 
 
An ESSAY. IJ7 
 
 Rome^ about the Number of Grains* Merfennut 
 contained in a Roma» Ounge, it ap- 'pJemuZ 
 pear'd, that even that Number vari- H paril 
 ed, fince One of thpfe Relations re- p^"^^ 
 ckoned 612 Grains in an Ounc?, cwwX 
 whereas the other allowed itbqt^"<^2. 
 576 Grains. And yet this I do not 
 wonder at, becaqfe I have my felf 
 found it fo difficult in Praftice, tp 
 get and keep Weights (for, as little 
 as this is wont to be fufpefted, the 
 the very Air may, in time, a little 
 alter them,) as exaft^ as I defired , 
 that I left off the hopes of it. And 
 one Remark, tho' commonly over- 
 looked, I think too confiderable tp 
 be here omitted. For^ whisre^sthe 
 accurate Gheta^ldush Tables of the^e/c^J?^" 
 Weight of Metals, and fome few Gaiic. 
 other Bodies, in reference to oneanq- ^'^^m^ 
 ther, are looked upon as the rnoft Au- 
 thentick that have been publifhed ^ 
 are accordingly made thej moftufe 
 of : ?Tis certain, that the Weights h« 
 pmployy are not divided,as Ours are. 
 I^pr, tha' indeed agcgr^ing to lun^. 
 
ijS Medicina HydroftaticA : 
 
 as well as with us, the Ounce con* 
 fifts of Four and twenty Scruples ; 
 yet the Scruple, which with us is di- 
 vided but into 20 Grains, he divides 
 into 24. But to return to Merfenms^ 
 a while after he had told us of the 
 Difference between his repeated 
 Tryals, and Thofe of other Men, in 
 determining the Weight of a certain 
 Body , he has this Paffage ; which 
 fhews, that he was not over-con- 
 fident of the Precifenefs of all his own 
 Peterminations. Cum autem(Qiith he) 
 pag, jj. lib. 16. DixijChelinum^ unde- 
 fim did denAxiorum^ cYcdimt tamta 
 aBi decern d/wtaxat, nil ajfero. 
 
 Having gone thorough the Firft 
 part of my Anfwer, to the Second 
 Query above propofed, it remains, 
 that I proceed to the Other part ; 
 which perhaps will not need more 
 than the following Refleftion. 
 
 Iconfider then, that t/jo^ it be 
 granted 5 that HydroftaticalExpe* 
 riments are not always either fingly 
 'gccurace, or exaftly agreeable among 
 
 them. 
 
An E S S A Y. i J9 
 
 themfelves 5 yet they may w^H be, 
 both accurate enough to be of very 
 good life, efpecially in Praftice ; and 
 lefs remote from being quite accu- 
 rate, than any other Ways that have 
 been hitherto known to be Pradifed, 
 of determining the Proportions of 
 Bodies in point of Weight and Bulk, 
 and of meafuring the Solid Con* 
 tents of ftable Bodies, whether hea- 
 vier in Specie than Water, or ligh- 
 ter. 
 
 The Firfi part of this Refleftion 
 may be deduced, as a Corollary /r^Ki, 
 or at leaft confirmed h^ the greateft 
 part of the foregoing Eflay. And 
 indeed , as little Skill as I have in 
 Hydroftaticks, I would not be debar- 
 red from the IJfe of them/or a con- 
 fiderableSumof Money ; it having 
 already done me acceptable Service, 
 and on far more occafions , than I 
 jny felf at firft expefted 5 efpecially 
 in the Ejf^we^ of Metals and Mine- 
 ral Bodies, and of feveral Chymical 
 Pfodu^iops. And I have been able 
 
 more 
 
140 Medicina Hydrojiatica : 
 
 ippre than once or twice, to unde^ 
 ceive Artifts and other Experimen- 
 ters, that, bona fide^ believecl they 
 Had made , or wqre Poffeflbrs of, 
 JLuaa fixa, (as they call it) and other 
 valuable things : And to make a good 
 Judgment of theGenuineneft or Fal^- 
 fity, and the Degrees of Worth, or 
 Strength, in their kind, of divers ri- 
 cher or poorer Metalline Mixtures, 
 and other Bodies, (fome Solid, and 
 fbme Liquid,) whofe fair Appea- 
 rances might otherwife have n^uch 
 puzzlqd, if not deceived, me. 
 
 But of This more rpay be found in 
 another Paper. For I rauft haften 
 to the Second part of our defigned 
 Reflexion, by reprefenting, That 
 our Hydroftatical Methods of difc^o- 
 vering the Weights and Bulks qf 
 Podies, tho' they h§ pot Mathema- 
 tically accurate, yet they are lefsre- 
 inote from being fb, than any Way 
 of Mcnfuration of Bodies, (efpeci- 
 ally fuch little Ones^ ^s we ufually 
 l^ve 0?-<^d \9. ^^i^anji"^ pn thq ac- 
 
 foujip 
 
An ESSAY. 141 
 
 count of the Materia, Med/cay) by 
 the Geometrical Inftruments,that are 
 hitherto known to be Praftifed ; or; 
 
 by the Way, whereby the T^^/^A* Ygruiam 
 Coitionis d^ Exfanfionis Mattria yer in HUto- 
 SpatUinTangibilibus, &c. was fra-^^^^^^^"p 
 ined by the renowned Sir Francis m,%. fc«l 
 Bacon^vjhoik judicious Refleftions up- 
 on the Rarity and Denfity of Bodies^ 
 fuch as their meafures are delivered 
 in that TabIe,do fufticiently manifeft, 
 as the Philofophical Genius of the'^Au- 
 thor, fo the Utility that may be de- 
 rived from even fuch Determinati* 
 ons of the Bulks and Weights of Bo* 
 dies, as fall fhort enough of being 
 accurate* 
 
 I might here tehte, that, to con- 
 vince Ibme curious Perfons, how 
 much Hydroftaticks may be made 
 ferviceable to as accurate Menfura- 
 tions, as ought to be expeQed in 
 Phyfical Experiments ; I defired a 
 VirtHo[o^ Firft, to put together two 
 Lumps of Metal (.mz, of Tin, and 
 of Lead) in a certain Proportion, 
 
 that 
 
142 MedUinA H/Jr^Jhthat 
 
 that he was to conceal fromme,bilt 
 to fet do^vn in Writing to prevent 
 Miftakes* Then I defired him to melt 
 the Metals (whofe refpeftive Spe- 
 cifick Gravities I knew before) into 
 oneMaft, and give me that Mafs. 
 And Thirdly, I weighed it carefully 
 in Water ; and didalfo Algebraically 
 examine it. Which being done, t 
 told him, that the Lead, he had im- 
 ploy'djamounted to fuch a Werght, 
 and the Tin to fuch another; which 
 being compared with the Quantities 
 be had committed to Paper, the Dif- 
 ference was found to be little more 
 than one Grain, and this it ftlf pro- 
 bably proceeded from fbme fcarce 
 avoidable Imperfeftion in the melt- 
 ing, pouring dut, &c^ of the giveri 
 Bodies. But becaufe fpecious Arith- 
 metick was employ'd in this Work, 
 ("to which, yet it was not abfolute- 
 Jy necefrary,Ji I ihall lay no Strefs 
 upon it ; becaufe, if I miftake not, 
 the paft Difcourft may fuffice to 
 give the H} droftatical Ways, of Men- 
 
 furation 
 
An ESSAY- 145 
 
 furation of Bodies, a preference to 
 their Competitors ; and may keep 
 it from being prefumptuous, to fay, 
 that they may be received as the beft 
 for Praftice, till fome other more ac- 
 curate, and yet as firmly grounded, 
 and as Prafticable, Ways of accom- 
 plifhing the fame purpofcs, fhall be 
 propos'd. 
 
 FINIS. 
 
A Previous 
 
 Hydroftatical Way 
 
 o F 
 
 Eflimating ORES* 
 
fj ' 
 
 .8 J '.HO snrjfimii 
 
C 147 ] 
 
 Advertifeiiae^ts, 
 
 X'u'H 
 
 IfQ^oiv there is a greater Nimihcr 
 of different k^ndscfFoJJlks^ than- 
 Iboft that are ytt known to belong 
 tothe Materia Medica. And, I con* 
 fefs^ t hat. the Per fans ^ which the foU 
 lowing PAper is chiefly de finned to affijt^ 
 are thofe that exflore Minerals with 
 an Aim not d$ Health, hut at Profit. 
 Bu,t yet Itv4S content y thit thz en- 
 ftiing Difcourfe fjould accompany the 
 foregoing Effay , as a kind of Jp- 
 pendix to it^ hcauft many of the Sub- 
 jeBsy about which both Tra&s are con^ 
 "utrfanty are tht fame ; and the fun- 
 damental Ohfrvcttiony ^viz. about the 
 Speci^ck Gravity of Chryjial or Mir- 
 hle^ and the Hydrojiatical Way cfap^ 
 plying it^ in Expl'rationfj is the fame 
 L 2 . in 
 
chst 
 
 in both : and alfo, {and indeed^ chiefly ^^ 
 becatife I was mndt to belkve^ that tt 
 mighty effecially at this Seafon^ be 
 grdtefuly and not unufeful^ to divers 
 Searchers after fro jit able Minerals, 
 
 This Paper (jh the Infer if t ion in* 
 timates^ was dejigned to be fent to 
 the Learned Secretary of tlie Royal So' 
 ciety 3 when it was expeSed, that hje 
 would begin again to. publifh Monthly 
 the Philofophical TranfaUions ^ that 
 had been long fufpended^ ' and as long 
 d^flred by the Curious, B^^ fi^^^ 
 fame Accidents have occur rd^ that occa^ 
 (ion a further dthy of their Public ^u 
 tion^ it was not thought fit , this 
 Paper (^after having been long already), 
 fjjould be any longer confined t0y 
 my Cloftt, 'Tis true^ that this Dif\ 
 courfe^ containing but an Application of ^ 
 an Hydroflatfcal Experiment :y I am 
 far^ as I ought to be^ . from propofing 
 it as a Treat ife of the Docimaftical 
 Art ; whofe ^rarjd Iriflrument is^ the 
 Fire Skilf-Uy mana^d. For which 
 reafon Ihaveforeborn tofet down in this 
 
 Papery 
 
C 149 ] 
 Paj?er, any of the Flux Powders, or 
 other Ways of Examining Ores ; or of 
 Reducing Them^ or other .¥ off ks^ to 
 Metals or Regulus's J thir either Say^ 
 Majlers are wont to employ^ or Ih\v^ 
 devifedy or try* d, ufonMrntYds. Bnt^ 
 this notvoithfiandingy onr rwpraSifed 
 Way of Efiimating Ores, may not he 
 ufelef ; and for that reafon^ null not 
 perhaps he umvelcome to foment hat Love 
 Mineralogy J much better than'jt hey Vn- 
 derfiand it : Efpecially coming forth at 
 a time, when many indiifirioits Perfons 
 of this Nation are excited to look after 
 profitable Minerals, hythe Repeal {that 
 has been made^ ft nee our AppendiK 
 was written^ of a difcoiiragi?ig AB of 
 Parliament ^ made in the Retgn of 
 Henry the IV. Jnd thd our Hydro^ 
 \fi;atical Waj^ of Efiimating Foffilts^ 
 will not determine ho.v Rich or Poor 
 they are in this or that particular 
 Metal ; yety (as is intimated at the 
 beginning in the enfaing P^p.r,) it 
 it may^ on many occaficns^frve to\ ep- 
 L I thofe 
 
C ijo ] 
 
 thofe that are Venturous^ and not Skil- 
 ful , from being deluded by. Cheats , or 
 from dtludifjg themf elves with ilU 
 grotr/idedExpeSations j which the Pro* 
 mifing appearances of divers Fofflles^ 
 efpccially March afitts^ will temptingly 
 Invite^ hut ntver Anf^vtr, 
 
 % 
 
[ISO 
 
 A Previous 
 
 Hydroftatical Way 
 
 o F 
 
 Eftimating ORES. 
 
 Jddreji to the Secretary of the R. S. 
 
 SECT. I, 
 
 A. 
 
 T a time, wherein fb many 
 ingenious, or induftrious .^^^^/'''f' 
 Men appear very Sohcicous^^g^,'^;^^ 
 todifcoverand to work Mines, both Exammof 
 Here and in New Englaf2d^ and O- ^^'^^* 
 thers of liis Majefties Americcin Co* 
 Ionics ; it will not, probably, be 
 thought unfeafbnable, nor prove un- 
 L ^ welcome 
 
C^2 3 
 
 come to the Seekers of Subterraneal 
 Treafures, if my defire to do them a 
 piece of Service, make me borrow 
 of a Paper, I long fince wrote about 
 jfome things relating to the Materia 
 Medica^ a few Paragraphs, that con- 
 tain a Way of Exploraiion of Mi- 
 nerals ; which tho' it reaches but to 
 One of their QuaUties, will, perhaps^ 
 hy reafbq of the Gonfiderablenefs of 
 of This, keep, on certain Occafi- 
 ons, feme Searchers after Mines 
 from beginning chargeable Works, 
 or profecuting them with too great 
 Expeftations, which are ufuaily fol- 
 lowed by proportionable Difappoint- 
 ments. And I make the lefs Scruple 
 to fuffer this Fragment to leave its 
 Company, and prefent it felf toyou ; 
 becaufe, after the misfortune, I have 
 formerly fignified to you, of* the Lois 
 and Spoiling of feveral of my Wri-, 
 tings, I know not when, if ever, I 
 piay h^ve Opportunity of Commu- 
 iiicating to my Friends the Treatife, 
 ilm. thele Paragraphs belong to. 
 
 That 
 
That Part of the forementioned 
 Treatife, that concerns my prelent 
 purpofe, is founded on an Experu 
 inent, whereof what you are abouc 
 to read, is One of the Applications. 
 
 I fliall then fuccinftly inform, you, 
 that theObfervation, whereon my 
 Difcourfe was grounded, is double^ 
 as will by and by appear; and that 
 the Rife of it, which will help to 
 underftand the Nature and Influences 
 of it, was this. I thought fit, (for 
 Reafons elfewhere given) to find out, 
 what was the Specifick Gravity of a 
 pure Stone, fuch :js I fuppofed Chry- 
 ftal or White Marble, or a Stony 
 Ificle, to be ; and found it by the Hy- 
 droftatical Way of Tryal, (doubt- 
 left not unknown to You,) that is 
 delivered in the Effay called Mdi- 
 cina, Hydroftaticit , whereof when 
 you pleafe, you may command 
 a fight, to have to clear common 
 Water, equal to it in Bulk, or Mag- 
 nitude, pretty near the R^tio, or 
 Proportion of two and an half to 
 one; or, which is fomewhac m.ore 
 
 obvious 
 
c 154] 
 
 obvious to conceive, as five to two. 
 I faid, pretty near, becaufe 'tis not 
 always exact, nor need be for our 
 prelent purpofe, but ufually enough 
 does fomewhat rather exceed that 
 Proportion than fall fliort of it ; but 
 that is fo little, that it may, on all 
 common*Occafions,befafeIy enough 
 neglefted by a Mineralifl: : Tho', if 
 one pleafes, one may make ufe of the 
 Proportion of 2 i to i^that is, of 1 1 
 to 4. 
 
 S E C T. IL 
 
 THe Ufes, that may be made to 
 our prefent purpofe of this 
 Fundamental Obfervation, are ei- 
 ther of a more General, or of a more 
 Particular, Nature. 
 
 As to the firfl: of thefe ; When my 
 Intention is only to difcover in ge- 
 neral, Whether a Foffile propound- 
 ed, or perhaps cafually lighted on, 
 may with probability be judged to 
 
 conraia 
 
contain, any Subftance, either Metal- 
 line, or belonging to Ibme Foffile of 
 Affinity to a Metalline Nature j 
 .andalfo, Whether, in cafe thefirft 
 Queftion be refoivM in the Affirma- 
 tive, the propofed Body does, indefi- 
 nitely fpeaking, contain much, or 
 but little, of the Metalline or other 
 Adventitious Subftance : When.l fay, 
 I would only make thofe General In- 
 quiries,! weigh the Body I would ex- 
 amine, firftin Air,and then in Wa- 
 ter, and obferve the Proportion in 
 Specifick Gravity between them ; 
 and if I find it weigh either lefs, or 
 but little more, than Chryftal or 
 Marble of the fame Bulk, I judge 
 it unlikely to contain any Metalline 
 Portion, confiderable for its Qiian- 
 tity. And ifit weigh manifeftly, or 
 fomewhat confiderably^ more than 
 Marble or Chryflal, I guefs, that, in 
 Proportion to that 5^xce(s,it abounds, 
 more or lefs, witb a Metalline In- 
 gredient, or one or other of Affinity 
 toa Metalline Nature. 
 
 Tq 
 
To explain my felf a little by 
 two or three Examples ; 'tis known, 
 that the Magnet is vulgarly reckonM 
 amongft Stoms , and its great Hard- 
 nefs confirms Men in that Opinion. 
 But having obferved, that Load- 
 ftones, efpecially thofe that come 
 from fome Places, that I elfewhere 
 take notice of, feem to be apparently 
 more ponderous than common Stores 
 of the like Bulk 3 We weigh'd them 
 in Air and Water, and found their 
 Specifick Gravity, efpecially of fbme 
 ihe Au. ^f them, fo far to exceed That of 
 thormenm Chryflal ot Marble, that it could not 
 "* /fn'^n ^^ difficult for us to conclude, that 
 "^Ex^lri^^ thefe Fofliles contained a not incon- 
 y?2tv7^j ^W fiderable Proportion of Metalline 
 ttloui Matter, which, by Collateral Experi- 
 the LW-ments, delivered in another Paper, 
 flone, as appearM to be of a Martial or Fer- 
 mrai. rugmous Nature. 
 
 Emeri is a Foffile well known to ma- 
 ny Tradefmen, efpecially Armourers^ 
 & Gtwfmiths ^hy whom ^tis common- 
 ly reputed a mere Stone. But finding 
 that its Weight in Water cpnfids- 
 ' " rably 
 
[ 157 3 
 
 rably exceeded That of Chryftal of 
 the fame Bulk, fince it was to that 
 Liquor very near, as 4 to i ; I con- 
 jeftured, that it contained a Metal- 
 line Subftance,as afterward, by pro- 
 per Tryals, I found it to do. Upon 
 the fame ground, (its Weight in my 
 hand) I concluded, that L^fis H^- 
 matttes^ that is commonly fold in 
 Shops, and, as its Name witnefTeth, 
 pafTes for a Stone, did not fparingly 
 participate of a Metalline Ingredi- 
 ent ; in profecution of which Con- 
 jefture, I quickly thought on Ways 
 whereby Idifcovered, that Iron or 
 Steel was the Metal it contained. 
 
 And not to accumulate Inftances 
 in this place, I fhall advertifeyou in 
 general, (what perhaps may here- 
 after be found uftful to feveral En- 
 quirers) that, upon the Grounds hi- 
 therto mentioned, I was invited to 
 guefs, that divers Bodies, that were 
 little fufpefted to be of a Metalline, 
 or Mineral, Nature, did really con- 
 tain a Portion of Subftance that was 
 &: AndjE remember, in particular, 
 
 that, 
 
E ij8 3 
 
 that, having met with Granats of 
 fcverai fizes, that were not Bohemim^ 
 but were found in other Parts of 
 Europej and fbme that I difcovered 
 in a kind ofTalcy that was brought 
 me from America; which Angular- 
 ly figured Stones, I fufpefted by 
 their Weight to be Metaliick, and 
 found, by HydmftaticJks, to have a 
 Speeifick Gravity confiderably fur-i 
 pafiing That of ChryftalUponthefe 
 Grounds, I lay, Ifuppos'd them to 
 participate, and that not very fpa- 
 ringly, of a Metal, one or more ; 
 and, by other Ways of exploring^ 
 found, that I had guefled aright; 
 fince I was able, notwithftanding 
 the great Compa£tnefs of fuch feem- 
 ingly vitreous Bodies, to difcover 
 there a Decornpofition, and CKtraS 
 thence a Metallick Subftance. 
 
 To thefe I might add other FoP- 
 files, and fome that were not, even 
 by Men not unskilful, fufpefted tO 
 have any Metalline Ingredients. 
 But I have not time to fpeak of 
 
 Them, 
 
L 159 3 
 
 Them,and therefore fhall proceed in 
 theclately begun Difcourfe. 
 
 > r ,!.rf;(i'..-:.. ', ':^n t:i 
 
 . ,, S E C T* III. 
 
 '"TT^'O illuftrate theif the general 
 J;^ vObfervation, formerly laid 
 down> and make it more diftinft, 
 I fhall. fubjoyn the following Re- 
 marksi 
 
 F/r/, I do not pretend, by this 
 WayVto:make any more than pro- 
 bable Conjeftures and Eftimates, a- 
 bout the Contents of the Bodies, I 
 examine by it : But tho^ the Efti* 
 m^tes,grounded on it, be not always 
 True, yer they may be frequently 
 Ufeful, as may be gathered front 
 fome of the fubfequent Obfervati- 
 
 Secondly^ If the Foflile propofed 
 be lighter, elpecially if it be much 
 lighter, than forauch Chryftal, it is 
 an almoft certain Token, that it is 
 
 not 
 
[ i6o ] 
 
 not a Metalline Ore. And this Ne- 
 gative ufe, if I may fo call itj, of ouf 
 Hydrojlaticks.m^y be more fafely re- 
 lyed on, than the Affirmative Con- 
 lequehces ufually can be. Thus,whea 
 I find \\\2itjet, the' a Foffile dug up 
 in Veins , efpecially in the Fyreman 
 Mount ains^(2iS 2l Learned Man, whole 
 Brother has nhere a Mine of jfe/ ^ 
 aflured me) has far Icfsof Specifick 
 Gravity , than Chryftal 5 I conclude 
 it. to be no Metalline Body. The 
 like Inference I make, on the fame 
 ground, as to Foffile Amber or Suc^ 
 cinum^ Sulphur vive^ and the Obfeir- 
 vation holds in common Sulphur; 
 ( clear or Semidiaphanous ) Eng- 
 lifli Tak, Venetian Talc^ and fome 
 other firm Concretions, whether 
 Brittle or not, that are dug out of 
 the Earth. Among thefe, I think fit 
 to mention particularly Black- Lead, 
 -left the Name it bears, fhould de- 
 ceive Men into a Belief, that 'tis an 
 Ore of that Metal. For having found 
 its Weight, in reference to Water, 
 to be but as I fj^ to i. And, gather- 
 :\ ing 
 
[ i6i ] 
 
 ing from the Smalnefiof its Specifick 
 Gravity, that it would prove to be 
 very ucilikeour true common Lead 
 •^, OreSy I fouod, upon Tryal purpole- 
 r ly mad^, th^t, 'twas a Mineral////\ge- 
 mrisy and ftemed, upon; the fcorepf 
 rnore than one Qy^lity^ to be of kin 
 to a fort of r^/^, that I have rr^et 
 with. 
 
 Thirdly^ We fhould, r. diftih^uifh 
 between the feversil Ufes, that 
 Fofliles may be fought for, and exa» 
 rnined, by Men of different Profefli- 
 ons, orDefigns. And therefore, if 
 a FofTile be found to be Ibmewhat, 
 and yet but very little, heavier iri 
 Specie^ than Chryftal or Marble; in 
 may pofllbly have a Metalline or Mi- 
 neral Portion, which, tho' very 
 fmall in quantity ,may confift of fucll 
 Efficacious parts, as niay make it de- 
 ferve theEfteem-of a Jeweller,a Phy- 
 fician, or aChymift. But if the 
 Surplus of Specifick Gravity be in- 
 confiderable, the Foffile it icM will 
 be fb too to a Mineralift, that feeks 
 not to gratifie his Curiofity,or make ± 
 M . godd 
 
C 162 3 
 
 food Medicine, but to fill hisPurfe. 
 or the Charge and Trouble of 
 working a Foffile, fo poor in Metal- 
 line Subftance, will probably either 
 exceed the Profit, or keep it from 
 being confiderable ; whereas, if the 
 Specifick Gravity do much exceed 
 That of Marble or Chryftal, it may 
 give good hopes of proving a Sul^- 
 jcft profitable to be wrought on. 
 
 fourthly^ But, here I muft give 
 notice, that, tho^ for the moft part, 
 the great Ponderofity of a Foffile 
 proceeds from a Portion of fome 
 Metalline Subftance, more ftriQly fb 
 called, that isimbody'd with the o- 
 ther part of the Concrete ; yet this 
 alone is indeed a certain Sign, that 
 the Foffile is not a mere Stom^ but 
 is not alone a fure Sign, that the 
 M neral Portion is properly Metals 
 lin€\ and therefore, where there is 
 juft Caufe of doubr, 'tis beft to en* 
 deavour by fbme Collateral Signs to 
 rciblve it.The Reafon, why I thought 
 fit to give you this Admonition, is, 
 that, befides AJe/4////;e Ore/ more pro- 
 perly 
 
pcrly fb called, there are other Foa^ 
 files, which fome call Semi-Meuts^ 
 others Media Mif9traliay2it\A Others a- 
 gain giveother Appellations toj which 
 FoflileSjtho' of Affinity to Metals, are 
 wont to bediftinguifhed from true 
 MetallineOres;fuch(Fo(nies) as are 
 (that I may here name the principal 
 of them) Antimony^ B//»^/^^^,(ufually 
 in our Shops called Tin-gUfs) Lapis 
 Calaminaris ^ 2LViA Pyrites ^ commonly 
 called MarcafiteSy and vulgarly, in 
 Englifli, Vitriol Stont^.^ But th^re 
 will not perhaps occur many Cafes, 
 wherein it will be nec^flary to have 
 recourfe to Collateral Signs, to dil^ 
 cern, Whether the Mineral Portion of 
 a Foffile, be , in a ftri£ler Sehfe, of 
 a Metalline Natur^or not : For thefe 
 5e«i/-A/e^4/jthat Ifpeakof, aremoftf 
 commonly found either in Veins, Or 
 in Mafles, or great Lumps of their 
 refpedive Kinds ; and eafily difcover^ 
 to one that cOnfiders them with fo 
 much as a moderate meafiire of At- 
 tention and Skill , what Specks of 
 Foffiles they belong^^to, ,1 have in- 
 S4 2^ dee<i 
 
deed from Devopfjhire received a 
 Lump of Matter, which the Owner 
 of the Mine, not knowing what t© 
 make of, defired ray Opinion of^ 
 wherein ITound feme Antimny mixt 
 with Lead, which was the Predomiii 
 nantBody* But fuch Mixtures oc- 
 cur not often enough, 'at leaft here 
 in Erigland^ to keep our Way of 
 Eftimating ponderous Fofliles from 
 being, on moft occafions, ufeful. 
 
 Fifthly ."tv^ be ^t^oftnecefrai 
 ry to 'give you notice in this 
 place, that there may be' a two- fold 
 Eflimate made of the $pecifick Gra^' 
 vity of Ores VOr-^e, when the Metal- 
 line Body prppofed is weigh'd in its 
 natural State, that is, as. *tis taken 
 but of the Earth, accompanied with 
 the Sparr, or other Heterogeneous 
 matter, that firmly adheres to it^ 
 Conly the loofe Earth being firft wa- 
 fl'.sd off:) and the Othr^ after it has 
 
 been 
 
been beaten fmail and feparatedfrom 
 ftony, and other HeterogeneouSjSub- 
 ftances, by the help of Water ; 
 where being skilfully agitated, there 
 is eafily difcovered a notable Dif- 
 parity in Weight between thele, and 
 the Genuine, or Metalline, parts of 
 the Ore, which being thus fever'd 
 from the reft, are called, for inftance, 
 wafhed Tin, if afforded by a Vein ef 
 that Metal. And fbmetinies alfb 'tis 
 very llfeful,if not NecelTary, to pre- 
 pare the Ore by rofting it, (as they 
 fpeak) once, oroftner, or by keep- 
 ing it feveral hours in a competently 
 ftrong Fire,a^ is ufually enough done 
 to prepare Copper-Ore, efpeciallyif 
 it be ftubborn. I have diltindlly 
 inentioned thele Two States , 
 wherein the Weight of an Ore may 
 be eftirnated ; becauie, I have obfer^ 
 ved,that in feveral Cafes 'twill much 
 import the Experimenter to diftin* 
 gilifh them carefully. For feveral 
 Ores, which, in their natural State, 
 have too little of Specifick Gravity, 
 'to make them judged worth the 
 14 3 Charge 
 
[ 166 '} 
 
 Charge of being wrought, may yet, 
 teing prepared by Water and Firq, 
 aftbrd a Metalline Portion fb heavy 
 in Specie^ that it may give fair hopes 
 pf containing in it fbme Portion pf 
 Silver, orofQold ; and, in that cafe, 
 a fmall Proportion of the Former, 
 and a much fmaller pf the Later, \ 
 would render the Ore confiderable, 
 and make it pretty Rich , tho' not 
 in reference to the quantity it yeilds 
 of the predominant Metal, as Lead, 
 Tin, pr Cppppr; yet in ^more ab- 
 foIuteSenfe, as it may better recoo)- 
 penle the Charges of him that fhall 
 work it. Which brjngs into my 
 mind, that fbme time agoe a piece pf 
 J^eadOre, then brought out of he- 
 Jxnd^ being offered me tojudge of ^ I 
 found it fp light in the Lump, that 
 I thought it not at all worthy to he 
 wroughf: for Lead 3 bqt afterwards 
 upon Tryal it appeared to be, t^o' 
 very poor in that Metal, yet fp well 
 ftor'd with Corpufcles of bilver, that 
 1 fcrupled not to incourage the 
 Pwner ro beftpw Pains and Coft 
 ijppn it. SECT* 
 
C'^7] 
 
 SECT. V. 
 
 BUt there is one Kind of Mine* 
 rals, that I have obferved to 
 impofe on Men ib often, that I think 
 it neceffary to take a particular no- 
 ticeof them in this place. For,^ot 
 to mention Examples, that I might 
 draw out of the Books of Travel- 
 lers and Navigators, I have met with 
 I know not how many, that have 
 built great hopes, and ibme, (which 
 is worfe) that have been at Char- 
 ges upon thofe illufbry Expedati- 
 ons of great raatters from Marcajites, 
 And J remember,! have had fent me, 
 or brought me, not only from Places 
 nearer home^but from hotter and coU 
 der Countries of the//?^/ej themfelves, 
 Foffiles, whereof I wasearneftly de- 
 fired to give my Opinion, that I 
 found to be but Mnrcafites : And ma- 
 ny of thefe Foffiles having two Qua« 
 lities, that jnake them very fit to 
 ' M 4 delude 
 
C i68 ] 
 
 delude the vulgar, and the unskilfii!, 
 namely^firftja Multitude of fhining 
 itreaks, or other giiftering parts ufu- 
 ally of a Colour near enough to That 
 of Goldjand fometimes to That of Sil- 
 ver ; and then, a Ponderoufhels ufii- 
 ally not inferior, atleaft, to that of 
 true Metalline Ores ; Marcajites, I 
 fay, being thus fitted to delude the 
 unskilful,! have had tpuch ado to un- 
 deceive fbme, that brought or fent 
 me them from Amtrica^ of the plea- 
 iing Confidence they had qjitertain- 
 ed, that thefe promifing Po'ililes 
 Were Lumps of rich Ore of Gold, or 
 Silver. Wherefore fince their Pon- 
 deroufnefs (which is tht Criterw^ o^ 
 Minerals, I am now treating of,) is 
 Pne of the Two chief Things thac 
 delude fo many, I think it expedi- 
 ent, tOiubjoyn feme few, but.vari- 
 ousjnftances of theSpecifick Gravity 
 oiMarcafuef^vjhtTthy it may appear, 
 that feme of them are, Bulk for Bulk, 
 far more ponderous than divers truq 
 Me,talline Qies, that I have? try 'd, 
 have been found to be. And indeed 
 '' ' ' ' ' this 
 
[169-3 
 
 this ' great PcHiderofity has feveral 
 times invited me, before I made any 
 Artificial Tryal of propounded Vot 
 files, and fometimes before I took 
 them out of the Bags or Papers to 
 look on them, to judge, tho' perhaps 
 to the Surprize of thofe that brought 
 them, that they were not true Ores, 
 but hhrcafnes. And , becaufe this 
 Miftake is fpecioudy grounded, and 
 has deceived many, whereof fbme 
 have undertaken Voyages betwixt 
 Europe and the Ladies, upon confi- 
 dence of the value of thefe ghftering 
 Stones; I fhalldecHne a httle the Me- 
 thod of this Paper, which confines 
 me %o the Hydroftatical Way of ex- 
 ploring Mineralsj to advertife thofe 
 whom it may concern, that they 
 may eafily try almoft any Stone, 
 that, by its great Weight and Luftre, 
 they fufpeft to be a NLtrcafite^ if they 
 put.it, either within a Crucible, or, 
 without One, into a well-kindled 
 ' Fire, and blow now and then upoA 
 it with a pair of Bellows. For, by 
 this meansj the Sulphur, wherewith 
 
 Mircifites 
 
MarcAfius are wont to abound, (fb 
 that Iremember,thatevcnby Deftil- 
 lation in a clofe VefTel, I had §iv of 
 good Qrimftone, like the vulgar, 
 outoflbiij of the Stones^ will take 
 Fire, and burn with a Flame for the 
 moft part blew, like that of com- 
 mon Sulphur. And, if when it cea- 
 fes to flame and fmoak, you take it 
 out of the Fire and let it coo!, you 
 will find it deprived of all the gau- 
 dy appearance of rich Metal it had 
 before, and turned to a brittle blac- 
 kifh Subftance,diflFering enough from 
 That of a Metalline OtQ^mcre (Iri&ly 
 fo cdikd. Thefe laft words ladd, be^ 
 caufe.in a lax Seofe/tis eafie to fhew, 
 that Marcajites, at leaft thofe that 
 i have tryed, may be looked upon as 
 a kind of Metalline Bodies, For, be* 
 fides that I have found divers of 
 them to contain Particles of Copper, 
 I found all, that I purpofely exami- 
 ned, to contain, and fbme of them 
 plentifully enough, Corpufcles of 
 Iron or Steel, as plainly appgar^d, 
 when, after the newly menrioried 
 
 Calcination, 
 
 ,-^-* 
 
Calcination, f for with crude Mar* 
 capes I found not the following 
 Tryal tofucceed) lapplyed to the 
 pulverized Remains a vigorous 
 JL.oad-ftone; to which great multi- 
 tudes of Martial Corpufcles quickly 
 adher'd. And, I remember, I found 
 in a Catalogue of the Fofliles of Mif- 
 nia^ publiflied by the experienced 
 Kentmannus^xhzx^ under the Head or 
 Title of Pyrites y he brings in fevc- 
 ral MarcafiteSy whereof fome con- 
 tained Copper, others Silver, others 
 Gold, and others both the laft nam- 
 ed Metals ; which brings into my 
 piind, that, having prefented,among 
 other Enghfh Minerals, a curioufly 
 fhaped, and very fine Marcapte^ to a 
 Virtuofo^ that is now O verfeer of one 
 pf the Emperors beft Mines ; He 
 quickly examined it by a peculiar 
 Way, not known to me, hoping to 
 find in it fbme Gold or Silver ; but, 
 infteadof that, obtained a Portion of 
 funning Mercury, which he was 
 pleafed to prefent me, and which^ I 
 prefume, I may have yet by me. 
 
C 17^ ] 
 T^ho' I thought it needful to give 
 the foregoing Caution about Mar- 
 captes\ for the Reafons before ex- 
 preft, yet my Defign is, only to keep 
 the lefs skilful from being deluded by 
 their promifing appearance. For 
 otherwife I do Hot deny, but that 
 'tis poffible for a skilful Artift, to 
 tnake (at leaft of fome forts) of 
 them a gainful ufe ; either by fixing 
 the Volatile Gold or Silver^ that may 
 be found in fbme of them ; or, by 
 graduating Silver, by their means ; 
 ^/jperhaps by fbme other Ways, that 
 I can but guefs at. But (to add 
 • TThat on this occafion,) that, for 
 'which I much more value Marcafiies, 
 is, That (NB) fomeu^hat more than 
 bare ' Conjeftures make me think, 
 that, being dexteroufly hand4ed, and 
 perhaps even without Additions, 
 they may afford very noble, as well 
 as uncommon, Medicines ; and par- 
 ticularly in Continual Feavers, tho^ 
 their Operation be ufually fcarce feq- 
 iible, but by their good Effefls, 
 
 SECT. 
 
C if3 ] 
 
 SEC T. VI. 
 
 ON this occafion, Imufl: not for- 
 bear to give an Advertife- 
 merit, that may be of good U{e 
 to divers Examiners of Ores, efpe- 
 cially fueh, as are Novices in the Art 
 of reducing them. And it is This, 
 that, as to many, who make Tryals 
 of Ores, tho' they much value their 
 ownFlux-Powders^orThofe that are 
 cry'd up by others, yet they com- 
 monly aft, as if they expeded no- 
 thing from thofe that they prefer, 
 but that they fhbuld more than O- 
 thers facilitate theFufionof the Cress 
 as that which being once done, the 
 Metalline part will be feparated by 
 its own WeightjOr, as it were,Spon- 
 taneoufly. But yet^having purpofe- 
 ]y examined the Matter more niceJy, 
 and compared the Quantities of Me- 
 tal, that we obtained from two Por- 
 tions of equal Weight of the fime 
 
 Ore, 
 
C ^74 ] 
 Ore, we found thattbore Proportions 
 did very confiderably differ, tho'that 
 which yeilded leaft Metal was flux'd 
 down with 3, Fo/fdant (as the French 
 compendioufly call,what0ur men,af« 
 ter the GermanSjCali aFlux-Powder^) 
 that is dear enough^and not undefer- 
 vedly efteemedjwhen fuchOres are to 
 be handled. And I little doubt, but 
 that from other Metalline Ores, a 
 greater Portion of pure Metal may 
 be obtained by Ibme, but little im- 
 ployed or known, F^W^;;//, and per- 
 haps cheap Ones toOjthan by Others 
 that are much more in u(e and fa- 
 mous ; Of which I may ellewhere 
 give fbme Inftances: Now, One that 
 Jirft occurs to my Memory, was af^ 
 forded me, by two equally heavy 
 Portions of the fame Lead Ore de- 
 void of Sparr ; whereof One, being 
 reduced with a due Weight of A^/- 
 tre and Tartar fulminated together, 
 afforded muchlefs of Malleable Lead, 
 than was obtained by means of half 
 or a quarter of the Quantity of Fi- 
 lings oi M.trsywhiQhf{or Tryals fake, 
 
 i 
 
C 175 3 
 
 I then imployed on the Other ; to 
 JheWjhow much better aReduftive 
 of that kind of Ore, that Metalline 
 Flux was, than even a fliarp and 
 fiery fixt Salt. 
 
 And yet, (to give you an Inftance 
 in a much more precious Mineral 
 than Lead Ore,) I fhall add, that 
 having, for Curiofities fake, try'd 
 fbme Ounces of good native Cmna- 
 bar finely pulverized; one half with 
 a fixt Alcaly of Tartar^ and the o- 
 ther with a different Flux powder,we 
 obtained from the firft Parcel twice 
 as much Mercury, as we did from 
 the other half, deftilled with ano- 
 ther fixt Alcaly ; even tho' it were 
 of a MineralNature. 
 
 Some Obftrvations ahut NativtGQld. 
 
 SECT. VII. 
 
 GOld^ being by far the moft No- 
 ble, and Precious,of Metals, it Hyr^^^' 
 may be ill taken, if I fhould here ncMizxa^ 
 leave the Ore or Mineral, that zi-^j^^ , 
 
 tOrdS its Ore. 
 
[ 176 ] 
 
 fords it altogether unmentioned 5 
 and therefore, tho' I have but Two, 
 or Three, Obfervations pertinent to 
 my prefent Subjed, to offer about it, 
 yet I think it may not be ufelefs to 
 -lay fomewhat of thaf Oxp in this 
 place. ' r^ .rj ; 
 
 I know, there are many learned 
 Men, and even Chymifts, that think, 
 there are no fuch things as Gold 
 Mi^es, properly fb called. And, I 
 confefs, that Irayfelfvi^as long kept 
 from being confident of the Affirma- 
 tive. And I was induced to this Dif- 
 fidence by confidering, that tho* ha- 
 ving had the Honour for divers Years 
 ^to be a Member of his Majefties 
 Council for Foreign Plantations,! had 
 the opportunity to converle with a 
 confiderable Number of Navigators, 
 and other great Travellers, and with 
 divers Perfons, that had fetled them- 
 felvesin the Indies, I made it more 
 than once my bufinels to inquire , 
 5 not, 'Whether they knew of any Ghl- 
 de?i Mwes in the popular fen(e of the 
 word, for, I kne\y, that there are in 
 
H^Hgdry^ Mmdohia^ arid fbme o- 
 ther ' Countries, Mines that afford 
 Gold enough to defer ve to be 
 wrought for it. V but, Whether there 
 are any feal Mines, or Veins, whereof 
 Gold is rnanifeftly the predominant 
 Metal. Ha\^ing, Ifay, propofed to 
 many this' Queftion, I was anfwer- 
 ed, That fdme of them indeed had 
 heard of fiich Mines, but none of 
 them hadeverfeenany* But after- 
 wards I fawlomeOrethat I judgM 
 true, that was prelented to his Ma- 
 jefty (Churles the Second ; and I a!fo 
 received from an unknown Virtnofo, 
 refidingin the E.^(l Indies^ together, 
 witha vefycivilLetter(whichlwi^h- 
 ed had been more Hittorical and k(s 
 Coniplemental,} among ctl;ier lefs 
 Valuable pieces of Ore, One in whofe 
 Clefts , and a little beyond them, 
 there appear fbme Lumps, whereiri 
 by their Colour, and other Signs, 'tis^ 
 fb apparent, that Gold is the predo- 
 minant Metal, that I little doubr^ 
 but that, if Iwould fpoil the Lump 
 by breaking the Spar, I fhoulid find 
 N thef^ 
 
r C 178] 
 
 thefe Metalline ProtuberanQes Mal- 
 leable , without the help of the 
 Fire. 
 
 But being unwilling to deftroy the 
 Entirenefs ofitjfhall makeonlyafew, 
 and fhort, Remarks about this Ore. 
 
 The biggeft Piece, and that which 
 was beft furnifhed with Metalline 
 parts, being about an Ounce and 
 a quarter in Weight, contained fb 
 ^reat a Proportion of Spar^ in refe- 
 rence to the Metal, that its Weight 
 to an equal Bulk of W^ter wasbut 
 as 2 Uo to I. . 
 
 But fomewhat to compenfate this 
 Smalnefs of the Metalline Portion, 
 That, that\vas of it, (eemed to be 
 all Gold, there being no Sign of any 
 Other Metal in that Lump of Ore, 
 nor in Ibme leffer Ones tbajt, I recei- 
 ved withit. ■".' ' , 
 
 The Spar (as our Mine-men ufe 
 to call that ftony Matter, in which 
 the trueOre is immediately lodged,) 
 did not looklike thtSpar ofLead Ore, 
 or that of any other of our^Englifh 
 Metals that I have lecn^bm feemed 2t 
 
 firft 
 
C'79] 
 
 firft view to be a kind of white Mar- 
 ble with a dafh of Yellow. 
 
 And upon Tryal, I found it todifFer 
 more kom the S^ar of Lead Ore , 
 which, with us,is ufually White, and 
 and almoft Stmi'd'taphsinous than 
 in the Colour. For, whereas our 
 Spar of Lead Ore is dftedtimes 
 fo fbft or tender, that it may eafily 
 enough bd cue with a knife, we 
 found the Sparry Portion of our Gold 
 Ore to be a Solid ftone, and that; 
 fo hard, that, being ftruck with a 
 piece of Steel, it would yield Sparks 
 of Fire. 
 
 Whereas alfo I found , that the 
 Spar of Lead Ore would be eafily 
 enough, and in a fhort time, (as a-, 
 bout a quarter of an hour) calcin'd 
 to a kind of Lime ; our Gold^nSpar^ 
 tho' kept Ibme hours red hot in a 
 Crucible, did not appear ro be at all 
 calcided. And whereas I had former- 
 ly obferv'd, that I could eafily dit 
 Iblve the spar of Lead Ore in fbme 
 Acid MtnftruumsdindtVQn indeftilled 
 Vinegar it felf,I did not fiad;tbat our 
 ' "N 3 Golden 
 
E ^8p ] 
 Golden Spar J tho' kept divers hours 
 in ikxongtt Minfirmtms, as Spirit of 
 Sa/ff Aqua. Fortis, and Aqua Regis, 
 wasdiflolved or rnanifeftly wrought 
 upon by any of them ; as if it were 
 of a glalTy Nature, as well as of a 
 very hard One. 
 
 ^^^ piece of Spar, that had fcarce 
 aqyGold at all that could be difcer- 
 ned^ being Hydroftatically exami- 
 nedj was in Specifick Gravity to Wa- 
 ter, as 2 too to I, which Ponderofity 
 does but very little exceed That of 
 white Marble, or That of fbme good 
 Spar of Lead Ore that was compared 
 with it. 
 
 ""^ If I had received a greater Quanti- 
 ty of Gold Ore, Ifhould have given 
 a lefs imperleft Account of this Sub- 
 j^ft. But thefe Notes, fuch as they 
 ai'e, may, perchance, not be unwel- 
 come to fome of thofe many Eng- 
 Jifh and other Searchers for. Mines, 
 that have never fecn true Gold Ore, 
 or have not had Liberty to make any 
 Tryals upon it, and yet are in Search 
 oF^Gold Mines, efpeciajly i^ !?^- 
 
C i8i J 
 tnaicA^ where, if I much mif^remem- 
 ber not, the "^ inquifitlve Gentleman, * General 
 that : conquerM it for the Englifh,^^"^^^*^** 
 told m^, at his return thence, that 
 the SpanifliGovernoi}rpf the Ifland, 
 when his Prifbnery confefled to him. 
 That ttiere was Mineral Gold, tbo' 
 the Spaniards did not dig deep for it 
 for want of Workmen. 
 
 S E C T; yiii. 
 
 ! ♦ 
 
 .:H' 
 
 Bllt; by the mention I have made 
 \of the true pre of Gold, I 
 would not difcourage any from feek- 
 ing.for that rich Metal in the Veins 
 of feme other Metals ; becaufe, in di- 
 verS; of thefe, I know it may fbme- 
 timesbe found blended with predo- 
 minant Minerals. This may appear 
 by tliofe Hungarian Copper Mines 
 of Crcmnitz^ whence a confidera- Memoirs 
 bleQiiancity of Gold is yearly ob.[^;^\^jJ.|J^; 
 tained. I have elfewhere alfo taken ry of T«n" 
 N 3 notice, 
 
[ l82 ] 
 
 notice, that I have ften an Englifh 
 Tin-Ore, Part of which I prefented 
 to the King, wherein there lay, in 
 little Cells, a good number of fmall 
 Leaves or Chips of Qold^ which I 
 faw there with pleafure. Andtho' the 
 Tin-men, not being able to feparate 
 them with Profit, ufually melted 
 both the Metals together, and fold 
 the Produft for mere Tin; yet an ex- 
 perienced Gentleman, who was 
 Owner of the Mine, ajQFured me, that 
 One of his Workmen, who had ma- 
 ny little Children, imployed them 
 with good Profit, to pick the Gold 
 with their fmall Fingers out of the 
 skilfully broken Ore. And ^^o' Lead- 
 Mines be looked upon,as thofe, which 
 the Matter,whereof Gold is made, is 
 feldomeft found to be near, and does 
 as it were avoid ; yet, there is a place 
 in Scotland^ (whofe Name I remem- 
 ber not,) where, over a Lead Mine, 
 upon or near the Surface of the 
 C'round, they oftentimes find Grains 
 or bigger pieces of Native Gold with- 
 out <S^^/ ; fbme of which by the in- 
 genious 
 
C 183 I 
 
 genious Owners favour, I was Mafter 
 of, and thought fbmetinmes worthy of 
 being prefented to that curious Exa- 
 miner of Ores, . his Highnefs Prince 
 Rupert, i And ftill I have one bit 
 of Native Metal by me, which, if 
 Imuchmiftake not, I had from the 
 fame place: which Foflile, tho^ I 
 found it Hydroftatically (becaufe 
 being Native I would not melt it) 
 not to bcy as the Owner fiippos'd, 
 pure Gold ^ yet Gold is the predomi- 
 nant Metal in it, and the piece 
 weighs forty odd Grains. 
 
 Since I wrote the laft foregoing 
 Linesvl have, in an old Colleftion of 
 my Noies,found Three ; whereof the 
 Firji. is '.thus ftt down, J Grain of 
 Scotch Gold, fnch as Nafure had made 
 it^ without any. adhering Stone or Spar^ 
 weighed'^iij + 21 Grains : The Se^ 
 coni thus, Another Graif7 of the fame 
 GoUy th/it had here and there fame 
 little Stone or Spar Jlicki?7g to it, and 
 partly inelofed in it, weighed ^iij ~j- 
 I Grains; So that the Heteroge- 
 neous Subftance being, according ro 
 N. 4 my 
 
II r84 1 
 rnyEftimate,^te4it weired about 
 .^ii)*- And the Third is fubjoyned in 
 l^hefe Terms, 4Gr^'^'^ of ^sosch Gold 
 rveigbedifj Jir^ 45 Grains ; in Water, 
 i?9 I Grains;jid&rij-|rjiixI'jrppor;*«a-* 
 
 to I. , ..!;f'l ^WvMi^A^'AiUfl 10 
 
 This . Lightsnefs of % lYcHoiw Me- 
 tal (heavier nhan Br a{s.(^; Silver) 
 defer ves aRefledion ;{tiutjil Unaat 
 ftay to make it. I ^viiiiM J}•M^;li 
 It feverai cimes happ^tts, that, a- 
 mong the leflerGrainspf. Gold, that 
 are more properly caMtd SahdXjold^ 
 there are found pieces,ibrD€ of which 
 ri have feen, that are firigly big e- 
 ^ough to betyedabout.withanHorfe- 
 hair, and ib weighed in Water, as 
 Lumps of .Ore of other. Metals are 
 wont to be. And to fuch bigger Frag- 
 nientsofGoId, \ism^nifeft, fey what 
 has been already delivered, that our 
 Hydroftatical Way of exploring may 
 be uftfully applyed. For fince, ac- 
 cording to the famous and diligent 
 Mtrftrinusi and feme efteemed Wri- 
 ter<i, pure Gold is toWater of the 
 fame Bulk, as (aboutj .18 toj *, and 
 
 by 
 
by nty Examen of very fine Gold^ I 
 found , that it equals about Nine- 
 te$n>times the Weight of as much 
 Water , ( I fay , about , becaufe 
 I unhappily loft the exadeft of my 
 Tryals upon Gold, among thofe made 
 w^bn the other Metals in a moft ex- 
 quifide Ballance) as is equal to it in 
 Bulk; it will readily appear, Whe- 
 ther the Fragment proposed be per- 
 feftiy pure or not. For, if its Weight 
 amount to near Nineteen times as 
 much Water in Quantity, we may 
 coriOlude it to be unaliayed ; and,as it 
 wants left pr more of thisPondero- 
 fity, we may conclude it to be more 
 orlefspure. 
 
 -4Ur, 
 
 '^^ S E C t; IX. 
 
 TIs known, that, fince we be- 
 gan efFedually to cultivate the 
 African Trade, ic frequently brings 
 into thefe Parts,' be fides things of lefs 
 value , confiderable Quantitfes of 
 what;^ from the moft ufual Size of it, 
 
 is 
 
I i86 ] 
 
 is by many called ^'W-G^/rf; but 
 which, by reafbn of the very une- 
 qual Bulks of the Grains, may per- 
 haps juftly be called Fragments of 
 Qold ; fince being brought from the 
 Maritime parts, where no Mines :of 
 Gold are yet found,they feem tohave 
 been broken off and wafhed away 
 from hidden Veins by the violence 
 of Waters, thar, having carried them 
 as far as they were able, left them 
 a Prey toMen.NOw,(becau(ethat un- 
 Ie(s it be perhaps brought by, or for, 
 i6mtFirtf4ofo)thtYQ is Icarce any Gold 
 that comes into Europe in Lumps, 
 under the form of Ore ; but a great 
 deal that is brought from Guinea y 
 (and thofe other parts of Africk^ 
 whichj for that reafbnjare comprized 
 under the Name of the Golden Coaft) 
 iri the Form chiefly of Sand or Gra^ 
 i)ely grofler or fmaller, ind partly 
 ilfo of lefs minute Pieces ; it may 
 conduce to the fcope of thefe Papers 
 to take notice, that, in making E- 
 ftimatesof the Genuinenefi, and the 
 degrees of Purity of thefe native 
 
 Fragments 
 
Ci87 3 
 Fragments of Gold, our Hydrofta- 
 calWay of exploring may be of no 
 fmallufe. 
 
 For frfty when we have once dif 
 covered the Proportion between pure 
 or exquifitely refined Gold, and Wa- 
 ter equal to it in Bulk ; (which Pro^ 
 portion I have lately given exaftly 
 enough, for ourprefent purpofe,) tis 
 eafie, by our Hydroftatical Method> 
 to examine the Finenefs of any other 
 Gold propofed ; fo , at leaft, as to 
 know, whether it be perfeftly Fine ; 
 and if it be not, whether it do con« 
 fiderably fall fhort of perfeft Fine- 
 nefs. But fince of this I elfewhere 
 treat, I think it more proper to ob- 
 ferve in this place, that when once a 
 Man has found th^ true Specifick 
 Gravity of a parcel of Sand-Gold, 
 (fmaller or courfer,) whofe Degree 
 of Finenefs he knows by Collateral 
 Tryals, or fbme other Means,(what* 
 ever they be) He may (as was for^ 
 merly noted when I fpokeof Metal- 
 line Ores,) take this Specifick Gra- 
 vity for a Standard/ with relation 
 
 to 
 
[ i88 ] 
 
 tp whieh,he may make hisEftimates 
 of the Fineneft of other parcels of the 
 like native Gold, that he is concern- 
 ed to buy, or to examine. And, by 
 ^^^this^ means, he may oftentimes pre- 
 ",5ir^t that chief Fraud of the Negroes, 
 , whereof feveral Traders to the Gol- 
 den Coaft are not a little apprehen- 
 .five 5 as being in danger to be much 
 •damnified by it. For they complain, 
 iti}d,ty tho^ thQ Blacks be other wife, 
 for the mod part, but a dull fort of 
 People ; yet they liave often made a 
 fliift to cheat the Traders, by clan- 
 deftinely mixing,with the rightSand* 
 Gold, Filings of Copper, or rather 
 of Brafs, whofe Colour daes fo re- 
 j femble that of Gold, that , the Fraud 
 is not eafily difoerned. And in the 
 jAccpunt of a late Voyage, made by 
 the French, to the Coaft of Africk^ to 
 , Tprade, efpecially for Gold, ^cis ac- 
 , Jknowledged, that the Officers were 
 ^egregiouOy cheated by the Blacks, 
 „.who, inftead of paying them for the 
 ^ Wares they brought, with Powder 
 - gf trueGpld, gave them Powder of 
 ot Brafs, 
 
C 1% 3 
 
 Brafs, or gilt Copper, which thofc 
 that were not accuftomed to make 
 Tryalof,are,as the Relater complains, 
 ftcfe^a^ares, in a fcarceevitable dan- 
 ger to becheated:as thefeFrenchmen 
 confels they were irl one day t@ the 
 worth of a thouland Crowns. But,in 
 regard, that, as Tryal has informed 
 me, Brafs is not quite half fo heavy as 
 fine Gold of the fame Bulk; if there be 
 any confiderable Quantity of Filings 
 of Brafs with the Gold 3 This Mix- 
 ture being put into fuch an Hydro- 
 ftatical Bucket , or wide-mouth'd 
 Glals, as is mentioned in the EiTay, 
 will manifeftly weigh lefs in Water, 
 than if it were all Gold. And by 
 comparingits Specifick Gravity , with 
 that formerly found, to the Grain- 
 Gold pitched upon for a Standard ; 
 the greater or lefferDecrement of the 
 fufpeded Gold, will help to make an 
 Eftimate of the Quantity of Brafs, 
 mingled with the natural Gold. 
 
 SECT. 
 
C 190 3 
 
 SECT. X. 
 
 T3 Ut,//^o'my prefent Undertaking 
 13 do not oblige me to confider 
 Sand-Gold, otherwife than Hydrd- 
 ftatically ; and, tho' it highly con- 
 cerns Merchants andOthers,that deal 
 in fo rich a Commodity as Gold, and 
 that is by fo many ftudioufly adul- 
 terated, to be furnifht with nice and 
 trufty Ballances ; yet, becaufe divers 
 Perfbns, efpecially Sea-men , that 
 trade to the Gold Coaft and other 
 parts, whereSand'Goldis tobemet 
 with, do, (perhaps too often) with- 
 out being furnifht with good Scales 
 and fufficient skill to ufe them, ven- 
 ture upon buying fuch precious 
 Wares ; it will not be to depart 
 from my general and main Defign, 
 which is to lerve the Publick ; if I 
 deviate a little from my Subjeft, and 
 add to the Hydroftatical Way , late- 
 ly propoledjOf examining Sand-Gold * 
 
 Two 
 
C 191 3 
 
 Two or Three Chymical ways to the 
 'ikmt purpofe. Firft, then, if he, that 
 would purchafjb Sand-Gold , doubts, 
 that there are Filings of Brals (or 
 of Copper) mixt with it ; in cafe 
 he have J^ua Fc?m/athand, he may 
 quickly difcoverthe Cheat, if there 
 be any. For, ^tis known to Chymifts, 
 that A^ua Fortis will not work upon 
 Gold, and therefore, if there be Fi- 
 lings of Brafs mixt with it, the Ope- 
 ration of theM;?/?r^»/z? upon thofe,to- 
 gether with the Colour betwixt blew 
 and green,it will thereby acquire, will 
 di{covertheDeceit.But,becau(c if Na- 
 ture hath mingled much Silver with 
 theOoldjtheProof by AqudFortis will 
 require Skill, and may puzzle thofe 
 that want its I Hiall add, that good 
 Spirit of Urine may befubftitutedin 
 its ftead. For, 1 elfewhere fhew, that 
 'twill readily work upon Filings of 
 Copper or Brafs in the Gold, and 
 gain from them a fine blew Colour ; 
 and this being a Mtnjiruum not cor- 
 rjofive, like the other, but harmlefs to 
 mojt Bodies, and a good Medicine 
 
 for 
 
for ^/^w/'^^ Bodies in feveralWfefci^ 
 (as the Jaf^nd/ce^PkuriJIes^romt kind 
 of Feavers^Coughs 2ind Afthma^s^ may 
 be fit to be carried about in Voyages, 
 and to be preferr'd to Aqua Ferns. 
 And^ to make the Operation of this 
 Liquor on Filings of Braft far more 
 quick, than if the Solution be at- 
 tempted an ordinary Way ; I thought 
 upon the following Expedient. I 
 took Filings of Braft, (and the hke 
 may be done with thofe of Copper,) 
 amounting to the Weight but of 
 Eight or Ten Grains, or perhaps lefs ; 
 and having with my Finger fpread 
 them fbmewhat thin upon a fmall 
 piece of white Paper, I moiftned 
 them throughly with good Spirit of 
 fermented (or putrified) Urine , 
 (which will not diflblve Gold) that^ 
 by this means, the Air might pro- 
 mote the diffblutive Afliion of the 
 Menftruum ; which, accordingly, it 
 did fo well, that, to the furprize of 
 the Beholders, there appeared, in lefs 
 than a quarter of an hour, and fbme- 
 times in a few minutes, a manifeft, if 
 
 not 
 
1 193 ] 
 
 hot alfoadeep and pleafant^ blew^ 
 Colour upon the Pa per j or on fome 
 of the^FiIings, (^rbocli^ Thofe thac 
 carry with them Spirit oi Hartshorn^ 
 or fuch other Volatile Alcalys for 
 Medicinal Ufes, (as fome modern 
 Ship-Chirlirgeons do,) may, for a 
 need,imploy That inftead of Spirit of 
 Urine. Nay, one may for the fame 
 purpofe make ufe of Urine it felf ne- 
 ver deftilPd, if it be Stale and Rank 
 enough, (as it grows to be, fooner in 
 hot Airs than in others*) Since ha- 
 ving for Tryals fake moiftn^d with 
 fuch Urine fome Filings of Brafs^- 
 thinly fpread on a piece of Paper, 
 there was a manifeft Blewnefs pro* 
 duced in about a quarter of an hour. 
 But I thought alfo of another Way^ 
 which Iprefumed would be better 
 lik'd by mofl Traders, as more Com- 
 modious ; becaufe the Agent, being 
 in a dry Form, cannot, like Spiritu- 
 ous Liquors, befpilt; and tho' it be 
 moreeafily procured, mayfervetbe 
 turn almoft as well. This Agent is 
 ^^mxaotiSd Armonixch^ of whicb^ 
 O when 
 
i 194 3 
 
 U^hen I have occafion toufeit, I re- 
 duce a greater quantity to Powder, 
 than 1 guefs the quantity of Water , 
 I ftiall need, will diffolve ; that the 
 Liquor may be (atiated with the Salt. 
 With this Brine I throughly wet 
 Filings of Brafs, (or Copper^ after 
 the forementioned nianner, thinly 
 fpreading them with my Finger on 
 a piece of Paper, or fome other fit 
 and flat Body 3 and in afhort time 
 (as about a quarter of an hour or 
 lefs,) there will appear aGreenifh 
 blew Colour, drawn from theBrals 
 by the Liquor : Which (Liquor, j I 
 fuppofe, I need not teliyou, willnot 
 work on the Gold, wherewith the 
 Brafs is mingled. 
 
 SECT. XI 
 
 I Have obferved fuch a Variety of 
 appearances, and difguifes, of 
 Metalljiie Bodies, and fbme other Mi^ 
 necals, that I would advift thole that 
 
 are 
 
^re given to the Search df Mine^, 
 and other FoflTileS; to have their Eyds 
 alu^ays open, when they pafs ( eF 
 pecially by Land; from one place to 
 another ; that they may be ready to 
 rake notice of any unknown, or un- 
 common, Foflile, that they chance to 
 lee in their Way ; and that having 
 takeii it up, they do not negled to 
 p^de it in their hands (which afi- - ncrXi^^ 
 ter a Httle Practice 'twill not be dif- 
 ficult to do, tho' notexaftly, yet not 
 unufefully) and, if they judge it to 
 exceed the Weight of Chryftal, or 
 Marble, ro examine it Hydrollatical- 
 iy at. their firfl: Conveniency* For 
 tliere are in England^ as well as in 
 divers other Countries, uleful FoP 
 files,that are wont to be overlooked 
 by the unskilful ; and I havefound in 
 this Kingdom, even upon, or verjr 
 near^the Highways, Eagle-ftones;and 
 fbme other Minerals, that wefe not 
 fufpefted to be of Englifh growth. 
 And, 1 remember, that having occafi- 
 on in the Country, to pafs by the 
 Workhoufeof-an ingenious Potte?*, 
 G 2 ths.r 
 
i 196 1 
 
 that I fometimes imploy'd in his 
 Profeffion ; and having view'd the 
 ground fbrnewhatattentively.among 
 iome other uncommon Foffiles that 
 I took notice of, I made a dilcovery 
 of Mangmefe^ or Magmfia^ whereof 
 I gave the Potter an Advertifement, 
 ^hich he afterwards thankfully 
 made ufe of, having found the Mine- 
 ral very proper for the glazing and 
 and colouring of his Veflels. 
 
 Nor was this the only kindnefs, 
 that skill in Mineralogy, as little as 
 mine was, enabled me then to do 
 him. For he having invited me to 
 view, very privately, a place w^here- 
 in there was great ftore of a Foffile 
 Subftance, that Men knew not what 
 to make gf , becaule they had not 
 leen, nor heard of, the like in E/^g* 
 land : The knowledge I had of fbme 
 7r^//^;;Mines,made mequiclily guefs, 
 What] it was that was taken for an 
 unknown Metal. For 'tis true, that 
 this Mineral was not divided into 
 Lumps of fuch Shapes and BignelTes, 
 as make glittering Foffiles. pafs for 
 ' S rones 
 
C ^97 ] 
 Scones among the unskilful, luch as 
 are the Marchafites whereof they 
 make Vitriol^ and are found by the 
 Sea-fhore, in or near the IJle of 
 Wtght^ and, ftho' not fo plentiful- 
 Ily) in other parts of EngU^d f where 
 I have found them 5 J but ran a great 
 way (and I had not Time or Li- 
 berty to try How far^ under ground, 
 like a Veine of Metalline Ore, But 
 this notw.ithftanding, I judg'd the 
 Mineral to be but a Manhafite, in a 
 Form, unufual indeed in E»^- 
 /andy but which is nOt without re- 
 femblers in fome parts of hafy; 
 which CoAjefture I found true the 
 lame day, by fome eafie Tryals,that 
 manifefted it to abound much more 
 in ynriolate Szltj than any Marchn- 
 fite that I had examined in the form 
 of Stones. So that, tho' I had no 
 opportunity to try, whether or no it 
 contained any better .Metal than 
 Iron ; yet I concluded, that. Ceteris 
 farihns , it might be employed to 
 tomakeftore of Vitriol, in far lefs 
 time, and with far lefscoft, than the 
 O J Mar- 
 
C f9S ] 
 ^Tarckzjites made ufe ufe of, in th^ 
 f^itriol VVorks at D e pt for dy Qr tl^^- 
 ^^yharc in E^g/a^/d. 
 " 'l remember a ifb, that a Mineral 
 of an odd, tho' pretty ,^ appearance, 
 being fent me, whofe Spegie^ uas 
 unknown to the Mine-men that dug 
 it up, Iguefs'dthat it was a Foffile, 
 that I had not found in a good Prin- 
 ted Catalogue oiox^vEngliflj Minerals, 
 XnamelyJiheOre oUBiifmuth. And in 
 this Conjetlure fbmeTry^Is,purpofe- 
 jy made of that Mineral, fufficiently 
 confirmed me 5 and gave me caufe to 
 be fbrry, that the Vem, that aflForded 
 k, was lo very fmall, as the Diggers 
 found it, of an Ore, that has Proper- 
 ties Curioqs enough ; and is by fbme 
 famous Chyrnifts affirmed to have 
 lome that arej not only Rare, but 
 ^^onderful. 
 
 But the chief thing t;hat; invites me 
 p recommend, in this place, to thofe 
 that Travel, an heedful eye on the 
 pre-]ike, or ponderous Subftances, 
 that may occur to them , is, That 
 One of the Applications of our ^e-. 
 
 neral 
 
C '99 ] 
 
 neral Remark, about the Specifick 
 Gravity of Folliles, may be extend- 
 cddg an Ufe^that has not,that Iknow 
 
 JV been made by Mkieralifts, sa^ 
 id which yet I thought fit not to 
 overlook : becaufe I lee no need, we 
 fhould be confin'd to examine only 
 thofe Fofliles, whereof we can ob- 
 tain Parcels,big enough to be weigh'd 
 in Water in the entire. Body. For 
 befides other Minerals, that may be 
 found profitable to the Phyfician, tlie 
 Drugfter, or the Mineralift ; the 
 OreSjOrWombSjOfMetalsthemfelves;, 
 may be divers times found difguis'd 
 in the Form of Earth, or of Mud, 
 eafie to be dryM : Which Foflilesjt ho' 
 (becauft they chance not be found in 
 l.umps^ unfit to be kept imme- 
 diately fufpended by an Horfe-hair ; 
 may be conveniently enough exa- 
 mined by the help of ^Glafs-Jar. 
 whofe Weights in Air, and Water, 
 and their Difference, (which gives 
 the Specifick Weight of the Veffel^ 
 have been taken once for all , 
 whichi ufually call an Hydrofl:aci- 
 4 Cii 
 
200 ] 
 
 cal Bucket. For this VeflTel, being 
 almoft filled with the prof)Ounded 
 FofTile, and carefully counterpoized 
 in the Air, and then thorowly wet- 
 ted with Water ; and when 'tis fo, 
 'warily let down into the Water, and 
 kept fufpended by an Horfe-hair to a 
 tender Ballance^ when,thefe things, 
 I fay, are done, the Difference be- 
 tween the Weight of the Mineral and 
 VeiTel, when they are under Water, 
 and their former Weight, being ob- 
 served ; and the Specifick Weight 
 already found of theVeffel it felf in 
 •Water, being fubftrafted from that 
 Difference ; there will remain the 
 Weight of the Foffileonly, (which 
 we here fuppofe, to be heavier in 
 Specie than Water , and not to be 
 difToluble in it) or the Mineral it felf, 
 in that Liquor ; and cdnfequently, 
 xhd Proportion between that Body, 
 and Water of the fame Bulk, as is 
 •^Ifewh^f e fufficiently declared. 
 
 SECT. 
 
C 201 ] 
 
 SECT. XII. 
 
 ^1 'O manifeft, thatThis Expedient 
 j^ may be of ufe in divers Cafes, 
 I fhall only here obferve, that a late 
 Author, who hath publifbed an kc- 
 count 0? Swedland^ declares, that one 
 of the beft forts of Swedi(b Iron 
 f'which,you know,is much efteemed 
 initskind^ is divers times found, in 
 the Form of a red Mudj at the bot- 
 tom of Lakes, or far lefler Stagnant 
 Waters ; which I the more readily 
 believe, becaufe I have found fbme 
 Englifli Okers ('that pafs but for red 
 Earth, or Stone of that Colour Q to 
 be richer in Iron, than I found iome 
 famous Oresof that Metal to be. And 
 another experienced Writer, who 
 gives us an Account of the Gold and 
 Silver Mines of America^ among 
 which he (pent feveral Years, takes 
 notice, that Gold it felf is found, 
 from time to time, difguifed into a 
 
 reddifh 
 
C 202 ] 
 
 reddifh Earth, or is (tho' unfurpeO:- 
 VdMttr tdlyj harbored in it. An Italian 
 chio. Mineralift, of repute in thelaft Age, 
 doth alfo take notice, that a reddilh 
 ibrt of Earth doth fometixnes con- 
 tain a Portion of the richeft Metals. 
 Ifhave obferved fbme European 
 Diamonds, as many call a fort of 
 clear and finely-Figured Chryftals,to 
 grow in a red Earth ; whence I have 
 taken up pretty ftoreof them. And 
 an inquifitive Traveller , who has 
 been in the /W/ej,prefented me with 
 a certain Earth, which he affirmed 
 to be from the Diamond Mines, (I 
 prefume, in the Kingdom of C^^Ari^t?;;. 
 da) which I found to be alfo red, and 
 which I made fome Tryals of, that 
 belong not to this place. 
 
 § E G T. xm. 
 
 BUt the profitableflUfe, that a 
 Mineralifts may make of our 
 Hydroftatic^l Bucket, is, to imploy 
 
 it 
 
t ?o3 ] 
 
 it much in weighing Variety of co- 
 loured Sancls,and Gravels; particular- 
 ly, fbme hereafter to bementioned. 
 
 And to let you fee, by an cafie 
 Inftance, how apt we ^re to over- 
 look Sands for want of trying them 
 by Weight, I fhall not tell you, 
 that I have fbmetimes feen a fort of 
 Sand that was flighted as common 
 or worthlefs, which, being wafhed 
 and viewed in a Microfcop^^ tho' none 
 of the befir, looked like an Aggre- 
 grate of fmall Granats, and perhaps 
 was fb ; but fhall here content my 
 felf to inflance in that black Sand, 
 that is commonly ufed in London- 
 and elfpwhere, only to dry up the 
 Ink of Words that have been new- 
 Jy written. for having obferved 
 whqn I had fbme qiiantity of this 
 in my hand, that it was manifefily 
 heavier than common Sand;! thought 
 it worth the b^ing e)^arnined by the 
 tiydroftatic^l Bucket ; by which 
 Tryal, that which we imployed^ ap- 
 peared to be to W^ter of the fnme 
 Bulk, near about a34 tr to i. And 
 
 having^ 
 
[ 204 ] 
 
 having,for Reafons that I cannot ftay 
 to mention, judgedthisSand to bea 
 Mineral of a Martial Nature, I was 
 confirmed in my Conjeaure,by mel- 
 ting it down with two or three parts 
 of Antimony, and cafting it into an 
 Iron Cone. But I was more than con- 
 firmed in the fame Conjefl:ure,when, 
 having try'd it with a vigorous 
 Loadflone, I found it to be far richer 
 in Metal, than any of the Englifh 
 Iron Ores I had made Try al of, and 
 (except perhaps One^thanany of the 
 Outlandifh : For,having taken, at ad- 
 ventures,fbme Drams out of a much 
 larger Quantity, andweigh'd it; I 
 found, that at leafl: Seven parts of 
 Eight would eafily be taken up by 
 the Magnet. But fuch Obfervations 
 as thefe, are not the things that chief- 
 ly move me to recommend the Excl- 
 we;; of Sands and Gravels totheMi- 
 neralift ; particularly, thofefbrtsof 
 them, that, being fbme what ponde- 
 rous, arelleddiftior Yellow, efpeci- 
 ally if they retain thofe Colours, af- 
 ter they have been made red hot, and 
 quenched in cold Water. But 
 
C 205 ] 
 
 ^W^Therefore to proceed to the men* 
 tion of richer Sands,'tisknown,That, 
 from the Coart of Guyny^Eurof^^n 
 
 . Traders,of feveral Nations,do yearly 
 bring Gold,to a great value, which 
 is vvafht'or pickt out of the Sand. 
 And even in Europe there are Ri« 
 vers,who(e Sand is inrichc by Grains 
 of Gold, for which the Tagus that 
 runs by Lisbon, and PaSolns^ were 
 famous among the Ancients. I knew 
 an induftrious Chymift, who own- 
 ed tome, that he gon Gold with 
 Profit, from the Sand , which he 
 found in fome places of the Banks of 
 the Rhine : and there is a litle River 
 in S^voy proceeding from the Moun- 
 tains there, on whole Banks, after 
 a Land Hood, I faw poor People bu- 
 fiethemfelves in fteking for Grains 
 of Gold. SomeTryal,Calfo; that I 
 caufed purpofely to be made, confir- 
 med me in a Conjecture, which poP- 
 fibly may hereafter prove Beneficial 
 to many ; namely, that the Sands of 
 divers places, if they be Skilfully 
 treated by a dextrous Chymift, may 
 -• afford 
 
[ 206 ] 
 
 afford much moreGoldj than ispicfet 
 or wafht, out of them in Form of 
 Grains.For befides, that there may be 
 many Atoms, or Corpufcles, of Gold 
 that are (b very minute, and ftick fo 
 clofe to Grains of Sand, that they are 
 neither taken notice of by the Eye, 
 norfeparable by wafhing, and pick- 
 ing ; befides this, I fay, there may, 
 as I conceive, be many Particles of 
 Cold incorporated with the Body of 
 the Sand, which may be a Kind of 
 Womb for matter of a Golden Na- 
 ture, that a skilful Artift, by the 
 help of proper Additaments, may fe- 
 parate with Profitjefpecially, if, with 
 Litharge or Minium^ he firft reduce 
 the Sand toaGlafs, and then take 
 care to get the Volar ikGold^hy giving 
 it a pure Body fit to retain and fix 
 it,fuch as is fine Silver: Out of which, 
 I remember^ we feparated by Sl^tar- 
 tation^ (the' without Profit, becaufe 
 of the Charges, and of the fmall 
 Quantity we could work w^ith 
 at ©nee,) from as much vitrified 
 Sand, and two or three fluxing Ad- 
 
 dkaments 
 
[ 207 ] 
 
 ditaments of fmall price,as were coti- 
 tainedinone Crucible, (that broke 
 too,befor^ Operation was near done,^ 
 fixteen Grains of pure Gold; that you 
 may yet fee, if you defire ic. 
 
 SECT. XIV. 
 
 IT need not ftartle you, that, in 
 reciting this Experiment, I made 
 mention ®f VoUtik Gold. For, tho', 
 I know,that diverslearnedMen,and 
 Ibme able Chymifts themfelves, look 
 upon it as a Fiftitious thing ; and 
 that fetms to bear ^ kind of Contra- 
 diGIon in its very Name ; in regard 
 of the perfeQ: Fixity they prefumeto 
 be an Eflential property of Gold : 
 yet I do not ftruple to diffent from 
 them, being warranted fb to do by 
 my own Experience* For, I have, 
 more than once, madeufe of a Way^ 
 wherein, by the help of an Addita- 
 ment, incoafiderable astoBulk, and 
 left as to Weight J one may, with- 
 
 ouc 
 
[ ^o8 ] 
 
 out a naked Fire, and in a Glafs re- 
 tort, fublime Gold, (not prepared by 
 previous Calcination) fometimes in 
 the Form of a yellow, or golden co- 
 loured, Salt; and fbmetimes,when the 
 Operation fucceeded better, in the 
 Form of thin Chryftals prettily fhapr, 
 Glofly, and as red as Rubies. But 
 this upon the by 3 it may perhaps be 
 more ufeful to Searchers of rich Fof- 
 files not found in Lumps* if I take 
 this occalion toobferve, that when 
 they meet with Sands, Earths, Mi- 
 neral Fragments, &c. that confide- 
 rably exceed Chryftal in Specifick 
 Gravity ; and by the Place wherein 
 they arc found, or by other Tokens, 
 give hopes of their containing 
 Corpufclesof a golden Nature: When 
 this, I fay, happens, it will not be 
 advifeable, haftily to rejetl fiich Bo- 
 dies;but rather carefully to try, Whe- 
 ther they do not deferve a better U- 
 fage* For, having fbmetimes had the 
 opportunity to difcover Corpufcles 
 of Mars^ as Ghymifts call Iron 
 and Steel, in afar greater Variety of 
 
 Fofliles, 
 
[ 209 ] 
 
 Fofliles, and of Difguifes, than even 
 many noted Chyn:iifts would have 
 imagined,or fome of theni coiild,up' 
 on heedful Tryaljdifcover ; I was 
 much confirmed in my Sufpicion, 
 That Corpufcles of a Golden Na- 
 ture may be concealed in divers 
 Bodies, wiiieh are thought not to 
 contain any Metal ; and that in 
 more of thofe Minerals, that are 
 lookt upon as Ores of Ibme othtr 
 Metalj becaufe of its being mani- 
 feftly Predominanrj there may be 
 mingled pretty ftore of Particles of 
 Gold or Silvers which f't>ecaure of 
 the greater Quantity of that other 
 Metal, or Mineral, that doth, as it 
 were, cover, or difguifethem'^) lye 
 imperceived, & ufually unfufpcfted, 
 by Perfcns not very well acquain* 
 ted w^ith fiich Matters ; and yec 
 may, by One that is very skilful^ bd 
 fepar^ited even with Profit. 
 
 SEC 
 
[ 210 3 
 
 SECT. XIII. 
 
 BUtthe Grounds of the foremen- 
 tioned Sufpicion being as yet 
 but Conjeftural, I ihall decline the 
 particular mention of them in this 
 place ; and fhall rather Advife^whh 
 reference to Ores in General, that 
 thofe that would apply the Hydro- 
 ftaticks to Therii, do labour to pro- 
 cure Samples of the Ores of differ- 
 ing Mines , elpecially if they be 
 found in the fame Country ; and 
 do either by Tryal or ftrift Enqui* 
 ry inform themfelves, what Propor- 
 t ion of the Metal, that denominates 
 them, they contain. For thele Por- 
 tions of Ores and Minerals, being 
 carefully weighed in Air and Water, 
 and their Specifick Gravities, being 
 thereby made known, they may 
 ferve for a, kind of Standard, by 
 Comparifon whereto we may of- 
 tentimes 
 
tdntinics make not altogether un- 
 ufeful Eftimates of the Metalline 
 Portions contained in other Parcels 
 of Ore, of that Species^ whether 
 afforded by the fame Mine, or Vein 
 of it, or by any other of the fame 
 Metal )Hydroftatically examined. 
 
 For Inftance, our Engliffi Lead* 
 Ores; that arc worth taking no- 
 tice of, oiay be, for diftinftion fake, 
 divided ifato Three Rinds or Orders, 
 arid id each of thefc, there may be 
 allowed a Latitude for greater, or 
 leffer. Degrees of Goodnefs. The 
 Firfi fort is of thofe Ores, that,in the 
 ordinary Way of melting, hold fbme 
 dfthentifrom 50 Ijbof Lead,in an hun- 
 dred Weight of Ore,to 4o;and others 
 to 45f lb of the fame Metal, arid thcfc 
 by feveral dre flighted, as mean ; 
 and foarce, if at all, worth work* 
 ihg ; efpecially, thofe that hold un* 
 der 35 or 40. As for the Seco»d 
 fort, that reaches from 45. to 60 Ife, 
 in the hundred ; the moft ufual Pro- 
 |»ortion, I have found in many Try- 
 P 2 a!s^ 
 
alshath been about half the Weight 
 
 of the Ore in clean and Malleable , 
 
 Lead. Tbefe Ores are-thought in,q 
 
 differently good and worth work-^o 
 
 ing; But other Ores goniprifed in - 
 
 this Second fortj held about 55, and > 
 
 fbme near 60, and thefe were, lookt. j 
 
 u(X)n, not only as Good, but pretty 
 
 Rich. And ^ tor the r^/V^! Sprt, in 
 
 Confifts, of thofe that y iel^^prn . 69^3 
 
 to 80. in the hundrc(^5, ajiici] thele^ 
 
 Ores are juftly reputed, very, Kkb^ 
 
 (in lead) efpecially thefe.thatcome 
 
 any thing near 8b ; for,J caofefs,' t 
 
 never mec ,with any th^t reach t f(^ 
 
 far, bur was affured by an ingeni-o 
 
 ous & skilful Gentlemanj;;Mafter ot) 
 
 his Majei[i:ies Royal Minr,. thAt ht 
 
 had found fome fuch upon Try ah, 
 
 But for me, I think that I have xiQtj 
 
 above twice or thrice nfiet with anyj; 
 
 that yielded me abovc:75. Thelei 
 
 lookt exceedingly Promifing^ as \ij 
 
 they vf ere ail Mecaljandl oblervedy- 
 
 whether the thing were cafual or 
 
 liot,. Ibme LvHnps to be conapofecfj 
 
 of 
 
C2in 
 
 of divers great Cubes like Dice, 
 flicking very hard to one another. 
 
 The Confiderations, that moved 
 me to offer the Advice given at the 
 beginning of this Section, invited 
 me to make Refearches of the Spe- 
 cifick Gravity, not only of divers 
 EngliDh Ores, as of Lead, Tin, &c. 
 Of which 1 had carefully made a 
 Colleftion, Cthat was loft by a fud- 
 den Fire, broke out in the place 
 where I kept them, j but of the Ores 
 that Vv^ere prelented me from feve- 
 ral Countries, both'in Eurx)pe and 
 jimerica ; as S^vediffj Copper and 
 Iron Ores, Germxn Silver and Tin- 
 GlafsOreSj Hm^arian Aiitimorihl 
 Ores 3 A'ew E;?;?*///^? Lead, Iron, and 
 Copper Ores, &c. TheEffedls of 
 fome few of which Refearches, that 
 chanced to come to, hand, vvhilft I 
 wasfeekingfor fome Hydroftatical 
 .Tryals of Drugs , I thought it not 
 amifs to infert in a Table annext 
 to the Medic iHo. Hjdrofldtica, > be^^ 
 caufe perhaps they may be of fome 
 
C 214 3 
 
 life, in making a previous Gonjcr 
 glure, about a Mines being, or not 
 being, likely to be wrought with 
 Profir, all other things concurring^ 
 thaf/hould do/o. Which laft Cladfe 
 I defire fhbuld be taken notice of ; 
 becaufe there are divers otlier Cir- 
 cumftances, befides the Proportion 
 of the Metalline partin the Foffile , 
 that are fit to be confidered, [as, 
 if Ae Plenty, or Scarcity, of the Mi- 
 neral; the Eafinefs or Difficulty of 
 corning at it , becaufe of its depth, 
 or its being, or riot being troubled 
 \vith Waters, &c; its Nearnefs tp 
 Plenty of Fuel 5 and the Conve- 
 niency of Water to drive Mills ; its 
 Kearners toyorRemotehefs from, the 
 Sea,' Of fbme Navigable River, con- 
 venient for its Tranfportation, to 
 omit, othei' important GircumftanV 
 ces] before One begins to work a 
 Mine 5 which as they happen to be 
 Commodioiis, or Inconvenient, may 
 fender the Attempt Advifeable, or 
 Imprudent, ^ ^^ 
 
 But 
 
C 21^5 ] 
 
 But Sir, I perceive, Ttho' late^ 
 that I have forgot, I was to write, 
 not a Book of the Tryal of Ores, 
 and other Minerals, but a mode- 
 rately, fized Letter, about an Hy- 
 droftatical Way of Exploring their 
 Specifick Gravity. And therefore, 
 to avoid increafing the already too 
 great Prolixity of this Paper, by 
 making an Apology for it , I fhall 
 lengthen it, only to beg you to Par- 
 don it, and to look upon the Wri- 
 ter, as 
 
 SIR, 
 
 Tourmojl huTnhle and 
 
 O^dient Servant 
 22. B, 
 
 ^dvun 
 
C H6]3 
 
 Adverttfement. 
 
 To give the Curious the Satis*: 
 fa&ionof feeing at one view, 
 and {b of eafily comparing toge- 
 ther, the Specifick Gravitys of a' 
 gofd t^umber and Variety of Bo- 
 dies; and to fave them the labour 
 ofturning orver many Leaves of the 
 foregoing 2 rs&; to find the particu- 
 lar Body, whofe Ponderofity they 
 defire to know ^Ihavecaufed to be 
 annexed a Table, containing in an 
 Alphabetical Order (^tho^ not a fcru- 
 pufouOy exadi: One,; the Names of 
 the Drugs, and other Bodices, whofe 
 Gravities are delivered in the fore- 
 going Papers ; without fcrupHng to 
 ^nd iome others, tliat I chanced to 
 h'ght on, in turning over feme of 
 my old and forgotten Notes, 
 
 But 
 
C 217 3 
 
 Bi)t I muft to the following Ta- 
 ble" prenrife this Adv^rtifemeflt^ 
 (warranted by fevexal paffages of 
 the foregoing Papers here laid to- 
 gether) That ^is nor to be expefted. 
 Every one that fhall try theSpecifick 
 Gravities of the Bodies here menti 
 oned, fhaJl find all of .them to be 
 precifely the fame, that the Table 
 exhibits : Since, (not to mention, 
 that perhaps every Experimen- 
 ter will not imploy fo much Care, 
 and be affifted with fo much Ufe, 
 in making Hydroftatical Tryals, as 
 Thofe this Table confifts of were 
 made with)the DifiFerence^that may 
 fometimes be found between his 
 Tryals and mine, may very proba^ 
 bly be imputed tQ that Variety of 
 Texture and Compadlnefs^that may 
 be found in feveral Bodies of the 
 fame kind, or Denomination; nei- 
 ther Nature, nor Art, being wont to 
 give all the Produftions that bear 
 the /am.e Name, a Mathematical 
 precifencis, either in Gravity or 
 in other Qualities. 
 
The TA'BLE. 
 
 « Weigh In IVa* 
 
 " bt Air ter in ProfortioHi 
 
 inQr, Qrains, 
 
 AMber . . , .306 12 lY-itoi. 
 
 Jgat . . . .2JI 155 2^|Jtoi. 
 A piece of AUom- 
 
 fione . . . • aSol 152J 2,4'toi* 
 Antimony good and 
 fupfofed to be 
 
 HmgATiat^ Qne^-t 591 295 4??y^o|. 
 
 Bezodrjlone . . .187 61 It^f-tOi. 
 
 J piece of the fajpe-- ^61* 22 i ^^J K) i . 
 
 j^ y?/;e Oriental t?/;e *- 172 60 I j|i to I. 
 
 Another. . . • 2J7 61 i^^^^qj^ 
 
 Coral red . . .159^ 801 2itJtor. 
 
The TM. 
 
 If^ight In 0a» 
 
 In Air ter in Profmim. 
 
 in Gr, Grains, 
 
 CorHeU4n . I .148 10 j Ji4?tof. 
 
 Calculus humMUd^'^^ 25170 1080 \ ^11 to I. 
 
 CocO'f^tl\ „ . .351 8j i^^^toi! 
 
 Native CrabsEyes, jjl j;6\ iJ^toi. 
 
 CrdsEyes Arti^cUL <)o\ 54 2 ^ to I . 
 
 CaIx of Lead . .. 138^ 123 Sj^toi. 
 
 Coffer Ston^ • . ; 65^ 49; 4'.°^toi. 
 
 Common Ciftnahar— 802 702 o iVo i. 
 Cinnabar of AntU 
 
 many ... . 197 169 7^tOl. 
 
 Ltnnabar N^ttve-^- 197 171 ^ ^"itox* 
 
 Coral White .^56 204 2^tou 
 
 Another pect fine - i j 9 %i^ 2 -iZ to !• 
 
 Cdculus humanus — 302 97 illtoi. 
 
 Copper Ore . . .1436 1090 4|iltoi'. 
 
 Copper Ore Rich . . 413 ^^ Ai^toi. 
 
 Cinnabar Native^ ■**' 
 
 very fparklmg . . 226 194 7^^^toi- 
 
 G. 
 
 Cold Ore not Rich^ 
 brought from the 
 
 Eafi Indies . . . I lOQ 6S^ 2^-1 tQ i. 
 
"^ JVHgh In W(U 
 
 In Air ter in ' Proportion, 
 in Gr, Grains. 
 
 Jnother Lumf of 
 
 Uhefame-y,.i %H5I 717 2-,thoi. 
 
 Grdnxti Mimra . !. 217 147 j itto I. 
 
 Gramte Bohemian'^ 4~itotol. 
 
 H I 
 Hematites Englilh'^i^']^ 1156 jfottoi, 
 
 I 
 
 Jx^^r; .... 173^- 83 ,-i 
 
 tor. 
 
 Lapis Ma^ati . . 450 295 2-iootO I. 
 A Fragment of the 
 
 fitne . . . .2l8i 123 2,Qotoi, 
 
 Ji not her . . . . 345 197 21ootOi. 
 A^othtr from jf^- 
 
 maica . . .2011 1 127 2TootO|. 
 
 I^apis Laznli cm ^^ 
 
 pff^f^e .... 585 256 2ToitOI. 
 
 Ltai Ore . . * 6^6 J90 ylootOi, 
 Another . . ,■ • ' 
 
The TM. 
 
 Wtight InWa- 
 
 In Air ter in Proportim, 
 
 in Gr, Grains. 
 
 Lapis CaUmimriS'- 477 3 80 4 -^^to TvC* 
 L^apLisJudak^s . .26'ih 164 2i^tOI, 
 
 M 
 
 Marcdfites * . . ScH 6ji 4-itotolj 
 Another from Stal- - . . : *r^ 
 
 bridge.:. .. .1243, 189 44 t# i. 
 
 hnother more fhi^ 
 
 niHg than ordu 
 
 nary, . . . 287 227 41oJtOi. 
 Mercury revived 
 
 from Ore ... 
 Manganefe a piece-' 351. 2.J0 3lootOl- 
 MimralCornifJjlike - . 
 
 A.jhinii2g Marca- 
 
 file . . . . 145 129 fioltoi. 
 
 O 
 
 '^•■; .„;^:.>. 
 
 O[ieocolla . . . i9f':'..'Xo8 2it^t0lV 
 Ore Silver., choice 
 
 from Sdi^^any . .. 45 S . 366 4ioQtoi. 
 
 Amthtr Pkc^ . . ,112© 960 7 'to-ii* 
 
 i^i ^ 
 
 Ore 
 
freight InlVa- 
 
 /» ^i'r ter in Proportisnl 
 
 *nQr. Graim. 
 
 OrtLeadfromCnm- 
 bcrlandii/V* ..187^ 1586^ 1^ to i;. 
 
 R 
 
 B^hwottros horn..%^6i 4260 i it^toi. 
 thtr Ykct . . 256 140 2"*ootol. 
 S 
 
 S/iphir . . . ; 
 
 Seed' Pearl . . • 
 
 Sjflphur vive, . .371 i8y 2 to I. 
 
 Germane very jjint .306 1 52 I *foi toi e 
 
 SUtelriJb . . . 779 467 2-foitoi. 
 
 A Piece of Talc like 
 Lapis Amian^ 
 
 thus • . . 596 JJ4 2 -loStoi. 
 
 ^Venetian .i 802 yoS 2-iottOl. 
 
 CJamaican ..li^j 12 j8 3 to 1. 
 
the Tdk. 
 
 " Weight 
 
 In Wd- 
 
 
 In Air 
 
 ter in 
 
 Prtportim. 
 
 inGr, 
 
 Grains, 
 
 
 New Engli[b Tin 
 
 
 
 Ore,Mr. Huberts. 8i2 
 
 613 
 
 4Tc!toi 
 
 Tm Ore black Rich. 1293 
 
 984 
 
 4".Votoi 
 
 Another fieceChoict* 2893 
 
 2JI4 
 
 5 to I 
 
 Tuttyapieee , . . 104 
 Tin-glajs . 4 • . 468 
 
 83 
 
 5 to i 
 
 419 
 
 9-iUo I 
 
 Vitrum Antimonii 
 
 T^rfi. .357^ ^S2^ ^^toi. 
 
 Vitriol Engl, /t ve- 
 ry fine piece . . 109J yi2 i"i*tlox.' 
 
 Unicorns horn a 
 piece .... • . 4©7 195 l^loi. 
 
 ^¥z 
 
(posrscKiTT. 
 
 WHen I began to fend the Ejfay^ cdleJ.^ 
 Medicina Hydroftatica, to the Prefs^ 
 and drexp up the foregoing Preface to />, 1 in- 
 tended it jhould in the fame Hook or Volume^ 
 be accompany^d hy another Help or two, to ex^ 
 pkrCy and Improve the Materia Medica. Btit 
 when the BJfajf it feif^ and the annexed Bpifile 
 about a prevwus Exploroiion of Ores had been 
 printed ojj \ I could not but perceive^ that the 
 Bulk of thofe two Tra3sfo far exceeded tvhat I 
 expe3edy that if Ifubjoyned what I at fir ft de^ - 
 ffgned to add to it, it would prove a mis-flyapen j 
 Book^ and inconvenient to he opend^ wherefore ' 
 it feemed expedient to divide the whole in- 
 tended fi^ork into tw^Vdlujnes orTomes ^whereof 
 tvhat had already paji the Prefs^ fhould make 
 the firft^ which that it might he the fconerfer- 
 I'iceahle [hould forthwith come abroad by it f elf 
 and the Second jhould con ftfi partly of the other 
 Papers abovementioned^ as relating to the 
 Materia Medica, and partly^ of a Supplement 
 to the fir ft Tome^ containing divers Hifiori* 
 caI Paralipomena, that by mi flake were omit- 
 ted J and are ft to be there f^pply'd out of a 
 fuller Copy, then that which by an Over fight 
 was mzde ufe of at the Prefs^ 
 
 F I N I a 
 
il^£l 
 
f^4».