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J j>;-> >■ .j> y;;> ;>:> »/i> _> A. . ■ ; ^_:>. ■■ ,_:» 3^-k 1^ _> i>' r> ' >:> ^5> »>0 3f> , -^.-.j ' -■ > -^^> ^. ^ . > > 'X* > j» > .-> J. > v>r> > > > > j :> > # LIBRARY aF CONGRESS.! 4 .■^J!0 # !f.f.&..^- |o?Mwf» I ^ _ I ^ UNITED STATES OP AMERICA. ^ - J2> s • y-^ ■^?> ^.:^-^- >:>:> <^<^ ' ■'-* > 3£> >:> ■ >:^ > > X> '^> r» l:> D^> ^> » ■ -!:3» :> > » :*> >J» 3>>. 3-) .^>B> . 'Z> J^jfc :» ^^> ■ !:> :^ > • >i 3> > Z> •::>- » >> :x» :>• ^>:>. bt> 3 vr. >^3 3 33 ^ >3: ^,^><>^> 3^>z> :>3r3 ,>3 :> '3^ 3 > > :> 3 3>^:>3 3> >->-/> ^-> 3-^::) ? >:>■ >3^3>_^ 3 3)3^ > 3».> :> > ' ■ »^ J> ::>3 ' >I> > :> .3 >o >_:> ^ J^ ^ >.)^ 33? ^^:> 3J> ^^ ^ J> 3J> 3» > > > > >^c>Sx> fT*^ 3>> 35 > ? i* / > ^ > > > " » - > 3 o 3^ >3'3 ^ > » > ^ J^ > ; . O > 3> > > o : :> : > :>:> 3 ^ ■03 > > . x> ~> > ;jT»" > 3>_: ^. f/l^- i3 -^ 3 ^ -> '^> ^ >„ 3 3 > >^ 3>_ , 3 ^> > > ^ ~> > , > -^"-^ ^^'^ -^^^^ / A PRACTICAL TREATISE ON PURE FERTILIZERS A PRACTICAL TREATISE ON PURE FERTILIZERS; AND THE CHEMICAL CONVERSION ■'• OF ROCK GUANOS, MARLSTONES, COPROLITES, AND THE CRUDE PHOSPHATES OF LIME AND ALUMINA GENERALLY, INTO VARIOUS VALUABLE PRODUCTS. ' ' '^r CGPYRIGI-. i CAMPBELL MORFIT, M.D., pSc^Siro}: M FORMERLY PROFESSOR OF APPLIED CHEMISTRY IN THE UNIVERSITY OF MARYLAND. With Twenty-Eight Illustrative Plates, or Construction Plans, drmun to Scale Measurements, NEW YORK: D. VAN NOSTRAND, PUBLISHER, 23, MURRAY STREET, AND 27, WARREN STREET. 1872. ENTERED ACCORDING TO THE ACT OF CONGRESS IN THE YEAR 1872, BY CAMPBELL MORFIT, IN THE clerk's OFFICE OF THE DISTRICT COURT OF THE UNITED STATES FOR THE STATE OF MARYLAND, PREFACE. This treatise is founded upon the special studies and large professional experience of the author in the technology of the mineral phosphates of lime and alumina. All of its teachings are submitted, there- fore, as practical knowledge, setting forth the subject systematically, in its most improved relations to science and econo- mics. The illustrations, which, with few ex- ceptions, are new, have been drawn large to a scale and as actual construction-plans, so that they may be fully expressive with- out long descriptions. Their creditable style vi PREFACE. is due to the draughting skill of Mr. H. Herbert Lewis, a talented mechanical engineer, who worked out the author's original designs. London, November iith, 1872. — -siT-^s^^^kr^-e — TABLE OF CONTENTS. CHAPTER I. PAGE The General Relations of the Subject - - i-6 CHAPTER n. The Raw Materl\ls. — Comparative Solubility of the Crude Phosphates. Bone-black ; Bone-ash ; Apatite ; Phosphorite ; Spanish Phosphorite ; Welsh Phosphorite ; German Phosphorite ; Russian Phosphorite ; Austrian Phosphorite ; Copro- lites ; Wicken Coprolites ; Calais Coprolites ; Rossa or Guaymas Guano ; Sombrero Guano ; St. Martin's Phos- phate ; Marlstones ; South Carolina Phosphate ; French Phosphate; Cooperite or Navasa Guano ; Orchila Guano. — Analytical table of the comparative composition of the crude or natural phosphates of Lime. — Sulphuric acid ; Brown oil of vitriol ; Chamber acids ; Table of strengths. — Hydrochloric acid ; Table of strength.— Crude ammonia liquor from coal-gas and bone-black works. — Table of the supply and value of nitrogenous wastes. — Woollen refuse ; Leather clippings ; Dried blood ; Dried flesh ; Carne cozida ; Greaves or cracklings ; Human excrements ; Sewage ; Suggestions for the conversion of the latter into ammonia salts ; Morris and Penny's pro- cess ; J. Berger Spence's and Dunn's process. — Sulphate viii CONTENTS. of ammonia ; Chloride of ammonium. — Sulphate of po- tassa ; Chloride of potassium. — Carbonate of potassa ; Salt of tartar ; Pearl ash. — Lime ; Carbonate of lime ; Chalk ; Whiting ; Hydrated sulphate of lime. — Nitrate of soda .... - 7-66 CHAPTER III. Chemical Data in Connection with the Raw Materials OF Artificial Fertilizers. Tri- or bone-phosphate of lime ; Di- or neutral-phosphate of lime ; Bi- or superphosphate of lime ; Precipitated phos- phate of lime ; Colombian phosphate of lime ; Sulphite of calcium phosphate. — Phosphate of magnesia. — Car- bonate of lime ; Organate of lime ; Sulphate of lime. — Fluoride of calcium ; Chloride of calcium. — Oxide of iron ; Phosphate of iron. — Oxide of aluminium ; Phos- phate of alumina. — Organic matters. — Silica and sand. — Water . - . . _ 67-91 CHAPTER IV. The Grinding and Sifting Apparatus. Burr-stone mills ; Roller-mill ; Chasers ; Revolving sifter ; Blake's crusher ; Howel-Hannay's centrifugal mill - 92-107 CHAPTER V. The Plant. Steam-boiler and engine ; Roasting furnace ; Platform and its accessories ; Elevator ; Lift ; Acid reservoir ; Mixer ; Stone digestion vats ; Solution vats ; Syphon ; Monte- jus; Precipitation vat ; Drying kiln ; Wash vat ; Evapo- CONTENTS. ix rating pan ; Mixing machines ; Can's disintegrator ; Poole and Hunt's mixer - - - - 108-146 CHAPTER VI. The Arrangement of the Factory Plant - - 147-152 CHAPTER Vn. The Rationale of the Processes for Refining the Crude Phosphates of Lime. Diagram of the progressive operations and their effects - 153-161 CHAPTER Vni. The Manufacture of Precipitated Phosphate of Lime. First fractional treatment or purge for the removal of car- bonate of lime ; Second fractional digestion for the solu- tion of the tri-phosphate of lime constituent ; the vacuo- precipitation vats ; the ammonia-generator ; Air-pump ; Filtration in vacuo ; Reclamation of the ammonia-preci- pitant for repeated use indefinitely ; Utilization of the purge liquor - . - _ . 162-202 CHAPTER IX. The Manufacture of Colombian Phosphate of Lime. First process : The use of whiting as precipitant ; Horizontal sieve ; Composition of the product ; the utilization of the mother-liquor or wash. Second pi'ocess : The use of iron and aluminium impurities of the mineral, as precipi- tant ----_. 203-225 X CONTENTS. CHAPTER X. The Manufacture of Di-Phosphate of Lime. Morfit's process (A) : Porcelain-lined vat ; Morfit's process (B) ; J. Thomas Way's process ; Ernest Deligny's pro- cess ; Way's chloro-phosphate of lime and the method of making it . - - - -226-276 CHAPTER XI. The Method of Reclaiming the Chloride of Calcium Mother-Liquor in Profitable Forms. As pure chloride of calcium ; as chloride of ammonium and hydrated sulphate of lime by means of sulphate of ammo- nia or gas-liquor ; by means of sulphate of potassa as chloride of potassium ; by means of phosphate of soda ------ 277-287 CHAPTER Xn. The Principles of the Super-Phosphating Processes. The maximum yield by pure tri-phosphate of lime ; the falla- cies of the usual methods ; the maximum yield by bone- ash ; by coprolites and marlstones ; Analyses - 288-297 CHAPTER XHI. The Manufacture of Pure " Super-Phosphate". Composition of the products from pure tri- and di-phosphates oflimg - - • - - -29S-302 CONTENTS. CHAPTER XIV. The Manufacture of Pure and Wholly Soluble Bi- Phosphate of Lime. The turbine ; the vacuo-leaching vat - - -303-314 CHAPTER XV. The Manufacture of " Commercial Super-Phosphate". Composition of the product from various crude bases. — The wells ----- -315-326 CHAPTER XVI. The Manufacture of Horsford-Liebig's and other Phosphatic Baking-Powders. The process of manufacture ; the directions for use ; Brown or bran bread ; Bread for gouty patients ; Confectioner's cakes ; White bread. — The steam evaporating-pan - 327-338 CHAPTER XVII. Gerland's Sulphite of Calcium-Phosphate. Its composition, properties, and manufacture ; Its uses as a fertilizer ; as a disinfectant. — The chemical analysis of the product - - - . -339-359 CHAPTER XVIII. The Chemical Treatment of"Redonda Guano" and "Alta Vela Guano" and Mineral Phosphates of Alumina and Iron generally, for Conversion into Fertilizers. Rcdonda guano ; Alta Vela crust ; A. B. R, phosphate rock ; Analytical table of their comparative composition and value ; Method for converting them into potential ferti- lizers ; Digestion vats of stone - . _ 360-377 CONTENTS. CHAPTER XIX. The Mineral Phosphates of Alumina and Iron as Raw Material for the Manufacture of Alum and other Useful Products. Peter Spence's process for making alum, sulphate of alumina, crude phosphoric acid and phosphates ; J. Berger Spence's and Peter Dunn's processes for removing am- monia from illuminating gas ; for the manufacture of phosphates of ammonia and lime.— Tovvnsend's pro- cess ------ 378-392 CHAPTER XX. The Mineral Phosphates of Alumina and Iron as Raw Material for Defecating Sewage. Their application in purifying and utilizing town sewage ; Forbes's processes ; Price's processes ; Morfit's "mother- water" as substitute for Alta Vela and Redonda guanos ; comparative composition of the sewage precipitates ob- tained by the use of the " mother-liquor" and sulphuric solution of Alta Vela guano - - -393-401 CHAPTER XXI. The Profitable Utilization of the Phosphat-Alumina Precipitate from Sewage as Raw Material for Various Products. For the reclamation of its nitrogenous matter as material for the manufacture of ammonia salts ; as raw material for the manufacture of alum and pure phosphates of alumina and lime ; as aluminate of soda or ready saponifier and common salt. — Phosphate of alumina in the manufacture of sugar ; in dyeing ; as a glaze for pottery - - 402-418 CONTENTS. xiii CHAPTER XXII. Special Fertilizers and their Preparations. The physical and chemical structure of soils. — Normal ferti- lizer ; Universal Dunger ; Fertilizer for cereal crops ; for leguminous plants ; for gramineous crops ; for sugar ; for root crops - - - . -419-431 CHAPTER XXIII. Formulae for the Chemical Analysis of Phosphatic Materials and Products. The chemical and ethical principles involved. — Instructions for the full analysis of bone-ash and mineral phosphates of lime ; of mineral phosphates of alumina and iron ; of "commercial superphosphate"; of compound ferti- lizers ------ 432-484 CHAPTER XXIV. The Commercial Valuation of Crude and Refined Fertilizing Materials - - -4'?5-5io CHAPTER XXV. The Mode of Using Hydrometers and Thermo- meters . _ . . -511-519 CHAPTER XXVI. Acid and Water-Proof Cements and Paints - 520-530 Index - - - - - . -531-546 ERRATA. Page 35.— In the heading of the table, read " SOg,"/^^ «' SO." 74. — In the sixth line from the top, read " O^" for " O." 95. — In the sixth line from the bottom, read "f,"/or " 3." loi. — At the bottom line, fead "fig. 3,^' for "fig. I." III. — At the eighth line from the top, read "D,"/or "o." 116. — At the fifteenth line from the top, read "G,"/or "d." 120. — At the seventeenth line from the top, read "a a," /or "aa." 120. —At the twenty -second line from the top, read " a," /or " /^." 191. — At the seventeenth line from the top, read " /;," /or "/." 192. — At the eighteenth line from the top, read "r,"/or "jc." 254. — At the last line, read "bone-ash, "_/(?;' "bone." A LIST OF THE ENGRAVED PLATES OR CONSTRUCTION PLANS. PLATE 1. ROLLER MILL 2. REVOLVING SIEVE 3. BLAKE'S CRUSHER 4. HOWEL'S CENTRIFUGAL MILL 5. PLATFORM, LIFT, AND ELEVATOR 6. DETAILS OF LIFT AND ELEVATOR 7. MIXER 8. DIGESTER OR SOLUTION VAT 9. TROLLEY FOR BRINGING UP CARBOYS 10. MONTE-JUS 11. PRECIPITATION VAT ... 12. DRYING KILN 13. EVAPORATING PAN 14. 15- CARR'S MIXING MACHINE 16. GROUND PLAN OF A FACTORY ARRANGEMENT ^7- I BATTERY OF PRECIPITATION VATS, \VITH AMMONIA- 18. j GENERATOR 19. VACUUM FILTER, WITH 4IR-PUMP AND MONTE-JUS PAGE 5 20 35 50 65 80 98 no 123 140 155 175 195 215 225 245 265 28s 305 XVI A LIST OF PLATES. PLATE 20. HORIZONTAL SIFTING AND STRAINING MACHINE 21. PUG-MIXER... 22. SOLUTION VAT COMBINED WITH VACUUM FILTER 23. DRAINERS ... 24. SUPER-PHOSPHATE WELLS OR PITS 25. FILTERING STANDS 26. I APPARATUS FOR THE TREATMENT OF MINERAL PHOS 27. j PHATES OF ALUMINA 28. DOUBLE-PAN FOR MAKING ACID-PROOF CEMENT AND PAGE 350 370 395 420 440 460 480 PAINT ... 500 PURE FERTILIZERS. CHAPTER I. THE GENERAL RELATIONS OF THE SUBJECT. The fructification of soils has its natural pabulum, undoubtedly, in the sewage of cities, towns, and habitations ; and it is de- sirable, both as respects agricultural inte- rests and the public hygiene, that thoroughly efficient means should be devised for uti- lizing this resource judiciously. Until this is done, the food required by growing crops must be supplied through the media of arti- ficial fertilizers. The manufacture of these products has become, consequently, an enter- prise of great magnitude, which is daily extending its area ; so that abundant sup- plies of the basis-material are indispens- able. Fortunately, the beneficence of Nature PURE FERTILIZERS. vouchsafes to us vast deposits of this basis- material, which she has distributed through- out the surface of the globe in the form of mineral phosphates, and as a temporary sub- stitute for sewage, while our enterprise and skill may remain at fault in managing the latter with a perfect facility.* These mineral phosphates consist of the various kinds of " Rock Guano," Coprolites, the fossils of Marlbeds, and the minerals Apatite and Phosphorite. The chief and valuable constituent of them is bone-phosphate of lime. In some few in- stances, phosphate of alumina is the prevail- ing constituent. All of these varieties of the mineral phos- phates differ from the typical phosphate of lime, which is bone-ash, in having a very dense, compact physical structure, owing to the peculiar state of aggregation of their che- mical elements. These elements vary with the kind of mineral phosphate, but besides tri-phosphate of lime, are commonly water, * Their geological distribution is explained fully in an interesting paper by VV. J. T. Dyer and A. H, Church, at pp. 159-185, vol. ii of Practice with Science. THE GENERAL RELATIONS. organic matter, silica, sulphate lime, carbon- ate lime, together with aluminium and iron oxides and phosphates. Some of them have only a secondary value as agricultural powers, while the others are objectionable, because they dilute the mass unprofitably. In an- other, and far more serious sense, however, their presence impairs the usefulness of the raw mineral ; for the latter, even when powdered finely, is by their cementing action rendered rather passive to decomposing in- fluences, and consequently a slow fertilizer. I say slow, because I do not share the opinion of many sagacious chemists, that phosphates of alumina and iron are without fertilizing effect ; nor yet that it is indispen- sable to change the chemical structure of the mineral phosphate of lime in order to give it action as a manure. They have inertia in those respects undoubtedly ; but it is my be- lief that the need of phosphoric acid by the growing crops is so great as to give them the energy to draw it from the most difficult source if none easier should be accessible. At the same time the strain which is thus put upon the assimilating powers of the B 2 PURE FERTILIZERS. plant must weaken its constitution and im- pair the quantity as well as the quality of the harvest. Upon the ground of expediency, therefore, and to economize time, labour, and money, this fault of the mineral phosphates should be corrected by a proper chemical treatment, preliminary to their application to soils. That is, they must not only be finely powdered, but converted into forms which are promptly sensitive to the solvent action of aqueous so- lutions of carbonic and organic acids, very dilute acetic acid, ammoniacal and potassic salts, and of the corresponding influences of the soil and plants as exerted during the progress of vegetation. The usual method of destroying the iner- tia, or passive condition of mineral phos- phates, is to act upon them with sulphuric acid which should convert their tri-phosphate of lime into soluble bi-phosphate. This plan is perfectly sound in principle ; but, on ac- count of the slovenly mode of carrying it out generally practised, variable quantities of the raw phosphate remain undecomposed, and, as a consequence, proportional amounts of free sulphuric acid are introduced. MORFlToii the Mann fact fur o/'Ferff Sijeciallv desif^iiHi for 1)'. McitiH s Woi'k on FerultZfiis rX^ C!':'.60,PaierTiDSi.erRow THE GENERAL RELATIONS. Here, then, consequently, are a profligate waste of two materials, a want of uniformity in the product, and a wide extent of dilution, by reason of the sulphate of lime which is formed, to say nothing of the disadvantage of the free sulphuric acid. What is wanted, then, are methods, simple and economical, for changing not merely the physical constitution of the mineral phos- phates, but also their chemical temperament, and in such a manner as to convert them into fertilizers at once concentrated and potential. These latter qualities are important, more es- pecially on the score of package and freight or transportation charges in extensive coun- tries, like the United States of America, where distribution of the products is mostly in small lots, to the interior of scattered and often remote districts. In such cases, the necessary or desirable dilution may be done by the farmer himself, and with suitable as well as inexpensive materials which abound at his door, and thus save him needless out- . lay. The chemical mind has been very active in suggesting ways of accomplishing the needed ROLLER IVIILL. Plate 1. -7^ IJHU FRONT ELEVATION SCI\lf. OF FEET J f ±- cliilW iVa^iJiiiNl loir IV. MurtV 3 Wijrk cti l''finili;-.'>j i Vii k-'eia Bro^iic;. D?.yiitSan. 1 -iii ^ Ttim ■ :ck C9.60.PaifiiTiDSterRow PURE FERTILIZERS. improvement. Treatment in furnaces with fluxes, and boiling in pans with salts of dif- ferent kinds, in order to render the phospho- ric acid constituent soluble, are the methods most commonly met with in books. The use of acids of several kinds, and in varied manner, also constitutes the substance of many recorded processes. But, in most cases, the chemical agent em- ployed is either itself an undesirable element to import into the fertilizer, or the mode of use is expensive, by reason of the agent not producing incidentally some tangible result to repay fully its cost. Then, too, there is the bulkiness of the raw phosphate, which renders the usual methods both troublesome and defective in economy. No plan of instruction is equal to the che- mical agricultural and commercial require- ments of the case which does not remedy these deficiencies. This consideration, there- fore, is held paramount in the processes of the following chapters. Self-compensating throughout, they will deliver the products in the most valuable forms with the least pos- sible manufacturing expense and waste. CHAPTER 11. THE RAW MATERIALS. The raw materials involved in the manufac- ture of artificial fertilizers are the animal and mineral phosphates of lime, sulphuric acid, hydrochloric acid, crude ammonia liquor, sulphate of ammonia, chloride of ammonium, sulphate of potassa, chloride of potassium, carbonate of potassa, lime, and nitrate of soda. The sources of the chief class, that is the phosphates, are all natural, the several indi- viduals being bone-black, bone-ash, apatite, phosphorite, coprolites, marl-stones, and the " rock guanos". Bone-Black. This material, known also by the title of "Animal Charcoal", is made by calcining PURE FERTILIZERS. bones in a manner to drive off all the volatile matters except carbon, which is left with the phosphate of lime. This residue thus formed, when ground to powder, is sold to sugar re- finers for decolorizing their solutions. After having been used and ''revived'' several times, its bleaching power has become exhausted, and then it is sold either as a manure or for conversion into ''superphosphate''. It con- tains a large amount of organic matter, more particularly when blood has been associated with it in the decolorizing or refining opera- tion. Bone- Ash. This is a greyish-white powder obtained by calcining raw-bones, in open vessels, so as to get rid of the moisture, organic matter, and carbon ; as these associates would interfere with the economy and convenience of trans- portation from distant countries where cattle abound and are killed for their hides, tallow, and bones. The supplies come mostly from the La Plata Districts of South America, and the Baltic, Mediterranean, and Black Sea ports, where the process of manufacture is conducted so wastcfully that the valuable THE RAW materials. ammonia distillate does not receive any con- sideration. The tri- or bone-phosphate of lime in this ash, as well as in the bone-black, is pecu- liarly sensitive to the assimilating action of growing crops. For example, one part of its phosphate is soluble in 6800 parts of car- bonic water, according to Warrington's ex- periments; and this solubility is even greater when alkaline salts are present. Both the bone-black and bone-ash are such superior fertilizers for direct application to the soil, that it would be profligate to use them as raw material for conversion into " superphosphate". So great and growing is the demand for these two materials, that their market price has advanced twenty per cent, within the last few years. Apatite. This is a hard mineral, sometimes crystal- lized and at others foliated or conchoidal, which is found generally in thin seams in crystalline or volcanic rocks. It varies in colour from light green to iron-stone red. The principal localities are Norway, Sweden, lo PURE FERTILIZERS. Switzerland, Bohemia, Saxony, Bavaria, Canada, New York, and New Jersey. In order to obtain a fair average sample, it is necessary to grind an entire ton, owing to the difficulty of excluding foreign minerals in mining it. According to Voelcker, the Norway apatite is always free from fluoride of calcium, which is present, usually, in the other varieties. The Canadian apatite is crystallized, crys- talline, granular, and massive, and of a sea- green, olive green, greyish, or reddish colour. It abounds, according to T. S. Hunt, in the Laurentian limestones of North Elmsley and North Burgess, where it forms numerous beds eight to twenty-four inches thick and about ten feet broad. The closely cemented structure of this mineral, even when finely powdered, makes it unsuited, in an economical sense, for direct application to soils. It must be previously converted into precipitated phosphate or su- perphosphate, for which purposes it is most eligible on account of its high content of lime phosphate and low proportion of waste con- stituents. THE RAW MATERIALS. ii The commercial supply of apatite is limited, owing to the difficult accessibility of its sources. Phosphorite. The best qualities of this material are found at Estramadura in Spain, and Amberg in Bavaria. In both of these localities it abounds, but does not reach foreign markets in any quantity, because of the great expense of mining labour, and of the difficulties of inland transportation at the sources. It derives its name from its property of be- coming phosphorescent when heated. It is found in thick beds flanked with apa- tite and quartz. It is fibrous in structure, of a light yellow colour, and very hard, as well as difficult to powder. It is a very superior raw material for conversion into refined phos- phates ; and to this preparatory treatment it should be subjected in order to render it a prompt and economical fertilizer. Welsh Phosphorite. The phosphatic beds at Cwmgwnnen in the Lower Silurian series of North Wales has an 12 PURE FERTILIZERS. area, according to W. J. T. Dyer and A. H. Church, of four miles long by a width of eighty yards and a thickness of fifteen inches. It is worked by adit levels driven in from the hill side, which it intersects almost vertically. German Phosphorite. Recent geological surveys have revealed very extensive deposits of this mineral in the districts of Staffel, Limburg, Hinterland, Wetzlar, Oberlahn, Unterlahn, the borders of the river Lahn and Dill, and other portions of the right basin of the Rhine. " It lies, generally, in diabase and shale overlapped or underlaid by lower and middle Devonian and by diluvial beds. The whole region is full of seams, beds and veins of black, red, and brown hematites." On account of its immense mass, the mine- ral of the Staffel and Limburg beds can only be mined by blasting. It is an amorphous solid, of a brownish-yellow or fawn-grey colour, with a splintery fracture ; but there are two varieties, one of which is friable and the other is soft. Though it contains some calcium fluoride THE RAW MATERIALS. 13 and carbonate, alumina, and oxide of iron, it is, nevertheless, a good raw material for re- fining purposes, and should be subjected to this preparatory treatment instead of being applied, in its natural powdered state, to the soil. The analysis, by Fresenius, in the table at page 30, represents a selected sample, doubt- less ; for that which forms a deposit of about four thousand German acres, near the Lahn river in Nassau, is several per cent, less rich. Its composition, according to Voelcker, is as follows : — Moisture - - - 0-36 Water of combinat ion - 1-85 Phosphoric acid (= = 3CaO, P05 65' 19) - 29-86 Lime - - 42-31 Magnesia - - 0-30 Sulphuric acid - 0-65 Carbonic acid - - 2-86 Oxide of iron - - 4-43 Alumina and loss in analysis - - 6-33 Insoluble siliceous matter - iro5 1 0000 Russian and Anstrian Phosphorite. The great phosphorite zone in Russia occupies an area of 20,000 square versts : 14 PURE FERTILIZERS. extending from the Volga, near Simbirsk, into the Desna district of Smolensk ; and thence, after a real or apparent break, into the government of Grodno. Grewingk's ana- lysis gives the following composition for the mineral : — Organic matter and constitutional water - 4*702 Moisture or accidental water - - 0910 Silica _ . - - 42-965 Fluorid of calcium - - 3-535 Proto-carbonate of iron - 3-847 Carbonate of magnesia - I -602 Oxide of iron - 0*922 Alumina - - - - 5-027 Phosphate of alumina - 1-874 Tri-phosphate of lime - 32-950 Potassa . - - - 0751 Soda - . . - 0-593 Sulphuric acid - 0-076 99754 Further southward, on the Zanks, on the Dniester, in Russian Podolia, and in the Bukowina, there are also deposits of phos- phorite, which Schwachofer describes as very rich on the average. The composition of the nodular portions resembles that of apatite. THE RAW MATERIALS. 15 Coprolites. True coprolites are not fossil excrements, as has been supposed, but worn and rounded fragments of fossil bones of a peculiar organ- ization. They are found in the green sand and crag of the lower chalk formation and adjoining strata. The false coprolites, as those of Suffolk, are a mixture of fossilized excrements, fish- bones, rolled stones, etc., forming beds in the more recent tertiary strata between the coral- line crag and the London clay. The coast of Suffolk and Cambridgeshire, England, are extensive localities for these phosphatic materials. They are also found abundantly in France and Germany, and to a small extent in Canada. Owing to the fluoride of calcium which they contain, hydrofluoric acid is evolved during the process of superphosphating them, and waste as well as discomfort ensue conse- quently. The presence of a large amount of carbonate of lime involves, also, a waste of acid ; to say nothing of the considerable pro- portion of alumina and oxide of iron, which not only are profligate constituents as regards i6 PURE FERTILIZERS. the consumption of the acid, but the means of rendering the "superphosphate" perma- nently damp. These circumstances, and the fact that their valueless constituents will di- lute the product to an extreme degree, reduce the coprolites to an inferior rank as a raw material, for the manufacture of refined phos- phate products. Nevertheless, they are em- ployed extensively for the purpose in Great Britain, — perhaps on account of their regular abundance and low price. They do not make " superphosphate" of good quality by the usual processes ; nor are they so profitable for the methods of this treatise as even the " South Carolina Phosphate"; and those in- ferior kinds of coprolites known as the "Wicken Coprolites" from Cambridgeshire and Bedfordshire; and "Calais Coprolites" from the Pas de Calais in France. Either of the two latter is to be obtained abundantly at a low price, and the following analyses will show their composition. The samples were obtained from a trustworthy source, and re- present fairly the average character of the respective deposits. They may be considered as typical members of the class of low grades of mineral phosphates of lime. THE RAW MATERIALS. 17 WICKEN COPROLITES. COPROLITES FROM PAS DE CALAIS. (Morfit.) (Morfit and B. W. Gerland. ) Moisture - - _ 1-66 Moisture 0-610 Loss by ignition 2-97 Sand, pyrites, etc., in- Silica, sand, & pyrites 24-46 soluble in HCl. - 33-340 Fluoride of calcium - 2 -02 Silicic acid 1-490 Sulphate of lime 1-53 Fluoride calcium 2-100 Carbonate of lime 10- 1 6 Sulphate of lime 2-487 Lime (as silicate and Carbonate of lime - 11-360 organate) 6-40 Lime as silicate, etc. 7-360 Tri-phosphate of lime 35-66 Tri-phosphate lime 29-150 Oxide of iron - 7-56 Tri-phosphate mag- Alumina - - 4-07 14-30 nesia - - - 2-552 Phosphoric acid 2-67 Oxides of iron, 2111 Alumina, 2-730 ^10-541 99-16 Phospho. acid, 5-700 ] 00-990 Rossa or Giiaymas Gitano. This is a very superior rock guano from Rossa Island, 28-3 north latitude, and 110-46 west longitude, near Guaymas, in the Gulf of California. It contains a portion of its phos- phate of lime in a di- or neutral state, and is almost wholly free from constituents which would waste acid. It is in hard lumps, but PURE FERTILIZERS. can be reduced to fine powder without diffi- culty ; and in this latter form is well suited for mixing with highly ammoniacal manures. For the purposes of this treatise, it may be considered almost a pure material, as the foreign matters are all excluded, by the action of the hydrochloric acid, in the very first stage of the refining processes. The analysis in the table represents a sample which I examined several years ago ; but, though the deposit is large, none has yet been brought into this market. Sombrero Guano. This is a rock guano constituting the entire structure of one of the Windward Islands in the Carribean Sea, called Sombrero. It is most probably a bone breccia ; as pieces of bone are found occasionally in the mass. It is not very hard, and forms a light yellow brown powder. I was the first to recognise the agricultural value of this mineral phosphate, and give it professional support when it was the object of great prejudice. The following analyses by Voelcker, of cargoes imported in 1871, show THE RAW MATERIALS. 19 that notwithstanding a greater dampness, owing to being mined now below the level of the sea, it reaches the market in quality as good as that of the earlier importations which are represented by my figures in the analytical table at pages 30, 31. Water and '\ Organic > matters j Phosphoric \ acid j Lime - - - Magnesia, "^ Ox. iron, f Carbonic C acid, etc. j Sand & Silica 2-99 5-08 9-42 9-19 5-49 9-52 689 21-20 32-32 30-84 30-98 30-84 32-86 30-48 31-16 27-82 45-96 47-65 44-98 44-33 45-83 44 77 45-18 35-72 II-2I 15-48 13-53 14-59 14-57 14-14 15-45 14-56 7-52 •95 I-I9 1-05 1-25 I 09 1.32 •70 lOO'OO loo-oo 1 00 00 lOO'OC 100-00 100 00 100-00 100-00 There is one portion of the island which gives a mineral of the following composition, according to analysis by Evans and Jones ; but none of it has yet been mined for market. Moisture and water of combination Silica Carbonate of lime Phosphate of lime Phosphate of alumina Alkaline salts - 6-01 lo-io 4'43 43 '3 5 30-20 5-91 1 0000 C 2 20 PURE FERTILIZERS. St. Martins PhospJiate. This mineral is from the island of St. Martin's, but has not been sent forward in any large quantity. The following analysis by Voelcker shows the composition of what may be considered an inferior sample. Water and loss on heating - 8-66 Carbonic acid - 11-57 Phosphoric acid - - 2476 Lime - - - - 4541 Alumina, ox. iron, and magnesia - 6-37 Insoluble silicates - 3-23 lOO'OO South Carolina Phosphate. This material comes from the neighbour- hood of the Ashley river, South Carolina, United States of America. It is in the form of hard nodules called Marlstones. The fish beds from which it is obtained are forty to fifty miles in extent. It may be ground with- out difficulty, and forms a powder sometimes of an olive-grey shade, at others of a brown- ish-buff colour, and soluble in acids. Of all the mineral phosphates of lime which z o I UJ O lO o > CO O z o > UJ bJ J < U THE RAW MATERIALS, 21 are available, in abimdant and regular supply , these marlstones are among those best suited for the purpose of this treatise. Their ratio of carbonate and organate of lime is not un- profitably large where hydrochloric acid is cheap ; and the solution of the iron and alumina constituents may be kept down in considerable degree by skilful manipulation. The remaining associates of the phosphate of lime constituent are merely valueless and not diluents or promoters of waste of acid. Their proportion of phosphate of lime, though only a moderate average, is thus really present in profitable degree. Another advantage is that the material may be bought at a comparatively lower price than minerals of the same class. The composition of that kind of *' South Carolina Phosphate" which gives a fawn- coloured powder, and as imported in 1870-1, is shown by the analytical table at pages 30, 31- Another variety, whose powder is olive- greyish in colour, and now coming forward (1872) in greater or lesser quantity, has the following chemical constitution, according to 22 PVRE FERTILIZERS. the full analysis of a sample from a recent cargo : — "SOUTH CAROLINA PHOSPHATE." (Morfit and B. W. Gerland. ) Moisture . - _ . I'll Organic matter - 1-34 Insoluble, silica, sand, etc. - 11-56 Pyrites - - _ - 1-24 Silica, dissolved by HCl. - 'Z6 Fluoride calcium - 2-62 Sulphate lime - 4-1 r Carbonate lime - 14*02 Lime, as organate, silicate, aluminate - 9-1 1 Tri-phosphate lime - 42-13 Tri-phosphate magnesia - 4"43 Oxide iron 1-83 \ Alumina - - - 2-0/ \ 8-39 Phosphoric acid 4-49 ) 100-92 A third variety of this phosphate is now being brought forward also, from Williman's Island, Prince William's parish, Beaufort County, S.C, formed by inlets on the eastern coast, about fifteen miles from the Atlantic Ocean. It comprises nearly 1600 acres, with a bed of phosphate running throughout, THE RAW MATERIALS. 23 which latter has been calculated to yield 10,000,000 tons. Dr. A. Voelcker, who examined this phos- phate, has reported that a careful and detailed analysis of the finely ground sample (un- washed) taken from the bulk at the Stores yielded the following results : — Moisture - - - - 191 ^Organic matter and water of combination 4*05 Phosphoric acid _ _ . 26'23 Magnesia - - - - -24 Lime _ _ - _ 3978 Potash - - - - '20 Soda - - _ . -65 Chloride of sodium - - - '05 Sulphuric acid _ _ _ 2*50 Oxide of iron - - - i'85 Alumina and a little fluorine - - 4'64 Insoluble silicious matter & soluble silica 15 '31 Carbonic acid - _ _ 2'6o lOOOO *Containing nitrogen - - - "09 Equal to ammonia - - - "ii "The presence of traces of nitrogenous or- ganic matter in this material appears to indi- cate its organic origin." 24 PURE FERTILIZERS. " Williman's Island Guano resembles near- est in character the Cambridgeshire Copro- lites." French PJwsphate. This is most probably a species of bone breccia, for, though of rocky character, fossil bones are found with it in some of the open- ings. It extends over a wide area of the depart- ments of the Lot and Garonne, the Lot and the Aveyron in France, where it is found in detached veins and small pockets underlying the grey limestone on the highest plateaux of the mountains between the rivers Lot and Aveyron. The solid veins run generally from eastward to westward ; and the loose boulders are found embedded in a ferruginous looking clay and sand. It gives a light fawn coloured powder. The following analyses by Voelcker of several of the cargoes of 1871 show that it is a very high quality of mineral phos- phate. THE RAW MATERIALS. "Ar- " Philo- " Hana- Components. "Topaz." "Denia." "Maria." "Rifle." mandMa- mene." ton." rianne." Water and loss ') by heating j 3-45 315 4"io 4-29 6-03 4'94 2-23 Phosphoric acid 3607 36-64 33-05 34-89 33-80 34-90 37-60 Lime 48 '43 4865 48-46 4709 48-25 4962 4652 Alumina and \ oxide of iron, magnesia, >• 9-56 9-04 1 2 '40 1 1 -02 9-24 889 13-04 carbonic acid, etc. ) Insoluble sili- \ cious matter j 2-49 2*52 1-99 271 2-68 1-65 •61 lOO'OO 1 00 00 lOOOO 100 00 lOO'OO 1 00 00 lOQ-OO Navasa Guano or Cooperite. The island which furnishes this mineral is on the coast of Hayti, in latitude 78 deg. 25 min. N., and longitude 75 deg. 2 min. W. As sent into the market by the proprietors, it is in brown lumps which give a powder like that of hematite. The very large proportion of iron and aluminium compounds, which it contains, distinguishes it from all other mineral phosphates of lime ; and owing to this and other characteristic features I gave it, some years ago, the name of Cooperite, after the enterprising Captain of the Com- mercial Marine who first brought it into notice. 26 PURE FERTILIZERS. My analysis in the table at pages 30, 31 represents its composition at that time ; and it is uncertain whether the quality has since improved. Those cargoes which arrive now are very variable in their degree of moisture ; and there is also a want of uniformity in the quantitative relation of the phosphoric acid constituent. The annexed analyses represent the com- position of a superior and an inferior sample ; so that the mean of the two may be accepted as the present average quality of the mineral. In my recent refining experiments on a large scale, I obtained from it about fifty-five per cent, of precipitated phosphate of lime in- dependent of the iron and alumina with which it was associated. The difficulty of prevent- ing the solution of a large portion of the oxide iron and alumina along with the phos- phate lime is the only objection to this raw material for superphosphating purposes, as it is cheap and in abundant supply. At the same time, the precipitated product which I obtained from it by my processes was of good quality and gave a "superphosphate" THE RAW MATERIALS. 27 much superior in every respect to that which any raw phosphate material, except bone-ash, could be made to yield. NAVASA GUANO OR COOPERITE. (MorfitatidB. IV. Gerland. ) Moisture - - - I 3 '94 2 3*13 Organic matter and loss by ignition - 5-07 - 5-32 Sand, silica, etc. - 4-43 - 4-37 Fluoride calcium - 1-27 - 1-40 Sulphate lime - I -09 - I -2 1 Lime, as organate, silicate, aluminate - 4-80 - III2 Carbonate lime - 4-63 - 6-52 Tri-phosphate lime ) 55-62 { 45-52 Tri-phosphate magnesia J 1-83 Oxide iron 1 Alumina - - - [ 19-86 - 22-24 Phosphoric acid J I007I 99-86 Orchila Gttano. This material is best known in the United States market. It is brought from Orchila, an island in the Carribean Sea, lat. 1 1 deg. 50 min. N., and long. 66 deg. 14 min. W., and belonging to Venezuela. Its natural form is that of a rather damp, fawn-coloured PURE FERTILIZERS. powder. Its loose texture is advantageous for its direct application to the soil ; but the pro- NOTE. — Charles P.Williams {CJicmical Neivs, xxiv, 306; and Journal of the Chemical Society, x, 269, i %'J2) has re- ported some very interesting results of a course of experi- ments upon the comparative solubility of several crude phosphates of lime. Care was observed to separate the dissolved phosphate of lime from any foreign associates in the liquor, so that its amount might be determined exactly. Molybdate of ammonia was the re-agent employed. Ac- cording to that Chemist : — One part of finely ground bone, containing 5678 per cent, of tri-phosphate of lime, dissolved in 5-698 parts of water saturated Avith carbonic acid gas. One part of finely ground South Carolina Phosphate, con- taining 57*89 per cent, of tri-phosphate of lime, dis- solved in 6-983 parts of water saturated with carbonic acid gas. One part of finely ground Orchila Guano, containing 49*67 per cent, of tri-phosphate of lime, dissolved in 8-009 parts of water saturated with carbonic acid gas. One part of finely ground Bone-Ash, containing per cent, of tri-phosphate of lime, dissolved in 8-029 parts of water saturated with carbonic acid gas. One part of levigated Apatite from Canada, containing 89-27 per cent, of tri-phosphate of lime, dissolved in 140-840 parts of water saturated with carbonic acid gas. One part of ground Apatite from Canada, containing 89-27 per cent, of tri-phosphate of lime, dissolved in 222-222 parts of water saturated with carbonic acid gas. THE RAW MATERIALS. 29 portion of phosphate of lime which it contains renders its money value comparatively small. As this latter is associated with a very large amount of carbonate lime and other profligate components, the guano is not well suited for refining purposes. The analytical figures in the annexed table represent a sample which I obtained direct from the proprietor's agent. The foregoing examples may be considered the commercial representatives of their class of materials ; for, with few exceptions, they are all now in the market. It is only the comparative expense of mining and trans- portation that makes any exceptional in- stances, and even those will disappear as soon as the contingencies of supply and de- mand may justify the bringing forward of present reserves. It is to be hoped, however, that in the meantime new and even cheaper sources, in rich abundance, may be found and developed ; for, as phosphate of lime is the basis of crops, and bountiful harvests cheapen bread, which forms the staff of life, such incidents would grow as well a humanitarian influence in the grandest and most practical sense. 30 PURE FERTILIZERS. Analytical Table of the Comparative Crude Phosphates Components. Rossa Gu- ano from the Gulf of California. (Morfit.) Apatite from Canada. (T.S.Hunt.) Apatite from Norway. (Voelcker.) Phospho- rite from Spain. (Ogston.) Phospho- rite from Germany. (Frese- nius.) Bone or tri-phosphate ) lime and magnesia J S3-08 91-20 90-74 8o-6S 74-64 Neutral or diphosphate ) lime - - -\ 18-03 — — — — Carbonate lime - — — — 4-26 3 '43 Lime, with organic \ acids, silica, and > alumina - - ) — — 4*59 1-83 1-34 Fluoride calcium — 7 60 — •II 526 Chloride calcium — 78 1-61 — — Phosphate alumina - — — 1 1-66 — — Phosphate iron - — — — Oxide aluminium 0-25 — traces 1 -50 108 Oxide iron 015 — — 6-42 Sulphate lime - 810 — — — Potassa salts 1 - _ _ o-sS Soda salts - - - — — _ 0-52 Organic matters 980 — — — — Water, constitutional - Water, accidental 362 — 0-43 •20 2-45 Carbon - - _ — — — — — Sand and silica - 6*20 0-90 1-64 12-34 4-83 99-53 100-48 10067 99-92 ICO- 5 5 THE RAW MATERIALS. 31 Composition of the Natural, of Lime. Bone-Ash from South America. (iMorfit.) Bone-Black from Sugar Refineries. (Morfit.) Sombrero Guano. (Morfit.) True Coprolites, Cambridge. (Way.) False Coprolites, Suffolk. (Herepalh). Marlstones or South Carolina Phosphate. (Morfit.) Cooperite or Navasa Guano. (Morfit.) Orchila Guano. (Morfit.) 7031 58-10 67-06 57-09 55-49 52-21 4680 45-84 1082 8-8o 5-34 13-27 13-40 [14-32 1-92 19-61 79 — 6-97 3-41 — 10-37 274 — — — 4-33 1-43 1-66 5-12 — — — — — 362 5-57 \ 6-78 \ 1 -60 — 1-95 3-13 1-78 2-14 r6i •80 889 320 11-62 11-36 1 — i-io traces traces J 370 — — -86 •80 •70 — I-02 — •20 } -So 1 -49 -61 •65 traces — 5-36 8-00 602 6-93 • 8-6o — ■ 4-05 I 6-26 — — ) 8-42 3-52 ' 3-05 4-74 12-54 -' 19-50 — — — — — 9-20 4-00 -68 6-93 12-45 13-96 4-50 1-24 ioo'34 99-80 100-08 99-98 99-57 100-43 10067 10026 32 PURE FERTILIZERS. SiilpJmric Acid. SO3. HO = 49. The composition of this acid in its pure state is as follows : — Dry sulphuric acid (SO3) - 40'00, or per cent. 81-63 Water of constitution (HO) 9*00 „ 18-37 Chemical equivalent - 49-00 „ 100-00 The range and strength of affinities which pertain to this acid render it the most im- portant and useful chemical agent in the arts. There are very few salts of other acids which it will not decompose. Moreover, it is cheap and abundant. Sulphuric acid is met with in commerce of two strengths, the first being known as Oil of Vitriol having a specific gravity of i "846, and the second, called Brown Oil of Vitriol, with a specific gravity of 1700. This latter is the acid as it comes from the leaden chambers in which it is made. By subsequent concentra- tion in platinum or glass vessels it becomes Oil of Vitriol or Monohydrated Sulphuric Acid (SO3 HO). The brown or chamber acid has the formula SO, HO + HO approximately. There are yet THE RAW MATERIALS. 33 weaker acids known in the factories but not met with in commerce and having respectively the specific gravity i'45o, i'35o, i'25o. Oil of vitriol is a transparent, colourless liquid of oily consistence which freezes at 29 deg. below o deg. F., and boils at 620 deg. F. It distils then without being decomposed, the fumes given off being those of dry sul- phuric acid (SO3). Sulphuric acid has a great affinity for water, and when one is added to the other so much heat is evolved that great care must be ob- served in mixing them. The dry acid (SO3) is not known in com- merce, and both the oil of vitriol and brown acid are solutions of dry acid in water, of dif- ferent strengths. The latter is much more economical than the former for manufacturing purposes, as all the expense of concentration is saved, strong acid not being required. There are thirteen carboys to the ton. In the manufacture of fertilizers, the con- sumption of sulphuric acid is so great that the cost of the carboys which contain it and the expense of transporting them are import- ant elements of consideration. It is advis- 34 PURE FERTILIZERS. able, therefore, to manufacture the acid on the spot or else to locate the manure works in the immediate neighbourhood of a sulphuric acid factory. As differences of strength are due to degree of concentration, the weaker the acid the less expensive will be its use. One pound of oil of vitriol of specific gravity i'846 \s practically equivalent to : — 1-26 lbs. of brown sulphuric acid of sp. gravity, 1700 176 „ chamber „ „ i*450 2-20 „ „ „ M 1-350 2-91 „ „ „ „ i'25o Every per cent, or pound of tri- or bone- phosphate of lime requires practically for its decomposition into soluble bi-phosphate of lime : — 0'64 lbs. of concentrated oil of vitriol of sp. gr., \'Z\6 082 „ brown „ „ 1700 1-14 „ chamber sulphuric acid „ i'450 142 „ M „ „ r350 1-87 „ „ „ „ 1-250 For the decomposition of each per cent, or pound of carbonate and organate of lime, there would be wasted Sprcully desigiie.i fca' D!^ Morfits Work an ir'ei-uiizer THE RAW MATERIALS. 35 0-98 lbs. of concentrated oil of vitriol of sp. gr. , 1-846 1-26 „ brown ,, ,, 1700 176 „ chamber sulphuric acid >i 1-450 2-20 „ >» » >» 1-350 2-91 „ V >> „ I 250 Urcs Table of the Quantity of Concentrated (SO HO) and Dry Snlphnric Acid (SO) in 100 parts of Dilute Acid at different densities. Liquid Dry Liquid Dry Liquid Dry Specific Acid Acid Specific Acid Acid Specific Acid Acid Gravity. in in Gravity. in in Gravity. in in 100. 100. 100. 100. 100. 32 100. 26-09 1 "8460 100 81-54 1-5503 66 53-82 1-2334 I -8438 99 80-72 I 5390 65 53 'oo I -2260 31 25-28 1-8415 98 79-90 1-5280 64 52-18 I -2184 30 24-46 1-8391 97 7909 I-5170 63 51-37 I •2108 29 2365 I -8366 96 78-28 I -5066 62 50-55 I -2032 28 22-83 I -8340 95 77-46 I -4960 61 49 74 1-1956 27 22-01 1-8288 94 76-45 I -4860 60 4892 1-1876 26 21-20 1-8235 93 7583 I -4760 59 48-11 I-I792 25 20-38 i-8i8i 92 7502 I -4660 58 47-29 1-1706 24 19-57 I -8026 91 7420 I -4560 57 46:48 I-I626 23 18-75 I -8070 90 73-39 I -4460 56 45-66 I -1549 22 17-94 1-7986 89 72-57 I -4360 55 44-85 I -1480 21 17-12 I -7901 88 7175 I -4265 54 44-03 I-I4I0 20 16-31 1-7815 87 70-94 1-4170 53 43-22 I -1330 19 15-49 17728 86 70 12 1-4073 52 42-40 I -1246 18 14-68 17640 85 69-31 1-3977 51 41-58 I-II65 17 13-86 I 7540 84 68-49 1-3884 50 4077 I -1090 16 13-05 1-7525 83 6768 1-3788 49 39-96 r-1019 15 12-23 1-7315 82 66-86 I -3697 48 3914 1-0951 14 11-41 I -7200 81 66-05 I -3612 47 38-32 I -0887 13 10 -60 I -7080 80 65-23 1-3530 46 37-51 I 0809 12 9-78 1-6972 79 64-42 1-3440 45 3669 1 -0743 II 8-97 I -6860 78 63 60 I -3345 44 35-88 I 0682 ID 81s I -6744 77 62 78 1-3255 43 35-06 I -0614 9 7-34 I -6624 76 61-97 1-3165 42 34-25 1-0544 8 6-52 1-6500 75 61-15 I -3080 41 33-43 I -0477 7 571 I -6415 74 6034 I 2999 40 32-61 1-0405 6 489 I 6321 73 59-52 I -2913 39 31-80 I -0336 5 4-08 I -6204 72 58-71 1-2826 38 30-98 1-0268 4 3 26 I -6090 71 5789 I -2740 37 30-17 I -0206 3 2-44 15975 70 5708 1-2654 36 2935 1-0140 2 1-63 I -5868 69 56-26 1-2572 35 28-54 10074 I o-8i 1-5760 68 55-45 I -2490 34 27-72 I -5648 67 5463 I -2409 33 26-91 D 2 MORFIT oil ih.\ hauil<'(tiuv.<'rFeHiU:j'r.s- ^ Plate 5. Blake's Crusher _ Front Elevation & Plan FIG. 3 FIG. 2 (o) koi t, 'M oooooooooo O n n nT^ .° o O O O O o o o O O O o O O O O n r, \^^ OOOOOOOOO O O ;^° ° ° o dti- Uj^i jr LXr I H iy-.-jJlv >.teaj " " - 10 — 4. Cutters' flocks - - 700 1,000 tons 5- Shoddy - - i8s. to I 10,000 „ 6. New woollen rags or cut tings . - - ■} 10 and \ upwards 1 Any quantity 7- Old woollen rags or cut tings ... -} 4 and "1 upwards j Any quantity Leather Clippings. The almost unlimited supply of this waste material, which abounds everywhere, and 46 PURE FERTILIZERS. may be collected at a nominal cost, renders it a very suitable basis for an ammonia process by destructive distillation. The quantity of nitrogen which it contains is always large, but varies more or less with the kind of leather waste. Dried Blood. In the extensive slaughter-houses of the United States of America, as well as in the abattoirs of France, the blood of the animals which are killed for food is either dried or solidified by coagulation, and thus econo- mised for market. Its condensed form and richness in nitrogen render it a most valu- able nitrogenous material for fertilizing pur- poses or the production of ammoniacal salts. Dried Flesh. In countries where cattle, sheep, and hogs abound and are killed for their hides and tallow and the flesh is boiled for extract of meat, there is a fibrinous residue which, when dried, becomes a most advantageous nitrogenous material for all the purposes of this treatise. The supply of it is very large. THE RAW MATERIALS. 47 Human Excrements. This source alone, if properly utilized, would supply the larger part of all the am- monia salts that are required by mankind. The dejecta of each person amount per day to 4j lbs. ; and these dejecta, comprising 3 lbs. of urine and 20 oz. of solid faeces, contain the average of 150 grains of nitro- gen, which is equivalent, in that element, to 6000 grains or nearly a pound of wheat flour. Two hundred pounds of wheat flour are con- sidered a liberal annual apportionment to each person. All this wealth of fertilizing matter might be economised by such a municipal regulation as would compel the inhabitants of towns or cities to construct their privies with box-recep- tacles and a automatic, hopper arrangement, by which the dejecta would become mixed with dry earth as they fell. The deodorizing and absorbent properties of the dry earth would render the mixture easy to be handled and removed for further drying in heated air- currents. Thus prepared and powdered, it would then be ready for combustion with 48 PURE FERTILIZERS. soda lime, according to the methods sug- gested at p. 53. In this manner, all the contained nitrogen would be eliminated as ammonia distillate, to be condensed into ammoniacal salt by means of sulphuric, hydrochloric, or crude phos- phoric acid. The solid residuum or calx would consist of sand, soda, and carbonate of lime, together with phosphate of lime or phosphate of soda. If the latter is present, it will have been formed from the phosphate of lime element of the faeces, by interaction with the soda under the fluxing influence of the high heat employed for the combustion. Indeed, the chemical and mechanical conditions of the combustion might be arranged so as to insure the total conversion of the phosphate of lime into phosphate of soda. The solid residue would then yield this latter as an aqueous solution by simple leeching with water. The phosphate of soda thus isolated, is a most valuable liquor for economising the wash or MOTHER LIQUOR in chapter xi. By merely mixing the two, an exchange of bases would take place, and pure phosphate of lime would THE RAW MATERIALS. 49 precipitate, leaving chloride of sodium or common salt in solution. On the other hand, if the combustion should be managed so as to preserve intact the phosphate of lime element, then the soda may be washed out by means of water and evaporated to dryness for repeated use an in- definite number of times. The remainder of the solid residuum is in itself a valuable mineral manure, or it may be dried, powdered, and substituted advan- tageously, for earth, as the drying and de- odorizing material to be used in the privies. Sewage. Several of the processes now in use for the defecation of town sewage render the latter a valuable source of ammonia. The precipitate thus produced carries down the suspended organic matter of the sewage ; and this latter may be then isolated by merely dissolving the earthy portion of the precipitate in hydrochlo- ric or sulphuric acid. The organic matter, on being dried carefully, is a most potential form of nitrogen, for direct use as a fertilizing agent, as it contains the equivalent of about 7 per 50 PURE FERTILIZERS. cent, of ammonia, associated with valuable humus matters. It forms, also, a most con- centrated material for combustion with soda- lime, to produce ammonia salts by Morris and Penny's process, described at p. 53 ; provided always that it is wholly or nearly free from sand and silica. At the same time, the decanted liquor being a hydrochloric or sulphuric solution of the de- fecating elements of the original material, is ready for purifying a fresh portion of sewage, as in the first instance ; and thus it may be made to serve for an indefinite number of repetitions of the process. The establishment, in this manner, of an independence of any possible failure in the supply of the Alta Vela, Redonda, or other of the mineral phosphate materials employed in the purification of sewage, is an important consideration, and invests the process with a capacity for emi- nent utility and economy. The ammoniacal salts are such necessary aids to profitable agriculture, that every means should be promoted to increase the supply of them. As a stimulus to enterprise in this direction, I have exposed the fore- IG. 2 C Plate 4. F ^9- MORFIT in /hcManii/ar/iirf o/7'c/tilizers: FIG. I FIG. 2 FIG. 3 I'l.Mt.- I-. ^r- j s- f^ J) Si ® // TT SCALE. OF FEET Centrifugal Mill_General View &. Details THE RAW MATERIALS. 51 going details, and set forth in Chapter xi a simple and practicable process for reclaiming the ammonia of gas-liquor wherever the latter may be found. The comparative abundance and cheapness of the several kinds of woollen and leather waste deserve the most serious consideration in this connection. I have long given the subject such study as my leisure would per- mit, and the plan for converting these ma- terials into ammonia, which would be most likely to succeed, is one assimilating in cha- racter to the analytical method of estimating the amount of nitrogen in organic bodies by combustion with soda-lime. The principle upon which such a process would be founded is safe and well-established, and consists in the property which nitro- genous organic bodies have of giving off the whole of their nitrogen in the form of ammonia, when strongly heated with hydrated alkalies. The soda-lime employed may be reclaimed an indefinite number of times ; so that the expense on this item would be at the lowest possible point. But there are mechanical difficulties which beset the necessary arrange- E 2 52 PURE FERTILIZERS. ment for effecting a progressive combustion on a large scale. My present idea is to use iron retorts, like those for making coal-gas, but longer, and with suitable valve-cocks for safety, and tube-attachments to convey away the gas and intercept the fluid portion of the distillate. The mixture of waste and soda-lime having been put into a series of retorts, the whole are to be closed and made air-tight at the joints by means of fire-lute. As it would cause a too sudden and. free flow of distillate to put fire under the retort throughout its entire length at once, the heating would have to be restricted at the commencement to the first twelve inches of the front or mouth por- tion of the retort, and pushed forward gradu- ally as the current of gas from the preceding part begins to slacken. It is necessary that a good fire should en- velope the top of the retort as well as the bottom. Indeed, it is the arrangement of the heating appliances, so as to produce a pro- gressive and perfect combustion of a large quantity of waste in each retort, that presents the chief obstacle to the installation of an THE RAW MATERIALS. 53 economical and ready-working process upon the basis which I have suggested. As the obstacle is not by any means insurmountable, I hope that it may soon have solution by some competent mind and hand. Richard Morris and Mulgrave Daniel Penny, manufacturing chemists of Yorkshire, England, obtained a patent recently for a process in this direction, which they describe as follows: — " The process is for treating shoddy and other animal waste to obtain ammonia and salts of ammonia therefrom. '' We decompose the shoddy, or it may be leather cuttings, horn piths, or such-like animal waste, in clay or iron retorts, heated to a cherry red ; and we admit jets of steam into the retorts. Retorts like those used for the manufacture of coal-gas, and similarly set in a furnace may be employed. ''The gases and vapours from these retorts are passed into a main, as in the manufacture of coal-gas, where tar and ammoniacal water are deposited. From the main, the gases and vapours pass into the retorts containing the alkaline matter. '' Lime is the material we commonly em- ploy. The lime retorts are similar, but of 54 PURE FERTILIZERS. greater length, say twenty feet or thereabout. They are heated to a white-heat. The gases and vapours are passed in succession through the lime retorts (six retorts are a convenient number to employ), and then they are caused to enter an absorbing tower where the am- monia formed is absorbed by acid, by prefer- ence sulphuric acid. The water and the tar which condense in the main, and the acid in the absorbing vessel, contain all the ammonia. " The acid is drawn off from the absorbing vessel from time to time, and saturated by distilling ammonia into it from the water of the main. Finally, the saturated solution is evaporated to the point of crystallization. "The gas, of which the quantity is large, is collected in gasometers, and it may be em- ployed for the purposes of heating and light- ing. An exhauster may advantageously be employed to draw the gas and vapour from the retorts, as is usual in the manufacture of gas. The shoddy, or animal-matter retorts, are re-charged in succession, as soon as it is found that the material in them is spent, and the residue is useful as animal charcoal or as manure. The lime retorts are also re-charged from time to time, whenever the lime is found to have become clogged with deposit and spent ; the gas and vapour arc caused to pass THE RAW MATERIALS. 55 first into the lime retort which has been longest charged, and last into that which has been most recently replenished. Sometimes we charge the last retort of the series with soda-lime or wdth caustic soda, in place of with lime, and so get a most perfect conver- sion of the nitrogen of the animal matter into ammonia. We purify the sulphate and other salt of ammonia by crystallization in the usual way, and from this ammonia salt caustic ammonia may be obtained by heating with lime, as is well understood." Sulphate of Ammonia. NH3, SO3, HO =66. This salt, when pure, is composed of — Ammonia (NH3) . - - i/'O, or per cent., 2575 Sulphuric acid (SO3) - - 40*0 „ 6o'62 Waterof constitution (HO) - 9*0 „ I3'63 Chemical equivalent - - 66*o ,, lOO'OO This is the neutral sulphate obtained on a large scale from the water of condensation, produced in the distillation of coal for gener- ating illuminating gas, and in the calcina- tion of bones for making bone-black or bone- ash. It is manufactured, also, from stale urine and other animal matters. It is in 56 PURE FERTILIZERS. crystals, which are colourless when pure, but dirty grey or brownish when crude. The crystals are six-sided prisms, with correspond- ing pyramidal tops, and • have a specific gravity of 175. They are very soluble in cold water, but insoluble in alcohol, and have a bitter, piquant taste. Sulphate of ammonia melts at 2840 F., but resists decomposition up to 356° F. Beyond the latter degree it loses ammonia, becomes firstly bi-sulphate, and changes finally into nitrogen, water, and bi-sulphate of ammonia, which sublimes. This salt is the means by which I change the chloride of calcium of hydrochloric solu- tions of mineral phosphates of lime, into chloride of ammonia and sulphate of lime ; so as to reclaim the hydrochloric acid profit- ably, and, at the same time, to free the preci- pitated phosphate of lime from any hygro- scopic or humid tendency. Each (ro) per cent, or pound of this neu- tral sulphate of ammonia is equivalent to I "32 neutral sulphate of potassa. For each pound (ro) of carbonate or or- ganate of lime that may have been dissolved THE RAW MATERIALS. 57 out of the mineral phosphate by hydrochloric acid (2-13), there will be required 1*32 pounds of sulphate of ammonia, and the products would be — 172 lbs. of hydrated sulph. of lime (CaO, SO3, 2HO) ; I'O/ lbs. of dry chloride of aminoiiium (NH3, HCl). Chloride of Ammonium, or Hydrochlorate of Ammonia. NH3, HCl=53-5. When pure, its composition is — Ammonia (NH3) - - i/'o, or per cent, 3178 Hydrochloric acid (HCl) 36-5 „ 68 22 Chemical equivalent - 53*5 „ 100*00 This salt crystallizes in needles, which are soluble in water and alcohol. It is always anhydrous, and sublimes unaltered at a tem- perature just below redness. It is commonly called Sal Ammoniac. Specific gravity, i "45 to 1*50. Its per cent, of ammonia is much higher than that of the sulphate (2575), and on this account, as well as for other good reasons, it is to be preferred for fertilizing purposes. 58 PURE FERTILIZERS. Sulphate of Potassa. KO, 803=- 87 "o. Its composition, when pure, is as follows : Potassa (KO) - - - 47-00, or per cent., 54*00 Sulphuric acid (SO^) - 40'00 ,, 46-00 Chemical equivalent - 87-00 ,, 100-00 This is a neutral salt in the form of colour- less hard crystals, which are very soluble in cold or hot water, and resist decomposition at even high temperatures. Its specific gravity in the anhydrous state is 2'625 ; but it varies from 2*623 to 2 "656 in the ordinary com- mercial article. • It is used alone or in conjunction with sulphate of ammonia for economising the chlo- ride of calcium wash liquor in the processes of this treatise, by precipitating the lime as sulphate and forming chloride of potassium. But it is in no sense as advantageous for that purpose as the sulphate of ammonia. Each per cent, (ro) or pound of carbonate and organate of lime which has been decom- posed and dissolved by hydrochloric acid (2" 1 3) from the raw mineral, requires 174 THE RAW MATERIALS. 59 pounds of this neutral sulphate of potassa, and forms — 172 lbs. of hydrated sulph.of lime (CaO, SO3, 2HO) ; i'49 lbs. of dry chloride of potassium (KCl). This salt is a secondary or reclaimed product in the clarification of oils and in many other manufacturing" processes. Dark coloured crystals cost less than the bright, and are sufficiently pure for this process. It is also sent to market largely from the natural deposits at Stassfurt, in Prussia, and in this form is known commercially as kainit; which contains, as an average, 23 to 25 per cent, of sulphate of potassa, associated with 14 to 28 per cent, of magnesia salts and 30 to 48 per cent, of chloride of sodium. Chloride of Potassium. KC1=74*5. Its composition is — Potassium (K) - 39"0, or per cent., 52*35=KO^ 63*1 Chlorine (CI) - 35-5 „ ^yGs Chemical equiv. - 74*5 ,, lOO'OO This is an anhydrous salt which crystallizes in cubes or rectangular prisms, and dissolves 6o PURE FERTILIZERS. in about two and a half times its weight of cold water. It volatilizes at a red heat with- out decomposing. Specific gravity i'95o. Carbonate of Potassa. KO, C02==69'o. When pure and ignited its composition is : Potassa (KO) - - 47'00, or per cent., 68' ii Carbonic acid - - 22*oo „ 3 1*89 Chemical equivalent - 69*00 „ ioo"00 As found in commerce, however, it is a more or less impure salt under the names of salt of tartar and pearl ash, and contains about 16 per cent, of water of crystallization. The first is in the form of a coarse granu- lated powder, insoluble in alcohol, but very soluble in water and even deliquescent. It fuses at a red heat without decomposing. Salt of tartar is refined pearl-ash, obtained by dissolving the latter in water, and leaving it to repose. The clear liquor contains all the caustic and carbonate of potassa, with some portion of the other soluble salts of the pearl- ash, and rests upon a sediment of insoluble impurities. The liquor being then drawn off and concentrated by evaporation, drops a fur- THE RAW MATERIALS. 6i ther portion of its foreign salts, from which it must be decanted. Thus largely freed from impurities it is finally evaporated to syrup and stirred into dry granular salt of tartar. It is employed in the processes which will be described for the mineral phosphates of alumina ; and would answer the required pur- poses in its crude form of pearlash. Lime. CaO=28. The composition of caustic lime when pure is- Calcium (Ca) - - 20-0, or per cent., 71 "42 Oxygen (O) - - - S'O „ 28-58 Chemical equivalent - 28*0 „ 100*00 It is largely diffused in nature as carbonate and sulphate, and forms the basis of lime- stones, chalk, the various kinds of marbles, calcareous spars, gypsum and many other minerals. Caustic lime is obtained by calcining lime- stone or other carbonate of lime in suitable kilns. In this way the carbonic acid is driven off and lime remains in a ''quick" or caustic state mixed with more or less of magnesia, 62 PURE FERTILIZERS. alumina, oxide of iron, silica, and the other impurities of the original raw material. These vary in quantity from 5 to 30 per cent, according to the kind of raw material ; and when the lime is to be employed in chemical equivalent proportion, the amount of foreign matters must be predetermined by analysis and excepted in the calculation. Any excess above five per cent, of impurities takes it out of the class of good lime for the processes of this treatise. Lime is in lumps, sometimes white and at others grey, very alkaline, and has such an affmity for water and carbonic acid that it must be kept in closed barrels protected from exposure to air. It is very soluble in acids, and forms salts with them. Hot water dis- solves it less readily and in less quantity than cold water, which latter takes it up in the proportion of one part of lime to every 730 parts of water. Specific gravity 2*3 to 3*0. When quick-lime is sprinkled to saturation with water it soon begins to give off hissing sounds, developes great heat and thick vapours of volatilized water, and finally en- larges its volume into a fine powder or THE RAW MATERIALS. 63 mass of slaked lime, which is a hydrate of lime=CaO, HO. In slaking the lime with half its weight of water, the temperature rises to 500*^. The longer it takes to fall to powder after the drenching with water for slakening it, the more impure it is. A good rich lime is never longer than three to five minutes in answer- ing favourably to this test. If the quantity of water is then further in- creased so as to give a liquid character to the mixture, the product is milk of lime. This milk must be strained through a fine sieve of galvanized wire cloth. One equivalent of anhydrous lime(CaO=28) corresponds with one equivalent of dry hydro- chloric acid (HC1=36'5) or one equivalent of dry sulphuric acid (503=40). Carbonate of Lime, This substance is noted in another place as to its more scientific relations ; so that it only remains to mention it here in its practical bearings upon the processes about to be described. The form employed is that commonly 64 PURE FERTILIZERS. known as whiting. It is prepared from chalk, a white earthy mineral which may be considered, practically, as pure carbonate of lime. That is, its impurities are in small pro- portion, and mostly mechanical, and easily removed. It is the elimination of these latter which changes the chalk into whiting. According to Schweitzer's analysis, the chalk of Brighton (Sussex) cliff is composed of — Carbonate of lime - 98-57 Carbonate of magnesia - - -38 Phosphate of lime •II Oxide of iron •08 Oxide of manganese •06 Alumina •16 Silica - - - - -64 loo-oo The process consists in grinding the chalk, diffusing the powder in a large volume of water, and leaving to repose only so long as may be necessary for the subsidence of the heavy particles. The liquor, holding in sus- pension all of the finer portion, is to be drawn off into a vat and allowed to settle. When this has been accomplished, the supernatant water is to be drawn to waste through taps. THE RAW MATERIALS. 65 and the residual white pulpy deposit dried in the air or in a moderately heated chamber. The dried mass is '' whiting'\ and so much more suitable than chalk as a chemical agent, that in many instances it will produce the desired effect where chalk would fail. Sulphate of Lime. CaO, SO3, 2 HO=86. Its composition is — Lime (CaO) ... 28-0, or per cent., 32*56 Sulphuric acid (SO3) - - 40*0 „ 46*51 Water of constitution (HO) - iS'O „ 20*93 Chemical equivalent - - 86'0 ,, loo'oo Ordinary sulphate of lime is known as ''ground plaster!' When this is calcined it becomes anhydrous, and is then called ' 'plaster of Paris! ' The form relating to fertilizers is that of artificial hydrate, because it is much more active as a fertilizer than the natural ground gypsum. It is the solid product obtained in the decomposition of the wash liquor (chapter xi) by sulphate of ammonia or potassa, and then dried at 120° F. From this source it will retain, generally, some little of ammonia or potassa salt. MORFIT on the Mami/actiwe oFFertilU^rs. jx5 of lime J Di- or Neu-"^ tral - phos- > phateoflime} Ei - phosphate "^ of lime } 3CaO. PO5 2CaO. PO5 f HO CaO. P0s + 2H0 72-o(-i56) 72- (-137) 72- (=118) 46-15 (= 100) 52-56( = IOO) 61-01 (- 100) Tri- or Bone- Phosphate of Lime. 3 CaO, P05=i56. This is the most common form, being widely diffused in nature as the earthy CHEMICAL DATA. 69 structure of bones and the basis of mineral phosphates, such as apatite, phosphorite, coprolites, rock guanos, marlstones, and the like. It is also a component of ammoniacal guanos ; and the chief constituent of bone- black and bone-ashes. When associated with gelatine and other organic matters in its natural condition of ground bone, it breaks up in the soil under atmospheric influences into forms which are not only soluble but very assimilable by the growing crops. In the state of bone-black it is scarcely less soluble in the soil ; and in the form of bone- ash falls only a few degrees in rank of solu- bility below the bone-black. Weak acids dissolve it readily ; and those of greater strength not only dissolve it but convert it into super-phosphate by abstracting two equivalents of its lime. In like manner, the presence of acetic acid, carbonic acid, chloride of ammonium, certain potassic salts, and chloride of sodium, causes it to split into more soluble phosphatic salts or states ; and it is in this manner drawn up by growing crops into the vegetal circulation. JO PURE FERTILIZERS. It may be prepared artificially from an aqueous solution of chloride of calcium by the addition of an aqueous solution of basic phosphate of soda ; or on a large scale by precipitating a hydrochloric acid solution of bone-phosphate of lime, or even of bone- ash, with pure ammonia. Strictly considered, however, this preci- pitate from the latter solutions is rather a mixture of several phosphates of lime, all quite prompt to assume solubility under the conditions existing in soils. When freshly precipitated from an acid solution, phosphate of lime is white and in- soluble in water, but peculiarly sensitive to the solvent action of water containing only a small quantity of ammonia or carbonic acid. This action, though gradual, is constant, and extends even to the precipitated phos- phate in a dry state. As existing in rock guanos or minerals, tri-phosphate of lime is not only cemented closely by associate ingredients, but has naturally a physical temperament which ren- ders it obstinate to the action of solvents CHEMICAL DATA. yi under the ordinary conditions pertaining to the soil. These natural forms are conse- quently so very slow as fertilizers J>er se that chemical treatment must be practised to render them soluble previous to their applica- tion. This is particularly necessary when they are accompanied with fluoride of calcium, silicate of lime, alumina, phosphate of alu- mina, oxide and phosphate of iron. Di- or Neutral-Phosphate of Lime. 2 CaO, HO, P05=i37. This phosphate exists in many mineral waters, but is rarely found in nature to any extent. The only two instances in my know- ledge are, that of the Colombian guano from Maracaibo, of which the stock has been ex- hausted long since ; and another rock-phos- phate from Rossa Island near Guaymas in the Gulf of California. It has been formed in nature, as it may be in the laboratory, by the gradual action of water, and particularly of water containing ammonia or alkali, upon bons-phosphate lime in a fresh state as exist- ing in bird dung or ammoniacal guanos. It 72 PURE FERTILIZERS. may be precipitated, too, from acid solutions ; and at the same time some bi-phosphate of lime is produced. As prepared artificially by adding an aque- ous solution of ordinary phosphate of soda to an aqueous solution of chloride of calcium, it is a white precipitate only slightly soluble in water, but very easily soluble in acids, and readily taken up by water containing carbonic acid, ammonia, ammoniacal or even potassic salts. Some little of it is formed in my process for manufacturing Colombian Phosphate, as described in Chapter ix ; and the methods, described in Chapter x, produce it nearly pure. Guanos or artificial manures, which may contain their phosphatic element in the state of neutral phosphate of lime, will prove to be very active and potential fertilizers. Chemically considered, it is the best possi- ble material for conversion into " superphos- phate". The economy of sulphuric acid and the very high degree of soluble phosphate thus obtained will be great advantages to both producer and planter. CHEMICAL DATA. 73 Bi-pJiosphate of Lime. CaO, 2 HO, POj^ 1 18. This phosphate exists, naturally, only in small quantities, as a component of certain mineral waters and organic products. It is prepared artificially by acting on the tri-basic or bone phosphate of lime with di- lute sulphuric acid, which takes away two equivalents of lime, and, with two double equivalents of water, forms hydrated sulphate of lime ; leaving the phosphoric acid with one equivalent of lime and two equivalents of water, as bi-phosphate. To make the decomposition perfectly intel- ligible, it is only necessary to formulate it as follows : — One equivalent of (CaO.2HO.PO5) Bi-phosphate of Lime. CaO 2SO3.2HO. 4HO. Two equivalents of ((2)CaO.S03.2HO.) Sulphate of lime. 74 PURE FERTILIZERS. The ascending lines represent the sokible product, and the descending lines indicate the insoluble one. As bone-phosphate of lime consists of three equivalents of lime (CaO, 28 x 3=84) and one equivalent of phosphoric acid (P, 32 + O, 40= 72), it follows that every equivalent = 156 when acted on by oil of vitriol or mono- hydrated sulphuric acid diluted with four equivalents of water (2) SO3 HO (=98) + 4HO (=36)= 1 34, will yield — 1. Bi-phosphateof lime(CaO(28)2HO(i8)POs(72) s = 118 parts by weight - - / _ 2. Sulphate oflime (2) CaO (56) 4HO(36) 2303(80) r~^90 = 172 parts by weight - -^ As much heat is generated during the chemical reaction, an excess of water must be added to provide for loss by evaporation. Taking this circumstance into consideration, then, by adding together the original items of the formula, the proof of the latter is made evident, thus : — One equivalent of bone-phosphate of lime= 156 by weight. Two equiv. of mono-hydrated sulphuric acid = 98 „ Two double equivalents of water of dilution= '}j6 „ Total - - 290 CHEMICAL DATA. 75 Converted into — One equivalent of bi-phosphate of lime = 118 by weight. Two equivalents of sulphate of lime = 172 „ Total - - 290 This salt is very soluble in water, and its aqueous solution when evaporated to syrupy consistence crystallizes in pearly scales, which are deliquescent. These scales, if heated too long, even moderately, assume in part an allo- tropic condition, which is somewhat insoluble. By igneous fusion it wholly loses its property of solubility. Of all the phosphates of lime this is the favourite one for agricultural purposes, on account of its great solubility and consequent fertilizing energy. I believe, however, that the phosphate prepared by precipitation from acid solutions of animal or mineral bone- phosphates, and named by me Gelatinous or Colombian phosphate of lime, is sufficiently potential for producing an active and rich vegetation at much less cost than the super- phosphate. Indeed, it is more than probable that this latter is changed into the former by the carbonic acid and other chemical in- je PURE FERTILIZERS. fluences of the soil before it has had time to exert much action by reason of its direct solubility when first applied. If this does not take place, then much of the bi-phosphate would be lost by reason of its solubility ; for the rain would wash down into the subsoil all that might not be absorbed by the plants immediately after its application. This por- tion would be nearly the whole, as it is not rational to suppose that the vegetal absorp- tion could be instantaneous as to the total of any fertilizing element. If there should be any carbonate of lime, alumina, oxide of iron, or powdered mineral phosphate mixed with the pure bi-phosphate, as in the ordinary commercial " superphos- phate", the soluble phosphate of the latter is apt to become insoluble even in the bags, on account of the formation of di- and tri-phos- phate. When this occurs, the " superphos- phate" is said, in trade parlance, to ''go back'\ Precipitated Phosphate of Lime. This salt is said to be of the same chemical composition as the bone-phosphate, but with CHEMICAL DATA. 77 the addition of quasi-constitutional water in proportion varying from four to six equiva- lents. It may have the formula sCaO, PO5 + 4HO, or sCaO, PO5 + 6H0, accord- ing to the manner in which it may be dried ; but most of this water can be expelled by kiln-drying. Practically considered, the cir- cumstances of its preparation influence also its composition. It is prepared always by precipitation with alkalies or alkaline earths, from solutions of the tri- or neutral-phosphate of lime in acids. My opinion is, that the precipitate com- prises all of the several phosphates, varying in proportion with the state of dilution and temperature of the solution and the kind and quantity of precipitant employed ; for I have certainly observed, that in its fresh pulpy state, it is not only very soluble in acetic and weak acids, but even splits into soluble forms under the action of water con- taining carbonic acid, ammonia, chloride of sodium, and many other saline matters. Very probably the carbonic acid of the soil may convert it gradually into bi-phosphate, di- phosphate, and carbonate of lime. 78 PURE FERTILIZERS. In its dry state it is scarcely less sensitive, and these properties give assurance that under the chemical influences of the soil it will prove as potential in fertilizing as the bi- phosphate, and at much less expense. In- deed, the bi-phosphate is first reduced, doubt- less to the state of precipitated phosphate, soon after it has been applied to the soil and the growing crops assimilate it in that form through the subsequent influence of carbonic acid and saline associates. It is on account of the composite nature and the tender properties above noted, that I have not given it a place in the preceding chemical table, and prefer to distinguish it by the title of Colombian phosphate of lime, when it is thrown down by whiting, and Pre- cipitated phospJiate when ammonia is the precipitant. Sulphite of Calcium-PJwsphate, This is a product of the action of sulphur- ous acid upon tri-phosphate of lime, and its chemical and practical relations are given in chapter xvii. CHEMICAL DATA. 79 Phosphate of Magnesia. The chemical equivalent of magnesium is i2"0, and it forms tri-, di-, and bi-phosphates, corresponding in composition with the simi- lar salts of lime, thus : — Tri-phosphate or sMgO, PO5 ; Di-phosphate or 2MgO, PO5, HO ; Bi-phosphate or MgO, POs, 2 HO. For all practical purposes, this salt may be considered as phosphate of lime, since it as- similates to the latter sufficiently, in chemical and agricultural relations, to justify the union of them under one head. Moreover, it is rarely present to any large extent in mineral phosphates of lime. Carbo7iate of Lime. CaO, CO2, = 50*00. Oxide of calcium (CaO) - 28"OOj or per cent. 56*00 Carbonic acid (CO2) - 22'00 „ 44*00 Chemical equivalent - 50'00 „ ioo*oo In nature, the more common forms of this chemical salt are the different kinds of chalk, calcareous spars, marbles, and limestones. It is very widely diffused, being an element 8o PVRE FERTILIZERS. of most of the river, spring, and other waters. It also enters into the composition of mani- fold other substances to a greater or lesser degree. When pure, it is perfectly white. On being calcined at, a red heat in an open furnace it gives off its carbonic acid and be- comes caustic or quicklime (CaO). Carbonate of lime is insoluble in water, unless the latter should contain free carbonic acid. With this latter it forms bi-carbonate of lime, which is soluble. Carbonate of lime is also soluble in acids. It is almost an in- variable constituent of rock guanos or other phosphatic materials, but it does not impart any value to the latter. On the contrary, until the discovery of my new methods for the treatment of these rock guanos, it was a real pest, in that it consumed acid to extend the weight and dilute the strength of the fer- tilizer from those materials without forming any compensating product. According to Warrington, when carbonate of lime is present with phosphate of lime, as in mineral phosphates especially, it way- lays the atmospheric influences of the soil and monopolizes their action by its greater r^ MORFIT (III llii'.ViiniiBrliiri' nrFertifi :its T ~r — J _. _i n DETAILS OF ELEVATOR LIFT & PLATFORM t I'lalo J 1 ,-!-- ^h -L.il>! H>glfa«a»T«t»t«ni.J- 1 CHEMICAL DATA. 8i chemical sensibility under the circumstances. Therefore the fertilizing action of the phos- phate associate remains dormant until the carbonate has been decomposed by the car- bonic acid of the soil. When the raw mineral phosphate is to be converted into precipitated phosphate or superphosphate, this carbonate of lime con- stituent is the first to seize and appropriate the earlier additions of hydrochloric or sul- phuric acid. In this way 2' 13 of hydrochloric acid (riy) or I '00 oil of vitriol (i'846) would be con- sumed by each per cent, of carbonate of lime. The profitless product thus imported into the resulting fertilizer would be i '29 hydro- chlorate of lime in the first case, and 172 of hydrated sulphate of lime in the second in- stance, according as one or other of these acids may have been used as the solvent. Hydrochlorate of lime (chloride of calcium) is not only an unprofitable element itself, in this connection, but also a deteriorating pre- sence, which renders the fertilizer product G 82 PURE FERTILIZERS. hygroscopic, and depresses the content of soluble bi-phosphate. So, also, the hydrated sulphate of lime thus forced into the fertilizer product crowds out soluble bi-phosphate, and renders im- practicable any high strength of the latter. Orgmiate of Lime. In making a chemical analysis of a mineral phosphate or " rock guano", and after appor- tioning the lime according to its well-known chemical affinities, there is frequently a resi- due which, in our present state of know- ledge, cannot be allotted confidently to any associate element. I assume, therefore, until I can inform my- self better, that it exists naturally in combi- nation with the organic acids, and probably the silicic acid and alumina which may be present. Be that as it may, for all the practical pur- poses of this treatise, organate of lime is to be considered as carbonate of lime, and treated with acids accordingly, in the manufacture of fertilizers. CHEMICAL DATA. 83 Sulphate of Lime. CaO, SO3, 2HO=86-o. Oxide of calcium (CaO) - 28-0, or per cent, 32-56 Sulphuric acid (SO3) - -40-0 „ 46-5 1 Water of constitution (2 HO) 180 „ 20-93 Chemical equivalent - - 860 „ loo-oo This substance is known in nature as Gyp Sinn when amorphous or crystalline, and as Selinite or Alabaster if crystallized. It is white in the first, and colourless in the second form. It is soluble to the ex- tent of three parts in 1000 of water, but in- soluble even in dilute alcohol. Boiling hy- drochloric acid dissolves it more freely, and so also does a solution of common salt. By calcination at 212° to 300° F., it loses its water and becomes Plaster of Paris. Its presence in rock guanos neither adds to, nor detracts from, the value of the latter. Though it does not waste acid, it dilutes the mother-material without improving its value. The economy of the raw mineral would be better for its absence. G 2 84 PURE FERTILIZERS. Fluoride of Calcium. CaFl = 39. Calcium fCa) - - 20'0, or per cent. - 5 1 "29 Fluorine (Fl) - - 190 „ 4871 Chemical equivalent - 39-0 „ lOO'OO Is known as Fluor Spar, and found gene- rally associated in nature with other minerals. It is also present in bones, to a small extent. Coprolites contain it, as also do some of the Phosphorites and Apatites. In its natural state it is yellowish, green- ish, or violet, and crystallized or crystalline. When heated, it becomes phosphorescent, and fuses at high degrees of temperature. Superheated steam decomposes it into lime and hydrofluoric acid. So, also, when fused with alkaline hydrates or carbonates, it is readily decomposed. It is itself used as a flux in the smelting of ores. It is nearly insoluble in water, but dissolves in very strong hydrochloric acid. When acted on by sulphuric acid it gives off noxious vapours of hydrofluoric acid, and it is on this account that mineral phosphates which con- tain much of fluoride of calcium are not a CHEMICAL DATA. 85 favourite material for superphosphating pur- poses. It also wastes acid in the usual mode of operating, but in the new processes herein described that defect may be lessened by careful manipulation in the digesting opera- tion. Every per cent, of fluoride of calcium would waste 273 of hydrochloric acid of specific gravity riy, or 1-28 of oil of vitriol of 1-846. Chloride of Calcium. Ca CI ==55'5. Calcium (Ca) - - 20"Oj or per cent. - 3603 Chlorine (CI) - - 35 "5 . „ 63-97 Chemical equivalent - 55'5 „ lOO'OO Chloride of calcium is a constituent of numerous river, spring, and well waters, as also of many mineral substances. When pure, it is white, and so very soluble in water that it is one of the most deliquescent sub- stances known. By igneous fusion it is per- fectly dried ; but, on exposure afterwards, soon absorbs moisture. It is also soluble in alcohol. Its presence gives a tendency to humidity to those substances which contain it. Solutions of chloride of calcium are de- 86 PURE FERTILIZERS^ composed by solutions of alkaline carbonates or sulphates. With the first, carbonate of lime is precipitated, and alkaline chloride forms in solution. With the latter, sulphate of lime is precipitated, while alkaline chlo- ride remains in solution. This is effected by a double exchange of bases, as, for example, with sulphate of potassa, thus :— In solution. YJZ\~ Chloride of potassium. Ca CI. + KO SO. As precipitate. CaO, S0^ = Sulphate of lime. This property is taken advantage of in the new and original formulae of Chapters ix, x, and XI, for recovering (in the profitable form of ammonium or potassium chloride) the hy- drochloric acid used for making the solution of the raw phosphate. Under other circum- stances, the use of this acid in the manufac- CHEMICAL DATA, Zy ture of superphosphate would be less favour- able to the economy of the product and also fatal to its perfect dryness. Oxide of Iron. Fca 03=8o'o. As existing in mineral phosphate, it is most probably sesqui-oxide. Two equivalents of iron (Fe^) - 56-0, or per cent., 70'00 Three „ oxygen (O3), 24.0 „ 30-00 Chemical equivalent - 800 „ loooo In its mineral state it has only a feeble affinity for acids. Being thus passive, most of it is left undissolved, when mineral phos- phates which may contain it are treated in the cold with acids. Oxide of iron as well as alumina are profit- less constituents of mineral phosphates, both as to freight, expense, and fertilizing action. They not only waste acid but form objection- able compounds when the mineral is being converted into " superphosphate." Phosphate of Iron. Fcz, O3, P05= 152-0. As associated with the other elements of mineral phosphates, it is possibly in the state S8 PURE FERTILIZERS. of phosphate of sesqui-oxide ; and anhydrous. But, when freshly precipitated from acid so- lutions, it takes up four equivalents of water (4HO) and becomes hydrated. In this latter form, it differs from the anhydrous phosphate in important particulars ; for it is then soluble in water containing carbonic acid, and also in weak acids, with certain exceptions. The hy- drated, when heated to redness, becomes an- hydrous, and then it is only partly taken up even by strong acids in the cold. The freshly precipitated phosphate of iron, as above, has considerable fertilizing energy, more particularly when associated with ammo- niacal and potassa salts, as these promote its solubility, and the assimilation of its phos- phoric acid by the growing crops. Oxide of Alimiiniiim. AI2, 0-^=^^v\. In its mineral state it is generally anhy- drous, and not very sensitive to the action of acids in the cold. When freshly precipitated it becomes quite soluble, and even water, con- taining carbonic acid, takes up a portion. In this condition it is also completely soluble in solutions of caustic potassa or soda. CHEMICAL DATA. 89 When mineral phosphates which may con- tain alumina are treated with sulphuric acid, the product is more or less damp, unless this property should be corrected by the means prescribed in Chapters viii and ix. It is also a diluting constituent of the raw mineral without countervailing advantages. Phosphate of Alumina. AI2, O3, PO^. The composition of the phosphate of alu- mina as it exists in the mineral phosphates, is even more doubtful than that of the phos- phate of iron constituent. In its natural hard state it is dissolved only slowly by the strong acids and the aqueous solutions of caustic potassa and soda. When precipitated from its solutions in acids, it is white, gelatinous, very soluble in acids, and more or less so in water containing carbonic acid and saline matters. When the precipitate is dried in the air, or by only moderate heat, these latter pro- perties remain unimpaired. In this latter condition it is serviceable for fertilization, upon the reasoning which has been noted for phosphate of iron, but in a greater degree. 90 PURE FERTILIZERS. Its formula, then, is probably AI2, O3, PO5, 9HO = 204*40, but it becomes anhydrous by ignition. The practical mode of converting phosphates of iron and alumina into fertilizers is described for redonda guano in Chapter XVIII. Organic Matter. This constituent of mineral phosphates is partly soluble and partly insoluble in acids. Most generally it contains little or no nitro- gen. In all cases it remains with the pro- ducts when the raw phosphates are converted into fertilizers by the processes described in this treatise. The action of the acids may modify its nature slightly, but the soluble portion goes with the precipitated phosphate, and the other forms part of the insoluble residue of the mineral. When the raw phos- phates are treated directly with sulphuric acid for their conversion into " superphos- phate," the presence of organic matters im- pedes the action of the acid in some degree, and also promotes its waste. In other re- spects it is merely an unprofitable diluting associate of the valuable components of the mineral. CHEMICAL DATA. 91 Silica and Sand. These form the part of mineral phosphates which is insoluble in either water or acids. They do not waste acids ; but are, neverthe- less, wholly valueless in themselves, being inert diluents of the raw material. Water. Is nearly always present in mineral phos- phates as an accidental or constitutional ele- ment. It is not in the way, chemically con- sidered, but swells, unprofitably, the bulk of the mineral and its cost of transportation. CHAPTER IV. ---ST^s-s^^ler-e-ss— THE GRINDING APPARATUS. In all extensive works the factory plant should comprise a grinding apparatus. But as such an arrangement involves the neces- sity of much space and a large amount of steam power, it is more economical, for mo- derate operations, to have the raw mineral powdered outside by a regular grinder. The business of the latter being a distinct branch of trade, I will devote a special chapter to the best means of practising it in connection with hard mineral substances. The usual machines for reducing the mi- neral phosphates to fine powder, are either French burr stone mills of the ordinary pat- tern, or cast-iron rollers like a mortar mill. The first are employed by certain manufac- turers for grinding coprolites. If the raw mineral should be in large lumps, it would THE GRINDING APPARATUS. 93 have to be passed previously through a pair of iron cracker-rollers, in order to break it into smaller pieces, as a preparation for the mill. The Roller Mill. Much less expensive and more generally used are the cast-iron rollers. A mill of this construction, with rollers of eight feet dia- meter, will grind 200 tons of mineral phos- phate per week of days and nights. The steam-power required to drive it is equivalent to that of eight horses, and three or four labourers suffice to attend it. It is all-important that the rollers should be heavy ; and the pan may either revolve or be fixed. Some manufacturers prefer the fixed pan ; but the other arrangement is adopted most generally. Plate i shows a front elevation of a mill of this latter con- struction, set firmly upon a foundation / of mason work. The pan is b, and the crush- ing rollers are a a , carried by the cross shafts c c , bolted together in the middle. These cross shafts have the clips g g on them to keep the rollers a a in place. The pan b is 94 PURE FERTILIZERS. carried by a vertical spindle d d' resting in the footstep p. The frame-work consists of the cast-iron uprights e e , the top entablature f, and the endstay //. The arrangement for motion comprises the shaft / and its plummet blocks 7n m , the driving pulley k, the bevel pinion it, and the circular rack o, fixed to the pan. The rollers turn round on a fixed axis by the revolution of the pan, and the mineral is kept under them by means of the scrapers. Some engineers construct these mills so that the grinding and sifting may go on si- multaneously in the same machine. Then the plan b, as shown in the drawing, must be made with a false bottom, upon which the rollers are to run. This false bot- tom is placed at a distance from the real bot- tom so as to form a chamber beneath for the collection of the sifted material, which passes through the fine holes with which the bottom is cullendered for the purpose. Or the pan may have only one bottom, and that cullendered, so that the material as fast as ground will sift through, and can be col- lected underneath by means of a shoot or otherwise. THE GRINDING APPARATUS. 95 When there is no such appendage to the mill, the sifting must be done by a separate instrument, as it is necessary to have the powder of uniform fineness in order that the subsequent chemical treatment may be facili- tated. The Siftei\ This implement, shown in side and end elevation by Plate 2, consists of a strong tim- ber support g carrying in the interior the two inclined and revolving cylinders of wooden frame-work, shown by the dotted lines at a a and b b'. Stretching over the circumference of the cylinders is fine galvanized iron-wire cloth. The two sieves are connected by means of the shoot c, and derive motion from the pulleys d and e. The two cylinders being set in mo- tion by steam-power, the mineral to be sifted is then thrown into the end a of the upper one, by a man standing on the platform, b, formed by the framing of the machine. The finer portion finds its way through the meshes and falls into the shoot c, which conducts it into the end of the lower cylinder b. The coarser portions which will not pass through c,6 PURE FERTILIZERS. the meshes are ejected at the end a of the top cylinder, the meshes of which should be coarser than those of the lower one. In like manner, when the finer portion of the upper cylinder falls into the lower one, that part which is fine enough passes through the gauze, while the portion that is too coarse finds its way out at the end d' . It would seem, from the practical experi- ence of manufacturers, that the most work to be got out of rollers even as large as eight feet diameter, is ij tons of powdered mineral per hour. With all these open mills there is an un- avoidable loss of powder, which escapes as fine dust, to the extent of several or more per cent., in many cases, according to its density. I feel confident, therefore, that better pro- gress and economy would be realised by the substitution of a different arrangement; or, in other words, by combining the powdering and mixing portions of the plant into one consisting of a Blake's crusher and a Howel- Hannay mill. A sifting machine will be un- necessary, then, and all the loss by escaping dust would be prevented. THE GRINDING APPARATUS. 97 A crusher is necessary to reduce the mineral only when it is in very hard lumps of size larger than an inch or two square. At all times, however, it will expedite the work of the Howel-Hannay mill, and economize the wear and tear of the machine to feed it with mineral of the size of inch cubes. Both of the above-named machines arc American inventions, but can be obtained in England. The Blake crusher is made at the Soho Foundry, Leeds, and is used extensively in this country. The Howel-Hannay mill will not only reduce the mineral to fine powder, but serve also, and even better, for powdering the finished fertilizer as it comes from the drying kiln. Blake s Crusher. This machine is shown by Plate 3, in which fig. I represents a front elevation; and fig. 2 a plan of the entire machine. The circle d is a section of the fly-wheel shaft, and the dotted circle e is a section of the eccentric. A pitman on rod f connects the eccentric with the toggles gg, which have their bearings forming an elbow or toggle- 11 98 PURE FERTILIZERS. joint. There is 2, fixed jaw h, against which the stones are crushed ; and this is bedded in zinc against the end of the frame and held back to its place by cheeks i that fit in re- cesses of the interior of the frame on each side. There is also a movable jaw j, which is supported by the round bar of iron k passing freely through it and forming the pivot upon which it vibrates. An india- rubber spring L is compressed by the forward movement of the jaw, and aids its return. The frame a (see plan, fig. 2), which receives and supports all the other parts, is cast in one piece, with feet to stand upon the floor or upon timbers. These feet are provided with holes for bolts by which it may be fastened down if desired ; but this is unnecessary, as its own weight gives it all the requisite stability. The fly-wheels bb are on a shaft which has its bearings on the frame, and which is formed into an eccentric between these bearings. The pulley c on the same shaft receives a belt from a steam engine or other power. Every revolution of the eccentric causes the lower end of the movable jaw to advance MORFIT SCALE OF FEET. / 2 3j>f ei>ilb/ d'-fti'J^ TViilinf.r;i- CPfkO, PDr,-.T^,rvoro,.», M OR FIT oil iheMamdaeliirc of'Fertiliirrs. DETAILS OF MIXER, IN SECTION, w////// / //m//////m//m , U ^' U "' J--J I , Fl C. 111. FlC. II. 3j«K;i.ill>' A-.Mvjtfdioi ll^Miii1'iis"At.H;.i.;'-n l;:^ - SCALE OF Ft FT. Plat( .■:-.LbroalB.Dayiic..Sx-. I.it>i '[ ru);ii'-T 'tt. C",60. Pau-iTiDs'f!' HcA'/, THE GRINDING APPARATUS. 99 towards the fixed jaw about a quarter of an inch and return. Hence, if a stone be dropped in between the convergent faces of the jaws, it will be broken by the next suc- ceeding bite ; the fragments will then fall down lower and be broken again, and so on until they are small enough to pass out at the bottom. The readiness with which the hardest stones yield at once to the influence of this gentle and quiet movement, and melt down into small fragments, surprises and astonishes every one who witnesses the opera- tion of the machine. It will be seen that the distance between the jaws at the bottom limits the size of the fragments. The distance, and consequently the size of the fragments, may be regulated at pleasure. A variation to the extent of five- eighths of an inch may be made by turning the screw-nut m, which raises and lowers the wedge N, and moves the toggle-block o forward or back. Further variation may be made by substituting for the toggles gg, or either of them, others that are longer or shorter ; extra toggles of different lengths being fur- nished for this purpose. n 2 lOO PURE FERTILIZERS. This machine is made of several sizes. Each size will break any stone, one end of which can be entered into the opening be- tween the jaws at the top. The size of the machine is designated by the size of the opening ; thus, if the width of the jaws be lo in., and the distance between them at the top 7 in., the size is called lo by 7. The following table shows the several sizes of machines which are offered for sale ; the product per hour of each size, of fine road metal from the hardest materials, Avhen run with a speed of 250 — the power required to perform its duty, — the whole weight of each size, and the weight of the heaviest piece when separated for transportation. Size. Product per Hour. Power required. Total Weight. Weight of Frame. Price Nett. On Wheels. cubic yds. Horse. cwts. qrs. bs. cwts. qrs. lbs £ s. d. £ s. d. 6 by 4 I^ 2i 36 18 75 80 10 „ 7 3 4 78 37 2 140 147 10 IS .. 7 4i 6 108 54 180 190 %o „ 9 6 8 156 74 240 255 24 ,,12 8 12 376 80 350 — The whole length of the machines (accord- THE GRINDING APPARATUS. loi ing to size) is from 4 to lo feet ; the height being 5 to 8 feet ; and the width 3 to 5 feet. The machines may be driven by any power less than that given in the table, and yield a product per hour proportionally. These machines may be set in one minute, to give the product any size from 2 inches, for road metal to fine gravel. The product of these machines per hour, in cubic yards of fragments, will vary consider- ably with the character of the stone broken. Stone that is ''granular ' in its fracture, like granite and most kinds of sandstone, will pass through more rapidly than that which is more compact in its structure. The kind of stone being the same, the product per hour will be in proportion to the width of the jaws, the distance between them at the bottom, and the speed. The proper speed is 200 to 250 revolutions per minute, and to make good road metal from hard compact stone the jaws should be set from \\ to i\ inches apart at the bottom. For softer and granular stone they may be set wider. These machines can be fitted with a screen, as shown by fig. i, when it is required I02 . PURE FERTILIZERS. to assort the crushed stone into different sizes. The Howell-Hannay Mill. The mineral, having been reduced to the size of gravel by the crushers, is next to be subjected to the action of one of these centri- fugal mills, constructed upon the principle of reducing quartz, stones, fossils, and other re- fractory substances of a similar kind to fine powder by percussion — that is to say, by the sudden check of the momentum of a body moving at great velocity. To this end a closed circular chamber is provided, and set in either a vertical or horizontal plane. On a shaft in the centre of this chamber is mounted a plate or disc with arms projecting therefrom towards the inner periphery of the chamber, and this periphery, against which the material to be operated upon is intended to be dashed with great violence, is furnished with ribbed or angular surfaces. The material to be crushed is fed in at one side of the chamber (at the centre thereof) by a hopper, and when crushed it is discharged through an opening on the other side, the rapid rotation of the THE GRINDING APPARATUS. lo-- arms on the central shaft while dashing the material against the ribbed or angular sur- faces of the chamber, causing also a current of air to carry off the powdered material at the discharge opening. A general view and details of this implement are shown by Plate 4, in which figs, i and 2 represent the side and end elevations of the improved machine. Fig. 3 is a plan of the same ; fig. 4 a side elevation of the machine, with one end of the crushing cylinder removed to show the con- struction of its parts ; fig. 5 is a plan of the interior surface of the cylinder ; fig. 6 is a modification of the same ; and fig. 7 repre- sents a section through the arms in the line X X oi fig. 4. A A are two supporting beams, on which are erected four upright standards B, two on either side, connected together at top by beams c, these being in turn connected and braced together by cross rails d, on which are secured bearings e, in which is supported a revolving shaft f. On one end of this shaft is mounted an armed disc G, and on the other a driving pulley h. The disc G is enclosed by a casing i, consisting of a cylinder j, and end-caps or covers k and k\ In the arrange- 104 PURE FERTILIZERS. ment represented in the drawing the cylinder J is armed on its interior with ribs, which may be either of a triangular form, as shown in figs. 4 and 5, or formed of pyramidal teeth, as shown in fig. 6, or they may be made in any other suitable form. Instead of teeth the inner surface of the cylinder may be left smooth, but the inventor prefers to use the teeth. The casing i thus constructed is firmly and permanently secured to the frame of the machine by means of screw bolts a and nuts b. On the end k next the frame of the machine, and at its centre, is cut an opening, through which the shaft f passes, whilst in the outer end k* of the cylinder, and at its centre is cut another circular opening d, but of larger size, for the purpose of feeding the machine with the quartz or other material to be pulverized, for which purpose a hopper of suitable shape and dimensions is attached to the machine. At or near the inner periphery of the cylinder there is cut through the inner end or disc k of the casing i another opening, to which is secured a carrying tube l, through which is forced by the current of air engen- dered by the rotation of the arms, the pul- THE GRINDING APPARATUS. 105 verized quartz or other substance as fast as produced, and by it conducted wherever de- sired ; or the spout may be let into the cylinder direct if deemed expedient. In this instance the arms, for the purpose of strength and to lighten as much as possible their weight, are represented as being cast on a disc G, which tapers from the shaft f out- wards, but if desired they may be cast on a hub, or in any other suitable manner con- sistent with strength, and they may either be made straight or curved. The disc on which they are cast (when a disc is used) may also be made in any suitable form consistent with the purpose for which it is intended to be used. On the inner surface of the cylinder ribs or teeth are formed, having the plane of their face set at right angles to the direction of the quartz or other substance as it is projected from the beaters or arms, under which circumstances they may either be made to run straight across the cylinder, as in fig. 5, or be cut somewhat of the form represented in fig. 6, so that the whole momentum of the quartz or other substance may be checked at once. As to the arms themselves, they may io5 PURE FERTILIZERS. be set at such angle to the shaft, and made in such form, curved or straight, as may be found best adapted for the most perfect execution of their work. In order to make the casing of the arms perfectly tight and strong, the ends or caps k k' are made to fit tightly over its ends, and the whole is then bolted firmly to the frame, and if deemed expedient for this purpose, a strip of lead, india-rubber, or other suitable material may be inserted between them. The operation of the machine is substan- tially as follows. The quartz or other mate- rial, broken to a suitable size, is fed in by hand, or by means of a hopper, through the open- ing in the outer cap k, when it is driven with great force and velocity by the arms or beater c of the disc g against the cylinder j, toothed or otherwise, and there reduced to powder, such parts as may not have been completely pulverized rebounding back, and being again projected by the arms against the cylinder until perfectly reduced. The pulverized ma- terial is carried and discharged by the cur- rent of air engendered by the rotation of the arms (or by other means suitably arranged THE GRINDING APPARATUS. 107 for that purpose) through the tube l, and by it conducted wherever desired. If required, the cylinder j may be made to rotate to in- crease the speed in the opposite direction to the arms, in which event the machine would require to be suitably constructed for that purpose. It may be driven by a number 19 pulley. The frame of the machine is repre- sented as being made of wood, but it may be of iron. The rest of the machine is made of iron, the face of the arms and teeth being chilled. To render this machine effective, it must be rotated with great velocity, say from one to two thousand revolutions per minute, ac- cording to the diameter of the machine ; and for this purpose a power of twelve to fifteen horses is required. The cost of a machine complete is from ^80 to ^100. CHAPTER V. THE PLANT. A PLANT for the manufacture of fertilizers comprises numerous pieces, each of which should be constructed and arranged with a view to durability and facile management. Manual labour being a capricious, and time an important element of cost in evolving the products, this consideration is indispens- able to the economy of their manufacture. In other words, the apparatus must be made throughout of the best materials and w^orkmanship, so as to save oft-recurring out- lay for repairs, and also be as nearly auto- matic as possible in order that it may move by steam-power, and do work quickly with the least possible personal attention. The pieces about to be described are those of general utility, and which constitute the actual requirements of a proper equipment. THE PLANT. 109 The supplementary apparatus pertaining to special processes will be set forth in their proper places. The Steam Boiler and Engine. The power of these implements must be according to the amount of work which they are to do. In all cases, however, it is much more economical and convenient to have them rather above than below the exact ca- pacity which may be required. The expense of a large boiler is very much less, propor- tionally, than that of a small one Boiler power of 40 to 60 horses is a none too liberal allowance for a large factory which may require much steam for other purposes besides driving the engine. Even for a manu- factory of moderate extent the boiler should be of 25 horse-power, and the engine of 12 to 15 horse-power. In all cases, a smoke-consuming arrange- ment should be attached, so as to facilitate the burning of the fine and cheap coal dust. The Roasting Furnace. This is a reverberatory furnace with a no PURE FERTILIZERS. broad bed for roasting those mineral phos- phates which may contain sulphur, pyrites, and much organic matter. Its position is shown at p on the ground-plan, plate i6. The preparation of the raw phosphate in this manner economises acid and saves time as well as labour in the subsequent operations. A furnace, i6 feet long and 13^ feet broad, with an arch of the mean height of 2 feet from the bed, will have the capacity for roasting three tons of raw mineral at each charge ; and four to six charges may be com- pleted in twenty-four hours. The Platform and its Accessories. This arrangement is shown by Plates 5, 6, and 7, and comprises a platform, an elevator, a lift, an acid reservoir, and a mixer. In the drawings, which are actual construc- tion plans to a scale, the side walls of the buildings are shown at a a, and the roof at B, c being a floor for the convenience of the workmen. The platform is seen at d, and is a strong timber work supporting the acid reservoir v and the mixer b, in connection with the ele- fstpuf i % ^ 1^ I- o o en a: o cc ul I- CO Ul o l-l LlJ| _l Ld < Q_ o y. MORFIT cm the ManiilacKirv orFcrtiUxcr.s Digester or Solution Vat 1, Fig I ^ ElEV AT 1 N. ScoLE OF Fee iii&ei fcf K Uorfita Wiidi n rernll2=! THE PLANT. in vator a a a and the cage u, which brings up the carboys of acid to the reservoir. The vertical guides for this lift are shown by / / /, and the gearing to hoist it by w w. The gearing x works the elevator, and the main shafting y hung to the roof of the building drives all the machinery. The platform o should be enclosed by a strong railing to prevent accidents ; and com- munication between the ground floor, it, and the floor c, must be established by means of a stairway with broad steps. The Elevator. This is to carry the powdered mineral from the floor to the mixer b. It is an endless flexible belt a a passing over a pulley at each extremity. A screw arrangement is for in- creasing the tension of the band in case this latter should become slack. Motion is com- municated by the counter shaft x driven from pulley on main shaft y. The belt being put in motion, dips up the powder from the floor beneath by means of the galvanized iron scoops or cups n n ii, \\hich, as they return downwards, drop it into 112 PURE FERTILIZERS. the hopper of the mixer b, where it meets the diluted acid, issuing in a graduated stream at the same time from the reservoir v. At this moment the powder and liquid are thoroughly intermingled by the revolving spindle of the mixer and its blades preliminaiy to passing down by gravitation through the shoot c into the stone vats beneath. The Lift. The lift is for hoisting the carboys of acid to the tank or reservoir v. It is fixed to the rear of the platform, and consists of two cages u ti, sliding between strong vertical guides / / /, and worked by the gearing w w, driven direct from pulley or main shaft y. While one is taking up the full carboys, the other is carrying down the empties. The reducing gear w w serves to diminish the speed and increase the power derived from the main shaft ; and there are three pulleys, one narrow and fast, and the other two broad and loose, driven from the main shaft by one open and one cross belt. By shifting the position of these belts, so that THE PLANT. 113 one or the other is upon the narrow pulley, the motion is reversed. The whole of this driving- arrangement is fixed conveniently to beams carried by the roof of the factory building. When dilute acid is to be used, it must be first emptied into a reservoir in the ground beneath, and thence pumped up by means of a pump constructed of lead and gutta-percha. This more convenient mode of hoisting is less applicable to strong sulphuric acid, which should be raised in carboys. So also hydrochloric acid, on account of its corrosive qualities, must be raised in car- boys or by means of the monte jus. The Acid Reservoir. This is a tank for holding the charge of acid which may be required for an operation. It consists of a wooden case v, lined with lead for sulphuric acid, and coated, inside and outside, with stearic pitch for hydrochloric acid. Such linings are necessary as protec- tion against the corrosive action of the acids. There should be two adjoining. The tops of the reservoir are level with the cage it at its 1 114 P URE FER TIL IZER S. highest point, so that when the lift brings up the carboys they may be moved readily on top of V. Then they are turned over, with their necks in the charging hole, so as to avoid any escape of fumes. As soon as a carboy is emptied, it must give place to a full one, until the reservoir is charged. The acid is drawn from the reservoir by means of a stone-ware tap. A suitable one, with bracket for fixing it in any convenient posi- tion, is made by Barnett, of Hoxton, Lon- don, and shown by figs, i and 2. The tall stem A is a pipe of lead or hard vul- canite connected with the acid reservoir, for the passage of the acid ; but a glass or vul- canite ball D, upon which a regulated pressure FiL'. I. Y\\^. 2. THE PLANT. 115 ' a, _ is applied by means of the screw and handle c, lessens or stops the flow, as required. By turning the handle so as to loosen the screw, the pressure of the acid forces up the ball D, and the liquid passes through the outlet F. In like manner by screwing down the ball, the outlet is closed. The packing e is made of felt. The body b of the tap may be made of lead, vulcanite, or stoneware, according as the tap is intended for the use of sulphuric or hydrochloric acid. This form of tap is not only cleanly and convenient, but very much less liable to be- come loose than any other kind. It were better to avoid the use of metallic nails in the construction of this reservoir, on which account the joints should be dovetailed and fastened with marine glue. The planks should be an inch and a half thick, and to give strength to the whole it must be bound with wrought-iron hoops or bands held tight by a coupling-screw arrangement at the ends. The Mixer. This is a wooden box, painted inside and 1 2 ii6 PURE FERTILIZERS. outside with the protecting pitch already mentioned. It is shown in place by b, Plates 5 and 6. A sectional view of its details is presented by Plate 7, and the description which follows will be in connection with this latter drawing. The sides of the box are f f, and fitting into the top of this box is the hopper e, which receives the powdered mineral as it falls from the scoop cups c of the elevator. The acid enters the mixer at the base of the hopper e, through the wooden pipe t, coated internally with the protecting pitch just prescribed, and connected with the reservoir. The fast and loose pulleys l, drive the spindle d, which carries the blades. The spindle g, of the mixer, is made of very hard and tough wood, and has four blades H H, passing through it. They are set at right angles to each other and at an angle with the axis of the spindle, as shown at h' h'. By this means they move like a screw, and force the mixed mass through the pass- age I, into the collecting-box, whence it passes through the shoots n n, into the vats or receptacles beneath. This collecting-box THE PLANT. 117 may be omitted, and then the wet mass will fall directly from the mixer into the vats. The number of diverging shoots should cor- respond with the number of vats to be fed, and each one must lead into its special vat or receptacle. The passage from the hopper to the mixer is seen at m ; and a semi-circular wooden valve p, working on a spindle R, closes the open- ings of the shoots at will. These are better shown in fig. 3 (Plate 7), which is a plan of the collecting-box, with its top removed to expose the valves p p p P', of which two (p p) are represented as closed, and two (p p) as open. All the parts should be covered with a protecting coating of the stearic pitch. The Digester or Solution Vat. The next implement to be installed is the stone vat in which the raw mineral is to be acted upon by the hydrochloric acid. It is shown by Plate 8 as constructed of flag- stones ; but any other material will answer which is proof against the action of acids. It is placed on the ground in advance of the elevator, and should constitute one of a row or series of ten. ii8 PURE FERTILIZERS. The drawing shows the whole arrangement in front, elevation and details. The form is that of a square box a, mounted upon a support of mason-work b, which rises from the ground about i8 inches. Each of the ends and sides, as well as the bottom, must be of an entire piece of stone without crack or fault. The bottom piece is large enough to cover the whole sur- face of the support b, which extends i6 inches beyond the circumference of the vat, in order to form a broad base c. The bottom piece c, is to be thicker than the sides and ends b c, and these latter are set into the former by means of a nicely- fitting groove cut around at about 12 inches from the circumference. In like manner, the ends are adjusted to the side-pieces by means of similar grooves in proper places. The front and back sides c c\ are 4 inches larger than the ends, in order to be grooved for receiving these latter. All the joints are first sealed with Portland cement or plaster of Paris, and then covered with a layer of stearic pitch. The whole is held firmly to- gether by the strong iron bands d d, with screw-nut ends c e. THE PLANT. 119 The bottom stone is 7 feet 8 inches square. The side and the end pieces have each a height of 4 feet ; but the length of the former is 5 feet 4 inches, while that of the latter is only 5 feet. This gives a clear ca- pacity of about 100 cubic feet to the vat, which is sufficient for the treatment of one ton of raw mineral and upwards at each operation. Surrounding the vat proper, and built up 2 feet from the base c, is a brick wall d, forming an enclosure of 4 inches diameter throughout, to act as a hot-air chamber e. This brick enclosure is to be capped with a thick flag-stone f, laid level, and kept firmly in place by means of cement and iron screw- bolts set into the brick-work. In the air-chamber, and surrounding the stone vat, is a circuit of iron tubes yy^ for the circulation of a current of steam, in order that heat may be applied during the process of digestion. These tubes should be coated on the outside with a thick priming of oxide of iron paint, and then with a layer of stearic pitch to prevent rusting. Each vat is fitted with a cover made of cast I2P PURE FERTILIZERS. iron plate and protected with paint and pitch, as just mentioned. To facilitate its move- ment it is hung upon pulleys, as shown by g, //, i, with the handle of the chain in reach of the workman, and high enough to allow convenient stirring of the contents of the vat as may be necessary. At the rear of the wall and coinciding with the top F of the air-chamber, there is a strong wooden platform g, to facilitate the stirring of the contents of the vat and removing re- fuse matter. The surrounding hot-air chamber of the vat may be dispensed with, and the whole structure reduced to a simple stone box by incurring some extra expense in the first in- stance for platinum heating tubes a a, figs, i and 3 of the Plate. They should dip directly into the contents of the vat, and are therefore adjusted by a screw-coupling attachment g g, to the steam-fed pipe o, above the vat. To eco- nomize the expense, the lower parts h, of the platinum tubes need only be 30 inches long, as the parts r, above the coupling, are iron elbows. These tubes are made by Benham and Froude, Chandos Street (W.), London. THE PLANT. 121 A tube of li inches diameter, and sufficiently stout for this purpose, will weigh 14 penny- weights to the running inch, and cost 17s. 6d. for that length, or ;^io los. per linear foot. Plain iron tubes, covered inside and out- side with hard vulcanite, as prepared by Cow, Hill, and Co., Cheapside, London, may be made to serve in place of those from platinum, but they require more care in the handling. These hard India-rubber coverings will resist the strongest hydrochloric acid, either hot or cold, and even hot oil of vitriol. Steam heat softens them so slightly as not to affect their usefulness in any great degree. The weight of the vulcanite coverings w^ould be four pounds or less per running yard, and their cost about 3s. Qd. to 4s. per pound, including workmanship. Porcelain-lined iron tubes, when the en- amel is free from lead, arsenic, antimony, or other ingredient which may render it destruc- tible by acids, or easily worn away, are very excellent substitutes for either of the preced- ing. They are both cheap and cleanly. T. and C. Clark and Co., Wolverhampton, manufac- ture this kind of ware in very superior quality. 122 PURE FERTILIZERS. The direction of currents of steam imme- diately into the vat affords facility of regu- lating the temperature of the digestion and rousing the contents by a ''blow up", as may become expedient or necessary. As platinum resists the action of acid, there is no wear and tear of these tubes, and the expense of using them is only the annual interest on their first cost. These screw-coupling attachments allow them to be moved at will, and thus two or four tubes may be made to serve for heating and stirring a series of twelve vats. The charging of the vat with the materials for a digestion is done in two ways according to circumstances. When the powdered mine- ral and acid are to enter in a mixed, moist state, the vat must be charged by means of the lift elevator and mixer (Plates 5, 6, and 7). On the other hand, if the materials are to go in separately, the charging is more conveniently effected from the platform g, Plate 8. To charge the vat from this platform with acid, the latter must be brought in carboys to the side upon a trolley (Plate 9) of wood. THE PLANT. 123 The platform of this trolley corresponds in height with that of the vat. The Syphon. The liquor of the vat, when clear, is drawn off from the settlings or insoluble residue, by means of a syphon ; because it is inconve- nient to fit taps to the sides of a stone vat. The most convenient form of this apparatus for large operation with acid liquors, more particularly when hot, is that designed by Mr. Harrison Blair, and shown by fig. 3. It consists of an iron tube, bent in the usual form, and with one leg longer than the other, but at the highest point of the arch there is a projecting tube which connects with a circular tight box a. To the lower part of this box is fitted an India-rubber tube, at the other end of which is a bucket b. The syphon being set with its short leg in the clear liquor of the vat, so as not to dis- turb the settled solid matter, and having its longer leg dipping into the liquid contained in the trough which is to lead the filtrate liquor away into a separate vat, the bucket is then to be filled with water and raised above 124 PURE PER PIL IZER S. . Fig- 3- the level of the box a. The water naturally passes then from the former to the latter; but now, on lowering the bucket b, it returns, forming a partial vacuum in a, and the air is drawn out of the syphon. This arrange- THE PLANT. 12 = ment is at once clean, convenient, and suit- able for acid solutions, whether hot or cold. Moreover, it is without risk to the workman. The Monte-Jus. When the solution liquor has been drawn off by the syphon from the digestion vat into the reservoir in the ground, it requires to be mounted into another vessel for the next operation. The reservoir is constructed, therefore, as a monte-jus. This piece of apparatus is substituted for pumps whenever the liquor to be raised from the lower to an upper vessel is too bulky or too corrosive to be pumped up. Its arrangement is shown by Plate 10. For this purpose, it may be made of cast iron as to the reservoir part s, and the top t. This reservoir is a mere round cylinder, with its top and bottom fitted to it by means of screw-bolts and india-rubber washers, so as to form air-tight joints. Before it is set into the ground its whole exterior and interior must be primed and coated first with oxide of iron paint and then with stearic pitch. At the top there is an iron tube c, protected 126 PURE FERTILIZERS. as above, or, better, lined with gutta-percha, for conveying the liquor of the digestion-vat from the tube-gutter into which the syphon drops it. The exit pipe A, similarly constructed, de- livers the contents of the monte-jus wherever it may be directed. In order that the confined air may escape when the monte-jus is being filled, there is a vent tube f. As just explained, the reservoir is charged through the tube c, and when nearly full the taps c' and f' are closed so as to form a her- metic chamber. The air-pump attached to the pipe d is then set in operation, so as to compress the air above the fluid in the closed chamber s. The tap on the end of the tube A being then opened, the fluid mounts and passes on to its destination, under the pres- sure thus applied to its surface. High pres- sure steam may be used instead of the com- pressed air of the air-pump. These implements as well as pumps are made by the engineers who do the work for soda manufactories. Gutta pcrcha and other kinds of pumps THE PLANT. 127 for mounting acids are made by A. Lerverd et Cie., 218, Faubourg St. Martin, Paris; W. Neill and Sons, Bold, St. Helen's Junction, Lancashire ; and John Cliff, Runcorn, Eng- land. The Precipitation Vat. This is the vessel into which the monte-jus delivers the acid solution, in order that it may be treated with a precipitant for the recovery of the phosphates which it has dissolved from the raw mineral. It is placed upon a strong base, at an elevation of twenty feet,* so that its contents may be drawn off when required through taps and gutters, by natural descent, into the receiving vessels beneath. There should be a pair of them at least. Plate 1 1 shows this vessel a as resting upon its brick- work support B. It is a large rectangular box made of thick wooden planks, and bound round with wrought-iron clamps d. These clamps or hoops are joined at the ends by a screw arrangement, fig. 3 of the Plate, so that they may be adjusted tightly by a nut connec- * By a mistake, the drawing (PI. 11) shows this base to be only two feet. 128 PURE FERTILIZERS. tion. Behind and near the bottom is a small manhole of about six inches diameter, as an outlet for the solid precipitate. Above it, but in the front of the vat and at a distance of ten inches apart, are other openings, bb bb, fitted with tampons, c c c c, for drawing off the supernatant liquor as may be required. The plug portion of the tampon is made of india-rubber, and has a hole through its centre in order that it may pass over the end of its handles. This latter is a wrought-iron rod with a screw cut and nut at the lower end for fixing the indiarubber plug tightly in place. Fig. 4, Plate 1 1, shows the tampon separately. Though it is not absolutely necessary for this vat to have a protecting coating, it would be better to paint it over with the stearic cement aforementioned, as acid liquors injure wood sooner or later. The heating and stirring of the contents are accomplished, when required, by means of steam-currents. For this purpose there are tubes s s s, dipping into the vat. They are attached by coupling-screws to the feeder, which is a large tube a, leading from the steam-boiler of the factory, and firmly fixed THE PLANT. I2g to the wall at the rear of the vat, and just above its top. The smaller dip-tubes s s s, are made movable because they require to be cleaned frequently of the rust which may form on them ; but the better way would be to have them porcelain-glazed on both inner and outer surfaces. An enlarged view of the coupling-arrange- ment is shown by fig. 5, Plate 11. This precipitation vat will serve very well for all ordinary operation, but in cases where it is desired to wash the precipitate wholly free from its mother liquor, and rapidly, then it would be expedient to employ one of the two forms of apparatus (Plate 17 or 22) de- scribed for special purposes in Chapters viii and XIV. By means of their vacuo-filter arrangement a large volume of precipitate may be cleaned in a short time. T/ie Drying Kiln. These kilns, shown by Plate 12, are in pairs generally, and should adjoin the eva- porating pan, in order that the contents of the latter may be drawn into them conve- niently, when required. They are to give the K I30 PURE FERTILIZERS. final drying- to the precipitate when it is to be sent into the market, either as precipitated phosphate, Colombian phosphate, or Colom- bian fertilizer. The pulp from the precipita- tion vat is led directly into the kiln by means of a movable connecting gutter. Fig. i on the plate shows a sectional elevation of this kiln. Its form and construction are much after those for drying white lead. The basin portion is about 12 inches deep, and should be w^ell lined with the best hydraulic cement and a coating of plaster of Paris. The bed of the basin, as well as the furnace portions, are to be built of smooth fire-tiles and bricks. In order that the heat may be distributed uniformly, so as to insure a moderate tem- perature, the flues are arranged as shown by fig. 2 on the plate, which is a sectional plan along the lines a and b. The IVash Vat. This vessel is that in which the liquor from the precipitated phosphate is drawn, and therefore it must be placed with its top below the level of the bottom of the precipi- tation vat. This position allows the liquor THE PLANT. i;i of the upper vat to be drawn into the lower through taps or by means of a syphon, with the least possible delay and labour. It is the exact counterpart in all other respects to the precipitation vat, described at page 127 ; that is, it is constructed of the like material and has corresponding dimensions. There should be a pair of them, side by side, or rather end to end. The Evaporating Pan. This may be made either of steel-plate, cast-iron, or sheet-lead, and is usually set W4th a duplicate. They receive the clear liquors which are drawn off from the precipi- tation and solution vats, in order to concen- trate them to the crystallizing point or eva- porate them to dryness. Plate 13, fig. i, shows a range of these pans: a being the pan portion, b the fire-door, c the ash pit. The whole is supported by masonry, that part where the front of the pans rests being a dome of fire-brick. The steel pan is almost 18 inches deep. The manner in which the flues are to be built is explained by fig. 2, Plate 13: b being the K 2 132 PURE FERTILIZERS. fire-grate of the furnace, and a' a' a the brick walls, which form the channels for the distri- bution of the current of heat throughout the bottom of the pan which rests upon them. If the pan is of sheet-lead there must be an intervening iron plate between it and the top of the walls a' a' a', both as a support and protection for its bottom. An iron stairway affords the facility to the workman of mounting to the top of the pan, as may be necessary for observing the opera- tion and attending to it. Mixing Machines. When the fertilizer prepared by either of the processes hereinafter described, has reached the dry state, it is more or less lumpy ; and for the purpose of reducing it to powder of uniform fineness, and frequently also of associating it with other substances, it must be passed through a mixing machine. The comparatively loose texture of the mass renders this operation both simple and rapid with a suitable implement. The machine in most general use, and which does its work, very satisfactorily, is THE PLANT. oj that known as Thomas Carr's Patent Disin- tegrator, made by the inventor at Bristol, England. My opinion, however, is that the Howel-Hannay centrifugal mill, already de- scribed and recommended in Chapter iv for powdering the raw mineral, will serve at the same time, and most advantageously, all the purpose of a mixer. Such a utilization of one machine for several different operations will therefore promote economy of both plant and space. The Howel-Hannay machine prevents all loss by escaping dust, and makes a powder of great fineness, whilst that of Carr produces a granular powder. Carrs Disintegvator. This apparatus is the invention of a gentle- man who has become distinguished for his practical genius in mechanical engineering. It is shown in two views by Plate 14; fig. i being a section elevation of side, and fig. 2 a front elevation, with front plates and front standard (a) removed. The iron disc b, cast in one piece with a tube b , which works on a wTought-iron shaft r, carries the wrought-iron or steel rods 134 PURE FERTILTZERS. a% which connect it with the annular disc a\ About a dozen of these rods are made longer than the others, and fasten the cast-iron disc a, which carries a second series of bars re- volving" in the same direction as the first. Connected with this is also a series of breakers a^ and d fixed at their extremities by the ring d' . These latter are of a strong flat section, and serve to break the larger lumps which would not pass, otherwise, through the bars of the cage. The cast-iron disc c' firmly keyed to the main shaft c, and driven by the pulley b\ re- volves in a direction contrary to the one just described, and carries two series of bars a\ secured at their extremities by rings. The hollow shaft b', working on the solid spindle c, is retained in proper position by means of the bearings at each extremity. As to this part, b^ represents two blocks of gun-metal bored to fit the shaft, and secured by means of the cup b and nut and bolt b\ The solid shaft runs at each end in gun- metal bearings of ordinary form, carried by the standard a, cast in one piece, with the bed-platc A. A casing of wrought iron a', en- THE PLANT. 135 closes the whole for the purpose of confining the pulverising material. As it is thrown off radially from the machine, the wooden sides y y of the casing are made almost to fit the larger disc. A perspective view of the machine in place is shown by Plate 15, which exhibits the method of feeding it, and also the arrange- ment of the driving-belts ; that one of these latter on the fixed spindle being open and the other crossed, so as to give an opposite direction to each series of rings. The machine represented by the plates is that known as the '' new improved 4 feet 6 inches size\ which costs, complete and includ- ing patent licence, ;^i2o: 10. The inventor explains the construction of his disintegrator, and the mode of managing it, as follows : — " It simply consists of a series of four strong cylindrical iron cages, of various sizes, formed of bars with open spaces of from 3 to 4 inches between them, arranged concentric- ally one within another, around or parallel with the shafts or axles, and rotated therewith with extreme rapidity (from 350 to 450 revo- i:;6 PURE FERTILIZERS. lutions per minute), in contrary direction to one another, by means of an open and a crossed strap ; the first and third cages rota- ting to the right, and the second and fourth to the left, so that, while there are only two motions in reality, yet from the way in which the cages intersect one another, there are re- latively four. " The material is thrown in at the central orifice either by shovels or elevators, and after the lumps, if very large, are broken by a stationary knife (fixed so that its blade may extend into the interior of the innermost cage, but never used with very hard mate- rials), they are thrown out by centrifugal force from the first cage at a tangent to its circle, precisely as stones are hurled from a sling, and at a speed equivalent to that at which the beaters of the said cage are rotating (which is usually 50 feet per second) ; when meeting the beaters of the next cage, moving in an opposite direction, usually at 60 feet per second, a collision ensues similar to that which takes place between a cricket ball and bat, the shock thus produced being com- pounded from the aggregate speed of the beaters, and the speed and weight of the ma- terial meeting them. The projectile impetus of the flying material is thereby arrested, and THE PLANT. 137 a fresh impulse given to it in an opposite direction, to meet the beaters of the third cage, travelling the reverse way; and so on in like manner with the fourth one, when, if the material is of a friable and non-fibrous nature, it is shattered by these successive blows into a fine granular powder usually like that of gunpowder, and in less than a second de- livered in a radiating shower at a tangent to, and from every portion of, the periphery (like coruscations of the fire-work known as the * Catherine wheel'), and then arrested in its flight by an external casing of wood or iron enclosing it, and usually formed like the paddle-box of a steamer. ''The power required for the 4 feet 6 inches size varies from 8 to 10, 12, and even 14 and 16 horse, according to the following circum- stances : First, the gross weight of material to be operated on per hour ; secondly, its hardness, tenacity and specific gravity; thirdly, the degree of fineness to which it has to be reduced ; and, fourthly, the speed which must consequently be maintained to accomplish the results required; for, as these four consti- tute, individually and collectively, a certain amount of work done in a given time, the power to execute the same must necessarily be proportionate thereto, as an adequate 138 PURE FERTILIZERS. effect can result only from an adequate cause. ** The average speed that the 4 feet 6 inches machines are driven at varies with the above circumstance, from 300 to 400, 500, and even 600 revolutions per minute. Where, however, the engine is deficient in power for the work it is required to do, and it is desirable to in- crease it by working to the best advantage, great care must be taken not to multiply the speed of the disintegrator too much against the engine, in proportioning the respective sizes of the pulleys, or the engine will be overloaded by the adverse leverage it has thus to contend with, and will therefore not be able to attain its proper speed; whereby its power (deficient as it was to start with) will be still further diminished instead of in- creased. For the faster the engine runs the more cylinders full of steam (or what amounts to the same thing, the more cubic feet of it) it uses per minute, and therefore the more power it gives out in the time ; — provided, of course, the boiler is large enough and has sufficient grate and heating surface to con- sume sufficient coal and generate sufficient steam to keep the engine running at an in- creased speed without diminishing the pres- sure of the steam. THE PLANT. 139 *' In driving the disintegrator it will be necessary to have an intermediate shaft, be- tween the engine and it, for the purpose of sufficiently augmenting the speed. This in- termediate shaft should be about 31 inches in diameter, and if driven by straps from the engine or its lay shaft, it should not be imme- diately above or below it, nor yet directly above or below the shaft of the disintegrator ; for, as the weight and sway of a long strap Avhen it partly rests on both pulleys are of great importance in preventing slipping, it follows that the more the shafts are on a level with one another the better ; otherwise the lower pulleys will lose the benefit of this weight, which is specially awkward if it hap- pens to be the smaller one. It would do, however, well enough, if a string, stretched from shaft to shaft, made an angle of about 45 degrees with the horizon, and, if convenient to make it more level than that, so much the better. *' The intermediate shaft should also be a good distance apart from the shaft by which it is driven, and also from the disintegrator it drives, in order to give ample length for the straps ; for short straps are very objec- tionable, especially when there is a great dis- proportion in the sizes of the pulleys : the 140 PURE FERTILIZERS. large pulley keeping a short strap at too wide an angle for it to embrace sufficiently the circumference of the small one, and give it proper hold on it, whereby it is liable to slip, thereby heating the machine, wearing itself out, and frequently flying off unless kept very tight, which is troublesome, and entails addi- tional friction on the bearings. The follow- ing example will give a sufficient idea of what is suitable. — If the pulley on the engine shaft is about 4 feet diameter, driving one on the intermediate shaft 2 feet diameter, it would be sufficient if these shafts were about 9 or 10 feet apart; and if the two other pulleys on the intermediate shaft were also each about 4 feet diameter, driving the small pulleys on the disintegrator ; then, as the difference in the sizes is here greater, from 11 to 12 feet between the intermediate shaft and the disin- tegrator is advisable, and if a foot or two more in both cases so much the better. " The pulleys will, of course, have to be proportioned to the speed of the engine, so as to multiply it as many times as is re- quired to give the disintegrator its proper speed ; only it is advisable that the smaller pulley on the intermediate shaft, that is driven from that on the engine, should be at least half as large again as those on MORFIT on the Jlff/iri/actarp nf'Fr?tLUr^cj's. JL'/' - 1 ^iV' ^k.'^t^V.■.t 1 lO: '^'- IlVnil ^ V.'i.J.'k j. ?rl Uil,'-;" cic Ds-\cvsi [a. ruljitri .'"?.oO.PriKiTC.sterPj« THE PLANT. 141 the disintegrator itself, as it has a much harder pull on it ; and if the engine is simul- taneously employed on other work, it is also very desirable that this pulley should have a loose one of the same size alongside of it, to admit the machine being thrown out of gear without stopping the engine. Of course, in this case, the pulley on the engine-shaft must be made double the breadth otherwise re- quired for the purpose. " Thus, having the means of throwing it in and out of gear is especially desirable with the large 6 feet 3 inches machine, the great weight of which makes it awkward to start at full speed, which is readily avoided by slowly shifting the strap from the loose pulley to the fast one, a partial slip of the strap ensuing during the gradual transit, which diminishes the abruptness of the start- ing. " Besides, without the loose pulley, the en- gine itself, would be found difficult to start with the largest size machine in gear with it ; for the power of a single engine on its first half stroke, is nearly wholly expended in giving motion to its own fly-wheel ; and if it had simultaneously to start a heavy machine also, and that at a speed very much greater than its own, it would be exceedingly liable to 142 PURE FERTILIZERS. be brought up when the crank lost its leverage, and came upon its dead centre, its fly-wheel not having attained sufficient momentum to carry it over. Nor is this all, for while the engine is awkward to start when unfreed from the disintegrator, it is under the same cir- cumstances equally difficult to stop it quickly, for the great speed and weight of the large sized one gives it sufficient momentum to powerfully re-act upon the engine when the steam is cut off, and drive it round many more times than its fly-wheel only would have done. " The straps should be very stout ones, and if double sewn so much the better. The one to drive the intermediate shaft should be 8 or 9 inches broad, and the two that come from it to the disintegrator should be 7 inches broad. All new straps will be found at first very troublesome, until by use they have ceased to stretch. " Stout belts of the same breadths will do as well as leather straps. The cross strap or belt should not be allowed to scrub against itself at the crossing, but should be kept separate by a small iron friction roller between it, 2^ inches diameter and 15 inches long, rotating on a vertical axle | in. diameter, sup- ported top and bottom. This would greatly THE PLANT. 143 save the strap from friction and wear, and it is especially desirable when belts are used. " It is indispensable that the cage should be enclosed in some way by an external casing or chamber, in order to arrest and pre- vent the too wide dispersion of the material, as it flies out with great force from every portion of the periphery. The shape of it, however, is of no importance so long as it effects this, and also shelters the straps, bear- ings, and men from the material falling on them, and at the same time admits of the machine being conveniently fed, and the finished material removed. But care should be taken that it is not so restricted that the material may be liable to cake and jam be- tween it and the sides of the machine, thereby acting like a friction-break on it, and involv- ing great waste of power. For it must be borne in mind that resistance caused by any such unnecessary friction here, is multiplied against the engine as many times as the speed of the disintegrator exceeds that of the engine, and therefore becomes very serious. A simple hopper sloping into the machine would be found convenient to guide the ma- terial in. The casing should be made to sepa- rate, so as to enable the workman to con- veniently scrape from it, occasionally, any 144 PURE FERTILIZERS. material that may have caked against it in- side, opposite the bars, between which and the casing there should be a clearance of 15 inches at least, and if double or treble that, so much the better, when the material is pasty. " With the high speed this machine is driven at, and considering the large amount of work it does, it would be false economy to stint it of oil, especially while new and the bearings not worn smooth and free, and there- fore more liable to heat. When working continuously at full speed, from two to three pints of oil a day, if found necessary to keep it cool, should not be grudged, especially while new ; and it should be inspected occa- sionally to see that the brasses do not get in- juriously hot. "When the raw material has not far to be brought to it nor the finished material to be far removed, five men will be sufficient to do fifty tons a day with it : two bringing up the material to it, one shoveling in, and two re- moving ; but with more men, two shovelers, and adequate power, the machine is capable of doing double that quantity. When the materials are hard and of considerable speci- fic gravity, the user must be especially cau- tious not to throw into a disintegrator of moderate strength solid pieces of an inordi- THE PLANT. 145 nate weight, or he may do more damage to it thereby in five minutes than five years' legi- timate work would eft"ect. The knife, with such hard materials, should be dispensed with." "When a soft and very adhesive material is used, a portion of it will adhere to each bar, but never on the side of the bar which strikes the material, but on the back side of the bar as regards the direction it is moving in. If, therefore, the engine is furnished with re- versing gear, and can be conveniently driven occasionally in an opposite direction, the Note. — There is a more modern mixer than Carr's, which, though not known in Great Britain, is spoken of very favourably by the many manufacturers throughout the United States, who use it there. The annexed draw- ing will give an idea of this machine as constructed by its inventors, Poole and Hunt, mechanical engineers, at Balti- more, Maryland. The containing vessel is an iron pan revolving hori- zontally around a support ; and in this pan a rubbing or L 146 PURE FERTILIZERS. machine will soon clean itself. Or the same might be effected, but with more trouble, by unlacing the straps, and making the cross and open straps exchange pulleys. Or the cleaning may be effected without either of the above plans : viz., by throwing in, while at full speed, a hundredweight or two of any brittle material, such as bone-ash or copro- lite." mixing apparatus turns about its support. In combina- tion with these two parts there is a guiding device for causing the rotation of the pan and mixer to move the mixed material to the central opening in the pan, through which it drops into a conduit or other suitable arrange- ment for being carried away. CHAPTER VI, THE ARRANGEMENT OF THE FACTORY PLANT. The ground selected for a factory building should be in an open situation, and con- venient to the sources of the raw materials, as well as favourably located for cheap trans- portation of the finished products. The vici- nity of navigable water or a railway station, in a manufacturing centre, is, therefore, the most eligible position. The factory building must be spacious and freely ventilated, so as to prevent discomfort- ing and unwholesome effects on the work- men from the noxious vapours which are in- cident unavoidably to the operations con- ducted therein. As best fulfilling these re- quirements, the lower part of the building, to the height of 12 feet, may be of mason-work, pierced by numerous windows, the sashes of L 2 148 PURE FERTILIZERS. which are hung upon pivots ; and the upper part wholly of wooden slat-work. The doors should slide on wheels and be very numerous in the front, so that a free draught may be obtained by opening them when the digestions are in progress. For the convenience and economy of super- posing the various implements, so that the contents of the upper may descend step by step and as required, through the series of vessels which are placed beneath, with as little delay and manual assistance as possible, the height of the main apartment should be 35 to 40 feet, and that of the wings and shed 15 feet. A syphon and several taps may be made thus to save the expense of many workmen, and also to render the apparatus as automatic as possible : an important point, considering the capricious character of manual labour. Plate 16 exhibits the general construction of a convenient factory, and the relative posi- tions of the several pieces of apparatus. It consists of two wings, c and G, a central apartment r, and a shed t at the rear. The left wing has four divisions, of which ARRANGEMENT OF FACTORY PLANT. 149 the front one c, is the office, and the second B, an engine room. Back of the latter in a are the boilers, while to the rear of all that part of the shed a is to be used as the coal and ash room. The office is subdivided by a sash-work partition, into two parts, in order to furnish a laboratory c , for the analytical and ex- perimental work of the factory. This labor- atory must be wholly shut off from the engine-room, so as to protect the latter from the corrosive vapours of the former ; but this need not interfere with the introduction of the necessary steam-pipes. The ventilation may be made complete by means of the windows and register-openings in the flue, which serves for the sand bath. Gas is the fuel to be employed for the ana- lytical operations, and steam-pipes are the media for warming the room. The shed t runs the entire width of the building at the rear, and is only 12 or 15 feet high. It is divided into several portions and fitted with suitable sliding-doors and windows. In the part b', the grinding and roasting operations are carried on, so as to I50 PURE FERTILIZERS. keep the main building free from dust. The position of the implements for this purpose is shown by n o p. It serves also for the storage of the crude minerals. The portion c is for general storage purpose ; while the part d serves for the fuel and work connected with the evaporating-pans and drying-kilns. The central apartment r is the general operating space. At the north-west corner the platform and its accessories m are placed, so as to be convenient to the grinding machines, from which the powdered mineral is shovelled through an opening e, at the base of the partition to the foot of the ele- vator. In front of the platform and elevator, about 20 feet distant is the series of stone digesters or solution vats s; and in the ground beneath, but close to the left hand wall, so as to be out of the way of accident, are two monte- jus I I. The ordinary precipitation vats are placed at L L, which show two pairs, one of which L l', may serve as wash vats. The vats for special precipitation and fitted with air-chambers, are to be set at k. In A RRA NGEMENT OF FA CTOR Y PLANT. 1 5 1 order to accommodate the large volume of wash-liquor, during its accumulation, for eva- poration, there is a tall reservoir q, for the reception and storage. At Y is the pug mill for converting the pulpy precipitate of phosphate of lime into superphosphate, and v vv v are the wells for the reception of the mixture of acid and pulp as it issues from the pug mill. In these wells it remains until chemical action is com- plete, and the mass has become hard. The drainers and a vacuo-vat for making: pure bi-phosphate of lime, or, in other words, for leeching superphosphate, have place at X and z. The right wing has several apartments. The first, in two parts, contains the evapor- ating-pan e, and the drying kilns d, both of these rooms being served with fuel and other attention from the shed-space d, in the rear. The division f in front accommo- dates the disintegrator, and the mixing opera- tion ; and the room g is that in which the finished products are weighed and packed for market. The upper part of this wing should be full 152 PURE FERTILIZERS. of windows, moving on a pivot, to produce currents of air for facilitating the evaporating and drying operations, as may be found necessary. There are two chimney-stacks, one at h for the steam-boiler furnace, and the other h', connecting with the flues of the evaporating- pans and drying kilns. The main pipe, or feeder, for supplying the steam to the appara- tus should run along the wall so high up that the heating branches may drop from it. This arrangement will prevent them being in the way of a convenient manipulation. As a proper economy of the operation can only be secured by an uninterrupted progress, the work must continue day and night ; and, therefore, two sets of hands will be necessary, to replace each other at the proper intervals. A plant constructed and collocated, as has been described, will promote a comfortable and economical course of the factory-work. CHAPTER VII. THE RATIONALE OF THE PROCESSES FOR REFINING THE CRUDE PHOSPHATES OF LIME INTO PRECIPITATED AND DI- PHOSPHATES OF LIME. The methods about to be described for the purification of "rock guanos" and other mine- ral phosphates, are founded upon certain prin- ciples, which may be stated as follows : — 1. The evolution of pure and concentrated products without any valuable ''waste' of the raw materials, and in a manner which secures alike to manufacturers and farmers the maxi- mum of honest profit and attainable benefits, 2. The use of chemical agents, which are not only very abundant and cheap, but easily managed, and capable of being reclaimed in forms that will pay their original cost, apart from the profit on the pure phosphate pro- ducts. Artificial fertilizers arc manufactured al- 154 PURE FERTILIZERS. most always in great commercial centres, and the customers for them live often in districts remote from convenient channels of distribu- tion. Hence the package and transportation expenses become most important items for consideration in connection with a manure. Previously to being sent forth into the mar- ket, it should be freed, therefore, from all inert matters ; for, to leave it burthened un- necessarily with any profligate constituents, is an imposition upon the confiding planter. Moreover, that manure is most economical and effectual which does its work through the first season of application ; for, though dura- bility is not incompatible with potency, the quality of permanence is superior only in the sense that none of the fertilizing virtue shall be lost by dissipation after the manure has been put into the soil. In other words, a soil should be manured rather for immediate fruitfulness than durable fertility : and thus half a ton of a pure and active fertilizer is worth double that quantity of a dilute or a sluggish one. The future had much better be left to the chances of a possible excess of the first than that the pre- REFINING PROCESSES. 155 sent should be jeopardised by the imperfect qualities of the latter. In fine, a manure whose forces are being long drawn out through a succession of years, is an injudi- cious investment, which involves a large capital of money and patience. I realize these precepts, practically, in some instances, by attacking firstly the crude phos- phate of lime with that chemical equivalent proportion of hydrochloric acid which is just sufficient to decompose and dissolve out the whole of the carbonate and organate of lime constituents. The solution thus formed consists of chlo- ride of calcium, and is to be drawn off into a separate vessel ; for this liquor may be eva- porated to dryness and utilized profitably in the manufacture of artificial stone by Ran- some's process, or for solidifying the ammo- nia of the liquor of the coal-gas works and bone-black works, as taught in Chapter xi. These two lime constituents act most profli- gately in the usual process of treating crude phosphates ; for they are the first to seize the sulphuric acid, and only to waste it by swell- ing the volume and weight of the product with superfluous sulphate of lime. MORFIT on the Manufacture of'FertiUzrrs. PRECIPITATION VAT DETAILS Plate 11. I z Fio. I. '— ' ■ ' I '-n-^H ' I ' ' L ' I ' _L. ' _l_i -----'^^^=^ I , I ' I'^SE 1 I SCALE OF FEET. 6 7 8 9 10 11 1Z 13 14- IS — I 1 I I I I I I I rJ i^e: Fic. II. ^ -e- -G- -e- -e- -Q- 3^ I . I . I . I I.I.I, r I . I . I . ~r I . I -I I . I r I , I I'D^ I 1 r I 1 I I 'I . I I I — r I I III Fic. Ill I ^3 — CTn r—o — C7- Fic. IV. SCALE OF FE ET. i i . 1 . I I , I. Spsoaliy diDij^u-ditM U'MwiUaWui-kolit'ui-lilincrS, VllKOiiL bi\.)uto Ijayi-ijn uiJ' FiC. V. I I I ^ ~[^2— Lv\Aw|~ riikiM'^ CV.DO.PaiwiioSJef I's 156 PURE FERTILIZERS. In my processes, on the contrary, the much cheaper hydrochloric acid is made to do not only that which sulphuric acid would fail to accomplish, but in such a manner that it may be reclaimed in forms which countervail its original cost. The second step in the refining operation, then, is to add hydrochloric acid again, and in rather greater proportion than will suf- fice to dissolve out the phosphate of lime and other soluble constituents of the mine- ral. There is thus left only the insoluble and inert matters, which are to be thrown aside as valueless. The liquor being drawn off into a separate vessel is a hydrochloric solution of phosphate of lime and magnesia, with certain impuri- ties, and represents the whole essence and value of the crude mineral. Passing to the third step, which is to get back the phosphates in a solid form, I neu- tralize the hydrochloric acid of the liquor with a reagent, in such a manner, as to keep in solution the associate-impurities, while pre- cipitating the phosphate of lime ; and, at the same time, to reclaim, the precipitant in a REFINING PROCESSES. 157 suitable form for indefinite repetitions of the operation or other useful purposes. The precipitate which is thus thrown down being a pure phosphate of lime in the state of pulp, has all the qualities for a rapid and entire conversion into pure " superphosphate" by mere passage through the pug mixer, with its bare chemical equivalent of sulphuric acid. There is, consequently, no v/aste whatever of acid, time, or labour, nor any crowding out of the soluble bi-phosphate element to make room for the intrusion of an excess of sulphate of lime or the presence of worthless matters. The product consists wholly of soluble bi- phosphate of lime in association with only that amount of hydrated sulphate of lime which is incident, unavoidably, to the chemical conver- sion of tri-phosphate into bi-phosphate of lime. This high degree of purity of the " super- phosphate" affords the facility of producing a soluble bi-phosphate of strength as great as 100 per cent. For, by simply leeching the pure " superphosphate" with water, all the soluble bi-phosphate is removed from its sul- phate of lime associate, and may be obtained 158 PURE FERTILIZERS. as a crystalline mass by evaporating the liquor to dryness. The following diagram presents a summary of the progressive operations and their effects. Components of the mineral. Action & products of the processes. I. Carbonate of lime I Oi'cfanate of lime r Removed by the first dose or fractional of hydro- chloric acid ; and re- \ claimed subsequently as chloride of ammonium or chloride of potassium and hydrated sulphate of lime. ■ Tri-phosphate of lime^ with all or most of the 2. \ iron and aluminum < oxides and phos- phates - - - - - ^ Sand and silica - - - Organic matter - - - Fluoride of calcium, with more less of Oxide of iron - - - Oxide of aluminium - Phosphate of iron and Phosphate of alumina - Dissolved out by the second dose or fractional of hy- drochloric acid and sepa- rated from the liquor in pure solid forms, indivi- dually ; by agents which are reclaimed subse- quently. l-\ Left as insoluble residue by the hydrochloric acid, and to be thrown away as valueless matters. REFINING PROCESSES. 159 There are many cases, however, in which the mineral phosphate will not yield its car- bonate and organate of lime constitutents to hydrochloric acid, without parting, at the same time, with more or less of the phos- phate of lime element ; and, therefore, the first fractional treatment may be considered a matter of expediency determinable for each case, according to the judgment of the ope- rator. If the first fractional treatment or digestion with hydrochloric acid is omitted, or rather merged into the second, so that the two be- come one and continuous, then the resulting solution differs from that of the previous in- stance only in containing more chloride of calcium ; the additional quantity of the latter being formed from the carbonate and organ- ate of lime constituents of the raw mineral. This chloride of calcium increases the volume and density of the liquor, so that more time and fuel are required in the subse- quent manipulations; but it is not, otherwise, an obstructive presence or modifier of the reactions hereinbefore explained. To get back the phosphate of lime of the i6o PURE FERTILIZERS. entire liquor thus made, either ammonia, car- bonate of ammonia, or carbonate of lime will answer as the precipitant, and the mother- liquor will have the composition of that al- ready described. But, when di-phosphate of lime is required instead of tri- or Colombian phosphate, either alumina, phosphate of alu- mina, oxide of iron, phosphate of iron, or milk of lime, must be substituted, as the pre- cipitant, for economical reasons. In each case, the precipitant being the stronger base, seizes the hydrochloric acid which holds the phos- phate of lime in solution and causes the latter to precipitate as a white powder. The mother- liquor is then a hydrochloric solution of the precipitant which may have been employed, together with more or less of chloride of cal- cium and the iron and aluminum constituents of the mineral. As the use of a full equivalent proportion of the precipitant would produce tri-phos- phate, the quantity is reduced to one half of the chemical equivalent of the tri-phosphate of lime contained in the liquor when it may be desired to make the precipitation as di- phosphate of lime. REFINING PROCESSES. i6i The quantitative adjustment of the precipi- tant, so as to restrict the ratio to the require- ments for producing either a tri- or di-phos- phate, leaves all the iron and aluminium com- pounds in the mother-liquor and delivers the lime phosphate in a pure state. Thus, then, the latter not only acquires an enhanced value, but promotes for the mother-liquor a wider and more profitable range of usefulness. The latter being now a hydrochloric solution of aluminium and iron oxides and phos- phates, is, in fact, a counterpart of the acid solution of "Alta Vela Guano" or other mineral phosphate of alumina as specially made for the defecation of sewage. It has all the advantages of this liquor, with the ad- ditional one of much greater cheapness. So great is the precision with which these re-agents may be made to separate the phos- phate of lime from its usual persistent asso- ciates, that I intend to found, also, an analy- tical process in connection with them, and thus solve a problem which, until now, has been full of chemical difficulties. M CHAPTER VIII. THE MANUFACTURE OF PRECIPITATED PHOSPHATE OF LIME. This product is in the form of a loose white powder, and has a fertilizing capacity only less potential than that of the Colombian phosphate, described in the next chapter. Chemical authorities generally consider it to be wholly a tri-phosphate of lime ; but it usually contains also some di-phosphate. Practically, it is a mixture of all three of the phosphates of lime ; for, being very sen- sitive, it splits into these latter promptly, under the chemical influences of the soil. Its degree of chemical tenderness in this respect varies with the density and temperature of the acid solution from which it is precipi- tated, and accordingly as the precipitant may be used in the gaseous or liquid state. It may be made pure, provided the raw PHOSPHATE OF LIME. 163 mineral is free from alumina and oxide of iron, and in any case it need not contain more than two or three per cent, of these matters, if proper care is observed in its pre- paration. Being free from foreign matters, that is, commercially pure, its superiority as a raw material for conversion into " superphos- phate" of very high degree, or even into a pure bi-phosphate, is very evident. The employ- ment of it for this purpose will not only re- duce the required amount of labour and acid to the lowTst possible ratio, but prevent all waste and unprofitable dilution of the pro- ducts. Moreover, the latter will be both dry and bright-coloured, in characteristic degree. Hitherto, all attempts to use ammonia as the precipitant have failed in practice on a large scale, because of the difficulty of adapt-, ing a suitable apparatus to the bulky volume of the raw materials and freeing the precipi- tate from that hygroscopic property which adheres to it through the presence of a slight proportion of chloride of calcium. However much the precipitate may be washed, this property cannot be removed by water alone. M 2 1 64 PURE FERTILIZERS. B. de Siebenthal was the first to suggest the reclamation of the ammonia precipitant, but omitted to describe the means. Moreover, he proposed the use of it in a liquid form as precipitant, which is impracticable, for that would require an immense stretch of appara- tus and labour for an operation of even mo- derate extent. The removal of these fatal obstacles was not an easy task ; but they have yielded in my conflict with them, and I am now able, after a patient study of the subject, to present the following method of manufacture, which is at once simple, practical, and, in all re- spects, economical. Though this process is able to evolve pure products from mineral phosphate of even poor and complex nature, it is yet expedient, for the sake of convenient manipulation and uniform results, that the manufacture should be conducted as much as possible with minerals of uniformly fair com- position and character. The ''South Caro- lina Phosphate \ therefore, will be taken as the raw mineral, with which to exemplify the following instructions. PHOSPHATE OF LIME. 165 The Purge or First Fractional Digestion The first step is to grind the raw mineral to fine powder, after which it should be well heated in a reverberatory furnace to dull red- ness for an hour. By this process of roast- ing, the iron constituents are reduced to the lowest degree of solubility in hydrochloric acid, and thus both the purity of the refined product and the economy of its manufacture are materially promoted. Moreover, part of the carbonic acid being driven off from the carbonate of lime element, there will be less inconvenience from effer- vescence in the subsequent digesting opera- tion. So, also, in like manner, any pyrites which may be present is converted into oxide of iron and the subsequent evolution of sul- phuretted hydrogen during the digesting with acid will be counteracted. At the same time, it must be mentioned that the presence of organic matter will cause the roasted mass to retain a certain amount of soluble carbon product, which occasionally renders more difficult and slow the subse- 1 66 PURE FERTILIZERS. quent digesting operation and clear settlings of the liquors. Care must be observed in this roasting operation not to fuse the powdered mineral, more particularly when there is much sand or silica present ; otherwise, this latter, in connection with some of the other foreign constituents, might re-act upon the phos- phate of lime element and diminish its solu- bility in acids. The powdered raw mineral phosphate, having been roasted, is to be brought to the foot of the elevator plates 5 and 6, and taken up by the cups ;/ ;/, so as to pass into the mixer b gradually, with a sufficient quantity of hydrochloric acid of specific gravity I'ly to decompose and dissolve out its carbonate and organate of lime consti- tuents. Assuming that "South Carolina phosphate" is the mineral under treatment, and that it has the composition noted in the table at p. 30, then its content of carbonate and organate of lime being 14*32 per cent, every hundred pounds of the mineral will require 30*93 pounds of hydrochloric acid (sp gravity riy) PHOSPHATE OF LIME, 167 and 3*o additional for contingencies, or say a total of 35 pounds for this preliminary step of the refining operation. The acid is to flow from the reservoir v (Plates 5 and 6) in a gradual stream, so that it will come in contact with the powdered mineral at the moment the latter enters the mixer (Plate 7) from the cups 11 n of the elevator ; and it may or may not, according to the judgment of the operator, be previously diluted with one-fourth of its volume of water. My own opinion is in favour of the dilution ; for it may happen, otherwise, that the mass will set into a stiff paste with only the volume of liquor represented by the strong acid. This consistence retards digestion in much greater degree than would the addition of water as suggested. The moist mass, as it falls from the mixer, is to be led through a wooden gutter into the stone digestion-vat described at p. 117, and shown by Plate 8. Here it is heated by the steam currents until effervescence has ceased. At this stage all of the carbonate and organ- ate of lime has been removed by solution in the acid, and together with more or less of i68 PURE FERTILIZERS. the iron and aluminum elements of the crude mineral. The liquor thus formed is to be drawn off, by means of the syphon, fig. 3, into the monte-jus (Plate 10, page 123). To the residue in the vat, fresh water is to be added, and the whole heated and stirred by the steam current as before, and then allowed to settle. The supernatant wash water is now to be drawn off into the monte-jus and mixed with the previous liquor for treatment, as explained in a subsequent chapter. It is to be known as i\\t purge liqttor. This fractional treatment of the mineral, with a restricted portion of acid as the first step of the refining operation, leaves it free • from those of its constituents, which would embarrass, otherwise, the subsequent mani- pulation by producing an excessive volume of liquor. Therefore, the contents of the vat now consist only of the phosphate of lime, constituent with sand, silica, organic matter, a portion of the aluminium and iron compounds, and fluoride of calcium, if any were present. PHOSPHATE OF LIME. 169 The Solution oy Second Fyactional Digestion. The second step is to relieve the phosphate from its objectionable associates, and this must be accomplished by a new treatment of the washed residue with hydrochloric acid. As the original mineral contains 52'2i per cent, of tri-phosphate of lime, every 100 pounds will require 137, or say 140, pounds of hydrochloric acid, of specific gravity I'ly, for this progressive stage of the refining pro- cess. It is to be poured directly upon the contents of the vat, after which the cover is lowered, and the whole heated and stirred by means of the steam currents until all the tri- phosphate of lime has been taken up in solu- tion. It is necessary to keep the vat covered during the digestion, otherwise there will be a great loss of acid by evaporation, and con- sequently an imperfect result. The whole is then allowed to settle, after which the fluid portion is to be drawn off into a monte-jus. The residue in the vat is then treated with fresh water, boiled, and allowed to settle as before. The wash water I/O PURE FERTILIZERS. having been drawn off into the monte-jus, there to mingle with the previous strong liquor, is to be washed a second time. The residue, having been thus cleaned of all its valuable matter, is now to be thrown out as waste, in order to make room for a charge of fresh mineral. The strong liquor and its two wash- waters in the monte-jus form a hydrochlo- ric solution of phosphate of lime, com- prising some little of iron and aluminium compounds, and represent the essence of the " South Carolina Phosphate" disembar- rassed of profligate and worthless associates. It now remains to get it into a solid form by means which are as convenient and self- compensating as possible. This has been rendered comparatively easy by the clean- ing away of the lime carbonate and organate in the first instance, and the contrivance of the following apparatus for the use of am- monia, in a gaseous state and for an indefinite number of repetitions, as the precipitating agent. The volume of this liquor, including wash-waters, is about 350 to 400 gallons from each ton of raw mineral under operation. PHOSPHATE OF LIME. 171 The Precipitation and the Vacinun — Filter Vats. Therefore, to proceed with the next or third step, the hydrochloric solution of tri-phosphate of lime must be raised from the monte-jus into the tall cylindrical vats shown by b b (Plates 17, 18, and 19), and through the openings ^"^'' (Plate 17). As the volume of the liquor expands largely in absorbing ammonia, a vat must not be filled to more than two-thirds of its height. Four vats, b b b b, and one generator, a, constitute a battery. This arrangement is with a view to economy of apparatus and space. In any case, at least a single pair of vats will be necessary for an uninterrupted progress of operations. The vats, as well as the generator, are in two cylindrical pieces of the best cast iron, bolted together at joints as shown, and made steam-tight by means of a type-metal or caoutchouc ring inserted. The height of each piece is nine feet, which makes a total depth of eighteen feet for the vats and generator severally. The lower piece is to have a thick- \^2 PURE FERTILIZERS. ness of one inch and a quarter for strength, but the upper may be an eighth of an inch thinner. Both the bottoms and tops are fitted on with steam-tight joints. The four vats are identical in construction, and receive their necessary charge of gaseous ammonia from the generator a. For this purpose there are connecting pipes o o o o, made of cast-iron, leading from the directing- valve e, and each terminating in two cocks p p, at the distances shown from the bottom of the vats. By this arrangement with the interior, the gaseous ammonia is thus made to pass from the generator through nearly the whole volume of liquor in the precipitation vat, by merely opening the lower and closing the upper one of the cocks//. When, after a time the bottom stratum of the liquor may have become thick with precipitate, the upper- most of the cocks is to be opened and the lower one closed, to prevent the further entry of the ammonia to that part which is already saturated. For the free exit of any gas that may escape absorption or be in excess, there is a cast-iron pipe s rising from the top of each PHOSPHATE OF LIME. 173 vat and dipping into a small cast-iron extra cistern / adjoining. This extra cistern is to be two-thirds filled with the original hydro- chloric solution of phosphate, and one of them will suffice for each pair of precipitating vats. The amount of gas escaping in this way will be so small, comparatively, that one charge of liquor will serve for many opera- tions, so that it will not need to be often re- placed by a fresh portion. As the precipita- tion which takes place in this cistern corre- sponds with the precipitation going on in the vats, the contents of the former are to follow the course of that of the latter, as soon as they have become thoroughly neutralized by the ammonia gas. The three cocks n ii n in each vat for test- ing the height of the contents within are fitted to a descending tube for carrying off the small try portions of liquor, and thus promote the convenience and comfort of the workman. There are also a hydrant-pipe g, and a steam-pipe /, connexion. The steam-pipe, descending into the vat from the latter, is to be perforated here and there throughout its 174 PURE FERTILIZERS. length, so that the contents of the vat may be stirred and intermixed thoroughly by an occasional " blow-up T In order that the vats may serve equally for the precipitation of the phosphate liquor and the filtration of the precipitate, their bottoms have a special construction ; that is, the under portion of each has an air-tight communication with a vacuum chamber v v, by means of the short pipe and cock ;/ ;/ n n. One of these chambers will suffice for a pair of vats. It is of the best cast iron, seven feet high, with an internal diameter of three feet, and fixed below the level of the precipi- tation-vats. Air is exhausted from the vacuum chambers by means of an air-pump x, communicating with each through the pipes ;/ ;/ (Plate 19) ; or steam may be used to form the vacuum. In this latter case, there must be a pipe /' con- necting with the steam-pipe from boiler, and a pipe g attached to the hydrant which sup- plies the other vats with water. This arrange- ment is shown by Plate 17 and will be ex- plained directly. The details of a precipitation-vat are shown PHOSPHATE OF LIME. 175 by Plate 18, fig. i, being a sectional elevation through the centre of the lower portion ; and fig. 2, a transverse sectional plan. In both of these figures, the letters of reference corre- spond for the same parts. a a are the sides of the vat, and b b the iron frame, bolted to the vat, in which slides the wedge-shaped door c. Bolted or cast upon a portion of this door-frame is a shoot d. The door c is raised or lowered by means of the screw e and the nut f. The gearing to this door consists of a bracket g bolted to the side of the vat, and, carrying the end of the screw, a pair of mitre wheels //, and a winch handle i, for raising, lowering, and screwing the door tightly into the wedge-shaped frame. The bottom of the vat k is strengthened by the ribs /////, and made to rise a certain distance into the interior of the vat, so as to make the level of the filter-plates ;;/ corre- spond with that of the bottom of the door, and also to give an inclination from the edge towards the centre, except at 11, immediately opposite the door. At this point it is left level, to facilitate the emptying of the vat after each precipitation. MOB FIT oil fhe Mccnu/actare ofFcj-tiUzcrs. Plate l: DRYING Kiln Fig. '//////////////^/////////////////// /M/////,. Sectional Elevation. Fic. II t/////././/////^^^^^^^^^ I m. ^^^^^ v///////////////////////m I Sectional Plan. Scale of Feet i>jiecia\iy iJesignedtbrDrMorfilsV/oritoii t'«uLiz iBnxiks DavxSon Lith rr'jVa'rfr •^'^.■SO p?.-' 1/6 PURE FERTILIZERS. Below the filter-plates the bottom is funnel- shaped, and terminates in a bend and flange, to which is joined the pipe that establishes communication with the vacuum-chamber. These filter-plates, m, are twelve in number, each one being a sector, so that it may be introduced conveniently through the door. Six of these are placed in position on the ribs 0, and covered with a coarse twilled woollen blanket. Over this are then set the remaining six plates, this arrangement being intended to prevent the clogging and over- weighting of the blanket. The dimensions of the several parts will be indicated by the scale attached to the drawings. The hydrochloric solution of phosphate of lime having been mounted into the precipita- tion-vats, by means of a monte-jus of ordinary construction, is ready to be treated with its required dose of gaseous ammonia. The Ammonia Generator. As before noted, the ammonia is evolved in, and sent forth from, the generator a (Plate 17); but, before proceeding to explain that PHOSPHATE OF LIME. 177 manipulation, I will complete my description of this part of the battery. In material, pro- portions, and chief points of construction, it is like the precipitation-vats. In the centre of the top is a manhole and lid of eighteen inches diameter, bolted on and joined in the usual manner, and made steam- tight by means of an inserted ring of type- metal or indiarubber. At the lower part, and on the side level with the bottom, is a sliding door m, like that which has been described for the pre- cipitation-vat on page 175, and by figs, i and 2, Plate 18. On the top of this generator is an arrange- ment, a, for feeding it with the ammoniacal wash or mother liquor, during the generation of the ammonia. An elevator, b (Plate 17), of the usual construction, brings up the am- moniacal matter from a suitable reservoir in the ground beneath, and drops it into the hopper of the generator. On the top of the generator is a relief-valve, c, opening inwards to prevent regurgitation of the liquor from the precipitation-vats, in case a partial vacuum should occur in the vat from any cause. A N 178 PVRE FERTILIZERS. safety-valve, d, is to restrict the pressure within a certain point ; and the gas generated within is carried off and conducted into either of the four precipitation-vats by means of a valve, Cy of special construction. Water is injected from the main supply, f, through the small pipes, g (Plate 17), as may be required. The current of steam, for heating the con- tents, enters from the main feeder, h, through the smaller branch-pipe, /. This latter dips to the level of the bottom and there diverges in two branches, k and /, each of which com- municates with a semicircular pipe laid round the interior and on the bottom of the vat. These two internal pipes form a ring, with their terminal ends abutting at opposite sides of the door ;//. They are perforated through- out their length or circumference with small holes for the issue of the steam at high pressure, for heating and stirring the contents of the generator. At the rear of the generator, or on the opposite side to the one seen in the drawing, are three try-cocks at different heights, and similar to those (;/ 1111) of the precipitation- PHOSPHATE OF LIME. 179 vats. These are gauges for determining the height of the liquor within or drawing it off. The generator, like the precipitation-vats, is erected upon a mason-work foundation rising four feet above the level of the ground ; but, unlike them, is surrounded to within six inches of the top flange, by a brick wall, with an intervening space between it and the cast- ing. This space is to be filled with ashes, powdered coke, felt, or other non-conducting material, to confine and economize the heat. A wooden platform, constructed at a level of about two feet below the top flange, so as to surround the battery, and with a suitable stairway, is to afford easy access to the covers, joints, etc., on the tops of the vats. Plate 18 gives the details of the feeder to this generator ; fig. 3 being a transverse sec- tion at right angles to its axis; fig. 4, a longi- tudinal section through the centre parallel to the axis; fig. 5, a complete elevation from the front ; and fig. 6, a complete elevation from the side. The letters of reference correspond for the same parts throughout all these figures, a is the hopper into which the semi-fluid ammoniacal matter is elevated by N 2 i8o PURE FERTILIZERS. the endless lift, and it is of large size, in order that it may be kept always partially full. Running up the outside of the hopper is a tube b, terminating at one end in a long, narrow orifice, and at the other in a pipe which dips into a small condensing cistern, as shown by c and d' in Plate 17. The gas which rises from the generator and fills the apparatus at each revolution escapes by its own elasticity, in part, through this aperture when it is first opened ; and the remainder is forced up by the descending mush liquor. As the revolution continues, the aperture at the base of the hopper be- comes uncovered, and the contained mush liquor falls through into the generator. ^ is a cylindrical chamber with closed ends, and the greater portion of its sides cut away, leaving only the two opposite parts g g, and the diaphragm h, which divides it. This chamber is turned, truly, to a slightly conical form, so as to insure the maintenance of a continuous good fit as wear and tear take place. The projecting collar /, or exterior flange at the large end, prevents the forcing of it in PHOSPHATE OF LIME. i8i too tightly, and a centre screw k, regulates the proper degree of pressure, and keeps the inner cylinder in position as wear and tear progress. / is the outer casing, open at each end, and bored to fit the chamber e. It is cast in one piece with the hopper, and terminates at the bottom in an aperture corresponding to the one at the base of the hopper and exactly opposite to it. This is extended in the form of a short pipe ;//, with flanges by which it is bolted to the top of the generator a. 71 is a worm-wheel fixed on a spindle firmly keyed into a socket o, cast upon the centre of the end, and concentric with the cylindrical chamber e. Rotary motion is communicated to this wheel by means of the spindle which carries the worm r, and is driven by a strap from the main shafting running on the pulley s s. A bracket t, to carry this gearing is bolted upon lugs cast on the side of the outer casing /. These are drawn to the same scale as the two previous figures. The ammonia mate- rial or materials are to be carried to the hop- per by the lift, and the feeding must be so 1 82 PURE FERTILIZERS. arranged as to keep the hopper nearly full. Motion is then given to the pulleys by means of a strap from the main shafting, and is transmitted by means of the worm and wheel to the inner cylinder. As this revolves from left to right, the portion g passing from the base of the hopper allows the contents to fill the space e, and as the revolution continues, the contents of the space e are poured into the generating vat through the pipe ;;/, and at the same time the contained gas takes their place. The further continuation of the revolution then brings the contents of the opposite space into the vat, and the gas that has replaced the contents of the first space e, finds an escape through the pipe b, and is condensed by dilute sulphuric acid contained in a suitable vessel or receiver, as shown by d\ Plate 17. Coincidently, the material in the hopper again fills the space e, and forces all the gases up the pipe b. Thus, as long as the revolution is uninterrupted, the material is fed into the generating vat without any of the contained gases being lost ; for, as the contents fall into the generator, the corre- sponding opening through which the mush PHOSPHATE OF LIME. 183 liquor enters the feeder is closed by the re- volving cylinder. Fig. 7, Plate 18, is a transverse vertical section ; and fig. 9, a transverse horizontal section of the four-way valve-cock by which the generated ammonia gas is distributed to, or shut off from, one or more of the four precipitation vats, as may be desired. A tell-tale window, of thick glass x, Plate 17, will indicate when any lime may be frothing over with the liquor ; and, in such case, the heating and agitation of the contents of the generator must be moderated. a a a a are the four branches, terminating each in a rectangular orifice b, of the same area as that of the circular one c, at the opposite extremity; ^is a hollow, conical plug, open at bottom, with one side aperture of same size as <^; n ul :£. H X O uJ n Ik 10 a: c/5 UJ Q. DC CC < o COLOMBIAN PHOSPHATE OF LIME. 22t, words, by this method, the oxides and phos- phates of iron and aluminum, whether natu- ral or prepared artificially, will serve singly or jointly for precipitating the phosphate of lime constituent from acid solutions of mineral or crude phosphates. The pulp required for an inaugural opera- tion is to be obtained by means of milk of lime from the mother liquors of the preced- ing process, or from that of the first di-phos- phate method in the next chapter. CHAPTER X. THE MANUFACTURE OF DI- OR NEUTRAL- PHOSPHATE OF LIME : AND OF CHLORO- PHOSPHATE OF LIME. This salt of lime deserves the best consider- ation, alike of manufacturers and consumers. It contains a higher ratio of phosphoric acid than the tri-phosphate. Hence, less of sul- phuric acid is required for its conversion into bi-phosphate, and it gives a more concen- trated product. For this same reason, it is a most advantageous basis-material for the manufacture of phosphorus. Though not directly soluble in water to any great extent, the di-phosphate is, never- theless, a most active and economical ferti- lizer ; for the chemical and atmospheric in- fluences of the soil split it promptly into soluble modifications which nourish a grow- ing crop as vigorously as would the bi-phos- DI-PHOSPHATE OF LIME. 227 phate. It is only the prejudice born of familiarity in the use of the bi- or superphos- phate, and of a want of experience with the di- or neutral-phosphate, that blinds the popular eye to the greater economy and equal potentiality of the latter as a manure. But, as time extends its production and brings it forward more abundantly into mar- ket, this di-phosphate will become better known and secure that appreciation which will give it a first place among fertilizers. The successful manufacture of this article is founded upon the studies of T. J. Way, Deligny, and myself, who are the only chemists from whom the subject has received any serious practical consideration. As the chemical characters of this di- or neutral-phosphate of lime have been de- scribed already at page 71, I will proceed at once to explain the methods of preparing it in a commercially pure state. Morfifs Process (A). Having selected a mineral or other crude phosphate of lime of uniform composition and reduced it to powder, the next step is to Q 2 228 PURE FERTILIZERS. add to it sufficient hydrochloric acid of specific gravity riy to dissolve out the car- bonate and organate of lime constituents. This is called the purging operation. If the raw mineral should contain any fluoride of calcium, the cover of the digester must be fitted with a flexible-joint pipe leading into the chimney for the purpose of conveying away the fumes. The acid may be diluted advantageously with water, and the purging manipulations should be performed with the aid of an eleva- tor and mixer, as described at pp. 111-115. The carbonic acid is thus got rid of more quietly and conveniently than if the powder and acid were mixed in mass. When all of the powder and acid has fallen from the mixer into the digesting vat (Plate 8), more hydrochloric acid must be added, and the whole well heated and stirred, as ex- plained at p. 207. The proportion of hydrochloric acid neces- sary to complete a digestion, will be the com- bined chemical equivalents of the carbonate of lime, organate of lime, tri-phosphate of lime, and iron and aluminium compounds DI-PHOSPHATE OF LIME. 229 contained in the raw mineral, and must be calculated according to the analysis of the latter and the data stated already in preced- ing chapters. But, after the purging operation, for the removal of the carbonate and organate of lime, the mineral mass should be treated with the remainder of the acid in divided portions or moieties. That is, the digestion should be continued with one-half of the residual acid as a second step ; and w^hen this latter has become charged with soluble matter, it is to be diluted with water, heated by the '' blow-tip\ allowed to settle, and de- canted or drawn off. After this decantation through a tap or by means of a syphon, the last moiety of fresh acid is to be added, and the digestion con- tinued. When the insoluble residue seems to be exhausted, water of dilution is to be poured in again, and the whole heated by a ''blow-up'' and allowed to settle, as pre- viously. The clear liquor is then to be drawn off, and the residue washed with seve- ral relays of fresh water, by means of the " blow-tip\ in like manner. The sand and 230 PURE FERTILIZERS. silicates, etc., forming the insoluble residue, are to be removed from the digester and thrown out as valueless waste ; the strong and wash-liquors are to be united in the precipitating vat. Before passing, however, to the precipi- tating operation, it is expedient to record a few notes respecting the choice of a digesting or solution vat for the raw mineral. In many mineral phosphates the presence of large ratios of insoluble residuum and organic matter cause the powder to form a thick mass with the acid, and this impedes the digestion. In such cases, the " blow-up' w^ould have to be used frequently, or even constantly, in gentle current, so as to supply the proper state of dilution by means of con- densed steam. This may cause such a con- densation of steam as to dilute the liquor excessively, and weaken its solvent power. Keeping the digester constantly covered during the operation, as is obligatory, to prevent the volatilization and loss of acid, will not hinder the excessive dilution, but rather promote it. If the raw mineral is easily soluble, this dilution will be imma- DI-PHOSPHATE OF LIME. 231 terial ; but there are many kinds of rock or fossil phosphate of lime which resist, with much obstinacy, the solvent action of even strong acids. In these latter cases, then, the double vat with surrounding hot-air chamber will be required for the operation of digest- ing them. The means of heating being a surrounding hot-air chamber, the ''blow-tip'' of open steam need not be used except for rousing the mass occasionally. Time, too, is an important element in the digesting operation ; for, while some of the mineral or fossil phosphates of lime give up all their soluble matter in six hours, others require twice, thrice, and even fourfold that time for their solution. The combined liquors in the precipitation vat, representing the soluble matter of the crude mineral, are an aqueous solution of chloride of calcium, containing a hydrochlo- ric solution of tri-phosphate of lime, together with iron and aluminium compounds. The vat may be of cast or wrought iron, coated with stearic pitch, and according to the form, dimensions, and general construc- tion shown by Plate 1 1 . But at the bottom 232 PURE FERTILIZERS. there must be a bed of closed iron tubes for the circulation of steam, in order to form a broad extent of heating surface. The ex- terior of these tubes must be coated with Clark's enamel.* The liquor in the precipitation vat is to be brought to boiling by means of the ''blow- up', and then treated cautiously with very thin and strained milk of lime until all the free hydrochloric acid has been neutralized. This is known as soon as the lime ceases to dissolve and leave the liquor clear or free from cloud. After having reached this point, the liquor * I am now having a vat constructed which combines efficiency, durability, and cleanhness in an eminent degree. It consists of only five pieces of cast-iron, each six by four feet, so that a large vat is formed with only a few joints ; which are made tight by hard india-rubber slips and nut- screws. The interior surfaces of the plates, as well as the steam-tubes and bottom-coil, are enamelled with porcelain, so as to be proof against corrosion. To give strength, the plates have ribs cast on the outside in a manner to form spaces for the insertion of felt cloth and panel covers, for maintaining the heat of the contents of the vat. Vats thus made are inexpensive, comparatively, and serve equally well for digestions, precipitations, and evaporations, whether hot or cold. DI-PHOSPHATE OF LIME. -i5 is to be treated further with a certain quan- tity of thin milk of lime containing only a little more of caustic or quick-lime than is equivalent, chemically, to one-half of the tri- phosphate of lime in the original raw mine- ral. Thus, if the latter, according to an ac- curate analysis, contained fifty per cent, of tri-phosphate of lime, and its digestion with hydrochloric acid has been conducted effectu- ally, the liquor from it will hold the entire quantity in solution ; and this will make a total of 1 1 20 pounds for every ton of raw mineral. Supposing, therefore, that one ton of the mineral be under operation, then the liquor for it will require o*i8 to 0*20 pound of pure quick-lime for the precipitation, as di-phosphate, of each and every pound of tri- phosphate of lime that it may contain. The lime must be added in the form of a thin milk and through a fine sieve, so that the passage of coarse particles or dirt may be intercepted. After all the lime has entered, the steam is to be turned off from the " blow-tif' into the closed tubular bottom, so that dry boiling and evaporation may go on regularly. As 234 PURE FERTILIZERS. the mixture becomes concentrated it thickens gradually, and when it has reached a state of very sluggish fluidity it will assume, suddenly, the consistence of a thick paste. The heat must be continued from this period until the paste acquires a certain degree of dryness, and then it is to be drenched with its volume of fresh water, heated and stirred for a few minutes by means of the '' blow-tip\ and left to repose for eight or ten hours. The clear mother- liquor is now to be drawn off from the settled precipitate of di- phosphate into a large storage vat for treat- ment, as hereafter directed. The precipitate must be washed with seve- ral relays of fresh water, with the aid of the '' blow-tip' \ and after each settling the wash- water is to be drawn off as before, and mixed with the strong mother-water in the storage vat. The precipitate is then to be dried in the same vat by moderate currents of steam coursing through the tubular steam-heating coil at the bottom. If the precipitate, as such, is to be sent into the market, there must be added to it, during the drying operation, an aqueous solution of DI-PHOSPHATE OF LIME. 235 one or more per cent, of sulphate of ammo- nia, in order to decompose any traces of chloride of calcium it may have retained, and remove thus the least possible tendency to dampness. Care must be observed not to over-heat the precipitate, otherwise its bright colour and solubility will be damaged. Therefore, the temperature, or rather the current of steam, must be diminished as soon as any sign of rusty appearance begins to show itself in the mass. With this precaution, the precipitate will be a beautiful white pulverulent mass, readily broken down by the back of the shovel, and is ready then to be packed in bags for market. Though the mother-liquor will show still an acid reaction when being drawn off from the settled precipitate, that is no indication of its having retained any tri-phosphate of lime. It is true that, by restricting the pro- portion of quick-lime precipitant, as directed, nearly all the iron and aluminium compounds are kept back in solution, but the precipita- tion of all the tri-phosphate of lime is as- sured if the manipulations are conducted properly. 235 PURE FERTILIZERS. The mother-liquor, then, is a mixture of aqueous and hydrochloric solutions of chlo- ride of calcium and iron and aluminium oxides and phosphates. To determine whether any traces of phos- phate of lime are present, it is only necessary to add a few drops of lime-water to a small portion of the liquor, which, in that case, will give a white precipitate. If there is any bluish-grey or brown tint in the precipitate, it may be inferred that the latter consists wholly of iron and aluminium compounds. My experience proves that, with the quan- tity of lime which has been prescribed and a faithful performance of the stated manipula- tions, there is little or no phosphate of lime left in the mother-water. The precipitate, consisting chiefly of di- phosphate, which is the prime object of the refining process to which this chapter relates, may be rendered nearly anhydrous by push- ing the drying process to extremity. But, for the sake of its handsome appearance and more active solubility in the soil, it is expe- dient to send it into market merely as a powder of ordinary dryness. In this form it DI-PHOSPHATE OF LIME. 237 retains water of constitution and some acci- dental moisture. To clear the mother-water of its iron and aluminium constituents and render it a pure aqueous solution of chloride of calcium for utilization, as directed in Chapter xr, thin milk of lime is to be added to it in a suitable vat until a red litmus paper, dipped therein, becomes blue. The above-named consti- tuents are thus precipitated, and after a re- pose of some minutes leave above a clear liquor of chloride of calcium, which is to be drawn off. The deposit is then washed with several relays of fresh water, drained, and pressed in cloths, or dried to powder in the kiln, according to the use for which it may be intended. If it is the product of a raw mineral which, like Cooperite or Navasa Guano, contains a very large proportion of phosphates of iron and alumina, then it may be reserved advan- tageously for the uses set forth in Chapters XIX, XX, and xxi. Dissolved in sulphuric acid, it becomes much superior to the "Alta Vela and Redonda Guanos" as a material for defecating sewage, 238 PURE FERTILIZERS. and manufacturing purposes. In hydrochlo- ric solution it is an excellent disinfectant. As a dry powder it is a fertilizer of fair but comparatively inferior grade. Morjifs Process (B). This important modification of the preced- ing (A) method possesses novelty and many great advantages. In the first place it elimi- nates the iron and aluminium compounds usually present in the raw mineral phos- phates, and thus delivers the phosphate of lime constituent as a pure product. Secondly, it utilizes as precipitant the iron and alumi- nium compounds which it eliminates. This means insures uniform results with the least amount of labour and the greatest simplicity of operation. It removes the ex- pediency, too, of roasting the raw mineral previously to digesting it, as prescribed here- inbefore, for rendering the iron and alu- minium constituents insoluble. Indeed, when these latter are in large pro- portion and mostly as phosphates, they can be turned to profitable account as by-pro- DI-PHOSPHATE OF LIME. 239 ducts. Hence, those highly alumino-ferru- ginous phosphates of lime, like " Navasa Guano" or " Cooperite", which are such ob- jectionable materials for the ordinary pro- cesses, become quite eligible in connection with this mode of treatment. The crude phosphate of lime having been selected, is to be powdered finely, and digested in a raw state with the requisite amount of hydrochloric acid. The propor- tion of the latter will depend upon the com- position of the former, as determined pre- viously by a careful analysis. There must be so much for the carbonate of lime con- stituent, an additional portion for the tri- phosphate of lime element, and a further quantity for their alumino-ferruginous asso- ciates. The data for calculation are given in the preceding chapters, and express the chemical equivalent ratios. The apparatus and manipulations are the same, also, as described for the (A) process just previously recorded. When the hydrochloric solution of the raw mineral, together with the wash waters from the latter, are in the precipitation vat, 240 PURE FERTILIZERS. they are to be mixed and heated to boiling by means of the '' blow-up!' Previously, however, a stock or capital of the alumino-ferruginous compounds must have been accumulated by precipitating the mother waters of the previous process with milk of lime, after the separation of their phosphate of lime freight. It is only necessary to add thin milk of lime until the mixture in the vats turns blue a red litmus paper. A slight excess of lime is unimportant. The greyish blue or lead-colored precipitate which falls down is the desired material. It may contain, pos- sibly, some little phosphate of lime, but that is immaterial ; for it is one of the advantages of this process that its operation and economy are undisturbed, whether an excess or deficiency of the precipitant may have been used. All is brought right by the easiest of manipulations, as will be explained directly in the proper place. The precipitate, after repose, is to be re- lieved of the clear liquor of chloride of cal- cium which rests above it. This is drawn off through taps suitably placed, or by means DI-PHOSPHATE OF LIME. 241 of a syphon, and economised as directed in Chapter xi. One washing with fresh water will now suffice for the precipitate, and it is to be accomplished by the aid of the " blow- ppr The wash water, after repose, is to be drawn off and mixed with the previous mother water. The precipitate, in its pulpy state, is ready now for use, as the precipitant of the hydro- chloric liquor obtained by digesting the raw mineral. This liquor consists of calcium, iron and aluminium chlorides, together with tri-phos- phate of lime, and iron, and aluminium phosphates in solution. It is to be brought to boiling by means of the '* blow-up^' and treated with the pulpy precipitate afore said by shovelfuls of the latter at a time. When the first portion is added it will not cloud the liquor if the latter is very acid ; but, as subsequent doses bring about the point of neutralization, a white precipitate begins to form. This is my Colombian phosphate of lime ; and when it ceases to be produced, the addition of pulp must be dis- continued. 242 PURE FERTILIZERS. As the pulp is rather lighter than the acid liquor, it floats on or near the top, so that it can be observed readily, by the perfect solu- tion of a preceding dose when it is proper or necessary to supplement it with a succeed- ing one. In this way an excess may be avoided, but at the same time can be removed, when it occurs, by the mere addition of some fresh acid liquor. The alumino-ferruginous pulp, in neu- tralizing the hydrochloric acid throws down only the phosphate of lime. All of the other constituents of the raw mineral which may have been dissolved out during the diges- tion, will remain in the mother liquor ; and this latter, after repose, is to be drawn off from the subsident precipitate for treatment, as will be explained hereafter. Upon the precipitate is now to be poured a quantity of fresh acid liquor, equivalent to the original volume of that just thrown down ; and this relay must contain the same total of phosphate of lime as the first liquor. Steam is then let in through the " blow-7tf' for five or ten minutes, after which the heat- Dl-PHOSPHATE OF LIME. 243 ing must be continued by means of the closed tubular coil at the bottom of the vat, until the mass evaporates to the consistence of a stiff, dry mush. Fresh water is then to be added, the whole mixed thoroughly by a current of steam through the " blow-iip^^ and allowed to rest. The precipitate which settles is di-phos- phate, containing more or less of tri-phos- phate of lime ; and the clear liquor above — to be known as the mother liquor — is a mixed solution of calcium, iron, and alumi- nium chlorides. Oftentimes, however, the alumino-ferruginous portion of the liquor may be chiefly phosphatic. The mother liquor is to be drawn off from the precipitate into a suitable vat or reser- voir ; after which the latter is to be washed with several relays of fresh water. The wash waters are in all cases to be mixed with the mother liquor. If the precipitate is to be converted into superphosphate, it should be taken directly after the washing, from the precipitation vat to the pug-mixer (PI. 21). On the other hand, when it is to be sent R 2 244 PURE FERTILIZERS. into market as such, it should be heated after the last washing by means of the " blow-up^' with an aqueous solution of one or two per cent, of sulphate of ammonia, to destroy any hygroscopic tendency that may be retained through lingering traces of chloride of calcium. Finally, it must be dried on the kiln ; and then crushed to powder with the back of the shovel, or by means of Carr's disintegrator ; after which it is ready to be packed into bags for market. The quantity of alumino-ferruginous pulp which may be required will depend, not only upon its state of moisture, but also upon its chemical composition. That is, if the pulp is more oxide than phosphate, less weight will suffice for the precipitation, and vice versa. In my experience, the only prac- tical way of determining this point with precision, and quickly, is to test a small portion of the liquor, experimentally. Thus, a given volume of ten fluid ounces of the acid liquor is treated, while boiling, with the pulp, until precipitation ceases. From the weight, or even the bulk, of the DI-PHOSPHATE OF LIME. 245 pulp consumed, may be estimated, with suf- ficient accuracy, the whole quantity which the total of the liquor in the vat will require. Of course, the entire volume of liquor must have been gauged previously ; and for this purpose it will be convenient to fix a permanent measure-rod to the interior side of the containing vat. The mother liquor and wash waters com- bined are an aqueous solution of calcium, iron, and aluminium chlorides, associated with hydrochloric liquor of alumino-ferru- ginous phosphates. Possibly, there may be present, also, some traces of phosphate of lime. This latter may be wholly separated by merely adding, with caution, only that quantity of alumino-ferruginous pulp which is necessary to precipitate it. The mother liquor, then, is an admirable means for defecating town-sewage, accord- ing to the methods explained in Chapter xx. But if its burthen of aluminium and iron compounds is large, then this must be sepa- rated and sold for the profitable purposes described in Chapters xix and xxi. Owing to its pulpy condition, it will be very soluble MOHII r Ml ihfM'iiuil.uliin I'/JWillix GROUND P LAN 246 PURE FERTILIZERS. in acids, and, therefore, a much more de- sirable raw material than "Redonda Guano", " Alta Vela Guano", and kindred minerals. Moreover, it will have the great advantage of being a domestic by-product, free from the risks and expenses of importation. The only treatment necessary to separate it from the mother water is the addition of thin milk of lime until the liquor turns blue a red litmus paper. The precipitate which falls leaves above a pure solution of chloride of calcium, which is to be drawn off and utilized, as directed in Chapter xi. The precipitate, after one or two washings, with fresh waters, is to be drained or pressed in cloth, and barrelled for market. As the mother liquor, from the treatment of the first lot of mineral, will serve to furnish the pulpy precipitant by this treat- ment an indefinite number of successive times, it will be seen that only the first batch is required for an uninterrupted continuity of precipitating operations. The mother liquor will give back always the whole of the precipitant when prompted by the addi- tion of milk of lime. DI-PHOSPHATE OF LIME. 247 There will be constantly, therefore, a daily recurring quantity of this by-product for the profitable applications set forth in Chapters XIX, XX, and xxi. y. Thomas IVays Process. My knowledge of this method is little beyond that which the specification of the patentee supplies. It, however, yields a handsome product in the form of a fine white powder, which has, according to Wanklyn's analysis, the following composi- tion, per cent. Hygrometric moisture - - - 2' 18 Constitutional water _ _ _ 14-69 Sand and matters insoluble in acids - - 9*24 Sulphate of lime - - - - 2* 17 Oxides and phosphates of iron and aluminium with ) a little of magnesia _ . J Lime - - 30*62 \ ^. . , , n- ^^ o _^, , . . , > Di-phosphate of hme - 66-83 Phosphoric acid 3 3" 21 ) 99"94 "This invention relates to the production from ordinary phosphate of lime and the use for manure of a compound of lime and phos- phoric acid intermediate in composition and 248 PURE FERTILIZERS. character between ordinary insoluble phos- phate of lime and acid or soluble phosphate of lime. By ordinary phosphate of lime I mean to express the phosphate of lime ex- isting naturally in bones, bone-ash, animal charcoal, and in the usual mineral varie- ties of this substance, and by acid phosphate or soluble phosphate of lime I mean that form of readily soluble phosphate of lime which is produced by the action of sulphuric acid on ordinary phosphate of lime, and which exists in the substances usually called 'super- phosphates'. The ordinary phosphate of lime first mentioned contains three equivalents or combining proportions of lime to each equi- valent or combining proportion of phosphoric acid, and contains lime and phosphoric acid in the proportion of lime 53'9, and phosphoric acid 46" I. I shall, for sake of convenience, call this tri-phosphate of lime, in reference to the three equivalents of lime it contains. The acid phosphate or soluble phosphate of lime contains only one equivalent or combining proportion of lime to each equivalent or com- bining proportion of phosphoric acid ; I call this mono-phosphate of lime, as containing only one equivalent of lime. It contains lime and phosphoric acid in the proportion of 28 parts of lime and 72 parts of phosphoric DI-PHOSPHATE OF LIME. 249 acid. Now, the compound of lime and phos- phoric acid, which is the subject of this in- vention, contains two equivalents or com- bining proportions of lime to one equivalent or combining proportion of phosphoric acid ; I therefore call this substance di-phosphate of lime, and it contains lime and phosphoric acid in the proportion of lime 43*8 parts, and phosphoric acid 56'2 parts. This compound is known by chemists to exist, and is de- scribed in some works on chemical science ; but it has not been made for practical use, nor by any of the methods about to be de- scribed, nor has it been used or proposed for use as manure, for which I have ascertained that it is well suited. For, whereas tri-phos- phate of lime, whether in its natural state or artificially produced, is not sufficiently solu- ble in water for purposes of vegetation, and the mono-phosphate or ordinary 'super-phos- phate' is so readily soluble in water that it is liable, in some cases, to be washed out of the soil by heavy rain, and so cause a loss of a valuable and expensive product, the di-phos- phate of lime is soluble to the extent of from 15 to 25 grains only in a gallon of pure water, and to a larger extent in water containing carbonic acid ; it is, therefore, free from both the causes of objection above referred to, and 250 PURE FERTILIZERS. its use for manure will be attended with great advantage and be found to be economical. " I have ascertained that di-phosphate of lime can be produced with sufficient economy to enable it to be practically used as a manure by the methods which I proceed to describe. " I. I take any form of tri-phosphate of lime, such as bone-ash, animal charcoal, coprolites, apatite, or phosphatic guano, and, having ascertained by analysis the proportion of carbonate and phosphate of lime in it, I add to it hydrochloric acid in such quantity as shall be sufficient to dissolve the carbonate of lime and also to unite w^ith one-third part or one equivalent of the three equivalents of lime contained in the phosphate of lime, avoid- ing the use of any considerable excess of acid beyond that mentioned above. I dilute the acid before employing it with as much water as shall have been found, by previous experi- ments, necessary to enable it to be mixed in- timately with the powdered phosphate, so that every portion may be well moistened ; and, in this mixing, I employ some suitable me- chanical arrangement, such as an ordinary pug-mill, used for mixing clay. I allow the mixture to rest until I find, by treating a small portion with cold water and testing the filtered solution by ammonia or lime water, that very DI-PHOSPHATE OF LIME. 251 little phosphate of lime remains in solution. I find that a gentle temperature given to the mixture greatly promotes the production of di-phosphate; and I sometimes diy the mixed materials on hot plates or by other convenient arrangement, taking care that the heat does not exceed 250" Fahrenheit ; I then add cold water, and wash out the chloride of calcium, which is produced from the carbonate of lime and the J part of the lime of the tri-phosphate. The washed residue is the di-phosphate of lime in a state more or less pure, which I dry for use at a temperature which should not ex- ceed 240*^ or 250^ Fahrenheit. Before allow- ing the wash-water to run to waste I render it alkaline by lime, and by subsidence or fil- tration I separate and preserve the insoluble matter which will contain phosphate of lime. As a source of tri-phosphate in the foregoing process, I prefer to employ bone-ash, or ani- mal charcoal, or tri-phosphate artificially pre- pared. In carrying this process into effect the proportion of hydrochloric acid to be used will depend upon the proportions of phos- phate of lime and carbonate of lime with bone- ash, animal charcoal, or other phosphoric sub- stance or mixture of substances employed and the strength of the hydrochloric acid itself. If liquid hydrochloric acid of specific gravity 252 PURE FERTILIZERS. 1-145, and containing- about 30 per cent, of real acid, is used, it will require 240 parts by weight of such acid for each 100 parts of car- bonate of lime, and 76 parts for each 100 parts of phosphate of lime present in the sub- stance or mixture of substances to be acted upon ; for instance, supposing that the crude phosphate contains 70 per cent, of phosphate of lime and 10 per cent of carbonate of lime, the quantity of acid of 30 per cent, to be added to each 1000 lbs. of such crude phosphate will be 240 lbs. for the carbonate, and 532 for the phosphate of lime, or together, 772 lbs. ; and so on, in relation to the varying propor- tions of the phosphate and carbonate of lime in different substances treated. As before mentioned, I find that the production of di- phosphate of lime is very much assisted by the application of a gentle heat to the mix- ture ; but I am careful to regulate the tem- perature, as, otherwise, the result of the action will be to produce the ordinary tri- phosphate of lime instead of the di-phosphate. I have named 250"^ Fahrenheit as a temper- ature which is both safe and sufficient for the purpose. This amount of heat may be ob- tained by hot plates, or ovens, or other ordi- nary means. When heat is to be employed, an excess of hydrochloric acid may be used DI-PHOSPHATE OF LIME. 253 with advantage, but arrangements must be made to collect and condense the fumes of the excess of acid which will be driven off. " 2. I treat any mineral or other phos- phate with sufficient hydrochloric acid to dissolve the tri-phosphate, and to the clear solution diluted with water, if necessary, I add bone-ash, animal charcoal, precipitated tri-phosphate, or finely-ground mineral phos- phate (preferring the bone-ash, animal char- coal, or precipitated tri-phosphate) in such quantity, that the tri-phosphate added is equal to that in the solution, and then I pro- ceed to mix and wash as in the previous case. This second process is, as will be seen, a simple modification of the process first de- scribed, and the instructions given in respect thereto will, for the most part, be applicable to the second process, and are sufficient for the carrying the said process into practical effect. "3. I treat substances containing tri-phos- phate of lime with sulphuric acid in the same manner as in making ordinary super-phos- phate of lime, and I dissolve out in a small quantity of water the soluble acid mono- phosphate produced ; to this solution I add bone-ash, animal charcoal, precipitated tri- phosphate, or any mineral phosphate, in fine 254 PURE FERTILIZERS. powder (preferring the bone-ash, animal char- coal, or precipitated tri-phosphate) in such quantity, that the tri-phosphate added is equal to that in the solution. I mix these materials as in the previous case ; but, as the mixture does not contain any chloride of cal- cium, it does not require washing ; but after standing in the moist state for a sufficient time to allow of the production of the di- phosphate (and, as is ascertained by testing, as already explained in respect to the first process) it is dried, if necessary, at a tem- perature of 240"^ or 250"^ Fahrenheit for use. In some cases I prefer to treat the phosphate of lime in the first part of this process with sufficient sulphuric acid to combine with the whole of the lime and to liberate phosphoric acid. In this case I add to the solution of this acid as much bone-ash, or other sub- stance as contains twice the phosphoric acid contained in the solution. In making use of the method 3, the solution of acid phosphate or of phosphoric acid produced by the action of sulphuric acid on phosphate of lime may, if necessary, be concentrated by evaporation before mixture with the bone-ash or other material. The quantity of this solution used should be sufficient to act upon the carbonate as well as the phosphate of lime of the bone- DI-PHOSPHATE OF LIME. 255 animal charcoal, or other phosphate ; the heat employed in this case may be as high as 350'' without injury. " 4. I evaporate a solution of tri-phosphate of lime in hydrochloric acid, and heat the residue to such temperature as shall be suffi- cient to enable the mono-phosphate of lime to react upon one equivalent of the chloride of calcium present and condensing the hydro- chloric acid vapours given off, I may digest the residue with chalk or other form of car- bonate of lime to decompose any mono-phos- phate of lime which may remain, and I wash the di-phosphate produced to free it from chlo- ride of calcium, taking care to precipitate from the wash-water by lime any phosphoric acid it may contain. In carrying out this process, I dissolve the crude phosphate of lime in hy- drochloric acid diluted with the smallest pos- sible quantity of water, so as to avoid un- necessary evaporation. I dry down the solu- tion in pans or ordinary evaporating furnaces, taking care to arrange for the collection and condensation of the acid fumes which will be driven off ; the heat should not exceed 350° Fahrenheit ; otherwise, tri-phosphate of lime may be produced. The materials should be frequently stirred ; and, in order to complete the decomposition, the dry products, after re- 256 PURE FERTILIZERS. moval from the furnaces, may be powdered, mixed, and again heated. I wash the di- phosphate with or without addition of chalk, according to the amount of acid phosphate undecomposed, and dry the di-phosphate as in the previous processes. I precipitate any phosphate in the wash-water with caustic lime. " 5. I find, that when a solution of phos- phate of lime in hydrochloric acid is precipi- tated by milk of lime or lime water, as is well known, a small part of this precipitate may be produced in the state of di-phosphate, and special precautions will be necessary, as hereinafter described, to prevent the greater part being produced in the state of ordinary tri-phosphate of lime. When preparing the di-phosphate of lime in this manner, I add the lime very gradually, and stop short in the addition of lime some time before the liquid becomes alkaline ; that is to say, whilst the mixture is still strongly acid with the acid mono-phosphate of lime and remains so. After continued stirring I run off the liquor, and, having washed away the chloride of cal- cium, I dry the residue, which is the di-phos- phate. I am careful to add t6 the liquor which is run off, and to the water with which I wash away the chloride of calcium from the DI-PHOSPHATE OF LIME. 257 di-phosphatc, sufficient lime to precipitate any phosphate it may contain before discharging it to waste ; or, I add, in the first instance, sufficient lime to render the liquid alkaline. And, to precipitate all the phosphate of lime, I run off the liquid, and digest the precipitate in a fresh and strong solution of phosphate of lime in hydrochloric acid, or in a solution of acid phosphate or mono-phosphate of lime, by which the whole or greater part is con- verted into di-phosphate of lime, which I wash and dry as before. "6. In order to precipitate the di-phosphate of lime free from tri-phosphate of lime from a solution of phosphate of lime in hydrochloric acid, I use carbonate of lime in the form of chalk limestone, magnesian limestone, or mar- ble, which I digest with the solution ; I find that, in this case, no tri-phosphate of lime is produced. If an excess of chalk or other car- bonate of lime has been employed, I get rid of this by digesting the di-phosphate in a further quantity of the phosphate solution. '* In carrying out the method I use any ordinary vessel or tank, and I prefer to employ chalk in very fine powder as a preci- pitant. I agitate the solution of phosphate in hydrochloric acid with the chalk in vats furnished with revolving];- arms or beaters, as 258 PURE FERTILIZERS. is well known, till such time as I find by examination of the liquid that the greater part of the phosphate is precipitated as di- phosphate, which I then wash and dry ; or I mix the solution of phosphate with chalk in a pug-mill, and leave the mixture at rest till the decomposition is complete, when I wash out the chloride of calcium by cold water. If the hydrochloric acid has been fully neu- tralized by phosphate of lime, the quantity of chalk to be used will be about one-third that of the real phosphate of lime in the solu- tion. " It will be understood that in all cases when di-phosphate is washed to separate chloride of calcium, the wash-water should be precipitated with lime to avoid loss of phos- phate. I use the di-phosphate of lime pro- duced by either of the foregoing methods without further treatment, or after the addi- tion of a small quantity of sulphuric or other mineral acid as manure, and I also employ it in the manufacture of phosphorus. I find that the di-phosphate of lime is only soluble to a limited extent in cold water ; when the water is heated the di-phosphate is converted into mono-phosphate or acid phosphate, and tri-phosphate or insoluble phosphate, and I sometimes treat the di-phosphate in this DI-PHOSPHATE OF LIME. 259 manner for the purposes of manure or for other practical uses." Delignys Process. This process, by Ernest Deligny, of Paris, refers to the production of sesqui-basic phos- phate of lime ; and I give the description of it in a translation of that chemist's own lan- i>"uag"e : — o o '' My process relates to the production of what may be termed sesqui-basic phosphate of lime, which product is obtained from bones, mineral phosphates, or other phosphatic sources, and which is soluble in water, or in water containing carbonic acid, and it con- sists, first, in submitting tri-basic phosphate of lime, either natural or artificially prepared, to the action of acid phosphate of lime, whereby a sesqui-basic phosphate of lime is obtained ; second, in submitting to the action of heat either that product, w^hich is obtained in effecting the decomposition of bones, co- prolites, or other phosphate of lime, by micans of hydrochloric acid, or a mixture of a solution of chloride of calcium and of acid phosphate of lime, whereby the chloride of calcium is in part decomposed, and a sesqui-basic phos- S 2 26o PURE FERTILIZERS. phate of lime formed. The solid sesqui-basic phosphate of lime thus obtained is to be separated from the salts of lime contained in the supernatant solution, and after having been washed and dried may be employed for such purposes as the acid phosphate of lime is now used, or for other applications. "The reactions and operations indicated in the Specification of Letters Patent granted to Michael Henry as a communication from Ernest Deligny, and bearing date the Twenty- first of April, One thousand eight hundred and sixty-nine, No. 1224, are obtained in metallic vessels heated by an open fire, and the temperature may be raised considerably above 212" Fahrenheit by reason of the quan- tity of chloride of calcium contained in the liquids. "In practically carrying out these opera- tions, however, difficulties are encountered when a liquid is heated in which a precipitate is formed. This latter adheres to the sides of the boilers and exposes them to the risk of being burnt. This evil is so much the more serious that it becomes necessary to employ leaden boilers, iron being too easily attacked. I, therefore, propose to apply the heat by in- jecting steam into the liquid itself, which also allows of the employment of wooden DI-PIIOSPHATE OF LIME. 261 vessels. It was, however, discovered that at the boiling temperature thus produced the re- actions were modified, and that whatever was the duration of the time of heating, the crys- tallized precipitate obtained remained in the state of sesqui-phosphate of lime, which may be represented by the formula, 2CaO, HO, PO5 X 3CaO, PO5 ; or a combination of an equivalent of bi-basic phosphate, with an equivalent of tri-basic phosphate, which re- tains up to 260° Fahrenheit an equivalent of water of combination. '' This novel product is obtained in the form of a fine white brilliant crystalline pow- der of great density, which is rapidly precipi- tated from the liquid in which it is produced. It is washed with the greatest facility, and is, by that means, completely freed from the chlo- ride of calcium, and it may be easily drained and dried. The resulting product is soluble in water, or in water charged with carbonic acid. The preparation of this product is effected by attacking mineral phosphates of lime or bones with hydrochloric acid, and thus producing a concentrated solution of soluble acid, phosphate of lime, and chloride of calcium, and effecting the reaction by means of heat of the acid phosphate of lime upon chloride of calcium and the precipitation 262 PURE FERTILIZERS. of the bi-basic phosphate of lime or of the tri-basic phosphate of lime, setting, thereby, free one half or the whole of the hydrochloric acid employed for dissolving the phosphates originally operated upon. The tri-basic phos- phate, upon being heated by means of a jet of steam with the acid phosphate, is converted into a sesqui-basic phosphate, and a crystal- line deposit is formed. The reaction is more easily produced if the acid phosphate be in excess ; or the sesqui-basic phosphate of lime may be produced by adding lime to a solution of the acid phosphate of lime, and thus producing tri-basic phosphate of lime, which by reason of the presence of the acid phosphate upon the application of heat con- verted into sesqui-basic phosphate of lime. Nearly the whole of the phosphoric acid con- tained in the liquid may be thus precipitated in the form of crystalline sesqui-basic phos- phate. It is advisable, however, not to preci- pitate the whole of the phosphoric acid, as, should iron be contained in the phosphates, it would be precipitated and would injure the purity of the product. As soon as the reaction is terminated, the supernatant liquid may be poured into a separate vessel and allowed to settle, and the liquid containing the chloride of calcium be separated (which may be applied DI-PHOSPHATE OF LIME. 263 to any of its known uses). The precipitated phosphate is drained and washed, and finally dried either in the open air or in a stove, which is heated by utilizing waste heat." Chloro-Phosphate of Lime. This is a peculiar product, originated by J. Thomas Way, who claims for it the grade of a potential fertilizer. The subject has been studied with the great ability which cha- racterizes all the professional work of that chemist ; and it is due to both him and the reader, that I should give the description of the process in its author's own language, which is as follows: — '* Heretofore, it has been usual to employ in the manufacture of superphosphate of lime, oil of vitriol or sulphuric acid to render solu- ble the phosphate of lime, which it does by combining with a part of the lime forming gypsum, which is practically insoluble and remains without inconvenience in admixture with the soluble phosphate. It has not been practicable to use hydrochloric acid in place of sulphuric acid in this manner, because the mixture, if so made, would be deliquescent and unfit for the ordinary purposes of manure 264 PURE FERTILIZERS. from its containing free or uncombined chlo- ride of calcium. ** Now, this process consists of different methods of employing hydrochloric acid in conjunction with sulphuric acid in such man- ner, that an article of high quality and free from the objection above-named, is obtained more economically than by the use of sul- phuric acid alone. ''The methods to be described depend upon the production of a compound of acid or mono-phosphate of lime with chloride of cal- cium in the proportion of one equivalent of each. This salt, which I call chloro-phos- phate of lime, was discovered by myself seve- ral years ago ; it is, practically, non-deli- quescent. *' If a phosphate of lime were met with in nature consisting of one equivalent of phos- phoric acid united with two equivalents of lime, it would suffice with such a phosphate to dissolve it in hydrochloric acici and evapo- rate to dryness to obtain the salt above- mentioned. During the evaporation the phos- phoric acid would decompose one half or one equivalent of the chloride of calcium present with the escape of an equivalent of hydro- chloric acid and the formation of mono-phos- phate of lime, which would unite A\ith the I T)I-PHOSPHATE OF LIME. 265 rest of the chloride of calcium to form ' chloro-phosphate of lime'. But it so hap- pens that ordinary phosphate of lime contains three equivalents of lime to one equivalent of phosphoric acid, and a solution of this when evaporated gives an equivalent of chloride of calcium in addition to that which can com- bine with acid phosphate of lime ; this addi- tional equivalent renders the product deli- quescent and practically unfit for manure. ** Now, the object of the processes to be described is to adjust the balance between the lime and phosphoric acid, so as to reduce the chloride of calcium left in the product to one equivalent for each equivalent of phosphoric acid ; and it is manifest that this can be done by decreasing the quantity of lime or by in- creasing the proportion of phosphoric acid. " I shall shortly recapitulate the methods by which I accomplish this object. ** I dissolve mineral phosphate of lime, burnt bones, or other substances consisting principally or largely of phosphate of lime, in hydrochloric acid of any convenient strength, preferring, however, a solution of this acid of sixteen degrees Twaddle or sixteen per cent, real acid. The solution of phosphate so made, which I shall call * the liquor', I deal with in one or other of the following ways : MOHh'IT on //i,M,iiitii;i,liiiT i.rl-rinln, Generator and Vats for Precipitation by Ahhonia. 266 PURE FERTILIZERS. " And, in order to a more easy compre- hension of the subject, I will, in the first in- stance, suppose that the liquor contains phos- phoric acid and lime in the proportion of one equivalent or combining proportion of the former to three equivalents or combining pro- portions of the latter. Where carbonate of lime has existed in the mineral or other phos- phate of lime the proportion of lime will be greater than this ; but to this I will after- wards refer. '* The following are methods of reducing the proportion of lime so as to produce chloro- phosphate of lime as the product : *'A. Adding sulphuric acid to 'the liquor', separating by filtration the sulphate of lime produced, and evaporating to dryness. " B. Adding sulphuric acid as in A, and evaporating the whole to dryness without separation of the sulphate of lime. " C. Evaporating the liquor to dryness, mixing the product with sulphuric acid, and drying up the mixture by heat. " The product in A is ' chloro-phosphate of lime', with some insoluble phosphate produced in the evaporation. *Tn B and C the chloro-phosphate is mixed with sulphate of lime. " D. Evaporating the liquor till crystals of DI-PHOSPHATE OF LIME. 267 chloro-phosphate form, separating the crystals and adding to them sulphuric acid to decom- pose the adhering chloride of calcium, and drying up the mixture or dissolving the crys- tals and recrystallizing. "In all these processes sulphate of soda may be substituted for sulphuric acid, but at an increase of cost and a diminution in the quality of the product. " By all of the above methods a portion of the base is either rendered insoluble or re- moved. " The methods of increasing the quantity of phosphoric acid in lieu of diminishing the quantity of base consist in substituting for the sulphuric acid phosphoric acid or acid phosphate of lime in the processes above set forth ; the whole of the base is thus converted into chloro-phosphate. Without dissolving the phosphate of lime, in the first instance, in hydrochloric acid, I sometimes add to pow- dered phosphate of lime sulphuric and hy- drochloric acid in such proportions as to form sulphate of lime and chloro-phosphate of lime, and I dry up the products for use. " Having thus recapitulated the processes which form the subject of the present patent, and each of which may in particular circum- stances possess advantages, I proceed to dc- 268 PURE FERTILIZERS. scribe more particularly the way in which they should be carried out. ** Process A. — I take any convenient quan- tity of the ' liquor' prepared in the manner already described, and having ascertained by chemical analysis how much phosphoric acid and lime it contains, I add to it such quan- tity of oil of vitriol, ' brown acid', or other form of sulphuric acid, as shall be sufficient to unite with one-third of the lime present in ' the liquor'. For instance, I take one hundred gallons of the liquor, and having found that this quantity contains seventy-one pounds of phosphoric acid and eighty-four pounds of lime (which are the chemical equi- valents in pounds in tri-phosphate of lime) I add forty-nine pounds (or one equivalent in pounds) of oil of vitriol, or a corresponding quantity of ' brown acid', this quantity being capable of uniting with twenty-eight pounds or one third of the lime present. I mix the sulphuric acid and the liquor by agitation, and by means of filtration through cloth or otherwise I separate the sulphate of lime, which has been produced by the addition of the sulphuric acid, which sulphate of lime I wash by successive quantities of water. The solution so obtained and the washings con- tain the phosphoric acid and two-thirds of DI-PIIOSPHATE OF LIME. 269 the lime originally present in the liquor. I evaporate these liquids in a reverberatory furnace or other convenient arrangement to a thick paste, collecting and condensing the vapours of hydrochloric acid which are given off during the process, and I further dry it up by steam or other heat, avoiding a tempera- ture much above two hundred and twelve degrees Fahrenheit. " I would remark that whilst it is necessary that the quantity of sulphuric acid should not be less than that above inclicated,a larger quan- tity is not objectionable (except on the ground of unnecessary expense), provided that it does not exceed twice the above amount. "When the liquor, as is frequently the case, contains more than 84 parts of lime to 71 parts of phosphoric acid, I use an addi- tional quantity of sulphuric acid, for such excess, in the proportion of 49 lbs. of oil of vitriol (or a corresponding quantity of ' brown acid' or other strength of sulphuric acid, for every such additional 28 lbs. present. For instance, supposing that in 100 gallons of liquor containing 71 lbs. of phosphoric acid I find 98 lbs. of lime instead of 84 lbs., then, in addition to 49 lbs. of oil of vitriol, as in the previous instance, I require to use 241 more to deal with the excess of 14 lbs. of lime pre- sent in the liquor. 270 PURE FERTILIZERS. " Practically it is generally known without chemical analysis what the nature of the liquor is by that of the raw phosphate from which it was produced, and the sulphuric acid necessary may readily be calculated. " In the final evaporation or drying up of the product I prefer to keep the temperature as little above 212"^ Fahrenheit as may be. Nevertheless the product is not destroyed at a temperature of 280" or 300° Fahrenheit, but at such temperature a larger proportion of the soluble phosphate becomes insoluble. " Process B. — This method is carried out essentially as in the case of A, with the ex- ception that the sulphate of lime remains in the product, which is not therefore of such high quality as regards per-centage of soluble phosphate as in the other process. ** Process C. — In this process I evaporate the liquor without addition of sulphuric acid, and the drying may with advantage be effected at a higher temperature than in A and B, namely, at 300° Fahrenheit, or even higher. With the dry product I mix sul- phuric acid by suitable mechanical means, subsequently heating the mixture to 2 12" or thereabouts to expel hydrochloric acid. The quantity of sulphuric acid to be used in this case can be calculated in the same way as DI-PHOSPHATE OF LIME. 271 in processes A and B, the calculation being based on the quantity of liquor evaporated, or the dry residue may be examined for the pro- portion of phosphoric acid and lime con- tained in it, and the sulphuric acid calculated as in the other cases. " D. — This process somewhat differs from that before described, inasmuch as the chloro- phosphate of lime is removed from the excess of chloride of calcium in great part by crystal- lization instead of the excess of chloride of calcium being separated from the chloro- phosphate entirely by chemical agency. I evaporate ' the liquor till it begins to show signs of crystallization. I allow it to cool, and I separate the crystals from the mother- liquor by drainage and pressure. *' I ascertain the quantity of chloride of calcium present in the crystals over and above the proper quantity to form chloro-phosphate, and I add an equivalent of sulphuric acid, or acid phosphate of lime, or half an equivalent of phosphoric acid for each equivalent of chloride of calcium in excess, and dry up the product at 212° Fahrenheit, or thereabouts, or I add the sulphuric acid in any additional quantity up to such quantity as is sufficient to decompose the whole chloride of calcium present, driving off the hydrochloric acid by 272 PVRE FERTILIZERS. heat, but in this case the product is no longer chloro-phosphate of lime, but a mixture of acid phosphate of lime and sulphate of lime, similar to that made by decomposing di- phosphate of lime by sulphuric acid. ** In dealing with the licjuor for crystalliza- tion, as now described, I sometimes add be- fore evaporation lime or chalk to neutralize free acid, by which the liberation of hydro- chloric acid fumes is avoided. The chalk or lime is added so long as it dissolves in the liquor. " When dealing with the liquor by increas- ing the proportion of phosphoric acid in re- lation to the lime, I obtain the acid phosphate of lime for the purpose from ordinary super- phosphate of lime, made by the action of sul- phuric acid on phosphate of lime. The phos- phoric acid is obtained by using an additional equivalent of sulphuric acid in excess of that employed in the manufacture of superphos- phate of lime. " I will give an example. I take lOO gallons of liquor, in which I will suppose, as before, that the relation of the lime to the phos- phoric acid is as three to one in equivalents, and that the lOO gallons contain 71 lbs. of phosphoric acid and 84 lbs. of lime. To this I add so much of acid phosphate of lime as DI-rilOSPlIATE OF LIME. 273 will contain 71 lbs. or an equivalent in pounds of phosphoric acid, that being the quantity of phosphoric acid in the state of acid phosphate of lime which will combine with the equiva- lent of chloride, of calcium in excess, or I add so much of a solution of phosphoric acid as will contain 35^ lbs., or half an equivalent in pounds of phosphoric acid, that being the quantity of uncombined phosphoric acid which will convert the chloride of calcium into chloro- phosphate. I evaporate the solution to dry- ness, as before. The product being, practi- cally, chloro-phosphate of lime, if the liquor contains an excess of lime beyond the three equivalents, I increase the quantity of acid phosphate or of phosphoric acid accordingl}^, in the manner described, in using sulphuric acid. Instead of using solutions of phospho- ric acid or acid phosphate, I sometimes em- ploy the superphosphate itself, and mix it directly with the liquor, but in that case the product is of lower quality. "It is also evident that the two processes of reducing the proportion of lime by sul- phuric acid, etc., or increasing the proportion of phosphoric acid by its addition or that of acid phosphate of lime, may be practised con- jointly, if any advantage is derivable from such a plan. 274 PURE PER TIL IZER S. "When I treat the raw insoluble phosphate without, in the first instance, preparing a liquor by dissolving it in hydrochloric acid, I proceed as follows : I take powdered mineral or other phosphate, and, having ascertained the proportion of tri-phosphate of lime and of carbonate of lime in it, I calculate, first, what quantity of sulphuric acid is necessary to de- compose the carbonate of lime, and what quantity will be required to unite with one out of every three parts of the lime present as phosphate. I also calculate how much hydro- chloric acid is necessary to unite with an equal quantity of lime. For instance, if the raw phosphate to be used contains 70 per cent, of tri-phosphate of lime and 10 per cent, of carbonate of lime, 221 lbs. will contain 71 lbs. or one equivalent in pounds of phos- phoric acid and 22' i lbs. of carbonate of lime. For this quantity of carbonate of lime I shall require 217 lbs. of oil of vitriol, and for a third part or one equivalent of the lime 49 lbs. of oil of vitriol, or in all about 71 lbs., whilst of hydrochloric acid of 30^ Twaddle or 30 per cent. I shall require 119 lbs. ; that being the quantity of acid of this strength which con- tains one equivalent in pounds or 36 lbs. of real hydrochloric acid. " I mix the raw phosphate with the acids DI-PHOSPHATE OF LIME, 275 by any convenient mechanical arrangement, and allow the mixture to lie for a time for completion of the chemical action, if neces- sary. I finally dry the product on hot floors or otherwise, at a heat not much exceeding 212° Fahrenheit. From this product, which is a mixture of chloro-phosphate of lime with sulphate of lime and the impurities of the raw phosphate, I may obtain the chloro-phos- phate by treatment with water and evapora- tion of the solution. " In the foregoing description I have pro- vided for the giving off of hydrochloric va- pours during evaporation of the liquors ; this acid would be condensed in the usual way practised in alkali works. But by a modifi- cation of the process such production of hy- drochloric acid can be avoided when desirable. When mineral phosphate of lime is dissolved in hydrochloric acid, the liquor is usually a mixture of free phosphoric acid with chloride of calcium, but prolonged contact with the phosphate causes this phosphoric acid to pass into the state of acid phosphate of lime by solution of a further quantity of phosphate of lime, and in this state the liquor will consist of one equivalent of acid phosphate of lime mixed with two equivalents of chloride of calcium. If to this liquor acid phosphate of T 2 276 PURE FERTILIZERS. lime from ordinary superphosphate of lime (or the superphosphate itself) is added in proper quantity (that is to say, one equivalent for each equivalent of chloride of calcium in ex- cess), and the liquor evaporated, chloro-phos- phate of lime will be produced without the formation or escape of hydrochloric acid. The same result will be obtained if to a liquor of the composition described sulphate of soda is added, and the sulphate of lime produced may either be separated before evaporation or may form part of the final product. The chloro-phosphate of lime, manufactured as above described, is valuable for use as manure either alone or mixed with other substances, or it may be used in the arts as a source of phosphoric acid. " I would have it understood that I claim the manufacture of soluble phosphate of lime in the state of chloro-phosphate (either for use as such, or for further treatment) by act- ing on the insoluble or natural phosphate with hydrochloric acid, preventing the preponder- ance of chloride of calcium by converting a portion of the base into sulphate or by the addition of a further quantity of phosphoric acid or acid phosphate of lime." CHAPTER XL THE MOTHER- LIQUOR OR WASH, AND THE MODE OF RECLAIMING ITS MATERIALS. In all of the preceding processes for obtain- ing the phosphate of lime by precipitation from its solution in hydrochloric acid, the mother-water is either wholly or partly an aqueous liquor of chloride of calcium. The almost invariable presence of carbonate or organate of lime in crude phosphate of lime makes this an absolute case, whether the pre- cipitant may be lime, carbonate of lime, am- monia, iron or aluminium oxide or phos- phate. Puye Chloride of Calcium. In the preparation of the phosphate of lime by ammonia, as described in Chapter viii, the preliminary treatment, with a limited portion of hydrochloric acid, is to restrict the 278 PURE FERTILIZERS. action of the latter to the carbonate and or- ganate of lime constituents of the crude phosphate. The liquor thus formed, how- ever, will contain also some little of phos- phate of lime, together with larger or smaller traces of alumina and oxide of iron, if the acid and the heat of digestion are strong. This trace of phosphate having been re- claimed by precipitating with milk of lime, which also frees the liquor of alumina and oxide of iron, the mother-liquor is then a pure aqueous solution of chloride of calcium. It is only necessary, therefore, to evaporate the liquor to dryness, or to such a dense state that it will solidify on cooling, in order to convert it into a saleable commercial article. It is generally packed in sheet-iron barrels or drums, holding each about four hundred weight. Owing to its pure state, it is well adapted for the manufacture of artificial stone by Ransome's process. Again, in the processes of Chapters ix and X, for making the Colombian and di-phos- phates of lime, the final mother-liquor is wholly an aqueous solution of chloride of calcium in a state of purity, and only re- THE MOTHER-LIQUOR OR WASH. 279 quires to be solidified by evaporation, in order to become a saleable and profitable article of commerce. Being thus made largely and as a by- product, it can be sold at a price which will render it independent of all competition. I have now in progress, with the co-opera- tion of Dr. B. W. Gerland, a course of practi- cal experiments for reclaiming the hydrochlo- ric acid by the concurrent action of a stream of sulphurous acid and blasts of steam and air in the chloride of calcium mother-liquor. This should form sulphate of lime and set free the hydrochloric acid, to be used over and over again an indefinite number of times for digesting the raw mineral, and thus adapt the process to those remote regions, inaccessible to acids, which contain deposits of mineral phosphate, pyrites, and sulphuret- ted ores. In the roasting of the latter, sul- phurous acid would be generated abundantly, so that a manufactory of refined phosphates could be thus established upon a single in- augural batch of hydrochloric acid. When the mother-liquor is chiefly a solu- tion of iron and aluminium compounds, it is 28o PURE FERTILIZERS. probable that it might be made to give up its hydrochloric acid, in a free state, by the action alone of superheated steam. Sulphate of Animofiia as the Economiser. As a certain amount of ammoniacal salt will be required for the composition of special fertilizers, a portion of the wash-liquor may be used advantageously for converting sul- phate of ammonia into chloride of ammo- nium, the latter being preferable in that con- nection. Not only is there a small money profit by the transformation, but a gain of bulk, for the equivalent relation of the base ammonia in the chloride is much higher than in the sulphate ; and much less of the weight of the former will correspond in nitrogen value with a much larger weight of the latter. For this purpose, the wash-liquor is to be run into a clean wooden vat, constructed as described at p. 127, and shown by Plate 11. Having been brought to 212^ Fahrenheit, a dense aqueous solution of sulphate of ammo- nia is then to be poured in during constant THE MOTHER-LIQUOR OR WASH. 2ai ag-itation and heating by the currents of steam. A double exchange of bases takes place, white hydrated sulphate of lime precipitates, and chloride of ammonium forms in solution. Repose being allowed, the solution rises to the top as supernatant liquor, and then is to be drawn off clear, through the cocks, into the evaporating pans (Plate 13). To the deposit is now to be added some fresh w^ater from the hydrant, and the whole boiled and allowed to settle as before. The clear wash-water is to be drawn off into the evaporating pan as was the strong liquor just previously. This washing is to be repeated with a second relay of fresh water in the same manner. The de- posit is then wholly or nearly free of all am- monium salt and is to be run off into large shallow troughs placed under an open shed, where it is left to dry spontaneously. When dried, it will be a valuable substitute for ground plaster in agriculture. A portion of it will be needed for drying the bi-phosphate of lime, as explained in a subsequent chapter. In the meantime, the liquor and its two wash-waters in the evaporating pan must be 282 PURE FERTILIZERS. undergoing concentration by heat to a dense solution. When it reaches the crystallizing point, the heat is to be stopped. On cooling, it will form a solid saline cake of chloride of ammonium, which can be broken up and packed in barrels for market. The expense of a separate vat for making the aqueous solution of alkaline sulphate may be saved by putting the requisite quan- tity of ammonium sulphate in the precipi- tating vat, and dissolving it there previously to the entrance of the wash-liqiwr. Then, by stirring as the wash-liquor enters, the de- composition will take place, as has just been explained. The currents of steam from the heating-pipes produce the necessary agitation and intermixture. Sulphate of potassa may be used in a simi- lar manner to re-place the ammonium sul- phate whenever it is desired to produce chlo- ride of potassium. I distinguish by the name of economisers those agents which are employed to reclaim the wash-liquor, because they convert the latter into valuable products by saving the cost of the hydrochloric acid and improving, THE MOTHER-LIQUOR OR IV A SIT 283 otherwise, the general advantages of the fer- tilizer. If sulphate of ammonia is the economiser, the necessary proportion of it is i -32 pounds for every per cent, or pound of carbonate of lime in the original raw mineral. This will produce I'oj pounds of chloride of ammo- nium and 172 pounds of hydrated sulphate of lime. In other words, every pound of sul- phate of ammonia will react upon the wash- liquor to produce o'8o pound of chloride of ammonium and i '30 pounds of hydrated sul- phate of lime. Sulphate of Pot ass a as the Economiser. If sulphate of potassa should be used as the economiser, the proportion required is 174 pounds for each per cent, or pound of carbonate of lime in the original raw mineral. The products from these ratios will be i'49 of chloride of potassium and 1 72 of hydrated sulphate of lime. That is, every pound of sulphate of potassa employed in decomposing the wash-liquor of chloride of calcium will yield o"856 lb. of chloride of potassium and 0-988 lb. of hydrated sulphate of lime. 284 PURE FERTILIZERS. A Mixture of Sulphates of AmmoHia and Potassa as the Economiser. A mixture of potassa and ammonia sul- phates may be apportioned from those data when it is desired to produce the mixture of those bases. To this end, one pound of sul- phate of potassa is equivalent to 0758 pound of sulphate of ammonia. On the other hand, one pound of sulphate of ammonia corre- sponds with 1*32 pounds of sulphate of po- tassa. When the decomposition of the wash is to be made by a mixture of these sulphates, the manipulations are the same as has been ex- plained for them severally. Crude Ammonia Liquor as the Economiser. The economiser may be crude ammonia liquor in place of sulphate of ammonia ; but then the lime is precipitated as carbonate with some little sulphate. The ammonia product, however, will be chloride, and in slightly greater quantity than from sulphate of ammonia as the economiser. This slight excess arises from the fact that gas-liquor THE MOTHER-LIQUOR OR WASH. 285 contains some chloride and other salts than the carbonate, which does the precipitation. These not being affected by the chemical action in the vat, evaporate to crystalline mass with the newly-formed chloride, when the liquor is put into the concentrating pan. The quantity required for decomposing the chloride of calcium or ivash-liquor will depend upon the strength of the gas-liquor. Assuming that it contains the usual average of o"47 per cent, of dry ammonia gas, then, for every hundred pounds of hydrochloric acid of specific gravity riy contained in the wash-liquor, there will be needed six hundred pounds of gas or crude ammonia liquor, with about twenty-five pounds addi- tional for contingencies. Owing to the presence of sulphate of am- monia, invariably, in the gas-liquor, the car- bonate of lime precipitate will ahvays contain more or less of sulphate of lime. The quan- tity of this precipitate cannot be precisely stated, on account of the variability in the composition of gas-liquor. If there is any iron present as impurity, it will give a greyish-blue colour to the precipitate, be- Details of the Precipitation Vat & Ammonia Generator Tnllma* CV,6(j.Palf'il..N i=:^r;r^:'::.c tm. 286 PURE FERTILIZERS. cause of the formation of sulphuret of iron with the sulphur of the gas liquor. Precautions must be observed to protect the workmen against the evolution of in- jurious sulphuretted vapour when gas-liquor is used. This is done by adding some chlo- ride of iron to the wash-liquor, in order to precipitate the sulphuret, avoiding the use of steam, and substituting mechanical stirring. In this case, small samples of the liquor must be drawn from the vat through try- cocks, and tested from time to time, to deter- mine when enough of gas-liquor has been added. This will be known when a further addition ceases to throw down a precipitate. The great profit afforded by the use of gas- liquor as the economiser renders it expedient to prefer that material to all the others, when a necessary supply can be obtained conve- niently. The abundant supply of chloride of cal- cium, as a cheap by-product in these pro- cesses, affords a convenient and profitable means of reclaiming from waste, as ammonia salt, the liquor of all of those gas-works which arc now inaccessible to sulphuric or THE MOTHER-LIQUOR OR WASH 287 hydrochloric acids. Being solid and heavy, it is indeed a most advantageous substitute for the latter in this connection, not only on account of its better transportation condi- tions, but for other good practical reasons. This "mother-liquor" may be utilized, also, by passing through it concurrent streams of gaseous ammonia and carbonic acid. Car- bonate of lime precipitates, and chloride of ammonium rests above as a clear liquor, to be evaporated to crystals or dryness for market. The precipitate, on being pressed and cal- cined, will give quick-lime, and at the same time reproduce its carbonic acid for subse- quent operations. Phosphate of Soda as the Econoniiser. Townsend's method of converting Redonda Guano into phosphate of soda (Chapter 20) gives a most advantageous liquor for convert- ing this " mother-liquor" into pure phosphate of lime and table-salt. By mere intermixture of the two liquors, the phosphate of lime pre- cipitates, and chloride of sodium remains in solution, to be drawn off and evaporated to dryness for market. CHAPTER XII, ON THE PRINCIPLES OF THE SUPER- PHOSPHATING PROCESSES. In the manufacture of " commercial super- phosphate" by the direct action of sulphuric acid upon crude phosphate of lime, it is ex- pedient to select that kind of the latter mate- rial which is most free from carbonate of lime, fluoride of calcium, iron and aluminium compounds, and sand or silica. The reasons are obvious ; for, phosphate of lime being the only constituent required, all of its usual associates are foreign to the pro- cess of conversion. Thus sand is a valueless component, and would dilute the product disadvantageously. Carbonate and organate of lime, oxides of iron and aluminium, are not only diluents of the product, but they in- vest it with a permanent tendency to damp- ness. Moreover, they waste both time and SUPERPIIOSPHATING PROCESSES. 289 acid ; being, in fact, barriers to the action of the sulphuric acid upon the tri-phosphate of lime constituent, for this last remains intact until they have been overcome chemically. I term them, therefore, profligate elements or associates. The decomposition of tri-phosphate of lime into bi-phosphate has been explained already in full, and by diagram at p. 73, Chapter in. It has been there shown, that a very large proportion of hydrated sulphate of lime is the inevitable accompaniment of the chemi- cal treatment of the first for conversion into superphosphate. So much is this sulphate in excess of the bi-phosphate, that even though the tri-phosphate under operation might be absolutely pure, it would not be possible to make it yield a product of better bi-phosphate strength than the following composition per cent. : — (i) Bi-phosphate of lime (CaO, 2 HO, POj) - 40-69 Hydrated sulphate of lime (CaO, SO3, 2HO) - 59-31 loo-oo But in Nature, the instances of a pure u 290 PURE FERTILIZERS. phosphate of lime are very rare, and on such a small scale, that they suffice only as cabi- net specimens. The highest grades known are the phosphorite of Spain and certain apatites of Canada. These contain as much as ninety per cent, of phosphate of lime, when selected or so screened that the richer masses may be separated from the poorer. This culling operation shows, however, that the inferior parts form so nearly the whole amount of the mineral as to render those sources, of a very rich material for super- phosphating purposes, very narrow indeed. They could not be depended upon for a supply of any greater uniform average rich- ness than seventy per cent., even were they conveniently situated for mining and trans- porting the product. Of all the raw stocks available for the manufacture of superphosphate, bone-ash is the most advantageous. This contains, on an average, seventy per cent, of tri-phosphate of lime, ten per cent, of carbonate of lime, and twenty per cent, of other, profligate con- stituents. The supply, though considerable, is very largely inadequate. Moreover, it SUPERPIIOSPHATING PROCESSES. 291 may bo applied directly to the soil without any preliminary treatment, as it is sufficiently active in its natural state for enriching the soil, and thus commands a price quite too high for this manufacture. Under the circumstances, then, which I have noted, the main reliance of the manu- facturer of superphosphate for his raw basis material is, and must continue to be, copro- lites, marlstones, and the so-called " Rock Guanos". The regular and abundant supply of these materials is no unimportant consideration in their favour. But, as the best do not average uniformly more than 60 to 65 per cent, of phosphate of lime constituents, and may fall as low as 40 per cent, in that element, it follows naturally that even under the first conditions there is a large ratio of profligate elements to dilute and deteriorate the super- phosphate product. For similar reason, the lower grades yield a product in which the superphosphate holds the low^est quantitative rank of all the com- ponents. These remarks refer to the usual methods of superphosphating, by mixing the u 2 292 PURE FERTILIZERS. powdered mineral phosphate of lime with dilute oil of vitriol, allowing it to dry and then powdering it. Assuming that no earth, ground plaster, or other material has been added to promote the drying of the product, and also that bone-ash or the best available " Rock Guano" has been employed as the basis material, then, with the most careful manipulation, it is not possible to produce a " superphosphate" of greater percentage strength than is expressed by the following analytical table : — (2) Bi-phosphate of lime (CaO, 2HO, PO5) - 32-00 Hydrated sulphate of lime (CaO, SO3, 2HO) - 5800 Undesirable forei^^n matters - - 1000 Total . , _ loooo Most generally, however, a more abundant material is employed, such as coprolites or marlstones, and these cannot be relied on for a higher uniform average of tri-phosphate of lime than 52 to 55 per cent. They contain, moreover, 12 to 15 per cent, of carbonate of lime. Hence, the product which represents the most of the superphosphate in the market SUPERPHOSPHATING PROCESSES. 293 can have, at best, only the impoverished composition, per cent., shown by the follow- ing table : — (3) Bi-phosphate of lime (CaO, 2 HO, POJ - 26-50 Hydrated sulphate of lime (CaO, SO3, 2 HO) - 54"5o Foreign and undesirable matters - - 1900 1 0000 I have assumed in these calculations that no excess of acid or water has been used to prevent the ''going back'' of the bi-phos- phate into an insoluble form or to add weight ; that no foreign matter has been mixed in to promote the drying of the pro- duct ; and that the manipulations have been skilful throughout, so as to assure a per- fect conversion of the whole of the tri-phos- phate element into soluble bi-phosphate. I have also excluded from consideration all fluoride of calcium, which is generally present in mineral phosphates of lime to an extent varying from one to ten per cent., and would reduce, consequently, the ratio of bi-phos- phate in the product by raising that of the sulphate. I do this to give to the usual pro- 294 PURE FERTILIZERS. cess and its products the most favourable ex- position that is possible. Yet, with all these concessions, its defects show forth most glaringly to reproach the manufacturer and to awaken the suspicion of the farmer or planter. It rarely happens that a superphosphate reaches the planter in such a pure state. It is most generally degraded either through fradulent design or unscientific and careless manipulation, to such an extent that com- mercial samples seldom answer to a higher test than twenty per cent., and often fall as low as fifteen to ten per cent, of bi-phosphate. These figures refer to actual bi-phosphate (CaO, 2 HO, PO5), and not to their equivalent in tri-phosphate (sCaO, PO5). I make this explanation because it is the custom in the English market to offer and sell *' super- phosphate" upon this false expression of its real strength. When it is remembered that I '00 of tri-phosphate of lime represents only 075 of soluble bi-phosphate, it becomes ap- parent, at once, that this deception is large in measure and unjustifiable. Evidence could not be more conclusive SUPERPHOSP HATING PROCESSES. 295 than that which has been just noted against the defects of the methods in general use for making " superphosphate". It proves them to be alike discreditable to the manufacturer and unfair to his customers. Even supposing that the commercial product is always free from any designed or unintentional adultera- tion, and has uniformly the composition of the exemplar (3) on page 293, it is still an imposition, to a large extent, upon the credu- lity and confidence of the planter. Fertilizers are manufactured almost always in great commercial centres, and the custom- ers for them live often in distant parts not unfrequently remote from convenient chan- nels of transportation ; consequently the pack- age and freight charges upon a manure be- come important items for consideration. Sulphate of lime is a material common to every locality at trifling cost, and silica, sand, alumina, and oxide of iron are natural parts of every soil. Yet these form at least three- fourths of the " commercial superphosphate" in question ; and the purchaser of every hundred pounds is compelled to pay for the packing and transportation of all that larger 296 PURE FERTILIZERS. worthless portion, in order to obtain the 20 to 25 per cent, of valuable bi-phosphate. To remove these great defects and to im- prove the advantages of the " superphos- phate " to both producer and planter, I worked out upon a scientific basis the prac- tical methods, described minutely in Chap- ters XIII and XIV. In my earlier efforts towards the construc- tion of these processes, I cleared away first only the carbonate of lime from the raw rhineral by means of hydrochloric acid. This preliminary treatment, however, while it re- duced very materially the bulk and weight of the diluting influence, still left in the residue all of the sand, most of the organic matter, and much of the iron and aluminium com- pounds. Consequently, when sulphuric acid was added, subsequently, to convert the phosphate of lime constituent, it became not only more or less wasted, but caused a ten- dency to dampness in the resulting super- phosphate. Moreover, although the product was of very much higher quality than could be made from the mineral in its original crude SUP ERPHOSP HATING PROCESSES. 297 state, it retained a large enough proportion of foreign matters to keep down its character to that of '' commercial superphosphate". These circumstances led then to the plan of treating the mineral phosphate with hy- drochloric acid and certain precipitants, so as to eliminate all the profligate elements. The cheap hydrochloric acid is made to do well the dirty work that is generally done badly by sulphuric acid ; and a pure tri- or di-phosphate of lime basis or " superphos- phate" is evolved by self-compensating means, from even inferior mineral ; so that all the subsequent operations of conversion are thus simplified and rendered economical to the utmost degree. CHAPTER XIII, ON THE MANUFACTURE OF PURE SUPER- PHOSPHATE" OF LIME. Thp: precipitated phosphates or the Colom- bian phosphate of Chapters vni, lx, and x, arc to be employed as the basis material. The use of either one of them simplifies the manipulation to the utmost, and reduces the expense of labour, time, and acid to the most economical degree. At the same time, the product is eminently superior both in quality and appearance. To convert it into *' superphosphate", it is only necessary to pass the well-washed precipitate through a mixing mill with the requisite proportion of sulphuric acid, and to lead the mixture into an enclosure where it may remain to ripen and dry. For this pur- pose, the precipitate in its wet pulpy state may be made to fall directly from the vat SUPERPHOSPHATE OF LIME. 299 into the pug-mixer (Plate 21), by means of an inclined gutter or shoot, a stream of acid being arranged to enter at the same time into the hopper of the mill while the latter is in operation. The pulpy mass and acid are made thus to mingle thoroughly. The enclosures into which the mixture is received are simply vats of mason-work, as presented by Plate 24. When the mass has remained in these enclosures several days it will have set hard into pure " superphos- phate", which is a mixture of bi-phosphate and sulphate of lime, and contains, in this instance, more of the former than can be pro- duced from any other known material. Every ro of dry tri-phosphate of lime re- quires o'8i of brown oil of vitriol for its con- version into, soluble bi-phosphate. No re- gard need be paid to the small amount of di-phosphate which is present in the pulp ; for, although this requires less acid than the tri-phosphate, there are always some iron and alumina associates to make a compensation- balance in this connection. When the "superphosphate" has become dry it is to be shovelled out, dashed to 30D PURE FERTILIZERS. granular powder by means of one of Carr's Disintegrators, and packed in bags for market. The pure state of this pulpy phosphate, and its loose texture, manifest their great advantage throughout this treatment. The composition of the product will be approximately as follows per cent. : — Soluble bi-phosphate of lime - - 39'00 Hydrated sulphate of lime - - SS'OO Water - - - - roo Sand and silica - - - "50 Iron and aluminium oxides and phosphates - 4*50 1 00*00 Its content of soluble bi-phosphate is equi- valent to 5 roo of pure tri-phosphate of lime. If the phosphate basis has been precipi- tated with due care, it will be free from iron and aluminium compounds and produce an equally pure superphosphate. Indeed, the di-phosphate, as made by my processes, can only contain those impurities by accident ; and, for that reason, and because it re- quires only half of the usual quantity of SUPERPHOSPHATE OF LIME. 301 oil of vitriol for its conversion, it is a prime basis-material for " superphosphate", in every sense. Assuming that the di-phosphate of lime is pure and de-hydrated, then every 100 lbs. will require 50 lbs. of brown oil of vitriol, with some water of dilution ; and form 160 lbs. of pure "superphosphate", having the following composition, approximately, per cent. : — Soluble bi-phosphate of lime (CaO, 2HO, PO^) 57'00 Hydrated sulphate of lime (CaO, SO3 2HO) - 41 00 Water, accidental . _ _ i-oo Sand and silica _ . . i-qo Iron and aluminium oxides and phosphates - traces 1 0000 The manipulations are the same as have just been described, and the product, which is white, sets and dries very promptly. Its content of soluble bi-phosphate is equiva- lent to 75 per cent, of pure tri-phosphate of lime. Owing to the concentrated nature of di- phosphate of lime and its great, potentiality as a fertilizer, it is eminentl}^ suitable for ?o2 PURE FERTILIZERS. direct application to the soil ; and I have mentioned it as a basis-material for pure superphosphate, rather as an item of instruc- tion than with a view to recommend its use in that connection. It is almost too valuable for that purpose. CHAPTER XIV. ON THE MANUFACTURE OF PURE AND WHOLLY SOLUBLE BI-PHOSPHATE OF LIME. The basis-material for this product is either the precipitated or Colombian phosphate of Chapters vni, ix, and x. It is to be taken in its wet pulpy state, after a good washing, directly from the precipitation vat, and led through a shoot to a broad box at the bottom of the elevator (Plates 5, 6, and 7), instead of into the pug-mixer (Plate 21), as was just pre- viously directed for the manufacture of pure ** superphosphate". In this instance, also, a weaker acid than the brown oil of vitriol may be used, as the resulting superphosphate need not be dry for the subsequent operation. Indeed, a certain amount of fluidity is even desirable. The chamber acid of i'45o will answer. This contains, in one hundred parts by weight, 304 PURE FERTILIZERS. 57*o oil of vitriol (SO3, HO) of specific gravity r845, or 46"48 (SO^) of dry sulphuric acid. The use of this weak acid will be a great economy when the manure factory has a sulphuric acid work annexed, for all the expense of concentrating it by evaporation to commercial strength for exportation is thus saved. The sulphuric acid is to be raised to the reservoir v (Plates 5 and 6), near the mixer b (Plates 5, 6, and 7), by means of the lift u. It may be delivered, also, to the mixer direct from a reservoir below, by means of a leaden pump, with the mouth of its delivery-tubes so adjusted as to let drop the acid in as gradual flow as may be required. Every pound of dry tri-phosphate of lime requires 51*28 pounds of dry sulphuric acid (SO3) for its decomposition, and this propor- tion is represented by rii pounds of the dilute acid of specific gravity r45o. The mass of pulpy phosphate having been brought by a gutter from the precipitation vat to the base of the elevator, is then to be carried up the belt and cups a a n n (Plates 5 and 6) to the mixer. As the pulp falls into BI-PHOSPHATE OF LIME. 305 the mixer a stream of acid should enter, so that the two may meet. Chemical action be- gins at once, and the decomposition of the phosphate goes on and becomes complete when the mass, after having fallen into the cylindrical vat (figs, i, 2, 3, 4, Plate 22) be- neath, is stirred and heated at short inter- vals, during ten or twelve hours. If the contents of the vat should tend to stiffen, they must be thinned by the addition of water, for a certain fluidity is necessary. Without it the motion of the stirrer would be difficult, and the decomposition of the tri-phosphate might not be thorough. The mass consists, now, of liquid bi-phos- phate of lime holding a little sulphate in aqueous solution, and a solid which is wholly hydrated sulphate of lime. By repose, the latter will settle with most of the former resting upon it as a clear supernatant liquor. This liquor is to be drawn off through the cocks of the vat, or by means of a syphon, into the basin portion of the kiln. However, as the mass retains yet a con- siderable portion of liquor, it must be washed X MORFIT on ihe ManiifatUuv orFenHhn \ Ground Line Details of Plant for Precipitation and Filtration. rfTiVhri^ r?i rfi fi^ rf^ fi^ flh ftl CB ill &i itl fTl itl ffl mil l mil I I I II I I I II III ill III III III 111 111 III iiimf Tniaial C^.60 httmoijr Speojlly deai^l fa KMiirfilfl Work ai 306 PURE FERTILIZERS. by the addition of fresh water. The liquor, instead of being drawn off as before, is allowed this time to percolate downwards through the mass into the lower chamber of the vat. To facilitate this process of dis- placement, the lower chamber is to be ex- hausted of air by means of the air-pump, for which there is a coupling-screw y:onnection in the vat at 7ii. The vacuum thus produced in the lower chamber causes the liquor to filter through rapidly from above. The washing is to be repeated once or even twice. The mass is then clean and ready to be pushed out by the motion of the stirrers through the holes and shoots / /, and wheeled away for sale as a cheap substitute for ground plaster. The wash-waters are to be run into the basin part of the kiln with the previous strong liquor, and heated until a film of crystals begins to form. At this stage, there must be great care to moderate the fire ; for I have observed that the bi-phosphate of lime, when evaporated beyond the consistence of a wet crystalline mass, is apt to assume in part an allotropic condition which is com- BI-PHOSPHATE OF LIME. 307 paratively insoluble. The heat must be stopped, therefore, when the liquor reaches the above-noted point. At this stage, also, it should receive its requisite proportion of drier. If, during the evaporation, there have been given off any white vapours of sulphuric acid, then the drier should be the Colombian phosphate, as it will thus neu- tralize the excess of sulphuric acid and add to the value of the product. Five to ten per cent, are to be added, and w^ell stirred in to make a thorough mixture. The whole is then transferred to the basin of the kiln, where it is left to dry at a very moderate heat, not exceeding 180'^ to 200*^ Fahrenheit. If there is no excess of sulphuric acid in the bi-phosphate, then the best drier is the hydrated sulphate of lime, which is deposited from the chloride of calcium or mother- liquor, treated in Chapter xi. It may be added in its pulpy or moist state to the bi- phosphate, and the whole must be mixed thoroughly by raking. When there is any tendency to cake on the bottom or sides of the kiln, the mass must be kept detached by means of a hoe. The X 2 3o8 PURE FERTILIZERS. mass, when dry, is to be dashed into a granu- lar powder by means of Carr's Disintegrator, previous to being packed into barrels for market. The product thus obtained is a mixture of 90 to 95 per cent, of pure soluble bi-phos- phate of lime with 10 to 5 per cent, of which- ever drier may have been used. Formerly, I used finely-powdered mineral phosphate of lime as the drier ; but I have observed more recently that this substance is apt to reduce the bi-phosphate partly into di- and tri-phosphates, more particularly when there is no free sulphuric acid present. The chemical interaction which sets up this change is promoted by the incidental water of the mixture. Indeed, it is the undecom- posed portion of tri-phosphate of lime, which exists almost invariably in the ordinary com- mercial superphosphates, that causes the bi- phosphate portion to ''go back\ according to trade language, or become insoluble directly in water. Although the lift elevator and vacuum vats comprise a convenient arrangement for the manufacture of soluble bi-phosphate, they BI-PHOSPHATE OF LIME. 309 are not indispensable implements. A much simpler plant may be made to answer with such an easy material as the "superphos- phate", prepared as directed in Chapter xiii. This material may be leeched of its solu- ble bi-phosphate portion by simply boiling it with water in the wash-vat for half an hour. Then, by repose, it divides into an upper stratum of liquor, which is aqueous bi-phos- phate of lime, and a lower deposit of solid hydrated sulphate of lime. The former is drawn off from the latter into the evapo- rating pan and reduced to a crystalline mass, as directed at p. 306. The solid residue in the vat is transferred afterwards to the stands (Plate 23), and allowed to drain. These draining stands are made of wood, and consist of a funnel- portion a, perforated with holes throughout its lower circumference, and supported by the frame-work c. They must be lined with a very coarse blanket or straw to prevent the choking of the holes with the solid matter. As the liquor percolates through, it is caught in the troughs b, which conduct it into a reserv^oir. 3IO PURE FERTILIZERS. When all the strong liquor which it re- tained has passed through, hot water is to be poured upon the contents of each filter, and allowed to run through. This washing is to be repeated a second time, in like manner, and the united wash-liquors or drainings are then to be reduced with the previous strong liquor in the evaporating pan. The residual matter of the filters is the same as the exhausted matter of the cylindri- cal vats ; or, in other words, hydrated sul- phate of lime. It is far superior to ground plaster for dressing clover lands ; but must be thrown out as waste where there is no market for it. The " superphosphate" and bi-phosphate of this process, unlike the bi- phosphate products of other methods of manufacture, do not ^' go back'' into tri- and di-phosphate after having been put into packages. It may be as well to note here that it has occurred recently to my mind, that the tur- bines used in sugar manufactories might serve well for separating the liquor from the solid portion of the superphosphate in the preparation of soluble bi-phosphate by this BI-PHOSPHA TE OF LIME. 3 1 1 process. It may be that the solid portion is too fine for this operation ; but, be that as it may, the suggestion is worth a practical trial. The saving of space, time, and labour, by this means, if it can be substituted for those prescribed, would be very great indeed. One thing is certain, that it would answer well for drying the precipitate of the wash- liquor ; for there the deposit is coarse crystal- lized sulphate of lime, which will allow its liquor to go through the holes of the turbine without passing them itself. I, therefore, will describe this machine. It consists of an iron cage A a (fig. 6), placed in the centre of an enveloping case b b, of cast-iron, and attached to the base of a central and vertical axis c c, to which a cog d d' communicates a motion of 1200 revolutions a minute. The walls of the cage are a fine cullender of very solid metal, and into this receptacle the stuff to be dried or cleared of liquor is to be placed. The machine being then set in motion, the very rapid volation drives the stuff against the walls, and sends the liquid portion through the fine holes. The solid is then to be removed for a new charge. So, 312 PURE FERTILIZERS. also, is the liquor to be drawn out of the jacket when it has accumulated sufficiently. Fig. 6, The machine must be well dried always, when it is not in use, in order to prevent its becoming rusted. BI-PHOSPHATE OF LIME. 313 It is the utilization of the centrifugal force which constitutes the principle of this ma- chine and its mode of operation. The solution vat, with vacuum filter com- bined (PL 22), which has been noted, is a cast- iron cylinderyy^ lined with lead or coated with stearic pitch, raised upon a brick-work found- ation 6>, and held firmly in place by the beams i i, bolted to the floor c. The perforated diaphragm, which converts it into a filter, is in segments k k, supported, first, by means of a strong ledge b b, running around the inner circumference a a, of the vat ; and, secondly, by a central column d, fastened to the bottom c, as shown by the cross section and plan views, figs. 2 and 3. This column carries at its upper surface the wooden footstep e for the end / of the shaft of the stirrer, and also a flange to sup- port the central portion of the segments gggg. These segments are cast with ribs on their upper face as rests for a plate simi- larly cullendered and coated. The interven- ing space between this double diaphragm is to be filled with clean coarse gravel or a blanket of loose texture as a filtering medium. 314 PURE FERTILIZERS. Fig. 4 gives an enlarged view of the stirrer, which is of wrought iron and covered with lead. Branch pipes s s s, leading from the steam-feeder r r, serve for heating the contents of the vat to facilitate solution ; and they enter from the outside to prevent inter- ference with the arms bbb oi the stirrer. CHAPTER XV. THE MANUFACTURE OF COMMERCIAL SUPER- PHOSPHATE OF LIME. The usual rough and ready method of pre- paring" this fertilizer is to make a mound about two feet high and six or eight feet in diameter, with a given weight of powdered coprolites, rock guano, marlstones, or other crude phosphate of lime ; then to shovel out the centre, so as to form a bowl with a rim or circumference ten or twelve inches thick, and fill the hollow with an equal weight of brown oil of vitriol previously diluted with water. This preparation being completed, the powder removed from the centre to form the bowl is put back by degrees ; that is, by shovelfuls at a time, until all has been added. By means of a hoe, the mass is mixed next into a paste, and incorporated, finally, with 3i6 PURE FERTILIZERS. the dry portion constituting the sides or walls of the bowl. It is left then for several days ; and, at the end of that time, if it should not be dry, it is to be. treated with a sufficient quantity of ground gypsum, pow- dered mineral phosphate, sawdust, peat, or kindred powder to bring it into a dry state. Finally, it is broken down to a granular powder, by means of one of Carr's Disinte- grators, and packed in bags or casks for market. This slovenly and unscientific mode of proceeding gives a product which has the important defects of very variable composi- tion, great dampness when iron and alumi- nium compounds are present, and excessive sulphuric acidity. The sulphuric acid, although in very large excess, by acting upon the lime in this man- ner, causes the sulphate of lime which it forms, to envelope that portion of the bone- phosphate of lime immediately beneath the outer surface of the particles of raw material, and make a coating sufficiently hard to pre- vent the further penetration of the acid. Thus a thorough contact of the acid with COMMERCIAL SUPERPHOSPHATE. 317 every particle of the mass becomes impossi- ble, and the consequence is, that the acid does its work imperfectly. Moreover, the quantity of water of dilution necessary to moisten the mass sufficiently is in excess of the proportion which the chemi- cal constitution of the products demands, and this excess must be dried out, subsequently, by the use of absorbent powders which add to the expense of the fertilizer as well as to its already attenuated state, agriculturally considered, without imparting any counter- vailing advantages. When operating in open pits the evolution of vapours is discomforting always to the workmen ; and if coprolites or other raw ma- terial containing fluoride of calcium, should be under treatment, the emanations during the chemical action are positively injurious to health. In a commercial sense, too, it is desirable to give the product as high a fertilizing strength as possible, for manures are gene- rally distributed from grand manufacturing centres into remote and scattered corners of country often not very accessible by means of 3i8 PURE FERTILIZERS. railways or other less convenient means of transportation. A concentrated fertilizer will cost much less for packages, packing and freight, than one of low grade, and is proportionally more economical to the planter, who can temper it as may be required, or according to his own judgment, at the moment of using it, and with dry earth, peat, or ground plaster. One or other of these materials is always ready at hand in every district of land, and costs little or nothing, comparatively. To get rid of all the defects just specified, and to operate on large quantities of material economically as to time and labour, the work must be done by machinery. The chief im- plements for the purpose are an elevator and mixer, such as have been described in Chap- ter v, at pages 111-115. The acid reservoir, as well as the mixing box, should be pro- tected by a lining of thin sheet-lead. The acid may be mounted from a reservoir or trough below, by means of a lead pump, or in carboys, by means of a lift. A given weight of the crude phosphate of lime mate- rial in fine powder having been dumped on COMMERCIAL SUPERPHOSPHATE. 319 the ground behind the mixing platform, is drawn up by the cups of the elevator, as ex- plained heretofore at page 112, and dropped gradually into the mixer, the stirrer of which is now set in motion. When the powder is being added, the acid must fall upon it with the proper amount of water of dilution, so that all may go through the mixing operation simultane- ously, as well as continuously, but in small charges at a time. To this end, the flow of acid from the reservoir or the pump, as well as that of the water from the hydrant, must be regulated accordingly, by means of feed- pipes and cocks of suitable bores. The en- trance of the acid and water in this manner causes a generation of heat, which assists the chemical action of the former upon the pow- dered phosphate very materially. The mass drops from the mixer in a moist state, and is conducted into a reception vat by means. of an inclined tube, according to the manner described in a previous chapter. These receptacles or wells should be of stone or brick-work, with walls at least twelve inches thick, to give strength for resisting the 320 PURE FERTILIZERS. internal pressure of their contents. Twelve feet high and eight feet square, are very proper dimensions for them. They should have a wooden roof covered with felt cloth or paper boards, which have been saturated with stearic pitch. Plate 24 will give the idea of a series of eight of these wells under one roof g g. To the latter is fitted, by means of a coupling- joint, the tube a leading into the chimney hearth, for conveying away the noxious vapours generated within the vat. To prevent the escape of these vapours into the factory, the joints of this roof must all be kept tight. There must be also an opening d d, for the end of the inclined tube through which the mixed mass passes into the wells. The entrance to each vat is fitted with a very strong wooden door, about two inches thick, well steadied against the wall, as shown by ^ <; when the wells are about to be filled ; for, otherwise, the semi-fluid mass of the interior might press it down and cause great inconvenience and loss. This prop arrangement c must be movable, COMMERCIAL SUPERPHOSPHATE. 321 SO that the doors can be put aside when the wells are to be emptied. Brown oil of vitriol of specific gravity 1700 is the kind of acid to be used. The total required will depend upon the composi- tion of the raw phosphate material, which must have been determined previously by chemical analysis. This once known, it is only necessary to weigh out the acid in the ratio of 1*21 pounds to every per cent, of carbonate and of 0"8i pound to every per cent, of bone-phosphate of lime in the raw phosphatic material. A further quantity, equal to about eight to ten per cent, of the whole weight of the mineral may be added as an excess to provide for contingencies, through the presence of fluoride of calcium and iron and aluminium oxides and phos- phates. Many manufacturers who make their own acid use a weight of the latter equal to that of the raw mineral, but this great excess does not benefit the product. The water of constitution required for the products from each per cent, of carbonate of lime and each per cent, of bone-phosphate of 322 PURE FERTILIZERS. lime is 0-36 and o"i2 respectively. But the heat of chemical action always dissipates a large quantity, and provision against that waste must be made by using an excess of the equivalent proportion. As, however, the brown oil of vitriol contains already a con- siderable quantity, it will not be necessary to make this excess greater than 20 to 30 lbs. for every 100 pounds of this same brown oil of vitriol w^hich may be employed. In that case, there will be no unnecessary delay in the drying of the contents of the wells. The mixture of powdered phosphate, acid, and water, will reach the wells in such a state of inter-action, that it will be found, within ten days, a hard mass of thoroughly decomposed raw material, consisting of bi-phosphate of lime, sulphate of lime, and the insoluble matters of the crude phosphate mineral. The per cent, of bi-phosphate will depend upon the per cent, of bone-phosphate which the raw matter contained. The presence of a large quantity of alumina in the latter may give rise to humidity in the product conse- quent upon the formation of sulphate of alumina. COMMERCIAL SUPERPHOSPHATE. 323 At the proper time, the doors which close the openings are to be removed, and the dry mass is then shovelled out and reduced to powder by a Carr disintegrator or Howel- Hannay mill, and packed for market. It is indispensable to the economy of this method that the raw phosphate material shall be as free from carbonate of lime and fluoride of calcium as possible ; for this method, unlike the processes of the previous chapters, fails to afford a compensating pro- duct for the acid wasted by those compo- nents. If bone-ash has been the basis-material, the product from 100 pounds will amount to 175 pounds, always provided that no excess of water or absorbent powders, as driers, have been used. This mixed product or "superphosphate", as it is called, commer- cially, will be made up as follows : — Bi-phosphate of lime _ - - 53'00 Sulphate of lime — from carbonate - ^'^"°°la7-oo „ „ „ tri-phosphate So'OO i Silica, organic matters, accidental water, etc. I ^- — say - - - - 3 Total amount uf product - I75'00 Y 2 324 PURE FERTILIZERS. This " superphosphate" will have the com- position, per cent., noted at p. 292, Chapter XII. It is not possible to make a greater strength of bi-phosphate in this way, except with cer- tain kinds of apatite, phosphorite, and rock guanos, which contain a very high per cent, of bone-phosphate of lime with very little of other than organic matters. In such cases, there is little or no dilution or degradation of the product by inert mate- rials. But even with pure bone-phosphate of lime only 75'64 pounds of bi-phosphate (CaO, 2 HO, PO5) can be obtained from 100 pounds of the former by this process ; and, at the same time, iio'25 hydrated sulphate of lime (CaO, SO3, 2HO) are produced. Consequently, its niaximiun product per cent, would be only as given at pages 289 and 300, Chapter xii. It must be remarked, that either on ac- count of inferior mineral or bad manipula- tion, the admixture of absorbent powders or fraudulent practices, there is rarely more than 25 per cent, of bi-phosphate of lime at best, in commercial superphosphate. More COMMERCIAL SUPERPHOSPHATE. 325 frequently, it falls to ten per cent., and even lower. In corroboration, here is the calculated composition per cent, of the best possible " commercial superphosphate" that could be made with " South Carolina phosphate": — Bi-phosphate of lime (CaO, 2HO, PO5) - 25-38 Hydrated sulphate of lime (CaO, SO, 2 :H0) - 52-82 Iron oxide and alumina - - 578 Organic matter - 5-14 Sand and silica - 8-92 Water 1-96 loo-oo This analysis represents a product of only 1556 pounds from 100 pounds of raw mine- ral ; that is of the rarest purity ; but in prac- tice it would be so much larger from the presence of driers, excess of water and acid, as to depress the quality of the " superphos- phate" at least twenty per cent. In Great Britain, generally, the analytical report upon a sample gives its equivalent value in tri- or bone-phosphate as the real content, seemingly, of the bi-phosphate. Thus, a sample of superphosphate from 326 PURE FERTILIZERS. bone-ash containing only 31 per cent, of actual bi-phosphate will be sold as having the richness of 41 '00 per cent.; these latter figures expressing the amount of tri- or bone- phosphate of lime to which the former are equivalent. CHAPTER XVI. HORSFORD S BAKING POWDER This modern substitute for yeast, in the manufacture of bread, originated with Eben. N. Horsford, Professor of Applied Chemis- try in Harvard University, of the United States of America ; but it is known in Great Britain and on the Continent as the Liebig- Horsford Baking Powder. It is a mixture of pure bi-phosphate of lime (CaO, 2HO, PO5) and bi-carbonate of soda (NaO, 2CO2), in chemical equivalent proportions. To make the acid element, it is necessary to have a very pure tri-basic or bone-phos- phate of lime. This is to be prepared by dissolving bone-ash in a clean wooden vat, with quite pure and dilute hydrochloric acid, allowing to settle well, drawing off the clear liquor into a clean wooden vat, and then 328 PURE FERTILIZERS. adding pure aqua ammonise until there is no further precipitation, or rather until the mix- ture blues a piece of red litmus paper dipped into it. After repose, the clear supernatant liquor or aqueous solution of chloride of am- monium is to be drawn off, evaporated to dryness as crude crystalline ammoniacal chloride, and barreled for market. The resi- due is then treated with water, stirred, al- lowed to repose, and the clear liquor drawn off as before, and mixed and evaporated with the previous liquor. A second washing, with a fresh addition of water, is now necessary to remove the last traces of ammoniacal salt, and this wash-water must also follow the course of the preceding two into the evapo- rating pan. The precipitate is next transferred to a series of filters, and there allowed to drain well. These filters are shown by Plate 25: a being the wooden support, c the coarse linen filtering cloths, and b the wooden pail for receiving the filtrate. Assuming that the bone-ash under treat- ment contains a liberal proportion of bone- phosphate and carbonate of lime — that is, HORSFORUS BAKING POWDER. 329 72 -f 9 = 81 — then the quantity of pure hydro- chloric acid (specific gravity riyo) required for the solution of every hundred pounds of ash would be 118 pounds. Should the acid be weaker than specific gravity 1*170, a pro- portionally greater quantity must be used. It will be more convenient and economical to make each and every operation with r39 tons of bone-ash, so that the amount of pre- cipitate shall equal very closely one ton of tri-basic phosphate of lime. The washed and drained precipitate from the I "39 tons of bone-ash, is then to be trans- ferred to a clean wooden circular vat, fitted with a wooden stirrer. This vat does not need any cover, nor yet to be coated with re- sisting paint, but is to be fitted with a ''blow- up'' or open steam-tube. Brown oil of vitriol of specific gravity 1700, and made from sul- phur, so as to be free of arsenic, is now to be poured upon the precipitate in a thin stream during constant stirring. It must be diluted previously with its weight of water, or, if more convenient, this proportion of water may be mixed instead with the precipitate in the vat. The necessary quantity of brown 330 PURE FERTILIZERS. acid (1700) for the precipitate, which is equi- valent to one ton of pure dry tri-phosphate of lime, will be sixteen hundred - weight. After all the acid is in, and the mixture has been well stirred, it is to be left for a week or ten days, care being observed to rouse it in the interval by frequent stirrings. The sulphuric acid abstracts two equivalents of the lime to form sulphate of lime, and leaves the remaining equivalent in combination with the whole of the phosphoric acid as soluble bi-phosphate. At the end of this time, the decomposition will have been complete, and clean water is then to be added, in order to thin out the mass. To promote this end, the stirrer must be put in motion. The whole is now left to repose, in order that the clean liquor may rise to the top. This is an aqueous solution of bi-phosphate of lime, with a little sulphate. All the rest of the sulphate of lime remains as insoluble matter. It, however, yet retains some of the soluble phosphate, which must be washed out with fresh water in the manner just described. This wash-water, when drawn off, is to be mixed with the first or previous liquor. HORSFORD'S BAKING POWDER. 331 To remove all suspended matter the mixed liquors must now be strained through a filter-cloth of sufficient fineness, or allowed a day's repose, in order that it may settle clean. The clear runnings are then to be evaporated in shallow enamel-lined iron pans, to a thick syrupy liquor, at which stage sufficient wheat- flour is to be stirred in to convert it into a dry powder. These pans A (fig. 7), arc made Fig. 7- of large size and superior quality, by T. and G. Clark and Co., Wolverhampton. They can be set in brick- work, over a naked fire ; but the drawing represents one with a cast- iron jacket B, so that it may be heated with steam. The price of the latter, with fittings, is £^\ 10 for one of 25 gallons capacity; 332 PURE FERTILIZERS. ^\\ for one of 50 gallons capacity; and ^11 for one of 100 gallons capacity. It is necessary that the powder shall be perfectly dry when cold, because any con- tained moisture would cause it to act prema- turely upon the bi-carbonate of soda with which it is next to be mixed. The powder would thus become stale, as it were ; or, in other words, inert, as a yeast substitute. The proportion of bi-carbonate of soda to be mixed with the bi-phosphate of lime is o"965 pound for every per cent, or pound of bone- or tri-phosphate of lime represented by the acid powder of bi-phosphate of lime. To the ton, therefore, produced, as just di- rected, there must be added eighteen hundred- weight and three-quarters of bi-carbonate of soda. Complete mixture of the two powders must be made by means of a Howel mill, kept well clean, interiorily, for the purpose. The baking-powder is then ready to be packed in glass bottles with cork stoppers, containing in their centre a wooden measure for holding sufficient powder to produce the rising of two pounds of fine white flour. This sufficient (quantity is one ounce. The HORSFORUS BAKING POWDER. 333 form of this stopper is shown by fig. 8, in which b represents the cork exterior, and a the interior wooden measure. This arrange- ment is not only convenient for packing, but also for the consumer, who would need, otherwise, a pair of scales to weigh out the proper quantity at each and every baking. The two powders may be packed and sold in separate bottles, to be mixed at the time of use. In such case, the measure- Fi2. 8. stopper of the bottle containing the acid powder must have the capacity for exactly one half ounce. On the other hand, the stopper-measure of the other bottle must hold fully one half ounce. In all cases, the measure must be ^^ struck''', that is, the con- tents are to be level with the top, for which purpose any excess must be scraped off with a knife, so as to leave a smooth flat surface. 334 PURE FERTILIZERS. Directions for Use. The flour having been sifted into a clean wooden bowl, is to be incorporated dry with the mixed powder in the proportion of one ounce for every two pounds of flour. Or, if the acid and alkaline powders are separate, then one half ounce of the first, and rather more by a grain or two of the latter, are to be used to every two pounds of flour. After thoroughly incorporating the whole by means of the hands, and throwing in a little table- salt, sufficient cold water or milk is next added to make a soft and rather thin dough. In the meantime, the pans must be made warm and the oven quite hot. Then, after having kneaded the dough only so much as is necessary to make it perfectly homogene- ous, it is to be put into the pans so as to leave about one-fourth of the top space free, and baked immediately. Thorough baking is indispensable to prevent doughiness of the crumb portion of the bread when stale or cold ; and, therefore, the loaves must not be removed from the oven until they are quite brown. HORSFORUS BAKING POWDER. 335 The pans should be of tin plate and round, about six or seven inches in diameter, and three to three and a half inches in height. The bread as thus made from white flour is light, sweet, and very superior. Care must be taken not to use less than the pre- scribed quantity of flour for the bread; other- wise, the latter will have a peculiar saline taste. Two pounds of good flour yield from three to three and a quarter pounds of baked bread. The chemical action which takes place in the mixture of flour, baking-pow^der, and water, is as follows : — the bi-carbonate of soda neutralizes the bi-acid equivalent of the bi-phosphate of lime, and phosphate of soda, v/ith precipitated phosphate of lime, is formed. Carbonic acid, being thus disen- gaged as gas at the same instant, rises through the dough, expands it, and makes it light and porous. There is no loss of flour as by the process of raising by yeast. Moreover, the phos- phates separated by the bran arc thus re- stored to the flour. 336 PURE FERTILIZERS. Brown Bread. The ordinary bran-meal, and also the "whole ground flour", will make very supe- rior bread with this powder, both as to light- ness and agreeable taste. A little salt must be added ; and, to prevent doughiness of the crumb part, the proportion of powder must not be less than one ounce of the mixed pow- der to two pounds of whole ground flour. Even as much as two and a quarter ounces of mixed powder may be used with four pounds of the flour without imparting any perceptible saline taste to the bread. This bread keeps well, and is far superior to that made from the same flour by any other method of raising. The ordinary bran-bread meal requires, at furthest, only one ounce of mixed powder with two pounds of meal. The precautions directed already, as to the baking, are to be observed more strictly with regard to these brown breads than to those from fine white flour. HORSFORHS BAKING POWDER. 337 Gout-Bread and Confectioners Cakes. The preceding mixed powder, with a cer- tain amount of sesqui-carbonate of ammoniae in place of a portion of the bi-carbonate of soda, becomes an excellent baking-powder for bread suited to gouty patients. Neutral phosphate of ammonia (2NH3, 2HO, PO5, HO) is thus introduced into the bread, and this salt entering the system, keeps in solu- tion the uric acid and urate of ammonia, which are otherwise painful secretions in that disease. At the same time, there is given oif a larger amount of carbonic acid than from the soda-powder, and this property adapts it admirably for making sweet cakes. So long as the ratio of carbonate of ammonia is not in excess, the bread and cakes will have only an agreeable taste and wholesome condition. To prepare the powder properly, one hun- dred pounds of the dry bi-phosphate of lime are weighed and put into a wooden trough. Assuming that ten pounds of flour are con- tained as drier in this hundred of powder, then there are ninety of acid or bi-phosphate of lime to be neutralized. For this purpose 338 PURE FERTILIZERS. 72 pounds of finely-powdered sesqui-carbo- nate of ammonia (2NH3, 2HO, 3CO2) are to be sifted in, and thoroughly intermixed with the acid powder. In other words, the equi- valent proportion of sesqui-carbonate of am- monia is o'8o for every per cent, (ro) of pure, anhydrous bi-phosphate of lime. In the same manner three hundred pounds of the acid powder are to be thoroughly in- termixed with 275 pounds of bi-carbonate of soda. These two double powders are finally mixed and sifted together, so as to produce an uniform fine powder. The com- pound powder thus formed is the baking- powder for gout-bread and sweet cakes. One ounce suffices for two and a half to two and three-quarter pounds of flour. It is to be used in the manner as directed for the soda powder, and the same precautions in baking are to be observed. It is indispensable that all these powders shall be kept dry until after they have been mixed with the flour previous to making the latter into dough. CHAPTER XVII. S-^-^*i5F^B!«-t-E— GERLAND S SULPHITE OF TRI-PHOSPHATE OF LIME. The action of sulphurous acid upon tri-phos- phate of lime has been studied specially by Dr. B. W. Gerland, who was the first chemist to give it attention ; and to him we are in- debted for all of our practical knowledge on this interesting and comparatively novel sub- ject. Sulphurous acid in aqueous solution dis- solves phosphate of lime with considerable energy ; more particularly when the latter is in an artificial precipitated state. The natural mineral forms of it are only less soluble than the artificial, and in proportion to their greater or lesser density of structure. The resulting solutions are perfectly clear, and contain phosphoric acid and lime in the same proportions as the original substance. Z 2 340 PURE FERTILIZERS. As sulphite of lime is very largely insolu- ble^ in water, even though the latter may be saturated with sulphurous acid, it is evident that this salt cannot have been formed ; and, therefore, the sulphurous acid must have dissolved the phosphate of lime without de- composing it. The sulphurous acid thus acts quite otherwise than sulphuric acid, which latter, under corresponding circum- stances, would produce sulphate of lime, to- gether with bi-phosphate of lime. The relative energy and proportion in which the different forms of tri-phosphate of lime are dissolved by an aqueous solution of sulphurous acid are shown by the follow- ing table. The solutions were obtained by suspending the phosphate material in water and passing sulphurous acid gas through the mixture. One thousand cubic centi- metres of the solution, made in this manner, were found to contain : — * Gerland's estimate is, that lOO cubic centimetres of the saturated solution contain 8-996 grammes of sulphur- ous acid and 0-258 gramme of lime, which arc equivalent to 0-553 gramme of sulphate of lime. SULPHITE OF TRI-PHOSPHATE. 341 Components. Pure Pre- cipitated Triphos- phate of Lime. Bone Ash. Bone Ash. Pieces of Bone. Pieces of Bone. Pieces of Bone. Pieces of Bone. Pieces of Bone. grammes. grammes. grammes. grammes. grammes. e;rammes. grammes. grammes. Sulphurous acid 218-38 141 82 159-446 36-019 36-848 35 597 33-536 32-550 Sulphuric acid 0-70 trace — 1-664 1-748 2-058 1-320 I -185 Lime 101-79 59-69 51-374 20-787 19-233 20-496 18-589 19-350 Magnesia — 2-79 2-896 0-582 0-460 trace trace Phosphoric acid 8289 47-42 40-093 15-287 14-508 15-925 74-076 15030 14-451 Total 40376 251-72 253-809 74-339 72-796 68-475 67-536 Specific gra- ) vity of the > I -3000 at 1-1708 at I -1881 at I -0650 at I -0600 at I -0680 at I 061 1 at I -0612 at solution - \ 48 -2°?. 53-3°F- 57-i°F. 6i' F. 63° F. 64-2°F. 50° F. 46-2°F. These results show that in the stronger solutions there is one equivalent of tri-phos- phate of lime to six equivalents of sulphur- ous acid ; while those which are weaker con- tain the latter in the ratio of only five equi- valents to one of tri-phosphate. The solutions prepared from bone-ash and bone-dust contain more lime than their con- tent of phosphoric acid requires to form tri-phosphate ; but the proportion of these is nearly uniform in the bone. The following table shows the composition 342 PURE FERTILIZERS. of the excess of bone-ash which was sepa- rated from solution No. 3, after having been washed and dried : — Matters insoluble in hydrocl liloric acid - 5-42 Sulphurous acid - - - trace Sulphuric acid - - - 0-29 Carbonic acid - - - 0-90 Lime - - - 48-25 Magnesia - - - trace Phosphoric acid - - - 38-59 Moisture and defi^ ciency - 6-55 100*00 The proportion of phosphoric acid to lime is one equivalent to 3-172; whereas the liquor No. 3 held them in the ratio of one to 3-268 ; and, moreover, the latter contained all the magnesia. Although the excess of bone-ash had undergone only this slight chemical change, the pieces were completely disinte- grated and reduced to fine powder. These solutions have the odour of sulphur- ous acid, but in less degree than an aqueous solution of the gas itself; and, on exposure to air, their surface becomes covered with brilliant crystals. The weaker solutions re- SULPHITE OF TRI-PHOSPHATE. 343 main unchanged, in closed vessels, for an in- definite length of time; but the stronger ones require to be kept at temperatures below 64^ Fahrenheit, in order to maintain their preservation. Above this degree, the latter decomposes and drops a deposit which in- creases, progressively, for days. This de- posit is a mixture of sulphite and di- or neutral - phosphate of lime, in which the former predominates. At the same time, the solution becomes richer in phosphoric acid, until finally this and the lime are present in about equal molecular proportions. The same decomposition will take place even during the preparation of the solution, if the temperature is allowed to rise above 64*^ Fah- renheit. When exposed in vacuo, the solutions crystallize into well formed hexagonal pyra- mids composed of di- or neutral-phosphate and sulphite of lime with much water of constitution. A mixture of variable proportions of di- phosphate and sulphite of lime is also preci- pitated from the solutions when the latter are boiled under reduced pressure, diluted with 344 PURE FERTILIZERS. alcohol, or treated with a current of carbonic acid gas. Although solutions of phosphate of lime in sulphurous acids have the strong tendency to form the compounds as just explained, it is remarkable that they lose it when heated rapidly and boiled under atmospheric pres- sure. Thus manipulated, they drop their phosphate completely as a definite chemical compound of tri-phosphate of lime with sul- phurous acid and water, which corresponds to the formula sCaO, PO5, SO2, 2HO. It is in the form of a crystalline white powder, which settles readily, but is very light when dried. The residual sulphurous acid escapes with the aqueous vapour. This compound differs from other sulphites in not having any greed for the oxygen of the air, as it remains unchanged when wet, dry, or heated. It holds its water up to 284*^ Fahrenheit, and at higher temperatures ; then water is given off with accompanying vapours of sulphur, sulphurous acid, and sulphuric acid. The sulphite of tri-phosphate of lime is neither soluble in, nor acted upon, by cold or SULPHITE OF TRI-PHOSPHATE. 345 boiling water. Dry chlorine and ammonia gases are without effect upon it; and aqueous ammonia affects it only slightly. A mixture of gaseous ammonia and oxygen or air is absorbed gradually by the sulphite, and pro- portionately sulphate of lime is formed. Sul- phuretted hydrogen turns the sulphites yel- low by developing free sulphur. Strong acids decompose it, oxalic acid more slowly and less perfectly, and weaker acids, like the acetic, with little or no energy, unless the air has access. A weak aqueous solution of iodine, — containing, say i2'69 grammes of iodine to the litre, — dissolves the compound by promoting the oxidation of the sulphurous acid constituent ; and this reaction affords a ready means of estimating the same. The sulphite of tri-phosphate of lime has not yet been made in any other way than that just described. Phosphate of lime, when digested with its solution in sulphurous acid, is not changed ; but the contact disposes the latter to form, gradually, sulphite of lime, which becomes mixed with the phosphate. This change progresses to such an extent, within a few days, as to cause a perceptible 346 PURE FERTILIZERS. diminution of the specific gravity of the liquor. Alkalies and alkaline carbonates throw down precipitates from these solutions, which differ from the sulphite of tri-phosphate of lime in both appearance and composition. The Method of Mannfachtre. The foregoing explanations will render easy the proper understanding of the pre- paration of the sulphite of phosphate of lime on a practical scale. Figs. 9 and lo show the construction and arrangement of the necessary apparatus for making it at the rate of thirty hundred- weight every twenty-four hours. The raw phosphate material is to be placed in the four wooden cisterns or vats Ci C2 C3 C4, and upon a false-bottom b, in order that it may not be washed away. If the bone-ash or phosphate material is finely divided, it yields promptly to the dissolving action of the sulphurous acid which is now to be led into it ; but, in order to increase the strength of the solution progressively, it must be pumped repeatedly from these cisterns or SULPHITE OF TRI-PHOSPHATE. 347 Fig. 9. 348 PURE FERTILIZERS. G^ (^ 035 l.iallv Jtsigi*UorKlLrfiisW.:#kaif£niU2ei. TruhiiTii 0^.60 pakaiiMnrRc«. SPECIAL FERTILIZERS. 421 In addition, there should be a reserve of rocks and organic matters, from which the decomposing influences of air, time, and the soil, will eliminate the foregoing elements at later periods, as will be necessary to insure a permartent fertility. The mechanical portion serves to facilitate the passage of water through the soil ; and, consequently, to precede its chemical action in the premises. This action consists in ab- sorbing and dissolving carbonic acid, ammo- nia, and other desirable elements from the air and the soil, and rendering assimilable by these means the elements of the latter, which otherwise would remain inert. Thus it assists, not only directly, but indirectly, in the nutrition of plants, and more particularly in the development of their organic portion. A clay-soil requires, therefore, to be deeply ploughed. The inorganic portion derives its constitu- tion from the mineral elements of the soil. By repeated cropping, a soil becomes ex- hausted of its fertilizing elements ; and they must be restored, therefore, from time to time, by means of deep ploughing, and the application of manures. 422 PURE FERTILIZERS. All plants are not alike, either as to the quality or quantity of their food ; that is, certain species are so far eclectic in this re- spect, as to exercise a g-reater avidity for the kind which is richest in their predominant element. Therefore, each of the great fami- lies of plants must be manured according to its peculiar appetite. Thus, for example : nitrogen and phosphates of lime are the pre- ferred nutriment of the cereals, including cotton ; nitrogen and potassa are the choice of the leguminous class ; and phosphates, potassa, and nitrogen that of the roots. The gramineous family differs very little from the roots in its appetite. But even though one of these elements may be dominant in distinct or individual crops, the latter cannot attain to a normal or abundant harvest, unless their peculiar food in the soil is associated, in degree at least, with all of the other requisite elements. The fertilizer is to be applied to the soil and intermixed thoroughly with the sur- rounding earth from the roots upwards. Its components must be in conditions for acting together within a given time, in order to pro- SPECIAL FERTILIZERS. 423 duce a wholesome growth of the crops. In- deed, it is expedient to have a portion of the fertilizer in active forms, so that in the early stage of the development of the plants, the latter may acquire that vigorous constitu- tion which will enable its organs to exert all their powers of assimilation and progress to a fruitful maturity. Saline manures, or those directly soluble, are liable to diminish the crops on light soils and dry seasons, more particularly when they may be mixed in injudicious or ex- cessive proportions. The more favourable season for applying them, therefore, is a wet one, which will promote their thorough diffu- sion through the soil. Keeping in view the foregoing principles, then, the following skeleton formula will re- present a fertilizer of just constituent rela- tions for general purposes. Phosphoric acid _ _ - 35'00 Potassa - - - - 45-00 Ammonia ----- 20'00 1 0000 These are the prime elements of fertiliza- 424 PURE FERTILIZERS. tion ; but, being always accompanied in natural soil or artificial fertilizers with the necessary associate elements of plants, they constitute a complete manure for any crops. The proportion of 250 to 300 lbs. of manure containing these three prime ele- ments in the percentage ratio above noted, will suffice to stimulate an acre of ground into the production of an abundant harvest, and leave behind some residue for the suc- ceeding year's crops. From this reserve, however, the predominant element of the harvested crops will have been almost, or nearly, entirely exhausted. This fact must be remembered in the rota- tion of crops ; so that in making one kind succeed another, the elementary relations of the subsequent fertilizer may be modified accordingly. In other words, having grown a crop of roots this year on a plot of ground manured with the normal fertilizer, then, if it is desired to prepare that plot the next year for a harvest of cereals, care must be observed to make the fertilizer richer in phosphate ; so as to restore the normal condition of the soil which has been disturbed by the peculiar SPECIAL FERTILIZERS. 425 exigency of the previous root-crop as to that element. Such are the simple rules which should regulate the composition and application of special fertilizers ; and, if faithfully practised, will, with the divine favour of rain and sun- shine, eventuate in successful cultivation and profitable harvests. Normal Fertilizer. Bi-phosphate of lime (CaO, 2HO, PO5) - iQ-oo Colombian or precipitated phosphate of lime* - 30'00 Chloride of ammonium _ _ - 25^00 Chloride of potassium _ _ - 25*00 Chloride of sodium - - - - 300 Sulphateof hme (CaO, SO3, 2IIO) - - 7"00 lOO'OO The above formula will serve for any plant, as it contains the elements of fertiliza- tion in very judicious proportions. Never- theless, for special crops it may be modified with some advantage, and according to the * The fertilizer must be kept dry always when it con- tains precipitated phosphate in association with bi-phos- phate, otherwise some of the latter might "go back" into di-phosphate. 426 PURE FERTILIZERS. examples which will be given after the next paragraph. Universal Dimger. There is a popular general manure made in Germany by Hosch and Enderich, which has the following composition. It is of a greyish-yellow colour, free from strong odour, and reddens litmus paper. Water - _ , . - 1472 Organic and volatile matters (ammonia, 7'8o) - 2681 Soluble bi-phosphate of lime (CaO, 2HO, PO^) - 10-13 Di- and tri-phosphates of lime - 19-48 Sulphate of potassa - 8-46 Sulphate of lime ] Sand, silica, etc. J - 20-40 1 00*00 Fertilizer for Cereal Crops. In this family, comprising wheat, rye, rice, Indian corn, barley, and cotton, the prevail- ing elements of nutrition are nitrogen and phosphate of lime, with a considerable amount of alkaline salts. The normal fertilizer should, therefore, be modified and composed after this formula : — SPECIAL FERTILIZERS. 427 Bi-phosphate of lime - 1 5 '00 Precipitated phosphate of lime - 35-00 Chloride of ammonium - 25-00 Chloride of potassium - i8-oo Chloride of sodium - 300 Sulphate of lime 4-00 1 0000 Fertilizer for Legiuniiious Plants. Beans, peas, and other members of this family of plants contain potassa, nitrogen, and phosphoric acid, as their prevailing ele- ments. Therefore, the following formula must be observed in preparing fertilizers for such crops : — Chloride of potassium - - 40*00 Chloride of ammonium - - 25"00 Bi-phosphate of lime - - 1500 Precipitated phosphate of lime - 2000 100 00 Fertilizer for Gramineous Plants. For the family of grasses, potassa is the dominant element ; and next in order are nitrogen, lime, and phosphoric acid. Conse- quently, a suitable manure should consist of:— 428 PURE FERTILIZERS. Chloride of potassium -. - 30-00 Chloride of ammonium - - 25-00 Sulphate of lime - - i8-oo Bi-phosphate of lime - - lO'OO Precipitated phosphate of lime - 13-00 Chloride of sodium - 4-00 1 0000 Fertilizer for Sugar. Sulphate of potassa - - . 35*00 Nitrate of soda _ . _ 40-00 Bi-phosphate of lime - - lo'oo Precipitated phosphate of hme - 15-00 It is a prevailing idea that alkaline chlo- rides should be excluded from fertilizers for sugar because of their deliquescing influence upon sugar, and it is in conformity with this prejudice that the formula has been con- structed. But the true and scientific posi- tion of the question has been recently set forth by E. Feltz {Journ. des Fabricants de Sucre, 1870, p. 52), and A. Marschall {Jour- nal of the Chejiiical Society, 1870, p. 457). The former chemist concludes, from his ob- servations, "that uncrystallizable substances, whether invert sugar or those classed as organic non-saccharine bodies, are the true SPECIAL FERTILIZERS. 429 molasses builders, and that they act as such in two ways : ist. By preventing a sufficient degree of concentration ; and, 2nd. By ren- dering a boiled mass so sticky, that even if sugar crystals are formed, they cannot be separated from the syrup." Marschall obtained results from his expe- riments which led to classifying salts as — " I St. Negative molasses makers ; 2nd. In- different bodies ; and, 3rd. Positive molasses makers. The negative molasses makers, or bodies which diminish the solvent power of water for sugar are, sodic sulphate, nitrate, acetate, butyrate, valerate, and malate ; mag- nesic sulphate, nitrate, and chloride ; and calcic chloride and nitrate. " The indifferent bodies which are without influence on the crystallization of sugar are potassic sulphate, nitrate, chloride, valerate, oxalate, and malate ; sodic chloride, carbo- nate, oxalate, and citrate, and caustic lime. "Positive molasses makers are potassic car- bonate (saline co-efficient 3*8), butyrate (saline co-efficient cq), and citrate (saline co-effi- cient = o"6). Belaine was shown to be a negative molasses maker." 430 PURE FERTILIZERS. Haughton Gill {jfournal of the Chemical Society, 1871, p. 269) also contributes an in- teresting paper on the saline compounds of sugar. Fertilizer for Root Crops. Potatoes, carrots, beets, turnips, and the like, require mostly potassa ; next nitrogen ; then lime; and, lastly, phosphoric acid. They must, therefore, be cultivated with this mix- ture : — Chloride of potassium - - 30-00 Chloride of ammonium - - 25-00 Sulphate of lime - - 20-00 Bi-phosphate of lime - - 10-00 Precipitated phosphate of lime - 15-00 100-00 Nitrate of soda may replace the ammonia- cal salts as the source of nitrogen, but five parts of the former must be taken in place of three of the latter, those being their equi- valent proportions. All the other elements of fertilization will be found generally in the soil ; and the plant acquiring full vigour in its early growth from SPECIAL FERTILIZERS. 431 the fertilizers prescribed, will be able to assimilate whatever additional nutriment it may need from the surrounding sources of the earth and air. In all cases, the land must have been well limed within two or three years, in order to rouse, chemically, its organic matters ; but not immediately preceding the application of the fertilizers by many months. For if the lime has not been in the ground long enough to have become wholly carbonate, or com- bined otherwise, it would cause a waste of the ammoniacal salts. In connection with this subject, the reader will do well to study the instructive paper of Dr. Aug. Voelcker, F.R.S., *' On the Produc- tive Powers of Soils in Relation to the Loss of Plant Food by Drainage", which is pub- lished in the yournal of the Chemical So- ciety for 1 87 1, p. 276 to 297. CHAPTER XXIII. FORMULA FOR THE CHEMICAL ANALYSIS OF PHOSPHATIC MATERIALS AND PRODUCTS. The phosphates of lime which come under chemical treatment for conversion into fer- tilizers have either an animal or mineral origin, but most generally the latter. Mineral phosphates differ in composition with their source and the care employed in preparing them for market. It becomes, therefore, indispensable to a well regulated system of manufacture, that each and every invoice of them which may be intended for conversion into fertilizers shall undergo, pre- viously, a full chemical analysis. The full analysis is particularly necessary, in order to distinguish what proportion of the phos- phoric acid may belong to alumina, iron, and other bases than lime. A correspondingly rigorous inspection CHEMICAL ANALYSIS. 433 should be practised also in regard to com- mercial superphosphates of lime, and indeed all kinds of artificial fertilizers, for the pro- tection of the consumer and in the cause of honest trade. The necessity for such an ab- solute custom will be seen in the very wide differences in the samples which may come under examination. This great diversity between their pretended and actual composi- tion-value, is due either to fraud or unskilful manufacture, and frequently to both. The highest average per cent, of soluble bi-phosphate of lime in commercial samples is 20 to 25 ; but this strength is peculiar to the products of certain manufacturers only. More generally they fall below 20 per cent., and often as far down as 5 to 10, without a corresponding decrease in price. The amount of contained soluble phos- phate of lime is often represented, in the analytical report, by the higher figures of bone-phosphate of lime to which it is equiva- lent. For example, every per cent, of soluble bi-phosphate of lime in the fertilizer is writ- ten as I 32, which latter record is a deception, having the effect of misleading the purchaser. F F 434 PURE FERTILIZERS. As a protection against errors of either accident or intention, the following instruc- tions in detail are given for the chemical analysis of such materials and products as come under consideration in this treatise. They are arranged to detect and estimate any and every element that is likely to be present. It is merely necessary to add that a certain familiarity with chemical principles and manipulations is indispensable on the part of the operator who may undertake to carry through an analysis. Bone- Ash, and Mineral Phosphates of Lime. All of these substances may be embraced in one general formula. The water used in the analytical operations must have been distilled ; and it is also imperative to have the reagents chemically pure. Previous to commencing the analysis, one or two sheets of blank writing-paper must be folded and stitched in book form, as a laboratory record or legend of the progressive steps of the analysis. The first step is to select a fair average CHEMICAL ANALYSIS. 435 sample of about half a pound of the ash or mineral to be analysed, mix it well, and then reduce wholly to powder about an ounce of it. A clean polished mortar, of iron or steel, is best for this manipulation. I . Accidental Water or Moisttire. Fifty grains of this powder are to be weighed upon a delicate balance. Besson, Rue de la Ferronnerie, Paris, makes a very suitable instrument for ordinary work at the low price of £^^. But there is certain necessary supplementary apparatus which, with packing, will increase the cost to about £fi. This consists, in part, of two deep watch- glasses, agreeing precisely in weight, so that one shall be a counterpoise of the other. The powder to be weighed is placed in one watch- glass ; while the opposite pan of the balance contains the duplicate glass as a counter- poise, together with the required weights. This promotes both a neat and convenient manipulation. The other supplement is a set of fine weights, ranging from 1000 grains to one- hundredth of a grain. The larger ones F F 2 43^ PURE FERTILIZERS. should be of gilt brass, and the smaller ones of gilt aluminium. The balance is of brass, and should turn, when fully loaded, with the hundredth of a grain. This degree of deli- cacy must be insisted on when giving the order. Fig. 1 2 shows the form of the balance. Fig. 12. The watch-glass ciy fig. 13, containing the 50 grains, precisely weighed, is next to be placed on a hot sand-bath c, with an inter- vening piece of hollow metal tube b, about two inches high, as a support, and to form a CHEMICAL ANAL YSIS. 437 hot-air chamber between the sand and the bottom of the watch-glass. The sand-bath may be a plain or porcelain-lined iron pie dish, containing white sand, and heated by a Fig. 13- gas-burner d, on a sliding-holder e, so that it may be lowered or raised at will upon the upright support f f, made of iron. Here the powder is allowed to remain over a heat not exceeding 212° Fahrenheit, until it ceases to lose weight ; and for determining 438 PURE FERTILIZERS. this point, it must be weighed from time to time, with its counterpoise-glass always in the opposite pan of the balance, until the weight becomes constant. The constant weight shows a loss, and this loss doubled represents the per cent, of accidental water or moisture in the original sample or raw material. If there should be any constituents of the mineral containing constitutional water, such as sulphate of lime or sulphate of ammonia, they will not lose it at the temperature just prescribed. 2. Organic Matter and Constittttional TVater. The weighed residue is next to be trans- ferred, carefully, to a platinum crucible, and heated to redness until all volatile matter is expelled. This is known when, after repeated weigh- ings from time to time, the weight becomes constant, and a calx free from carbonaceous matter remains. Should any carbonate of lime be present in the raw material, this CHEMICAL ANALYSIS. 439 would lose some of its carbonic acid at the heat prescribed, and thus lead to error. As a preventive, the contents of the cruci- ble must be cooled, then moistened with some drops of aqueous solution of carbonate of ammonia, carefully dried, and heated only to dull redness for a few moments, so as to expel the ammonia without its carbonic acid. Restitution of lost carbonic acid being thus made to the lime, the crucible is allowed to cool and then weighed. The weight thus obtained, less that of the crucible, when de- ducted from the previous weight, will show a loss, and this difference, multiplied by two, expresses the per cent, of organic matter and constitutional water in the raw material. The residue, or calx, multiplied by two, re- presents the total per cent, of fixed or earthy matters, and is to be reserved, as a, for further treatment. Fig. 14 shows the mode of burning off the organic matter. The platinum crucible a is to be closed in the first part of the heating to prevent such a strong draught as might drive off unburned particles. Later, how- ever, the cover must be removed, and placed 440 PURE FERTILIZERS. as shown by a , so as to promote access of air. The steel tongs b, of proper form for hand- ling the crucible, are shown at the side of the gas-burner support. The trivet c, of plati- a Fig. 14. num wire, which is laid upon the ring g of the support as a rest for the crucible a, is shown by c c . p^ O CO ul H CO ■-3 ■¥ 't: CO -^ PQ CHEMICAL ANALYSIS. 441 If, in the progress of the analysis, the presence of salts containing constitutional water should be developed, — for example, sulphate of lime, — then the figures for this constituent are to be deducted from the vola- tile portion expelled by ignition. The resi- due doubled expresses the per cent, of total organic matter in the raw material. The precise figures for constitutional water will be obtained, as directed, a little further on, and in proper places. But, supposing, for example, that 5*8 are found to be, subse- quently, the per cent, of sulphate of lime, then, as the constitutional water is 0*2647 for every per cent., this proportion is to be de- ducted from the weight of organic matter and constitutional water. The residue ex- presses the amount of organic matter in the raw or original material. This constitutional water is not, however, to be formulated as a separate item, for it must be apportioned to the constituents to which it belongs, chemically. The manner of calculating it to its proper affinities will be explained hereafter. 442 PURE FERTILIZERS. 3. Sand and Silica ; Soluble and Insoluble Organic Matters. Another portion of 50 grains of the pow- dered raw or original material is to be placed in a clean beaker glass a, fig. 15, drenched Fig. 15- with pure hydrochloric acid, covered with a glass dish or a deep watch-glass d, and CHEMICAL ANALYSIS. 443 digested over a gas flame c, until all the soluble matter has been taken up. It should be here noticed whether there is any effervescence on the addition of the hy- drochloric acid or any corrosion of the under surface of the glass cover of the beaker, for the first would denote the presence of carbonate of lime, and the latter that of fluoride of calcium. To modify the action of the flame, and to diminish the danger of fracture of the beaker glass, a fine wire gauze of brass or copper should be interposed be- tween the former and the latter ; or, better still, a sand-bath b may be substituted for the direct flame. In either case, when the solution is complete, the cover is to be re- moved and the beaker glass further heated on the sand-bath for the evaporation of its contents to dryness. This expels all excess of acid, and renders the silica insoluble. At this stage, it is to be left to cool; after which, the contents are to be moistened with pure hydrochloric acid and a little water, and again heated on the sand-bath for 15 or 30 minutes. Water being now added for dilution, the liquor is then filtered upon a weighed or 444 PURE FERTILIZERS. counterpoised filter. The filtering operation is shown by figs. i6 and 17 : a being the Y'w. 16. paper filter, properly folded; b, the glass fun- nel for holding it ; c, the wooden support of Fig.. 17. the funnel ; and d, the beaker glass, to receive CHEMICAL ANALYSIS. 445 the filtrate or clear liquor passing through the filter. White paper, of a porous but strong texture, is made both in France and Germany, for filtering purposes ; and filters of different sizes may be bought ready cut at any dealers in chemicals and chemical apparatus. The weight of the ash of these filters is generally noted on the package. A counterpoised filter is one which has been weighed, with great precision, against a duplicate ; and its use becomes necessary for weighing those precipitates which must be dried instead of being ignited. Con- sequently, the duplicate is to be marked al- ways, and dried with its original fellow, previous to being put into the opposite scale pan at the time of weighing. When the contents of the beaker have been poured upon the filter, there are still some solid particles adhering to the sides and bottom of the glass. These must be loosened by a feather, and washed out by means of a spritz bottle half filled with water. This spritz bottle, a, fig. 19, is an ordinary six or eight ounce vial, fitted with a cork bored in the centre for the passage of a glass-tube. 446 PURE FERTILIZERS. which must be drawn out fine at one end. By blowing through this tube, the internal air is compressed, and the bottle being dex- terously inverted, its water comes out with the force of a strong jet, which may be directed upon any desired point. After the entire contents of the beaker have thus been Fiiz. 1 8. Fig. 19. poured and spritzed upon the filter, the latter is allowed to drain. Hot water is then added three or four times, in order to wash out any traces of the solution. Each relay of water must be allowed to pass through the filter before its successor is poured on. The filtrate is b, and the filter is c. The filter c is to be placed first between the folds CHEMICAL ANALYSIS. 447 of bibulous paper, and then on a dish over a hot sand-bath, and there left to dry until it ceases to lose weight. The constant weight doubled, represents the per cent, of insoluble organic matter, sand, and silica, of the origi- nal raw material. This having been recorded in the legend, the filter and its contents are then burned to a calx in a platinum crucible. The organic matter is thus destroyed, and the calx being weighed, its weight doubled, less that of the crucible and ash, of the filter, deducted from the previous weight of the dried filter, expresses the per cent, of insolu- ble organic matter. The calx, multiplied by two, represents the per cent, of sand and silica. The amount of insoluble organic matter deducted from the total organic matter pre- viously estimated, gives the per cent, of soluble organic matter. 4 and 5. Sulphate of Lime, and Lime. The filtrate b having been on the hot sand-bath during all the interval, is by this time reduced very much in volume by evapo- ration, and thus prepared to receive a dose 448 PURE FERTILIZERS. of alcohol about equal to double its own volume, which must now^ be added. This will render insoluble and precipitate all the sulphate of lime which the liquor may con- tain. After eight to twelve hours of repose, it is to be filtered off and washed, by passing several relays of diluted alcohol through the filter. The filtrate is d, and the filter is e. The latter must be set to dry over a sand- bath. The filtrate d is next to be treated with pure sulphuric acid, added dropwise, until it red- dens a piece of blue litmus paper dipped into it. This precipitates all the residual lime, as sulphate of lime. After eight to twelve hours of repose, it is to be filtered off, washed with diluted alcohol, and the filter (say f) dried between the folds of bibulous paper, over a hot sand-bath, as before explained. The contents are then to be carefully transferred from the paper to a platinum crucible, and the filter paper rolled up and laid loosely at the top. Heat from a gas flame is then ap- plied, so as to produce a low redness, and when the paper is reduced to ash and the sulphate of lime has been wtII heated, the CHEMICAL ANALYSIS. 449 crucible and contents are to be weighed. This weight, less that of the crucible and ash of the filter, when doubled, expresses the total of lime, except that existing as sulphate in the original or raw material. This lime is to be apportioned among the phosphoric, carbonic, and organic acids, as will be ex- plained in the proper places. The filtrate, say G, is, in the meantime, set upon the hot sand-bath to lose its alcohol by evaporation. While this operation is going on, the filter E, now dry, is to be ignited and weighed after the manner just noted. The nett weight doubled, expresses the per cent, of dry sul- phate of lime (CaO, SO3) in the original material. But as sulphate of lime is na- turally hydrated always, it must be recorded with its proper equivalent of constitutional water affixed, which is 0*2647 for every per cent., and makes the formula CaO, SO3, 2HO. All the alcohol having been evaporated from the filtrate, aqua ammoniae is now added to the residual solution until the odour of the reagent is strongly perceptible. After six hours of repose, it is to be filtered G G 450 PURE FERTILIZERS. and washed with water containing aqua am- monias. The long repose is necessary, in order that the phosphate of magnesia may separate completely by crystallization. The filtrate is h, and the filter is j. 6. Phosphoric Acid. The filtrate h contains only the phospho- ric acid belonging to lime, and is to be treated at 90° Fahrenheit, first with a solu- tion of chloride of ammonium, rendered strongly ammoniacal and carefully stirred. Solution of chloride of magnesium is now to be poured in cautiously until a precipitate or even cloudiness ceases to form. The whole is then left for four or five hours to repose in the cold ; after which it is filtered, and the filter washed with water, rendered ammonia- cal ; then dried, finally ignited, and weighed. The precipitate formed is the phosphate of magnesia and ammonia (NH3, HO, 2MgO, POj, 12HO) ; but, by ignition, it loses its ammonia, and becomes pyro-phosphate of magnesia (2MgO, PO5). Every per cent, of this latter contains o'639 per cent, of phos- phoric acid. This phosphoric acid belongs, CHEMICAL ANALYSIS. 451 as before stated, to lime, and must be written in the record as tri- or bone-phosphate of lime. To make this salt, every per cent, of phosphoric acid requires ri66 per cent, of lime = sCaO, PO5. This proportion of lime is to be deducted from the total lime already estimated. Fresenius and many other chemists pre- scribe an allowance of one and three-quarter milligrammes, for every hundred cubic centi- metres of the combined filtrate and washings from the ammonia-magnesic-phosphate, to compensate for an equivalent portion re- tained obstinately in solution. But Parnell, with whose experience my own agrees, ob- serves that such a correction is rendered unnecessary by the presence of an excess of the strongly ammoniacal solution of mag- nesium salt. 7 . Phosphate of Iron . The contents of the filter j* are to be transferred by means of a platinum spatula * When the alumina or iron is in large proportion it carries down, unavoidably, some of the phosphoric acid G G 2 452 PURE FERTILIZERS. and the spritz bottle to a small beaker, treated with pure hydrochloric acid, and digested on a hot sand-bath, until wholly dissolved. Aqueous solution of pure caustic potassa is then to be added in just sufficient excess to re-dissolve the alumina and phos- phate of alumina, w^hich it precipitates at first. Oxide of iron and phosphate of iron with phosphate of magnesia remain undis- solved, and are to be filtered off, thoroughly washed with hot water to remove every trace of potassa ; then dried, ignited, and weighed as filter k. The filtrate is l. The weight of the calcined filter k ex- presses the quantity of oxide of iron, phos- phate of iron, and phosphate of magnesia combined, which the raw material contains. To estimate them separately the calx is to be put into a beaker, and dissolved by the heat of a sand-bath in just sufficient hydrochloric belonging to lime. To prevent this source of error, I am now engaged in experiments by which the manufacturing processes, described at pp. 223 and 241, will be rendered precise analytical methods for separating phosphate of lime from its association with iron and aluminium com- pounds. CHEMICAL ANALYSIS. 453 acid for the purpose. Aqua ammonia is next added, until the liquor blues red litmus paper, and then acetic acid in excess. Oxide of iron and phosphate of magnesia are held in solution, while phosphate of iron precipi- tates. This latter is to be filtered off, washed with hot water, dried and ignited, and weighed. The weight doubled, expresses the per cent, of ferric phosphate in the raw ma- terial. The composition of this ferric phosphate varies with the temperature of the liquor, its state of dilution, and the strength and pro- portion of the aqua ammoniae employed as precipitant. If the quantity is large, its con- tent of phosphoric acid must be determined by separation after the manner hereinafter described. 8. Oxide of Iron. The filtrate from the phosphate of iron — containing the phosphate of magnesia and oxide of iron — is now to be diluted largely with boiling distilled water, treated with aqua ammoniae, y>/5/ to perfect neutralization, and filtered rapidly. The oxide of iron on 454 PURE FERTILIZERS. the filter is to be washed with hot water, dried, ignited, and weighed. The weight doubled, expresses the per cent, of that ele- ment contained in the original raw material. It is indispensable to have the liquor dilute, hot and free from any excess of free ammo- nia, so as to prevent the oxide of iron carry- ing with it some of the phosphate of mag- nesia. 9. Phosphate of Magnesia. The filtrate from the oxide of iron, just mentioned, is to be evaporated to a small volume upon the sand-bath, allowed to cool, then treated with aqua ammonite in excess, and set aside for ten to twelve hours. At the end of this time, the phosphate of mag- nesia will have crystallized out, and is to be filtered off", washed with ammoniated water, dried, ignited, and weighed. The process of ignition drives off the ammonia, and changes it into pyro-phosphate of magnesia (2MgO, PO5), every per cent, of which contains o'639 of phosphoric acid. CHEMICAL ANALYSIS. 455 10 and II. Phosphate of Ahtmina, and Alumina. The filtrate l, which was set aside pre- viously, is now to receive attention. It con- tains alumina and phosphate of alumina dis- solved in caustic potassa. This latter is to be fully neutralized by the addition of hydro- chloric acid, which first precipitates and then re-dissolves the aluminium compounds To throw them down wholly, it is next necessary to add carbonate of ammonia in excess. They are then filtered off, thoroughly washed with hot water, dried, ignited, and weighed. The weight expresses the Joint amount of alumina and phosphate of alumina in the raw material, and is to be noted in the record. The next step is to transfer the contents of the platinum crucible to a beaker glass ; add hydrochloric acid ; heat the solution on a sand-bath ; and dilute largely with water. This done, a large quantity of solution of citric acid is to be poured in ; and, finally, aqua ammoniae, with a slight excess of solu- tion of sulphate of magnesia containing chlo- 456 PURE FERTILIZERS. ride of ammonium. The vessel is then covered, and left to repose in a cool place for twenty-four hours ; after which, its contents are to be filtered and washed with dilute ammonia water. The filter contains the phosphoric acid as phosphate of ammonia and magnesia, but mixed with greater or smaller traces of alu- mina and basic citrate of magnesia. To re- move these, the contents of the filter must be dissolved in hydrochloric acid, treated anew with a very small quantity of solution of citric acid, and re-precipitated by ammonia. After being washed with ammoniacal water, dried, and ignited, it is to be weighed as pyro-phosphate of magnesia (2MgO, PO5), every per cent, of which contains o"639 of phosphoric acid. As this portion of phos- phoric acid belongs, naturally, to alumina, it must be calculated to the latter, and written down in the table of results as phosphate of alumina. Every vo of phosphoric acid re- quires 0722 of alumina. The proportions of phosphoric acid and alumina thus determined being subtracted from the joint amount previously noted, give CHEMICAL ANALYSIS. 457 the proportion of alumina in the mineral other than that which is combined with phos- phoric acid. As only fifty grains of raw material are taken for analysis, the figures of result must be doubled, in order to make them express the per cent. 12. Alkaline Salts. The calx a from the organic matter and constitutional water determined in an earlier stage (page 439) of the process and then placed in reserve, is now to be treated for the separation of alkaline salts and fluoride of calcium. For this purpose it is boiled with an ounce of distilled water, allowed to cool, and then filtered and washed. The filter is m, and the filtrate is N. The filtrate n contains the alkaline salts (with some little sulphate of lime, probably), and is to be evaporated to dryness in a pla- tinum capsule on a hot sand bath. Its con- stant weight less that of the capsule is then taken and noted in the tabular result as 458 PURE FERTILIZERS. alkaline salts. It must be doubled to ex- press the per cent. In rock guanos and mineral phosphates the alkaline salts consist, generally, of chlo- ride of sodium with sulphate of soda ; and their proportion is very small. But to de- termine whether any potassa is present, as well as to separate it in such case, the direc- tions hereinafter given on that point, for ana- lysis of superphosphates, must be followed. To determine whether any appreciable quantity of sulphate of lime remains with the alkaline salts, it is only necessary to add very dilute alcohol to the latter, after weigh- ing them, which will leave the former undis- solved. It can then be separated by filtra- tion, dried, ignited, and weighed. Its weight is to be deducted from the previous weight. 13. Fluoride of Calciuni. If the presence of fluoride in the raw ma- terial was made evident by the corrosion of the glass cover to the beaker, in the earlier treatment for the separation of sand and silica, its quantity is now to be determined by fusing the contents of filter m in a plati- CHEMICAL ANALYSIS. 459 num crucible with a mixture of six parts of carbonates of potassa and soda and two parts of silicic acid. This operation converts all the fluorine and phosphoric acid into soluble alkaline salts. The mass, w^hen cold, is to be treated with water, which renders liquid the soluble salts. The liquid is to be filtered off", and treated with solution of carbonate of ammonia which precipitates the silica. This latter is to be filtered off, and washed with a dilute solution of carbonate of ammonia. The liquor is now to be treated with hydro- chloric acid until it reddens blue litmus paper, and afterwards with a slight excess of solution of chloride of calcium. Fluoride of calcium, together with phosphate of lime, drop from the solution, and this precipitate is to be filtered off, washed with hot water, dried, ignited, and weighed. The calx is now to be placed in a platinum capsule, and heated with sulphuric acid until all the fluorine is expelled as hydrofluoric acid. Care must be observed not to let the heat be sufficiently high to volatilize any of the sul- phuric acid. The residue is then digested with hydrochloric acid to dissolve the phos- 46o PURE FERTILIZERS. phate of lime, and afterwards with its own volume of alcohol to precipitate the lime as sulphate. After five or six hours' repose this latter is to be filtered off, washed with alcohol, dried and weighed. Every ro of dry sulphate of lime contains 0'4ii7 of lime or oxide of calcium. The filtrate from the sulphate of lime is to be evaporated on a sand bath, for the vola- tilization of the alcohol, then treated with a mixture of sulphate of magnesia and chlo- ride of ammonium, and finally with an ex- cess of aqua ammoniae. After six or eight hours' repose the phosphoric acid will have separated, wholly, as phosphate of magnesia and ammonia. This latter is to be filtered off, washed with hot water, dried, ignited, and weighed as pyrophosphate of mag- nesia. Every i"o of this latter salt of mag- nesia contains 0'639 of phosphoric acid. The total of lime and phosphoric acid hav- ing now been determined, so much of the former must be apportioned, by calculation, to the latter as is necessary to make tri-phos- phate of lime, or, in other w^ords, i'i66 of lime to every ro of phosphoric acid. The '- " ~^' — ' „l L. L...^ WicentBr TriibnerS: C?.6C.PaieiTL0sterRcw. MORrir on ihe Manulacluir nfFertili^'r^ SpecialVy dEsigiied for K Morfiis Work ai Feniliza- Triibner k C?.6C.Pajei7io5tprRDW. CHEMICAL ANALYSIS. 461 residue of lime belongs to the fluorine which is expelled, and every vo of CaO makes or is equivalent to i'40 fluoride of calcium (CaFl). The figures obtained must be doubled to ex- press the per centage. 14. Carbonate of Lime. If on the addition of acid to the raw ma- terial, there is any effervescence, this action denotes the presence of carbonate of lime. To determine the amount, a separate or new portion of fifty grains of the raw material in fine powder must be taken, and treated in a special apparatus shown by fig. 20, which is drawn one-third smaller than the natural size. It consists of a very light glass flask a, as the vessel for receiving the powder ; a glass pipette b, and a drying tube c, containing chloride of calcium, both of which latter con- nect with the former by means of a tightly adjusted cork h. The pipette is to be filled with either sulphuric acid or a very strong solution of tartaric acid, by dipping the lower end into the liquor and drawing the latter up into the bulb by placing the 462 PURE FERTILIZERS. mouth at the upper end. This portion is then fitted with a piece of india-rubber tube and one of Mohr's clamps d, shown enlarged by fig. f. The clamp and india-rubber tube serve to exclude or admit air into the flask ^ 5 Fie 20. as may be required ; it being only necessary to press upon the keys g g with the fingers when it is desired to open the tube, and to remove them when it is to be closed. When the weighed portion of powder has been put into the flask, the latter is to be closed tightly CHEMICAL ANALYSIS. 463 with the cork stopper, and the whole appara- tus and contents carefully weighed on the fine balance. This weight having been noted in the record, the acid is then made to flow from the pipette in drops, by pressing the keys of the clamp at short intervals. Carbonic acid having a much feebler che- mical affinity than either sulphuric or tar- taric acids, is displaced by either of these latter from its combinations, and driven off in the form of gas, as indicated by the effer- vescence which takes place ; and if in its escape it should be involved with any me- chanically mixed water, this will be arrested by the chloride of calcium as it passes through the drying tube, — that salt being a hygroscopic substance. Nothing but car- bonic acid escapes ; and after all the acid has been allowed to fall upon the powder, and effervescence has ceased for some ten or twenty minutes, the lips are to be applied to an india-rubber tube temporarily drawn over the end of the exit tube e, and the residual traces of gas drawn out of the apparatus by suction. This india-rubber tube being then removed, the apparatus is to be weighed 464 PURE FERTILIZERS. again. The difference between this second and previous weight shows a loss which ex- presses the amount of carbonic acid in the raw material. The carbonic acid is to be calculated to lime (CaO) and in the propor- tion of I '27 lime to every i.o of carbonic acid. The equivalents of lime belonging severally to the fluorine and the carbonic and phosphoric acids being now added to- gether and deducted from the total of lime previously estimated, may leave a remainder. In that case the remainder is to be set down in the table as Lime with organic and silicic acids, and probably also with alnmina. The results are to be arranged in the order shown by the following table. Recapitulation . Moisture - - say 2 00 Organic matters - - - n 2-50 Sand and silica - - - » 3 '00 Fluoride of calcium - - M 4'00 Sulphate of lime - - » S'oo Carbonate of lime - - » 7'oo Lime (with organic and sii licic acids) - „ 2-00 Bone-phosphate of lime - ■ - „ 5800 Bone-phosphate of magnesia - „ 3-50 Phosphate of alumina - - „ 500 CHEMICAL ANALYSIS. 465 say 3-00 „ 2-00 „ I -oo „ 2-00 lOO'OO Phosphate of iron Oxide of aluminium Oxide of iron Alkaline salts Total The phosphoric acid is thus shown in its individual combinations and not totalized as tri-phosphate of lime, according to the mere- tricious style of ^^ commerciar chemistry. FORMULA FOR THE CHEMICAL ANALYSIS OF MINERAL PHOSPHATES OF ALUMINA AND IRON. In the preceding formula, instructions have been given for the separation of the alumi- nium and iron compounds from those of lime, because there are very few mineral phos- phates of lime which do not contain more or less of those compounds. On the other hand, there are certain mineral phosphates of alumina and iron wholly free from lime associates. To ana- lyze these, therefore, is a simple process, it being necessary to follow only those parts of the formula already explained, which apply II II 466 PURE FERTILIZERS. to their special components. Taking " Re- doiida Guano' as a typical specimen, these components are, in their proper order of arrangement, generally as follows : — Water _ . _ - Organic matter - _ _ Sand and silica . - - Sulphate of lime _ . _ Phosphate of alumina Phosphate of iron . _ _ Oxide of aluminium . - - Oxide of iron _ _ _ Total a. Water. An average sample of about four ounces having been selected, is to be reduced, wholly, to fine powder in a polished iron or steel mortar. Fifty grains are then to be heated in a platinum crucible on a very hot sand bath, until the weight becomes constant. The loss of weight thus produced expresses, when doubled, the per cent, of water in the mineral, b. Organic Matter. The residue is further heated, but over a CHEMICAL ANALYSIS. ^67 gas flame, to redness until it ceases to lose weight. The difference between its constant weight after the heating, and its previous weight, expresses, when doubled, the per cent, of organic matter in the mineral. c. Sand and Silica. The calx is then to be emptied from the crucible into a small beaker glass, drenched with hydrochloric acid, and heated on a sand bath. After an hour, sulphuric acid is to be added very cautiously, for otherwise too violent action may ensue, and cause the ejection of some of the contents of the glass. Enough acid must be added to thin the mass to fluidity. After which, digestion is to be continued until all the soluble matter is taken up, as will be indicated by the liquor having assumed a thick syrupy con- sistence without solid residue at the bottom. It is then evaporated to dryness on the sand bath, treated with a few drops of hydro- chloric acid and sulphuric acid, and again digested for ten minutes. Hot water being then added to make a thin dilution, the whole is to be stirred and filtered. The H II 2 468 PURE FERTILIZERS. washed, dried, ignited, and weighed filter represents the sand and silica. d. Sulphate of Lime. The filtrate may contain, in rare instances, some small portion of sulphate of lime ; therefore its volume must be reduced two- thirds by evaporation on a sand bath ; after which a double volume of alcohol is to be added. If it contains sulphate of lime, this salt will precipitate, and must be filtered off, washed, dried, ignited, and weighed. e. Alumina aud PJiosphate of Alumina. The filtrate contains alumina and oxide of iron together with their phosphates, and must be evaporated to expel alcohol. Solu- tion of caustic potassa is then added in ex- cess, so as to hold in solution the aluminium compounds while it precipitates those of iron. These latter are to be filtered off, washed with hot water, dried, ignited, weighed and set aside as a. The filtrate is now to be treated for the separation and estimation of its alumina, CHEMICAL ANALYSIS. 469 and phosphate of alumina, precisely in the manner described, for filter k, in paragraphs 10 and 1 1 of the preceding formula. f. Oxide of Iron and Phosphate of Iron. The calx a contains only these two com- ponents, and it is to be digested in a beaker glass with sufficient hydrochloric acid to effect its solution. The further treatment is then precisely similar to that described in paragraphs 7 and 8 of the preceding formula. FORMULA FOR THE CHEMICAL ANALYSIS OF COMMERCIAL SUPERPHOSPHATE OF LIME ; AND COMPOUND FERTILIZERS. The commercial superphosphates of lime vary in their composition, according to the skill and integrity which may have been practised in the manufacture of them. Che- mical analysis is the only mode of deter- mining their value previous to use, and should be made as follows. A. Water. Average the sample- fairly, weigh out a portion of 50 grains in a counterpoised 470 PURE FERTILIZERS. watch-glass, and dry over a sand-bath at 200° to 212° Fahrenheit until weight ceases to be lost. The loss which the constant weight indicates, will, when doubled, express the per cent, of accidental water in the sample. B. Bi-Phosphate of Lime. A fresh portion of 50 grains is to be tri- turated in a porcelain mortar with distilled water, and poured into a small glass funnel loosely plugged in its stem with cotton-wool. When the liquor has run through into a beaker glass beneath, a fresh relay of cold water is poured on and allowed to infiltrate through as before. In this way the infiltra- tion is further repeated thrice with cold, and subsequently several times with boiling water or until all the soluble matter has been displaced or washed out. This will be shown so soon as the filtrate, running through, no longer leaves a decided tache, when a drop has been evaporated to dryness upon a platinum spatula. The use of cold water insures the extraction of any soluble aluminium phosphate that may be present ; CHEMICAL ANALYSIS. 471 for, according to Warrington, hot water would coagulate and keep it back. The filter is a, and must be kept in reserve as the insoluble portion. The filtrate b con- tains all the soluble phosphate, together with some little sulphate of lime, and any sul- phates of alumina and iron that may have been in the sample. It is to be reduced, by evaporation on a sand-bath, to a small volume, and treated with alcohol for the precipitation of the sul- phate of lime. This latter is then to be fil- tered off, washed, and added to the reserved filter A, containing the portion of the sample insoluble in water. Lime-water is now to be added to the filtrate c, a little at a time, until precipita- tion or cloudiness ceases to be formed. Great care must be observed to restrict the lime as nearly as possible to the exact quan- tity, and this is nice manipulation. The better way will be to keep back about one- eighth of the liquid, so that this reserve may be at hand for a readjustment of the neu- trality, in case of too much lime-water having been added to the first portion. Very thin 472 PURE FERTILIZERS. milk of lime, strained through a bolting or other fine cloth, may be used instead of lime- water, and with the advantage of producing less volume of liquid ; but, in this case, the manipulation must be more expert, so as to prevent the addition of any excess of lime. This treatment throws down all the phos- phoric acid as phosphate of lime, with any alumina and oxide of iron, which may have been present in the solution. The precipi- tate is to be filtered off, washed, and noted as D. The filtrate is e. The filter d is to be transferred to a beaker glass, and dissolved in just sufficient hy- drochloric acid, by the heat of the sand- bath. A small quantity of water is added, and afterwards a double volume of alcohol. Finally, sulphuric acid is to be added, a drop at a time, until all the lime has precipi- tated as sulphate. The sulphate of lime, thus formed, is then filtered off, washed, and thrown away. The filtrate contains all the phosphoric acid with the alumina and iron. It is to be evaporated on a sand-bath for the expulsion of alcohol, and then treated with ammonia to throw down the alumina and CHEMICAL ANALYSIS. 473 iron. Filter, wash well with hot water, and set aside as filter f, containing iron and alu- mina. The filtrate now holds only phosphoric acid, and is to be treated precisely as directed in paragraph 6 of the first formula. Every ro of phosphoric acid (PO5) is equivalent to, or makes, v6^ of biphosphate of lime (CaO, 2HO, PO5). If it is only desired to estimate the amount of soluble bi-phosphate which the sample may contain, the analysis here ends. But as this component is often associated in arti- ficial mixtures, with precipitated phosphate, bone-phosphate, ammoniacal and alkaline salts, it is proper that the formula should comprise instructions for a thorough analy- sis, in the progress of which, any and every probable component may be detected and estimated. c. Alumina and Iron. Therefore, the filter f is to be ignited and weighed. The weight having been recorded, the calx is then dissolved in hydrochloric acid by the aid of the sand-bath, and treated 474 PURE FERTILIZERS. with citric acid, as directed in paragraphs 7 to II, for the separation of any phosphoric acid which it may contain. The weight of the phosphoric acid deducted from the pre- vious total weight of the calx leaves the weight of- the aluminium and iron oxides. Both weights must be doubled to express the per cent, relations, and are to be recorded in the table among the soluble constituents of the sample. D. Chloride of AuinwJiiimi. The filtrate e having been poured into a platinum capsule of known weight, is to be evaporated to dryness upon or over a sand-bath at a temperature not exceeding 212^ Fahrenheit. When it ceases to lose weight, its constant weight is to be noted. The crucible and contents are then to be heated over a gas flame, much below redness, until vapours cease to be given off. Chlo- ride of ammonium, if any is present, thus volatilizes ; and the capsule being now weighed will show a loss on its previous weight. This loss, doubled, expresses the per cent, of chloride of ammonium in the sample. ^ CHEMICAL ANALYSIS. 475 EE. The residue is now dissolved in water, diluted to a given number of cubic centi- metres, and then divided into two equal por- tions, G and H. It should be remarked here, that the solution may contain both chlorides and sulphates of the alkalies, together with sulphate of ammonia. F. Sulphate of Ammonia. The portion g must be treated with chlo- ride of barium in a careful manner, so as to avoid an excess. The precipitate is then to be filtered off, washed with hot water, dried, ignited, and weighed. Every i 'o of this cal- cined filter of sulphate of baryta (BaO, SO3) contains 0*34335 of sulphuric acid, and this acid is to be apportioned, as will be explained hereafter. The sulphates having been converted thus into chlorides, are to be evaporated to dry- ness, as before, and the constant weight noted. Afterwards, the mass is to be heated, as in the previous instance, to expel any chloride of ammonium that may have been formed from sulphate. It must be weighed, therefore, again, to determine the amount of 476 PURE FERTILIZERS. loss, if any. Every ro of this loss, being chloride of ammonium, represents r257 of sulphate of ammonia. G. Potassium Chloride. The residue is then dissolved in water, and a little carbonate of soda added to precipi- tate any excess of baryta salt that may have been added. The liquor is then filtered and washed. The filter is thrown away ; but the filtrate is to be reduced, by evaporation, to a small volume, treated with a strong solution of neutral chloride of platinum in slight excess, and evaporated in a porcelain capsule nearly to dryness over a water-bath. A mix- ture of alcohol, of 80 per cent, strength, and ether, is then added, and the whole left to digest for some fifteen to thirty minutes. The double salt of chloride of platinum and potassium is thus rendered wholly insoluble, and must be filtered off upon a counterpoised filter, dried, and weighed. Every ro of this salt (KCl, Pt, CI2) contains 0-30507 of chlo- ride of potassium, and every ro of this latter salt is equivalent to r 166 of sulphate of potassa, or o'523 of potassium deducted from CHEMICAL ANALYSIS. 477 the previous weight (paragraph f) gives the amount of chloride of sodium in the filtrate. To determine whether any of the potassium or sodium may have existed originally as chloride, it is first necessary to test the H portion of the liquor previously noted, with nitrate of silver. If any precipitate falls, it must be filtered off upon a counterpoised paper, washed with hot water, dried, and weighed. Every ro of the chloride of silver thus precipitated contains '2472 of chlorine, and every i*o of chlorine is equivalent to 2* 10 of chloride of potassium. The chlorine is allotted to potassium, first, because this latter is a stronger base than sodium, though it is possible a part of it may belong really to the latter, if it were known how to deter- mine that point and portion under existing circumstances. H. Sulphate of Potassa. If there should be more of potassium than the chlorine requires, this residue was origin- ally in the form of sulphate. Therefore, as much of sulphuric acid as it may require to convert it into KO, SO3, must be deducted 478 PURE FERTILIZERS. from the total baryta product of the portion of liquor G. Every vo of potassium needs 1*23 of oxygen and sulphuric acid jointly, to convert it into sulphate of potassa. J. Chloride of Sodium. If the amount of chlorine obtained should be more than sufficient for all the potassium, then the excess is to be calculated to sodium as chloride of sodium. Every vo of chlorine (CI) is equivalent to 0-6486 of sodium (Na), or I '648 of chloride of sodium (NaCl). This proportion of chloride of sodium is to be deducted from the total amount of soda salts, previously determined. K. StilpJiate of Soda. The remainder of the sulphuric acid should exactly or closely fit the residual amount of chloride of sodium, already determined, as sulphate of soda is most probably the form in which it originally existed in the sample. Every ro of chloride of sodium is equivalent to 0*684 of sulphuric acid, and every ro of this latter makes 1782 of sulphate of soda. As only 50 grains of the sample were CHEMICAL ANALYSIS. 479 taken for the analysis, and this portion was divided into moieties, for the estimation of the chloride of potassium and sulphates of potassa, soda, and ammonia, the figure results for these latter must be multiplied by four, in order to express the per cent, relations. L. Nitrate of Soda. Though this salt is not comprised in any of my products, it may be a component of other fertilizers, as it is now largely used in their manufacture ; and, therefore, a proper formula for chemical analysis should com- prise instructions for detecting and esti- mating it. Its presence may be determined by leach- ing a sample of the fertilizer with water, filtering, and evaporating a few drops of the filtrate to dryness in a platinum crucible. If now, on adding to the dry mass a few drops of sulphuric acid and heating, there should be an appearance or smell of orange-red nitrous fumes, they are proof of the presence of a nitrate, which is most generally nitrate of soda. In that case, then, a fresh portion of 50 grains of the original sample is to be di- 480 PURE FERTILIZERS. gested in a beaker glass and on a hot sand- bath with distilled water. All the soluble matter of the sample will be thus taken up ; and the whole is to be filtered and washed. The filter, being foreign to this determina- tion, is to be thrown away. The filtrate is to be treated with thin and smooth milk of lime until this latter ceases to throw down a precipitate. Filter and wash. The filter containing alumina, oxide of iron, and phos- phate of lime, is to be thrown away ; as all of these matters have been estimated accord- ing to the instructions in previous para- graphs. There remains nothing in the filtrate but alkaline salts and nitrate of soda, with some sulphate of lime. It is to be evaporated to dryness and constant weight, in a plati- num crucible the weight of which has been previously noted, and there is then to be added to the saline mass some pure powdered silica. The silica must be pre- viously heated, to insure perfect dryness, and its proportion must be four to six times the supposed weight of the nitrate of soda. The mixture of the two having been made MOEFir PI..4 ,. •) ale _'/ Elevation MOB FIT on the Manufhetnrv of Fertilisers. Elevator and Digestion Vats_ End Elevati ON. CHEMICAL ANALYSIS. 481 intimate by stirring with a glass rod, the whole is then carefully weighed and its exact weight recorded. The crucible being then covered, is to be heated for one half hour over a gas flame to a redness which is so low as to be only barely visible in the day time. At this temperature the nitric acid of the soda (or potassa) will pass off, while any alka- line chlorides or sulphate that may be pre- sent remains undecomposed. The crucible and contents being weighed again, when cool, will show a loss which represents the amount of nitric acid expelled. Every ro of this nitric acid (NO5) is equivalent to o"5796 of soda (NaO), and represents i'5796 of nitrate of soda. The result is to be multi- plied, of course, by two, in order to make it express the per cent, relations. The portion of the fertilizer soluble in water having been thoroughly analyzed, the next operations must be with the insoluble part which was placed in reserve as filter a, at an early stage of the examination. The quali- tative and quantitative steps are one and the same in this formula, — that is, they proceed together. 1 1 482 PURE FERTILIZERS. M. Precipitated Phosphate of Lime. The filter a having been perfectly dried, its contents are weighed and then transferred to a beaker glass. . Pure concentrated acetic acid of specific gravity i'05 is next to be added, and the whole left to digest in the cold for half an hour. By this treatment, carbonate and precipitated phosphate of lime are dissolved, while the bone-phosphate of the natural mineral remains nearly un- touched, on account of its dense physical structure. The whole is then filtered and washed ; the filter being j and the filtrate k. The filtrate k is treated with a slight ex- cess of aqua ammonise filtered and washed. The filter is then dried, ignited, and weighed. The weight, multiplied by two, expresses the percentage of precipitated phosphate of lime, which may contain, also, some possible trace of free carbonate of lime. N. Carbonate of Lime. The filtrate from the preceding filter is to be treated with oxalate of ammonia, until a precipitate or cloudiness ceases to form. The CHEMICAL ANALYSIS. 483 oxalate of lime is then to be filtered off, washed, dried, ignited, and weighed. As oxalate of lime changes into carbonate by ignition, the weight, doubled, represents the per cent, of carbonate of lime in the sample. o. Organic Matter. The filter j having been thoroughly dried at 212^^ Fahrenheit, its contents are then weighed and afterwards calcined in a plati- num crucible. The loss of weight thus produced by igni- tion represents the amount of organic matter in the sample. p. Sand and Silica. The remaining calx is now to be treated with hydrochloric acid, and carried through the operations explained at length in para- graphs 3, 4, 6, 7, 8, 9, 10, II, and 13 of the first formula of this chapter. In this manner, each and every one of its probable constitu- ents will thus be detected and estimated. The formula just given is made compre- hensive, so that it may apply in the first part to commercial superphosphates of lime, and 1 1 2 484 PURE FERTILIZERS. in its entireness to any and every fertilizing mixture of artificial manufacture, however complex. The constituents having been separated and quantitatively determined, should be formulated according to the following ar- rangement. Recapitulatioit. Soluble bi-phosphate of lime - - - Precipitated phosphate of lime Bone- or tri-phosphate of lime Bone-phosphate of magnesia - - _ Chloride of ammonium _ _ _ Chloride of potassium - _ _ Chloride of sodium - - - - Sulphate of ammonia _ _ _ Sulphate of potassa _ _ _ Sulphate of soda - - - . Nitrate of soda . _ _ - Sulphate of alumina _ _ _ Sulphate of iron - _ _ _ Phosphate of alumina _ _ _ Carbonate of lime - - - - Lime, with organic and sihcic acids and alumina - Fluoride of calcium - . _ Alumina - - - _ - Oxide of iron - - _ _ Sand and silica - - _ _ Organic matter - " - Water - - . - . Total CHAPTER XXIV. ON THE COMMERCIAL VALUATION OF CRUDE AND REFINED FERTILIZING MATERIALS. In computing the value of a fertilizing mate- rial there should be a close adjustment of its commercial and agricultural relations. The prime elements of a profitable ferti- lizer are nitrogen, phosphate of lime, and potassa. To determine, however, the com- mercial and agricultural worth of a fertilizing material, it is necessary to ascertain its pre- cise composition and nature by a fidl chemi- cal analysis. The questioning, in this re- spect, must be both scientific and conscien- tious ; for no mere partial investigation will serve the importance of the subject. Not only must it be learned what constituents are present, but in which forms they exist and with what associates they may be accom- panied. 486 PURE FERTILIZERS. In a general sense, the form or state regu- lates the agricultural value of a fertilizing element ; but the character of its associates affects, more or less, the computation. AmmoJtia. Thus, as to azotized matters, those which contain their nitrogen in the form of ammo- niacal salts are the most active; while others, on the contrary, like woollen waste, horn, and leather clippings, which contain it in a com- paratively dormant or quiescent state, acquire chemical or fertilizing momentum, so to speak, only by the aid of time and decompo- sition. These influences add to the first cost and change the classification or money rank of the material. Here, moreover, sub- stances of this kind which are most prone to decomposition, are worth more, proportion- ally, than others of their class. Intermediate between these two, is a third form existing as urea, urate, and phosphate, in farm-yard manure, bird guanos, human excrements, and kindred substances ; which, though not active or dormant, are more potential than cither. I use this term, potential, to desig- COMMERCIAL VALUATION. 487 nate a great sensitiveness to the assimilating powers of the growing crop, whereby the plant is enabled to take up its nutriment in condition and quantity as may be wanted to produce the highest degree of progressive development with the least possible expendi- ture of time and fertilizer. This form of nitrogen being the most valuable, in every sense, should constitute the standard of esti- mation ; but, unfortunately, the supply of it is too limited, at present, to justify that posi- tion for it. Later, when its source becomes amply extended by the separation of the organic matter from the phosphate-sewage precipitate, as suggested at pp. 397 to 405, it may assume the controlling position in the appreciation of nitrogenous substances. In the meantime, there remain only the ammonium chloride and sulphate as a solid standard of comparison. The abundant and regular production of crude ammonia liquors in the coal-gas and bone-black works, render those salts, already, the most prominent part of the ammonia supply ; and this source not only assumes a progressive increase, but is becoming widened by lateral feeders from the 488 PURE FERTILIZERS. utilization of woollen wastes for the purpose. Not Jong hence, it will expand into yet larger proportions, when the excrements of mankind are turned into this account or cur- rent, after the manner which I have noted at p. 47 ; or the air is exploited for the purpose. With this explanation, therefore, ammonia must be set down at its average value in ammonia salts, which is £^c)0 per ton or 1 8s. per unit ; the present market price of ammonium chloride being ;^30 per ton, while that of sulphate of ammonia is £^22 per ton. Materials containing nitrogen in a dormant or quiescent state are to be rated at a figure so much less as will cover the manufacturing expense of converting that nitrogen into its equivalent of ammo- nia salt, with twenty per cent, superadded for profit and contingencies. The unit refers to the ton of 2240 pounds, and is used in accordance with the prevailing British custom, which requires that the com- putation shall be made by unit rather than by per cent. Every per cent, of any constituent of a material, when multiplied by twenty, becomes COMMERCIAL VALUATION. 489 a unit. Thus, for example, if a material should contain seventeen per cent, of ammo- nia or the equivalent in nitrogen, with the cost of conversion added, it is said to have 17 units of ammonia, although the latter represents in fact 380 pounds of ammonia in the ton of the material. The method of calculating by per cent, is, however, the more rational one, as it gives expression to the actual quantity or propor- tion of the valuable constituent of a raw material. On the other hand, the unit method excludes from the computation 240 pounds of the ton, as a concession to trade influence. Phosphates of Lime. Bone-ash or animal phosphate of lime is the typical expression of this material ; and pure apatite and phosphorite may be taken as the best representatives of its mineral condition. Animal Phosphate of Lime. Bone-ash has a peculiarly sensitive tem- perament in its chemical relations, and is 490 PURE FERTILIZERS. well suited for immediate potential effect upon soils. It is more uniform in composi- tion than any other kindred material, and contains a higher average of actual phosphate of lime. Moreover, in this material there is only an inconsiderable proportion, compara- tively, of profligate matters associated with the phosphate of lime constituent. On these accounts it holds a commercial and agricultural position apart from other kinds of its class. The laws of supply and demand regulate, therefore, its market price, which is at present £^(i ' 15 to £^^ per ton, or 2s. per unit. This value refers to ash con- taining 70 per cent, of tri-phosphate of lime, that being the usual strength. Bone-black and bone-dust are to be esti- mated by the above standard, for similar reasons, but according to the proportion of tri-phosphate of lime which they may con- tain. At the same time, their content of nitrogenous matter must be taken into con- sideration. This is potential in character, and its money value is to be computed, as explained already under ammonia, and added to that of the phosphate constituent. COMMERCIAL VALUATION. 491 Miiiei^al Phosphate of Lime. The mineral phosphates of lime, even of the highest grade, have a dense structure and rocky nature, which give them a chemical, as well as physical temperament, quite distinct from that of bones, bone-ash, or bone-black. Moreover, a greater or lesser quantity of the phosphoric acid which they may contain is combined, almost invariably, with iron and alumina ; whereas, the animal phosphate of lime holds that acid wholly as tri-phosphate of lime. The presence, too, of foreign asso- ciates with the lime phosphate element is an important modifying influence in deter- mining the commercial value of a mineral phosphate. I restrict my remarks to the commercial value because mineral phosphates in their natural crude state are very slow indeed as direct agricultural agents. The foreign mat- ters which they contain exert a cementing action upon the valuable phosphate of lime constituent, and thus impart to this latter an inertia which militates against its fertilizing activity. Though vegetation will draw its 492 PURE FERTILIZERS. nourishment from the most available source, however difficult, its vigour of structure and productive capacity will be more or less feeble if the nutriment should be either de- ficient in quantity or obstinate to the atmo- spheric and solvent influences of the soil. Plants thrive best when their food is present in assimilable or potential forms ; and, con- sequently, time and money are both wasted in sowing fertilizers which may be tough in nature or sluggish in action. The phosphate of lime constituent re- quires, therefore, to be separated from its disadvantageous association of foreign mat- ters ; and this involves the expense of chemical agents, labour, time, etc. The foreign matters, to say the least, are unprofitable diluents of the phosphate of lime constituent. Indeed, their presence in mine- ral phosphates is an injurious influence of important degree. Apart from their cement- ing action, they have the disadvantage of importing into the products a humid pro- perty and a large degree of dilution, without any compensating advantage whatever, when the crude mineral is treated with acid for COMMERCIAL VALUATION. 493 conversion into pure phosphates of lime. They not only waste acid in this manner, but really are barriers to its free action upon the phosphate of lime constituent, as the latter remains intact until the associate matters have been overcome chemically. As promoters of waste and excessive dilu- tion, I term these foreign matters profligate elements or associates ; and they consist of fluoride of calcium, carbonate of lime, organ- ate and silicate of lime, oxide of iron and alumina, in first degree ; and of sand, silica, and organic matter, in secondary importance. Pure tri-phosphate of lime, divested of all associates passive in themselves, or which might paralyze its fertilizing action, is, there- fore, the only sound basis for computing the value of a crude phosphate of lime. There is no such standard in Nature, practi- cally considered ; but if one should be found, it would be worth double the market value of a mineral containing only 50 per cent, of tri- phosphate of lime, plus the cost of the acid, labour, and manufacturing expense which the residual moiety of profligate elements would entail in the conversion of two tons of 494 PURE FERTILIZERS. such crude material into the one ton of pure phosphate. As the per cent, of phosphate of lime falls, that of the profligate associates rises ; and hence the convenience and expense of re- fining a crude mineral are dependent upon the prevailing circumstances in this respect ; and, correspondingly, the value will progress downwards or upwards in regular arithmeti- cal proportion. The medium grades of mineral constitute the major part of the crude phosphate re- sources, and, being unsuited for fertilization until they have been chemically prepared, it follows that the basis for computation must be selected from them. And, as seems to me most justifiable, I take one containing 45 per cent, of actual tri-phosphate of lime, the present market value of which is tenpence one farthing per unit, or thirty-eight shillings and sixpence per ton. This kind of mineral phosphate of lime has expression in the Wicken and Calais Coprolites, and the best quality of ''South Carolina Phosphate'. Taking, then, a crude mineral of 45 per cent, of lime phosphate strength, at its pre- COMMERCIAL VALUATION. 495 sent market value of £\ : 5 for 2*20 tons, the only datum that is needed to form a table of the money value of different grades of raw phosphate is the mere expense for chemicals, labour, fuel, etc., which would be consumed for refining that quantity of crude mineral into its equivalent of ro ton of pure or standard phosphate of lime. This would be £^ : 15, according to my experience, and must be dis- tributed, therefore, through all the degrees from 45 to 100 of the scale, in order to ex- press a correct graduation of the value. There are, consequently, fifty-five degrees which are to share the amount which is to be apportioned ; and, as the ratio of phosphate may rise degree by degree, in the raw mine- ral, each degree will hold not only its original value of tenpence farthing per unit, but an additional one acquired by the saving of the refining expense which, otherwise, would be involved by displacing its equivalent of pro- fligate elements. Starting, therefore, at tenpence farthing per unit for a raw mineral containing 45 per cent, of actual tri-phosphate of lime, there must be a progressive advance of one 496 PURE FERTILIZERS. farthing for each degree, so that when the natural quality of the mineral may have risen to purity, as in some specimens of apatite, it will represent a value of two shillings per unit. In like manner, the scale may be carried downwards by diminishing the valuation, progressively, a farthing for each degree of actual phosphate of lime strength ; but, for manufacturing purpose, the mineral should not have less than twenty-four degrees, in that respect. In other words, mineral phosphates cease to be profitable when they contain less than 24 per cent, of actual phosphate of lime. The following table is founded upon this basis, and refers to the actual per cent, or degree oi phosphate of lime, because it is my habit always to distinguish that portion of phosphoric acid thus united from that which may be combined with the oxides of iron and aluminium that are present, and for the simple reason that the latter is, agriculturally, much inferior in value to the former, and should be estimated separately. This explanation is rendered necessary by the fact that analyses of mineral phosphates COMMERCIAL VALUATION. 40)7 are made often in a '' commerciar style most discreditable to science and the chemical profession. Not only are incongruous con- stituents grouped together, in the report, under one head ; but the total of phosphoric acid is expressed most frequently by its eqid- valent in tri-phosphate of lime, as if there were no other phosphate present : and when, in fact, much of the phosphoric acid is com- bined actually and less profitably with alu- mina and oxide of iron. Such a presentment implies a character which is unreal, and practises a deception which is mean. Science, in its dignity, is regardless of all interests but those of truth and humanity. Its mission is to serve the good of mankind, and not the profit of an individual or class. The chemist, then, in his professional quality, is a high priest of science, who assumes, as a trust, the obligation of administering its rites with- out fear or favour in respect of results or persons ; and, in betraying this confidence, he becomes not only a false prophet, but deposes himself by the act from his sacred office. K K 498 PURE FERTILIZERS. Mor jit's Table of the Value of Crude PhospJiatcs of Lime of Different Grades. Per cent, of actual tri- phosphate of lime. Per cent, of profligate associates. Value of the raw mineral per unit of tri-phos- phate of lime. Per cent, of actual tri- phosphate of lime. Per cent, of profligate associates. Value of the raw mineral per unit of tri-phos- phate of lime. S. D. F. S. D. F. 45 55 10 I 77> 27 I 5 I 46 54 10 2 74 26 I 5 2 47 53 10 3 75 25 I 5 3 48 52 II 76 24 I 6 49 51 II I 77 23 I 6 I 50 50 II 2 78 22 I 6 2 51 49 II 3 79 21 I 6 3 52 48 I 80 20 I 7 53 47 I I 81 19 I 7 I 54 46 I 2 82 18 I 7 2 55 45 I 3 ^l 17 I 7 3 56 44 I I 84 16 I 8 57 43 I I I 85 15 I 8 I 58 42 I 1 2 86 14 I 8 2 59 41 I I 3 ^7 n I 8 3 60 40 I 2 ^^ 12 I 9 61 39 I 2 I 89 II I 9 I 62 38 I 2 2 90 10 I 9 2 63 37 I 2 3 91 9 I 9 3 64 36 I 3 92 8 I 10 65 35 I 3 I 93 7 I 10 I 66 34 I 3 2 94 6 I 10 2 67 33 I 3 3 95 5 I 10 3 68 32 I 4 96 4 I II 69 31 I 4 I 97 3 I II I 70 30 142 98 2 I II 2 71 29 I 4 3 99 I I II 3 72 28 I 5 100 200 COMMERCIAL VALUATION. 499 Precipitated Phosphate of Lime. This being a pure, or nearly pure, product eliminated from the raw mineral phosphates at great expense, is much more valuable than any corresponding grade of natural phos- phate of lime. Being very sensitive to the atmospheric and solvent influences of the soil, it represents the potential condition of its class. In making the preceding table, only the bare expense of materials and manufacture, without margin for profit, was added to the first cost of the raw minerals, in order to fix the value of different grades of natural phosphate. For the reasons above noted, however, and also because there is a great economy secured, as to package and transportation charges, in connection with the pure concentrated artificial product, its value would be fairly computed by adding fifty per cent, to the figures noted in the table for natural phosphates. In other words, pure precipitated phosphate of lime has an actual worth of three shillings, at least, per unit. As it is inexpedient to dry out all its moisture, the presence of water, even to the K K 2 500 PURE FERTILIZERS. extent of ten per cent., should not be con- sidered an impurity to degrade its quality and rating ; which latter, however, refers here to the anhydrous state. Colombian Phosphate of Lime. This form of precipitated phosphate of lime contains more or less di-phosphate, and, consequently, has a higher degree of potenti- ality. Its value is, therefore, greater, and will be fairly computed by calculating its total of phosphoric acid to lime, and esti- mating the equivalent of tri-phosphate of lime, thus deduced, according to the rule prescribed above for precipitated phosphate, — that is, at three shillings per unit. Di-phosphate of Lime. This phase of phosphate is met with only occasionally in Nature. In such instances, its phosphoric acid must be calculated to lime as tri-phosphate, and the equivalent thus deduced is then to be rated according to the table at p. 498. The artificial product requires a different consideration. By reason of its chemical MORFIT on .'hr ynnn/arliiir of'FertiliXffx Pan for Melting Stearic Pitch. ■II. t^, >. :^ •^ T ic*i( a' ••!' COMMERCIAL VALUATION. 501 tenderness, it is in the same category for potentiality as the Colombian Phosphate, but in higher degree. Though the cost of its preparation is not greater than that of the Colombian Phosphate, it contains a much larger ratio of phosphoric acid, and, there- fore, must be estimated accordingly. The proper way to determine its value will be to calculate its content of phosphoric acid to lime as tri-phosphate, and value its equiva- lent of the latter at three shillings per unit. As it contains about six and a half per cent, of constitutional water, and may hold, advantageously, as much more of accidental moisture to insure impalpability of powder, 10 to 15 per cent, of water should not be allowed to disturb the valuation above given. Indeed, a product which does not contain more than 10 per cent, of water and 10 per cent, of foreign matter is pure for all practical purposes. Bi-phosphate of Lime. The processes for making pure precipi- tated or di-phosphate of lime are so simple, economical, and advantageous, in all re- 502 PURE FERTILIZERS. spects, that I do not recognize any other materials as a proper basis for the manufac- ture of bi- or superphosphate of lime. My views on this point have been set forth already in Chapters xiii and xiv. It is only necessary to remark now, that either precipi- tated, Colombian, or di-phosphate will yield a "superphosphate" of the highest possible quality at even a lower cost than the cheapest of crude mineral phosphates when great purity, concentrated form, and economy of packing and transportation are considered. The ''superphosphate" of promiscuous composi- tion, therefore, as made from mineral phos- phates (often carrying 90 per cent, of w^orth- less matter, and even at the best, when pre- pared from good bone-ash, never richer than 30'0 per cent, of anhydrous bi-phosphate of lime), is being pushed into merited disrepute by the chemical improvements of the day in connection with this subject. As made from the pure sources, " super- phosphate" will contain nothing but the chemical equivalent proportions of bi-phos- phate and sulphate of lime which rightly be- long to it. Its value, therefore, will be the COMMERCIAL VALUATION. 503 first cost of the precipitate, plus that of the quantity of sulphuric acid required to convert it into bi-phosphate, with 10 per cent, added for profit. Thus, — 100 tons of pure precipitated phosphate of lime - ;^i5oo ^2 „ brown oil of vitriol of specific grav. r/oo 287 Manufacturing expenses^ profit, etc. - - 150 ^1937 The product is, quantitatively, 190 tons of " superphosphate", containing, practically, 39 to 40 per cent, of actual bi-phosphate of lime, or CaO, 2HO, PO^ As commercial "super- phosphate", therefore, it is worth, say £10 per ton, or five shillings per unit of actual bi-phosphate of lime. I have estimated the bi-phosphate of lime, with its constitutional water, as part of its formula, and for the reason that this water is an element of its nature, which cannot be alienated without modifying the properties of the original bi-phosphate disadvantageously. Pure Bi-phosphate of Lime. This salt is made from the preceding "superphosphate" by merely leaching it in water and evaporating to crystallization the 504 PURE FERTILIZERS. solution of bi-phosphate thus obtained. loo tons of precipitated phosphate of lime give 75 tons of pure bi-phosphate, at a cost of ;^I987, plus lo per cent, for manufacturing expense. This makes a total of ;2^2200, which, divided by 75, gives ^^30 as the value per ton, or six shillings per unit of pure bi-phosphate of lime =CaO, 2HO, PO5. The usual commercial custom is to estimate the anhydrous bi-phosphate as equivalent to tri-phosphate of lime ; and, by this means, o'64i is made to appear as roo per cent. Such a valuation is fictitious, and could not be evolved under a just system of computa- tion. My figures will refer, therefore, to the actual bi-phosphate of lime as it exists, naturally, in the "superphosphate" or pure bi-phosphate of lime, according to the for- mula CaO, 2HO, PO5. Di-phosphate requires less acid than the precipitated phosphate of lime for its conver- sion into "superphosphate", but the product from it is much smaller, and this incident makes the two correspond closely in value as raw material for conversion into superphos- phate. But, as the "superphosphate" from COMMERCIAL VALUATION. 505 di-phosphate of lime would contain a greater per centage of bi-phosphate than that made with precipitated tri-phosphate, a given weight of a product from the former will be worth more than a corresponding quantity of product from the latter. Degree and de- gree, the bi-phosphate from either source has the same value, which is five shillings per unit. But for the obstinate popular prejudice in favour of " super-" or " bi-phosphate", di- phosphate would come into general use as a substitute for them. It is much more econo- mical and fully as potential, if not quite as active, in fertilizing effect. Indeed, it is more than probable that most of the bi-phos- phate, which may be sown, ''goes back'' into di-phosphate long before the growing crop has had time to take it up and assimilate it. Phosphate of Magnesia. This is to be estimated according to its ratio of phosphoric acid and after the rules prescribed for the phosphates of lime, ac- cording as it may be in a mineral or arti- ficial state. 5o6 PURE FERTILIZERS. Phosphate of Alumina. This salt, in its natural rocky state has only a commercial value; and, as "Alta Vela Guano" is the sole representative of its class, which comes to market at present in abun- dant and regular supply, it must be taken as the standard at the current price of £'^ : lo per ton of 35° phosphate strength, or one shilling per unit of phosphoric acid which it may contain. As the proportion of phospho- ric acid may fall, that of the alumina and foreign associates must rise ; and, conse- quently, the less valuable becomes the mine- ral. Owing to the uncertain composition of the phosphate of alumina as existing in this kind of mineral, the system of computing the value of the latter will be somewhat arbi- trary. It may be wholly meta-phosphate of alumina (AU O3, 3PO5), or a mixture of that and pyro-phosphate (2AI2 O3, 3PO5, loHO), when dried at 110°, together with more or less of free alumina. In any case, the greater the presence of alumina, the larger will be the quantity of acid required for the chemical treatment which it must undergo to become COMMERCIAL VALUATION. 507 serviceable in agriculture or the arts. There- fore, the value of this class of minerals is to be gauged according to the content of alu- mina and the composition and cost of the " Alta Vela Guano" at the present market price or rate. But it is not difficult to make a scale upon this basis, for the presence of a very large quantity of constitutional water in most cases excludes any appreciable amount of foreign or profligate matters. The small margin thus left for the latter constituents is almost wholly filled by silica and oxide of iron. There is, therefore, no disturbing ele- ment of calculation, but the variableness of the ratio of alumina to the phosphoric acid. Assuming, then, as a starting-point, that the value of a mineral phosphate of alumina is one shilling per unit, when the ratios of alumina and phosphoric acid are as 33 to 31, and that there are no profligate constituents, for example, as in the '*Alta Vela Guano"; then, for eveiy gradation of the former down- wards, there will be a proportional rise in the value of the mineral. Thus, it is only neces- sary to calculate the actual cost of removing the alumina degree by degree, in order to 5oS PURE FERTILIZERS. determine the improvement in value for pro- gressively augmenting ratios of phosphoric acid. Morfifs Tabic of tJic Commercial Value of Different Grades of Mineral Phosphate of Alnniina. Ratio of alumina. Ratio of phospho- ric acid. Value unit per Ratio of alumina. Ratio of phospho- ric acid. Value per unit. S. D. F. S. D. F. 22-0 310 I 17-0 31-0 I 8 3 21'0 31-0 I I 3 i6-o 31-0 I 10 2 20-0 31-0 I 3 2 15-0 31-0 2 I I9'0 31-0 I 5 I 14-0 31-0 230 i8-o 31-0 I 7 — — — A range has been given to these computa- tions which will comprise all the kinds of this mineral now known even by specimens only. As, however, the figures affixed refer exclusively to the phosphate of alumina in its crude state, there remains yet to explain the values of the phases of artificial phos- phate of alumina as made in the phosphate- sewage process (Chapters xx and xxi), or other method of precipitation from an acid solution of the raw mineral. Here the same principles come into play as for the precipi- COMMERCIAL VALUATION. 509 tated phosphate of lime. The original rocky character of the mineral has changed to a soft pulpy condition, most tenderly sensitive to acids, alkalies, and the growing influences of vegetation ; so that, in fact, a new physical nature has been assumed. As, however, the chejnical composition of the precipitate will not differ materially from that of the alumina phosphate constituent of the original mineral, the values of the different grades will be fairly expressed by adding twenty-five per cent, to the several degree-computations of the preceding table. Phosphate of Iron. The values of the different grades of this constituent, whether natural or prepared arti- ficially, can only be estimated arbitrarily, but may safely be taken at half the rates com- puted for phosphate of alumina. In either of the two preceding cases the valuation refers to the purposes of sewage- defecation, the alum manufacture, and agri- culture ; for it will be seen in Chapters xviii, XIX, XX, and xxi, that both the phosphate of alumina and phosphate of iron are capable of 510 PURE FERTILIZERS. many and profitable applications. Indeed, this wide range of practical usefulness makes the commercial appreciation of the phos- phates of alumina and iron much greater than their agricultural value. The remaining items pertaining to this subject are chlorides of potassium, sodium, and ammonium ; sulphates of potassa, soda, and lime ; nitrate of potassa and nitrate of soda, each of which has a current value varying with the supply and demand, as may be learned by reference to any market price- list of the day. CHAPTER XXV. THE MODE OF USING HYDROMETERS AND THERMOMETERS. A HYDROMETER is a Convenient glass instru- ment for measuring the density or specific gravity of fluids. It is often referred to throughout this work; for instance, in speak- ing of an acid, the strength is stated as being of so many degrees Baume or Twaddle; that is, it has a specific gravity correspond- ing with the degree to which the hydrometer sinks in the liquid. For those liquids lighter or rarer than water, viz., alcohol, ethers, and the like, the scale is graduated differently than for the heavier or more dense, examples of which latter are the acids, saline solutions, and syrups. There are several kinds of hydro- meters ; but that called Baume s is the most used, and to this my remarks will refer. 5^2 PURE FERTILIZERS. The scale for the liquids rarer than water is graduated upwards from o, at the bottom of the stem, as shown by fig. 21. For liquids denser than water, the graduation is reversed, as in fig. 22. Fin;. 21. Ficf. 2; As it would be troublesome, and with many impracticable, to estimate the specific gravities of liquids in a scientific way, these little instruments are a great convenience ; for, by taking out a portion of the fluid to be tested, and placing it in a tall glass cylinder (fig. 23), its degree Baume may be asccr- HYDROMETERS & THERMOMETERS. 513 tained by noting the point to which a hydro- meter sinks therein. From this datum its specific gravity is deduced by calculation, according to the proper formula on p. 514. Fig. 23. For instance, suppose the hydrometer sinks in alcohol to 35^ then its specific L L 514 PURE FERTILIZERS. gravity is 0*852, and this again can be translated into its absolute spirit strength by comparison with any accurately calculated alcohol table. So, also, if a hydrometer for liquid denser than water sinks in acid to 66°, it denotes that the acid has a specific gravity of i '846. The presence of foreign matters will cause the hydrometer to give a false indication, but for nearly pure liquids the instrument answers satisfactorily ; and, indeed, under all circumstances, it serves very well for noting a progressive increase or diminution in the strength of solutions or other liquids. The temperature of the liquid should be 60° to 62" Fahrenheit, at the moment of testing it. The following rules, by Pile, in connection with hydrometers, will be found convenient : To convert Baume's degrees into specific gravity munbers. For liquids lighter than water. B°+'^34 ^ specific gravity. To convert specific gravity numbers into Baumes degrees* For liquids lighter than water. .. ^^ 1 34 = Bo. bp. grav. HYDROMETERS & THERMOMETERS. 515 To convert Baume's degrees into specific gravity numbers. For liquids heavier than water. 144 144 ^= specific gravity. To convert specific gravity numbers into Baume's degrees. For Hquids heavier than water. 144 - — ^^^^ = BO. sp. grav. For converting the degrees of Tzv addle s hydrometer into specific gravity numbers multiply by ^, and add i"OOo; thus — Twaddle "So" x 5 =400 + 1000= sp. grav. 1-400. For converting specific gravity numbers into the degrees of Tzuaddle's hydrometer deduct I'OOO, and divide by 5 ; thus — Sp. grav. 1*400- 1000 = ^^ — = Twaddle 80°. Vulcanite is now substituted, sometimes, for glass, in the manufacture of hydrometer and thermometer scales. Such instruments are much more durable in every respect. They may be purchased at Blaise and Co.'s, No. 67, St. James's Street, London. Thermometers. The thermometer is an instrument made wholly of glass, when intended for chemical L L 2 i\ 516 PURE FERTILIZERS. o) purposes. Fig. 24 shows one with the scale graduated upon porcelain en- amelled upon the tube, so that the de- grees may be easily read and the in- strument readily kept clean. It is a measurer of the variation of tempera- ture in bodies. The principle upon which it is constructed is the change of volume which takes place in bodies when their temperature undergoes an alteration, or, in other words, upon their expansion. In the construction of thermometers, the fluid employed for measuring the change of tempera- ture is usually metallic mercury, be- cause it expands uniformly and has a very wide interval between its freezing and boiling-points. There are several different thermo- metrical scales, all constructed upon the same principle, but varying in their graduation ; the boiling and freezing- points of each, though corresponding in fact, being represented by different numbers. The Fahrenheit scale is most used Fig. 24. HYDROMETERS & THERMOMETERS. 517 in this country ; that of Celsius, called the centigrade, in France and the continent generally, except Spain and Germany, where Reaumur's scale is preferred. In the Fahrenheit thermometer, the inter- val between the freezing and boiling-points of water is divided into 180 degrees. The freezing-point is placed at 32*^, and hence the boiling-point at 32+ 180= 212*=*. Reau- mur divides the distance between the two extreme points of water into 80^, and Celsius spaces his thermometer (the Centigrade) into 100 equal intervals, the zero point, as in Reaumur's, being placed at freezing. The Fahrenheit scale is most convenient, be- cause of the lesser value of its divisions ; but, as it frequently happens that the manu- facturer has no choice in the kind, but is compelled to take such as can be con- veniently obtained, I give formulae for con- verting the degrees of one into those of the others. In the graduation of the scale it is only necessary to have two fixed determinate tem- peratures, and for these the boiling and freezing - points of water are universally 5i8 PURE FERTILIZERS. chosen. The scales can be extended beyond either of these points by continuing the graduation. Those degrees below zero or o*^ have the minus (— ) prefixed, to distin- guish them from those above : thus 55° F. means fifty-five degrees above zero, Fah- renheit's scale ; and —9^ C, nine degrees be- low zero, centigrade scale. The thermome- ters for general use, very seldom, however, extend either way beyond the boiling and freezing-points of water, but they are gra- duated sometimes to 400° or 600°. One of soo'^ Fahrenheit is cheaper and con- venient for general manufacturing purposes. The following rules will be found con- venient for converting the degrees of the several scales into each other : — To convert Centigrade into Fahrenheit degrees. Multiply by 9, divide by 5, and add 32. To convert Centigi^ade into Reaumur de- grees. Multiply by 4, and divide by 5. HYDROMETERS & THERMOMETERS. 519 To convert Reaumur into Fahrenheit de- grees. Multiply by 9, divide by 4, and add 32. To convert Reaumur into Centigrade de- grees. Multiply by 5, and divide by 4. To convert Fahrenheit into Centigrade degrees. Deduct 32, multiply by 5, and divide by 9. To cotivert Fahrenheit into Reaumur de- grees. Deduct 32, multiply by 4, and divide by 9. CHAPTER XXVI. WATER AND ACID-PROOF CEMENTS AND PAINTS. In the construction of mason-work for che- mical purposes, it is necessary that the cement employed shall be not only strong and durable, but proof against the action of water ; and, if possible, also resistant of the action of acids. The following means are the best known for accomplishing those re- quirements. Hydraulic Cement. The Portland Cement, as made in London and its vicinity, fulfils all these requirements, except the last, in more eminent degree than any other; and it is best to employ that kind. Without intending to discuss princi- DURABLE CEMENTS AND PAINTS. 521 pies* which regulate the hydraulicity of cements, I will remark that the lime which is to be used for works which are to resist the action of water, must be made of a lime- stone containing a certain amount of clay and magnesia with some little manganese and iron. The proportion of these ingre- dients combined should bear the relation of 20 to 30 per cent, of the carbonate of lime constituent. In a lime-stone of such a com- position the soluble silica, alumina, and magnesia, will be most likely to hold that proportional relation to the lime which seems necessary to a prompt and complete hydrau- licity of a cement. If there should be an excess of lime over and above the chemical proportion required to form the triple silicate of lime, alumina and magnesia which constitutes a good hy- draulic or water-cement, it would in time be washed out gradually by the water ; but the * According to Fremy, aluminate of lime plays a most important part in the hydraulicity of cements ; and he has reported the results of his researches on the subject, in the Journal de Pharmacie et de Chiuiie, at p. 20 of vol. 2 for 1865. 522 PURE FERTILIZERS. cement will remain hard, and unimpaired in strength and durability. In the event of there being no excess of lime, the silicate formed by mixing the cement with water will be so closely bound as to its constituents, that it will resist to a considerable degree even the decomposing action of acids. A very good hydraulic cement may be made according to the following formula. The ingredients are — best quality fat lime, 68 to 74^ parts by weight ; refractory clay, 271 to 42} ; sulphate of lime, 4f to 9*0 ; and boracic acid, 0*105 ^o 0*40 1. All the substances are calculated in the anhydrous state. The cements formed be- tween these limits vary in the rapidity with which they set, but are of equal quality, and attain, in the course of time, the same degree of hardness. The substances are mixed after being ground to a fine powder. They are then made into bricks with water, and are baked at a white heat. After this, they are reduced to an impalpable powder. This powder, mixed with water, is then used as the cement, cither plain or coloured, and can be moulded as required. DURABLE CEMENTS AND PAINTS. 523 Bottger's Cement. This is a very good cement for sealing joints. It is made by mixing finely-powdered chalk with an aqueous solution of silicate of soda, of 33° Baume, so as to form a stiff mortar. It sets hard in six to ten hours. Sorer s Cement. This is a very hard cement, and will serve for sealing the joints of mason-work. It is a hydrated basic oxychloride of magnesium, prepared by mixing calcined magnesia with an aqueous solution of chloride of magne- sium of 20^^ to 30" Baume. The denser the solution, the harder will be the cement. Bituminous Cement, or Stearic Pitch. When the digester vats are built, they may be lined with the preceding cements if intended for solutions of a neutral character. But for operations of an acid nature they must be covered with a cement or paint of thorough protective power against the chemi- cal friction of acids. This coating must also 524 PURE FERTILIZERS. have a high softening-point, more particu- larly where heat is to be used in the vessels painted with it. The material fulfilling more nearly than any other all these requirements, is the black pitchy residue obtained in the distillation of fats for the manufacture of stearic candles, and in the refining of "cotton oil foots". It is black, insoluble in water and acids, and retains its hardness so obstinately, that it is difficult to melt it alone at a temperature be- low 300° Fahrenheit. Being a refuse article, its market price is very low. In order to fuse it, a particular apparatus is necessary, as shown by Plate 28. It con- sists of a strong jacketed pan a a, made of wrought iron plate, and set in brick-work. This pan is heated by steam, which enters the jacket through the pipe b. The con- densed steam runs out through the tube c, which, during the heating, must be kept partly open by means of a cock as a safety- valve. The stirrer d is a wrought iron shaft rest- ing in a footstep at the bottom of the pan. Its blades or arms are of two kinds : the DURABLE CEMENTS AND PAINTS, 525 lower ones being a series of loose scrapers of forged iron e e e, and c strung upon a rod f. This arrangement insures the scraping of the bottom of the pan and prevents accumulation of lumps of bitumen upon the heated surface of that portion of the metal ; while, at the same time, it is a protection against break- age, which might happen often, if the blade were more stiff, from the obstinate tenacity with which the pitch adheres to the metal when it is only partly melted. The upper blades gg, are made of a form to produce agitation of the contents of the pan, and also to scrape the sides, so as to keep them clean of adhering pitch. The stirrer is driven by steam, through means of the gearing h, affixed to a beam above. The pan, as shown by the plate, has the capacity for melting five hundredweight of pitch at each operation ; and four meltings may be made in twelve hours. The temperature required to effect the fusion being about 310° Fahrenheit, and, as the generator would have to be heated up to a pressure of sixty-five pounds per square 526 PURE FERTILIZERS. inch, in order to give steam of that degree, it will be safer and more convenient to use a super-heater, as an auxiliary means. This apparatus, of inexpensive form, shown by o, at the side of the pan, consists of a coil made of very thick welded iron tubes k k, and put together by joints. The connections with the generator are shown at in, and with the pan at n. The whole is set in brick- work, with a furnace beneath, and this latter has a damper- arrangement for the management of the heat, according as steam of a moderately or very high temperature may be required. A little boiled linseed-oil will facilitate the fusion, but the addition of this fluid must be limited to ten per cent, of the pitch, for fear of lessening the hardness of the product. When the whole is fused and has become quite cold, it is to be thinned with spirits of turpentine or petroleum naphtha to such con- sistence as may be required. When the pitch is to be used as a cement it must be applied in its hot fluid state, and as thick as possible ; for which purpose, con- sequently, it should not contain any spirits DURABLE CEMENTS AND PAINTS. 527 of turpentine. It takes several days to dry when mixed with oil alone ; but this objec- tion is countervailed by advantages. In this form it covers iron well with a coating which is very adhesive, though not even. To make an even coating, turpentine must be added, so as to thin the cement to the consistency of a paint, which may be applied readily with a brush. As the drying is very rapid, several suc- cessive coats may be put on in a day. This latter paint, applied thick and in several coats, is the protecting covering for iron and other vessels, which has been pre- scribed throughout this work. It may be made even without the aid of linseed-oil or the super-heater, by means solely of turpen- tine and at the ordinary temperature of the atmosphere. Vessels coated with this material will re- sist the action of acid liquors at temperatures even beyond 225° Fahrenheit. Marine Glue. This cement, which is proof against the action of both water and acids, may be made 528 PURE FERTILIZERS. by heating gently one pound of india-rubber with twelve pounds of coal-tar, mixing thoroughly, and then adding and melting in twenty to twenty-four pounds of powdered shellac. The whole is then to be dipped out, and poured on a slab to cool. When used, it requires to be heated above 250° Fahrenheit. This cement is much more expensive and less advantageous than that made with the pitch from fats. Too frequent remelting spoils it. Substitute for Marine Glue. A good water and acid-proof cement may be made by melting together equal parts of gutta-percha and pitch, and casting into sheets or sticks on a plate. It may be made hard or soft by using less or more of gutta- percha. Cement to Resist Stdphuric Acid. Take caoutchouc, melt it by a gentle heat, treat with 6 to 8 per cent, by weight of tallow, taking care to keep the mass well stirred ; add dry slaked lime, so as to give DURABLE CEMENTS AND PAINTS. 529 the fluid mass the consistency of soft paste ; and, lastly, stir in 20 per cent, of red lead, whereby the mass which would otherwise remain soft becomes hard and dry. This cement resists, according to Dr. Wagner, boiling sulphuric acid. A solution of caoutchouc, in twice its weight of raw linseed-oil, aided by heating, and the addition thereto of an equal weight of pipe-clay, yields a plastic mass, which also resists most acids. Cei lie Jits for Steam-Pipes. A very excellent cement, which is imper- meable by air or steam, and very suitable, therefore, for making tight the joints of steam-pipes, is made by kneading together into a perfect mixture the following ingre- dients : — Graphite, finely powdered - - 3 lbs. Lime, slackened and sifted - ~ 3 ., Sulphate of lime, in fine powder - 8 „ Boiled linseed oil - - - 7 »> Artificial Stone. A very excellent stone or cement may be made by melting together 200 pounds of jM m 530 PURE FERTILIZERS. stearic pitch, 20 pounds of sulphur, and barely enough of spirits of turpentine to give it a thin pasty fluidity. At this stage, 50 pounds of finely-powdered lime, 200 pounds of ground plaster, and 25 cubic feet of very fine sand are to be added by degrees, and well stirred into the mixture, after which the mass is to be melted and pressed into bricks. This stone hardens in five to eight days. INDEX. Acid reservoir, the, 1 1 3 Alabaster, 83 Alkaline salts, estimation of, in mineral phosphates, 457 Alma, M. de, 416 Alta Vela guano, 50, 161, 223, 237, 246, 360-363, 395, 399, 400, 402, 403, 406, 407, 409 ; analysis of, 364 ; treat- ment of for manure, 365 ; replaced by Morfit's "mother- liquor", 398 ; valuation of, 506, 507, 508 Alum, from phosphate of alumina, 408 Alumina, estimation of in mineral phosphates, 455 phosphate of, not without fertilizing effect, 3 ; estimation of in mineral phosphates, 89, 408^ 414, 455 ; commercial valuation of, 506, 508 phosphate, left in mother-liquor when phosphate of lime is precipitated,, 378 ; useful for defecation of sewage, 161, 402, 414; in manufacture of sugar, 415 ; in dyeing, 417 ; as glaze for pottery, 418 phosphate of, Peter Spence's patent for treatment of mineral, 379 ; also J. Berger Spence and Peter Dunn's, 383, 385 ; also Townsend's^ 389 and iron, formula for the chemical analysis of mineral phosphates of, 465 Aluminate of soda, a ready saponifier, 409 Aluminium, oxide of, 88 M M 2 532 INDEX. Ammonia, sources of, 44 ; wool, 44 ; leather clippings, 45 ; dried blood and flesh, 46 ; excreta, 47 ; sewage, 49, 399, 406 ; atmospheric air, 488 Ammonia, its defects as a precipitant of phosphate of lime, 163 crude liquor of, production and constitution of, 39 ; estimates of evolution from coal, 40 ; separation from gas-liquor, 41-44 ; as an economiser, 284 ■ generator, the, 176 hydrochlorate of, 57 phosphate of, 41 sulphate of, constitution and manufacture, 55, 57 ; use as an economiser, 280, 284 commercial valuation of, 486, 487, 488, 489 Ammoniacal wash, 197 Ammonium, chloride of, 7, 57 ; produced from sulphate of ammonia, 280 Animal charcoal, 7 Analysis, '' commerciar, meretricious character of, 465,496, 497 Analyses of— Apatite, by Hunt, 30 ; by Voelcker, 30 German phosphorite, by Fresenius, 13 Russian phosphorite, by Grewingk, 14 Wicken coprolites, by Morfit, 17 Pas de Calais coprolites, by Morfit and Gerland, 17 Phosphorite, 30 Suffolk and Cambridge coprolites, 30 Sombrero guano, by Voelcker, 19 Ditto, by Evans and Jones, 19 Ditto, by Morfit, 30 St. Martin's phosphate, by Voelcker, 20 South Carolina phosphate, by Morfit and Gerland, 22,30 Ditto, by Voelcker, 23 INDEX. 533 Analyses of — French phosphorite, by Voelcker, 25 Navasa guano or Cooperite, by Morfit and Gerland, 27, 30 Bone-ash, by Morfit, 30 Bone-black, by Morfit, 30 Guaymas guano, by Morfit, 30 Marlstones, by Morfit, 30 Orchila guano, by Morfit, 30 Rossa guano, by Morfit, 30 Table of comparative composition of crude natural phosphates, 30, 31 Wool, by Scherer, 44 Brighton chalk, by Schweitzer, 64 Tri-, di-, and bi-phosphates of lime, 68 " Superphosphate", commercial, 289, 292, 293, 325 ; pure, 300, 301, 323 Gerland's sulphite of tri-phosphate of hme, 341, 342,359 Redonda guano, by Johnson, 364 Alta Vela guano, by Voelcker, 364 A. B. R. guano, 364 Sewage-precipitate by sulphuric solution of Alta Vela guano, 400 ; by Morfit's "■ mother-water", 400 Apatite, 2, 7, 290; characteristics and sources of, 9, 10 ; solubility of, 28 ; analysis of Canadian, 30 A. R. B., a rock phosphate, 361 ; analysis of, 364; treat- ment for manure, 365 Artificial stone, 530 Austrian phosphorite, 13 Bahia, nitrate of soda, 66 Baking-powder, Horsford's, 327 ; directions for use, 334 Baltic, the, 8 534 INDEX. Barreswill on gas-liquor, 42 Baumes hydrometer, 512 Bavaria, 10, 11 Bi-phosphate of lime, 73, 75, 303-314. 502, 503, 504 Bituminous cement, 524 Black Sea, the, 8 Blair, Harrison, 123 Blake's crusher, 96, 97 ; table of sizes of, 100 Blood, dried, a source of ammonia, 46 '' Blow-up, the", 229, 234, 241, 242, 244 Bohemia, 10 Boiler, steam, the, 109 Bone-ash, the typical phosphate of lime, 2, (yj ; its sources, 8 ; value as a fertilizer, 9 ; its solubility, 28 ; analysis of by Morfit, 31 ; the best material for '^superphos- phate", 200 ; but too good for the purpose, 291 ; method of analysis, 434; commercial valuation of, 489 Bone-black, made by calcining bones, 7 ; value as a ferti- lizer, 9 ; analysis of by Morfit, 31 ; ammonia incident to its production, 44 ; its solubility in soil, 69 ; com- mercial valuation of, 490 Bottger's cement, 523 Bone-dust, commercial valuation of, 490 Bread, brown, 336 ; gout and confectioners' cakes, 337 Brighton chalk, 64 Bristles, ammonia in, 44 Calcium, chloride of, constitution and properties of, 81,85; reaction with sulphate of potassa, 86 ; how utilized, 155, 277, 286 ■■ fluoride of, 84; estimation of in mineral phos- phates, 458 oxide of, 61 INDEX. 535 Calcium, phosphate, sulphite of, 'j^ Cambridgeshire coprolites, 15 Canadian apatite, 9, 10; coprohtes, 15 Carolina, South, phosphates, 20; analysis of by Morfit and Gerland, 22, and by Voelcker, 23 ; 170, 202, 204, 206, 208, 325 Carr, Thomas, his disintegrator, 133, 244, 376 Celsius's or centigrade thermometer, 518 Cement for steam-pipes, 529 Cements, water and acid proof, 520, 523, 528, 529, 530 Cereal crops, fertilizer for, 426 Chalk, 64 Charcoal, animal, 7 ; peat, for sewage, 396 Chemical analysis of phosphatic materials and products, formulae for, 432 Chemistry, " commerciar, style of analytical, 465, 496, 497 Chilian nitre, 66 Chloro-phosphate of lime, Way's, 263 Church, A. H., 2, 12 Clark's enamel, 232 Clegg, on ammonia in gas-liquor, 40 Cliff, 127 Collas, M., uses phosphate of alumina for dyeing, 417 Colombian guano or phosphate, 71, 72, 75, 78, 130, 160, 162, 216, 278, 301, 307; manufacture of, 203; first process, 204 ; the mother-liquor or wash, 221 ; second process, 222 ; formation of, 241, 298 Confectioners' cakes, 337 Cooperite or Navasa guano, 25, 237 : analysis of, 31 Coprolites, 2; their nature and sources, 15, 16; Wickeu and Pas de Calais, analysis by Morfit and Gerland, 17 ; value of, 494 Deligny, 227; his process for di-phosphate of lime, 259-263 536 INDEX. Digester, the, or solution vat, 117 Digestion, first fractional, 165 ; second ditto, 169 Di-phosphate of lime, 70, ^2, 226, 227, 238, 501 Disinfectant, sulphite of tri-phosphate of lime as a, 353 Disintegrator, Carr's, 133, 244, 300, 316, 323 Dominique, his report on phosphate of alumina in the puri- fication of sugar, 416 Dreschfeld, Dr. J., experiments with Gerland's sulphite of tri-phosphate of lime, 354 Drying-kiln, the, 129 Danger, universal, 426 Dunn, Peter, 41 ; patent for treatment of mineral phos- phate of alumina, 383, 385, 408 Dyeing, use of phosphate of alumina in, 417 Dyer, W, J. T., 2, 12 Elevator, the, 1 1 1 Engine, the steam, 109 Estremadura phosphorite, 1 1 Etchelss, W. G., on supply and market values of woollen waste, 45 Evans and Jones, analysis of Sombrero guano, 19 Evaporating-pan, the, 131 Excreta, human, a source of ammonia, 47 Fahrenheit's thermometer, 517-519 Factory plant, arrangement of, 147 Feathers, ammonia in, 44 Feltz, E., on sugar fertilizers, 428 Fertilizers, normal, 425 ; universal dunger, 426 ; for cereal crops, 426; for leguminous plants, 427 ; for gramine- ous plants, 427 ; for sugar, 428 ; for root crops, 430 compound, formula for analysis of, 469 INDEX. 537 Fertilizing materials, commercial valuation of, 485 Filter vats, 171 Flesh, dried, a source of ammonia, 46 Fluoride of calcium or fluor spar, constitution of, and pre- sence in rock guanos, 15, 84; estimation of in mineral phosphates, 458 Forbes's defecation of sewage by phosphates of alumina and iron, 395 ; should be supplemented by filtration through peat charcoal, 396 Formulae for chemical analyses, 432 ; of phosphates of alumina and iron, 465 ; commercial "superphosphate", 469; compound fertilizers, 470 French coprolites, 15 ; phosphates, 24 Fremy on cements, 521 Fresenius, 13 ; analysis of German phosphates, 30 Furnace, the roasting, 109 Gas-liquor, as a source of ammonia, 40 ; its extensive pro- duction, 43 Generator, the ammonia^ 176 Geological distribution of the mineral phosphates, 2 Gerland, Dr. B. W., analyses of Pas de Calais coprolites, 17 ; of South Carolina phosphates, 22 ; of Cooperite or Navasa guano, 27 ; his sulphite of tri-phosphate of lime, 338; method of manufacture, 346; its properties, 353'; and analysis, 356 German phosphates, 11; coprolites, 15 Gibbsite or Alta Vela guano, 361 Glue, marine, 527, 528 Gill, Haughton, on sugar, 430 '"Going-back" of commercial "superphosphate", 293, 308, 310, 505 Gossage's coke-towers, 36 538 INDEX. Gout bread, 337 Gramineous plants, fertilizer for, 457 Grewingk's analysis of Russian phosphorite, 14 Grinding apparatus, 92 ; roller mill, 93 ; sifter, 95 ; Blake's crusher^ 97 ; Howel-Hannay mill, 102 Guaymas guano^ 17, 71 Gypsum, 83 Hayti, 25 Henry, Michael, 260 Herepath, analysis of Suffolk coprolites, 31 Horn, ammonia in, 44 Horsford's baking-powder, 327 Hosch and Enderisch's universal dunger, 426 Howel-Hannay mill, 97, 102, 323 Hunt, T. S., on apatite, 10; analysis of Canadian apatite, 30 Hydraulic cement, 520 Hydrochloric acid, its constitution and production, 36 ; Ure's table of specific gravities, 38; preferred to sul- phuric acid for solution of phosphates, 156 Hydrometers, mode of using, 511 Inertia, fertilizing, of certain mineral phosphates, 3 Iron, oxide of, in mineral phosphates, 87, 453 phosphate of, not without value as manure, 3 ; espe- cially when freshly precipitated, Z'^ ; estimation of in mineral phosphates, Zj, 451 ; left in mother-liquor when phosphate of lime has been precipitated, 378 ; conjoined with phosphate of alumina for sewage pre- cipitation, 402 phosphate of, commercial valuation of, 509 Johnson, analysis of Rcdonda guano, 364 INDEX. 539 Kamrodt, on sources of ammonia, 44 Kiln, the drying, 129 Knapp, on gas-liquor^ 42 La Plata, 8 Leather clippings a source of ammonia, 45 Leguminous plants^ fertilizer for, 427 Lerverd, A., et Cie., 127 Liebig-Horsford baking-powder, 327 Lift, the^ 1 12 Limburg and Staffel phosphorite, 12 Lime, constitution and diffusion of, 61 carbonate of, its constitution and diffusion, G^,, 288 ; disadvantages of in association with phosphate of lime, 79-82 ; estimation of in mineral phosphates, 461 chloro-phosphate of, 226 ; Way's process for produc- tion of, 263-276 Colombian phosphate of, yZ, 203, 221, 241, 298, 500 Gerland's sulphite of tri-phosphate of, 338 ; method of manufacture, 346; its properties, 353 ; analysis, 356 mineral phosphates of, method of analyses, 434 ; valuation of, 491. Table of their value per cent., 498 organate of, 82 phosphate of, its three chemical phases, 6^ ; tri- or bone-phosphate, 62> ; its solubility in the soil, 69 ; various characteristics, 70 ; pure rare in Nature, 290 ; errors or tricks in estimation of, 326, 432, Commer- cial valuation of, 493-497 bi-phosphate of, 73 ; favoured by agriculturists, but inferior to precipitated phosphate, 75 ; production of pure and wholly soluble, 303-314. Commercial valua- tion of, 502, 503, 504 540 INDEX. Lime, di- or neutral-phosphate of, 70-72 ; manufacture of, 226 ; ought to have first place among fertilizers, 227 ; Morfit's process (A), 227 ; and process (B), 238. Commercial valuation of, 501 precipitated phosphate of, its solubility in the soil, 75 : its production and characteristics, 76-78 : pulpy condition, 157 ; only less potent than Colombian guano, 162 ; eminently suited for conversion into "superphosphate", 163 ; but almost too good for the purpose, 302. Valuation of, 499 precipitated phosphate of, process of manufacture, 164 ; the purge or first fractional digestion, 165 ; the solution or second fractional digestion, 169; the pre- cipitation and the vacuum filter vats, 171 ; the am- monia generator, 176; the ammoniacal wash or mother-liquor, 197 ; the purge-liquor, 199 sulphite of, 340 "superphosphate" of, principle of production of, 288; manufacture of commercial, 315-326; delusive analy- ses of, 325 sulphate of, 65 ; constitution and presence in rock guanos, '^'^ Magnesia, phosphate of, 79; estimation of in mineral phos- phates, 454; commercial valuation of, 505 Maracaibo, Colombian guano from, 71 Marl-stones, 2, 7, 20, 30 Marine glue, 527, 528 Marschall, on sugar fertilizers, 429 Martin's, St., phosphate, 20 Mediterranean, the, 8 Mill, the roller, 93 INDEX. 541 Mineral phosphates of lime, commercial valuation of, 491, 492 alumina, 3 ; standard for valuation of, 494-495 commercial valuation of, 508 Mixer^ the, 115 ; mixing machines, 132 Monte-jus, the, 125, 169, 372 Morfit's " mother-liquor" as substitute for Alta Vela and Redonda guanos, 398 ; comparative composition of several precipitates, 400 table of the value of crude phosphates of lime, 498 table of the value of crude phosphates of alumina, 508 Morris and Penny's ammonia process, 50-55 Mother-liquor or wash and mode of reclaiming its mate- rials, 197, 221, 277-287; its merits in sewage defeca- tion, 223, 235, 243, 378, 398, 402-418 Nassau phosphorite, 13 Navasa guano or Cooperite, 25 ; analysis of by Morfit and Gerland, 27 ; by Morfit, 31, 237 New Jersey, 10 New York, 10 Nitrate of soda, 66 Norway, 9, 10 Ogston, analysis of Spanish phosphate, 30 Oil of vitriol, 32, 321 Orchila guano, 27 ; analysis of by Morfit, 31 Organate of lime, 82 Organic matter in phosphates, 90 542 INDEX. Pan, the evaporating, 131 Paints, water and acid proof, 526 Passive condition of certain mineral phosphates, 3 Pearl-ash^ 60 Peat-charcoal, in the defecation of sewage, 396 Penny and Morris's ammonia process, 50-55 Peru, nitrate of soda from, 66 Phosphate of ammonia, 41 Phosphates, mineral, their wide diffusion in nature, i ; their constitution, 2 ; comparative solubility of, 28 ; must be finely powdered, 4 ; South Carolina, 20; analyses by Morfit and Gerland, 22, and Voelcker, 23 ; St. Martin's analysis by Voelcker, 20 ; French, 24 ; ana- lysed by Voelcker, 25 ; organic matter in, 90 ; sand and silica, 91, 442; v/ater, 91; South Carolina, 164, 166, 170, 202, 204, 208, 494 ; Colombian, 203 Phosphates, super, manufacture of, 288, 298-302, 315-326; delusive analyses of, 325 of alumina. vSr^ Alumina of lime, analytical tables of, 30, 31. See Lime of magnesia. See Magnesia • of iron. See Iron of soda. See Soda Phosphorite, 2, 7 ; characteristics and sources of supply, 11; Welsh, II ; German, 12; analysis, 13; Russian and Austrian, 13 ; Spanish, 290; analysis of Russian, 14 ; and of Spanish, 30 Phosphoric acid in sewage, 399 ; estimation of in mineral phosphates, 450 Phosphorus, 226 Pile, 514 Pitch, stearic, 113, 231 Plant, the, for manufacture of fertilizers, 108-146; arrange- ment of, 147-152; steam-boiler and engine, 109; INDEX. 543 roasting-furnace, 109; platform and accessorieSj no; elevator^ in; lift, \\2 \ acid reservoir, w^; mixer, 115 ; digester or solution vat, n/ ; syphon, 123 ; the monte-jus, 125 ; precipitation vat, 127 ; drying-kiln, 129; wash-vat, 130; evaporating-pan, 131 ; mixing- machines, 132; Carr's disintegrators, 133-146; Poole and Hunt's mixer, 145 Plaster of Paris, Z^^ Platform, the, and its accessories, 1 10 Pockston on ammonia, 40 Poole and Hunt, Baltimore, their mixer, 145 Portland cement, 521 Potassa, carbonate of, 60 sulphate of, 58, 282, 283, 284 Potassium, chloride of, 59 Potential, the application of the term in this treatise, 486, 499 Pottery, phosphate of alumina as a glaze for, 418 Precipitation, the, 171 Process, Morfit's (A), 227 ; and (R), 238 Profligate constituents of mineral phosphates, 493 Purge, the, or first fractional digestion, 165 liquor, the, 199 Ransome's artificial stone, 155, 221, 278 Redonda guano, 50, 237, 246, 287, 360, 361, 362, 371, 374, 376, 379' 383. 385, 390, 395. 399' 400, 408 ; analysis of, 364, 466 ; treatment for manure, 365 ; P. Spence's treatment of, 379; also J. B. Spence and Dunn's, 383; Townsend's, 389 ; replaced by Morfit's " mother- liquor", 398; commercial valuation of, 508 Reservoir, the acid, 1 13 544 INDEX. Reynoso introduces phosphate of alumina to sugar- refining, 416 Roasting-furnace, the, 109 Rock guanos erroneously classified, 360 Roller-mill, the, 93 Reaumur's thermometer, 519 Root crops, fertilizers for, 430 Rossa or Guaymas guano, 17, 30, 71 Russian phosphorite, 13 Sal ammoniac, 57 Salt, table, 409, 410 Salt of tartar, 60 Salts, alkaline, estimation of in mineral phosphates, 457 Saponifier, a ready, in aluminate of soda, 409; method of use, 413 Saxony, 10 Scherer, on ammonia in wool, 44 Schwachofter, on Russian phosphorite, 14 Selinite, 83 Sewage, the natural means of fertilization, i ; a source of ammonia, 47, 406 ; suggested method of treatment, 47-49 ; phosphate of alumina for defecation of, 161 ; Morfit's "mother-water" an admirable precipitant of, 223, 237, 402-418; its utilization a paramount problem of hygiene and economics, i, 393 ; analysis of pre- cipitates by Morfit, 400 of the Thames, 393 Shoddy a source of ammonia, 53 Siebenthal, B. de, 164 Sifter, the, 95 Silver, nitrate of, 220 INDEX. 545 Soda, alumiiiate of, 409 nitrate of, 66 phosphate of, 48 ; as an economiser, 287 Soda-lime, 51, 52 Soil, elements of fertility in, 420 ; variety of fertilizers, 422 Sombrero guano, 18; value first recognised by Morfit, 18 ; analyses by Voelcker, 18, Evans and Jones, 19, and Morfit, 31 SoreFs cement, 523 Spanish phosphorite, 290 Spence, John Berger, 41 ; his patent for treatment of phosphate of alumina, 383, 385, 408 Peter, his process for producing alum from phos- phate of alumina, 379, 408 Stassfurt, 59 Steam-boiler and engine, 109 Stearic pitch, 113, 231, 523 Suffolk coprolites, 15 Sugar, phosphate of alumina, use in manufacture of, 415 ; fertilizers for, 428 Sugar-cane, the, cited, 416 Sulphite of calcium phosphate, ^^ Stone, artificial, 530 Sulphite of tri-phosphate of lime, Gerland's, 338 ; method of manufacture, 346; its properties, 353; analysis, 356 Sulphuric acid, its slovenly use in treating mineral phos- phates, 4; constitution and manufacture of, 32; tables of specific gravity, 34, 35 Superphosphate of lime, manufacture of, 288, 298, 315, 326; formula for analysis of, 469 Sweden, 9 Switzerland, 10 Syphon, the, 123 N N 546 INDEX. Thames sewage, 393 Thermometers, mode of using, 515 Tounsend, Joseph, his conversion of Redonda guano into phosphate of soda, 287 ; his patent for treatment of phosphate of alumina, 389, 408 Turbines, 310 Twaddle's hydrometer, 515 Universal dunger, 426 Ure, sulphuric acid table, 35 ; hydrochloric acid table, 38 Vacuum filters, the, 17 1 Valuation of crude and refined fertilizing materials, 485 Vat, cast-iron, 232 Vat, the solution, 117; the precipitation, 127; the wash, 130 Vats, the filter, 171 Venezuela, 27 Vitriol, oil of, 32, 321 Voelcker, Dr. Augustus, on apatite, 10 ; analysis of Ger- man phosphorite, 13 ; of Sombrero guano, 18 ; of St. Martin's phosphate, 20; of South Carolina phosphate, 23 ; of French phosphate, 25 ; of Alta Vela guano, 364 ; on soils and drainage, 43 1 Wagner, 529 Wanklyn, analysis of Way's di-phosphate of lime, 247 Warrington on action of carbonate of lime, 80 ; on coagu- lation of alumina salts by hot water, 471 Wash-vat, the, 130 INDEX. 547 Way, J. T., analysis of Cambridge coprolites, 3 1 ; his pro- cess for di-phosphate of lime, 227, 247-259 ; and for chloro-phosphate of lime, 263-276 Welsh phosphorite, 1 1 Whiting, 64 Wicken coprolites, 16, 17, 494 Williams, Charles P., on solubility of crude phosphates of lime, 28 Williman's Island, 22 Wool, as a source of ammonia, 44 Woollen waste, 45 Wright, on ammonia, 40 THE END. T. KICHARDS, 37, GREAT QUEEN STREET, LONDON. €>!^ y r> j'-y :» 3,-'- -^■'9> ~> ^> ^ s* •"> - :> ^ > > ^ : o J > > > J > :>> .: > , > > ") ■> J>) '>> > >> o. > IJ^ >>J> :3L»> ^??-^ 3 >^:» '^^^ >OK> -^:> y*i>> ,:r ' ^ - ' X » > ^ > : ■-■. _» > > -> > > ^ > ~>v-^ > ■: > > ^ > >:> > ■ :? - > ~-yys> > -> ■ > >x^^ :> > ^ :>> ?> :> > > > '> i > :> :> > > ^ > >2> > ?' 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