LIBRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORNIA. 
 
 Class 
 
WORKS OF PROF. A. S. MILLER 
 
 PUBLISHED BY 
 
 JOHN WILEY & SONS. 
 
 A Manual of Assaying. 
 
 The Fire Assay of Gold, Silver, and Lead, includ- 
 ing Amalgamation and Chlorination Tests. Third 
 Edition, Revised and Enlarged. 12010, viii-f 148 
 pages, 41 figures. Cloth, $1.00. 
 
 The Cyanide Process. 
 
 An Introduction to the Cyanide Process, includ- 
 ing the Determination of the Applicability of the 
 Process to an Ore. Second Edition, Revised and 
 Enlarged. i2mo, viii-|-95 pages, 28 figuies. Cloth, 
 
 $1.00. 
 
THE CYANIDE PROCESS 
 
 AN INTRODUCTION TO THE CYANIDE PROCESS, 
 
 INCLUDING THE DETERMINATION OF THE 
 
 APPLICABILITY OF THE PROCESS 
 
 TO AN ORE 
 
 BY 
 
 ALFRED S. MILLER 
 i 
 
 FORMERLY PROFESSOR OP MINING, METALLURGY, AND GEOLOGY 
 
 UNIVERSITY OF IDAHO 
 Author of A Manual of Assaying 
 
 SECOND EDITION, REVISED AND ENLARGED 
 FIRST THOUSAND 
 
 NEW YORK 
 
 JOHN WILEY & SONS 
 
 LONDON: CHAPMAN" & HALL, LIMITED 
 
 1906 
 
f'lERAL 
 
 Copyright, 1903, 1906 
 
 BY 
 
 ALFRED S. MILLER 
 
 EGBERT DRUMMOND, PRINTER, NEW YORK 
 
PREFACE TO THE SECOND EDITION. 
 
 As stated on the title page, this book is intended, as 
 "an introduction to the cyanide process, including 
 the determination of the applicability of the process 
 to an ore." It was written primarily for the con- 
 venience of the writer's students in doing laboratory 
 work, and the first edition was printed for the writer. 
 The demand from most of the gold-mining regions of 
 the world for copies of this book has made it necessary 
 to issue a second edition. 
 
 A mining engineer, after receiving a copy of the first 
 edition, wrote, "It is certainly the most compact and 
 Ho the point' book on this subject that is printed." 
 If the writer has succeeded, even in a measure, to 
 write a " compact" and "to the point "'book on this 
 subject, it should be welcomed by all who are not 
 already proficient in this subject. 
 
 Figures 9 and 10 are from photographs of laboratory 
 work. Figures 14, 15, and 16 are taken from the cata- 
 logue of the Hendryx Electro Cyanide Company. The 
 other illustrations are taken, by permission, from the 
 catalogue of the Pacific Tank Company. 
 
 Moscow, IDAHO, February, 1906. 
 
 iii 
 
 155755 
 
PEEFACE TO THE FIRST EDITION. 
 
 A NUMBER of books on the cyanide process are on the 
 market. Articles on this subject constantly appear 
 in the proceedings of scientific associations, and in the 
 mining and metallurgical journals. It might, at first 
 thought, appear unnecessary to publish another book 
 on this subject, especially since books cannot keep 
 up with the progress of such a subject. But there 
 are many mining men and students, who, on account of 
 their limited knowledge of chemistry, and of the prac- 
 tical operations of the cyanide process, are not able 
 to receive much benefit from the publications mentioned 
 above. 
 
 This book has not been written for the expert, or 
 for the man who " knows it all"; but for the larger 
 number of persons who have no knowledge of this 
 subject, and are looking for a book that will give them 
 a start, and sufficient of the fundamental principles to 
 understand the literature on this subject. It is also 
 intended to serve the purposes of a syllabus and a 
 laboratory guide. 
 
 Clearness was aimed at even at the expense of repe- 
 
 iv 
 
PREFACE TO THE FIRST EDITION. V 
 
 tition. Conciseness is essential to attain the object 
 sought in this book. 
 
 This being largely a chemical subject, technical 
 terms and chemical equations could not be altogether 
 avoided; nor would it have been desirable to do so. 
 
 Acknowledgment is due the Pacific Tank Company 
 for kindly loaning the writer the cuts used in illustrating 
 this article. 
 
 Moscow, IDAHO, January, 1903. 
 
CONTENTS. 
 
 PAGE 
 
 INTRODUCTORY 1 
 
 CHAPTER I. 
 
 GENERAL DESCRIPTION OF THE CYANIDE PROCESS 3 
 
 Methods of operating the Cyanide Process: The Percola- 
 tion Method; The Agitation Method; The Double- treat- 
 ment Method : ; The Circulating Method. Methods of 
 precipitating the Gold from the Cyanide Solutions. 
 
 CHAPTER II. 
 
 INTERFERING SUBSTANCES 12 
 
 Acidity; Base Metals (general) ; Iron; Soluble Sulphides; 
 Iron Sulphide; Copper, Organic Matter; Antimony; 
 Arsenic; Aluminum; Magnesium; Cobalt; Manganese; 
 Zinc. 
 
 CHAPTER III. 
 
 THE CHEMISTRY OF THE CYANIDE PROCESS 18 
 
 Chemical and Mechanical Means of supplying Oxygen to 
 the Solution; Decomposition of Potassium Cyanide; 
 Strength of Solutions; Reactions in the Zinc Boxes; 
 Determining the Strength of Solutions; Methods to 
 save Calculations ; To bring a Weak Potassium Cyanide 
 Solution up to Any Strength ; To reduce the Strength 
 
 vii 
 
Vlll CONTENTS. 
 
 PAGE 
 
 of a Solution; To make a Definite Volume of a Weaker 
 Solution from a Stronger Solution; Methods for assay- 
 ing Cyanide Solutions; Testing Cyanide Solutions con- 
 taining Zinc ; Titrating Complex Solutions. 
 
 CHAPTER IV. 
 
 DETERMINING THE APPLICABILITY OF THE CYANIDE PROCESS 
 
 TO AN ORE 35 
 
 Extraction Tests; Acidity; Consumption of Cyanide; 
 Precipitation Tests ; Amalgamation Tests. 
 
 CHAPTER V. 
 
 NOTES 43 
 
 Strength of Solutions; Calcining; Roasting; Crushing; 
 The Clean-up ; Used Solutions Less Powerful than Fresh 
 Solutions of the Same Strength; Silver Ores; Other 
 Notes; Useful Information. 
 
 CHAPTER VI. 
 
 SHORT DESCRIPTIONS OF SOME CYANIDE PROCESSES 52 
 
 McArthur-Forest Process; Siemens-Halske Process; The 
 Pneumatic Process; The Betty Process; The Godbe 
 Agitation Process; The Begeer Cyanide Process; The 
 Decantation Process; Precipitation by Zinc Dust; The 
 Bromo-Cyanogen Process; The Holderman Process; 
 The Moore Process; The Hendryx Process; Sample 
 Specifications and Prices of Cyanide Plants ; Illustra- 
 tions of Vats, False Bottoms, and Cyanide Plants. 
 
 APPENDIX. 
 
 VOLUMETRIC ANALYSIS 80 
 
 ATOMIC WEIGHTS ....,.,. 90 
 
UNIVERSITY 
 
 THE CYANIDE PROCESS, 
 
 INTRODUCTORY. 
 
 THE first use of potassium cyanide to dissolve gold 
 in ores, on a commercial scale, is of comparatively recent 
 date. McArthur and Forest took out a patent on the 
 cyanide process in England in 1887, and in the United 
 States in 1889. It was some years after this before a 
 success was made of the process, and not until a success 
 had been made of the process elsewhere did it come 
 into use in America. 
 
 That gold is soluble in potassium cyanide was known 
 for a long time. Hagan mentioned it in 1806. Dr. 
 Wright used gold-cyanide solution in electroplating 
 in 1840. Eisner published his observations in 1844, 
 claiming that the solution of the metals is due to the 
 action of the oxygen aborbed from the air, which " decom- 
 poses part of the cyanide.'^) 
 
 J. H. Rae took out the first patent in the United 
 States in 1867, for the extraction of gold by a " current 
 of electricity and suitable solvents or chemicals, such, 
 for instance, as cyanide of potassium." This was 
 
2 THE CYANIDE PROCESS. 
 
 followed by other patents from time to time; but none 
 of these processes came into general use, until McArthur 
 and Forest took out their patents. ^^^^/ 
 
 The process was developed by many experimenters, 
 and practical workers of the process. In many instances 
 the same facts have been discovered independently by 
 workers in different parts of the world. This makes it 
 impossible to credit everything that is known of this 
 subject to the person that may think he deserves such 
 credit. As this is largely a chemical subject, much 
 that is known depends on the general principles of 
 chemistry, which are the common property of all. 
 
CHAPTER I. 
 GENERAL DESCRIPTION OF THE CYANIDE PROCESS. 
 
 / A DILUTE solution of potassium cyanide dissolves 
 gold and silver contained in crushed ore, and, with 
 some exceptions, does not attack, to a large degree 
 (during the time necessary to dissolve a large per- 
 centage of the gold), any of the other constituents .of 
 the ore. The gold and silver are then precipitated 
 from the solution, and, after proper treatment, cast 
 into bars. This constitutes what is known as the 
 "Cyanide Process." ; 
 
 Different methods have been devised by which these 
 results are attained. A general idea of the working 
 of this process may be obtained from Fig. 1, which 
 is a laboratory plant by which about 100 Ibs. of ore can 
 be treated at a time. A potassium cyanide solution 
 of the best strength * is put into the uppermost tank. 
 The ore, crushed to the best size,* is put into the next 
 lower tank. Above the bottom, this tank has a per- 
 forated false bottom which is covered with duck filter- 
 cloth. The solution, from the uppermost tank, enters 
 the tank containing the ore from the bottom. After 
 the ore has soaked the best length of time,* the gold- 
 
 * As determined by experiment. 
 
THE CYANIDE PROCESS. 
 
 FIG. 1. Laboratory Cyanide Plant. 
 
GENERAL DESCRIPTION. 5 
 
 bearing solution * is drawn off from below, and passed 
 through the rectangular wooden box below. This box 
 is divided into six large and six small compartments. 
 The solution flows down through the small compart- 
 ments and up through the large compartments (for 
 arrangement of box, see Fig. 2). Each large compart- 
 ment is fitted with a wire screen, near the bottom, 
 above which the compartment is filled with zinc shav- 
 
 PIG. 2. Wooden Zinc-boxes. 
 
 ings. The zinc precipitates the gold and silver from 
 the solution, and the solution runs down into the 
 lowest, or sump tank. From this tank the solution is 
 poured back (pumped back in large works, see Fig. 5) 
 into the uppermost tank, enough strong solution is 
 added to bring the used solution to the strength it had 
 before it was put on the ore, the ore in the next lower 
 tank is replaced by fresh ore, and all the other operations 
 are repeated as before. 
 
 * Generally, the first solution of potassium cyanide is followed 
 by a weaker solution, or a weak solution is used first, followed by 
 a stronger solution; and the last potassium cyanide solution is 
 followed by a water-wash. 
 
THE CYANIDE PROCESS. 
 
 FIG. 3. Iron Zinc-boxes. 
 
 These are light rectangular, sheet-steel boxes, absolutely water- 
 tight and thoroughly coated with acid-proof paint. 
 
 In service the boxes are arranged in series as shown. Each 
 box has two compartments and the solution passes down the narrow 
 and up through the large compartment in which the zinc shavings 
 are placed, and overflows into the next box. 
 
 FIG. 4. Improved Iron Zinc-boxes. 
 
 It will be noticed that the box is made round instead of square; 
 this avoids the necessity of filling out corners. Each compart- 
 ment has a capacity of one cubic foot of shavings. The iron is 
 thoroughly protected by acid-proof paint and every box is fitted 
 with a perforated iron shavings-tray. Each box forms one com- 
 partment, and generally six or more compartments are used in 
 series. 
 
GENERAL DESCRIPTION. 
 
8 
 
 THE CYANIDE PROCESS. 
 
 Methods of operating the Cyanide Process. The 
 principal methods of operating the cyanide process 
 are the percolation method and the agitation method, 
 or some modification of these methods. 
 
 The Percolation Method. In the percolation method 
 the solution is allowed to percolate through the ore. 
 
 FIG. 6. Agitator, Style A. When the extraction is complete 
 the agitators are discharged into leaching vats, and filtration is 
 accomplished by means of vacuum pumps, or the pulp is filter 
 pressed. 
 
 This method has been described under " General 
 Description of the Cyanide Process." 
 
 The Agitation Method. In the agitation method, 
 after the cyanide solution is put on the ore, the ore 
 is agitated by mechanical agitators (shown in Figs. 6 
 
GENERAL DESCRIPTION. 9 
 
 and 7\ or by cold or hot compressed air, which is 
 allowed to enter at the bottom of the tank (Pneumatic 
 Process, Figs. 12 and 13). The air agitates the ore, 
 and supplies oxygen. The use of oxygen in a cyanide 
 solution is explained under "The Chemistry of the 
 Process." 
 
 FIG. 7. Agitator, Style B. 
 
 By the agitation method more gold is dissolved than 
 by the percolation method; but power and additional 
 potassium cyanide are consumed/^ Agitation may 
 shorten the necessary time of contact of the solution 
 with the ore sufficiently that there will be less consump- 
 tion of cyanide by agitation than by percolation. 
 
10 THE CYANIDE PROCESS. 
 
 s The Double-treatment Method consists in treating 
 the ore with a cyanide solution in a tank; and, after 
 draining, the ore is transferred to another tank, and 
 again treated with a stronger or weaker solution, which 
 is sometimes followed by one or two weaker solutions. 
 
 FIG. 8. Agitation, by Centrifugal Pump. 
 
 This arrangement is used at many cyanide plants, particularly 
 for the agitation of slimes in connection with decantation or filter- 
 pressing. One advantage is that agitation can be readily started 
 even if the material has settled compactly on the bottom of the 
 tank, because, the suction-pipe being connected by a loose elbow, 
 suction can be started on top of the charge, and as the material 
 loosens up the weight of the pipe will cause it to gradually settle 
 until finally the suction takes place at the bottom of the tank. 
 
 In the Circulating Method the solution is allowed to 
 percolate through the ore, and is constantly pumped 
 back on the ore the ore being kept covered with the 
 solution during the time of the treatment. 
 
GENERAL DESCRIPTION. 11 
 
 ^Sometimes, after the solution is put on the ore, the 
 ore with the solution is pumped from one tank to another, 
 which agitates the ore and supplies oxygen. 
 
 Methods of precipitating the Gold from Cyanide 
 Solutions. Precipitation of the gold from cyanide solu- 
 tions is effected by zinc shavings (McArthur-Forest 
 Process); by electricity (Siemens-Halske Process) \ 
 by zinc shavings covered with lead (The Betty Process) ; 
 by electricity on amalgamated copper plates covered 
 with a layer of mercury (The Pelatan-Clerici Process); 
 by zinc filaments; by sifting zinc dust into the gold- 
 bearing cyanide solution, and keeping the solution 
 with the zinc dust in agitation by compressed air; 
 by charcoal. ( (VA^^a^^ 
 
CHAPTER II. 
 INTERFERING SUBSTANCES. 
 
 Acidity .-^If the ore contains an acid, decomposition 
 of potassium cyanide results) ^Sulphide ores or tailings, 
 which have undergone oxidation, usually contain sul- 
 phuric aQid.)rThe soluble acid can be washed out of 
 the ore by water, or the soluble and the insoluble acids 
 can be neutralized by lime or soda?) A large excess 
 of lime or soda must be avoided, as it ^consumes zinc, 
 if zinc is used to precipitate the gold; /and, with ore 
 containing a soluble sulphide, an alkaline sulphide 
 would form, which interferes with the extraction. 
 
 When sulphides* of alkaline earths only are present, 
 the lime may be added to the ore or to the solution; 
 but when ferrous salts are present, an alkaline wash, 
 followed by a water-wash, should precede the appli- 
 cation of the cyanide solution (see under Iron). 
 
 Base Metals. It has been generally stated that 
 weak solutions of potassium cyanide attack the com- 
 pounds of the base metals less in proportion to the 
 gold than strong solutions. (This has been attributed 
 by McArthur and Forest to the "selective action" of 
 potassium cyanide for gold. W. A. Dixon considers 
 this action to be due to the larger proportion of oxygen 
 
 12 
 
INTERFERING SUBSTANCES. 13 
 
 to cyanide in a weak solution, on the theory that cyanide 
 attacks free gold so long as free oxygen is present, 
 (then attacks the compounds of the base metals^) Julian^ 
 and Smart * state that the proportion of gold and min- 
 eral matter of the ore dissolved in a weak solution is 
 the same as in a strong solution: "the same propor- 
 tionality exists with solutions of all strengths within 
 working limits." For practical purposes it is sufficient 
 to know that a weak solution of potassium cyanide 
 gives better results than a strong solution. 
 
 Base metals dissolve regardless of the strength of the 
 solution, or the amount of oxygen it contains r (Base 
 metals are usually in the ore in the form of compounds, 
 and gold in the metallic state .") The compounds of the 
 base metals exchange their bases for the potassium in 
 the potassium cyanide, and form a compound with the 
 cyanogen (metalepsy), or cause some other compound to 
 be formed with the cyanogen j Metallic gold being unable 
 to replace the potassium in the potassium cyanide, it 
 becomes necessary to add some element or substance, 
 as oxygen, bromine, etc., which will set the cyanogen 
 free, which will then dissolve the gold, and form a com- 
 pound with it, or a gold-potassium cyanide" ) 
 
 When a solution contains the required proportion of 
 oxygen to dissolve the gold, the gold is more rapidly 
 dissolved than when a solution contains less oxygen, 
 which leaves the solution weaker in cyanide to be acted 
 on by the base metals.; 
 
 The action of potassium cyanide solution on com- 
 
 * " Cyaniding Gold and Silver Ores" by H. Forbes Julian and 
 Edgar Smart. 
 
14 THE CYANIDE PROCESS. 
 
 pounds of the base metals depends somewhat on the 
 physical condition and the chemical combination of 
 these metals. Compounds of zinc and copper physically 
 hard are generally not much attacked by cyanide solu- 
 tion, freshly precipitated oxides or hydrates of iron, 
 zinc, copper, and lead, which may result from an alka- 
 line treatment of the ore, are more readily dissolved 
 than gold by a potassium cyanide solution. N The car- 
 bonates of the metals are also attacked by the cyanide 
 solution. 
 
 Iron.4rlron in the ferrous condition is attacked by 
 potassium cyanide solution, and thus consumes cyanide. 
 Ferrous oxide or ferrous hydrate in the ore, or resulting 
 from a lime or soda wash on ore containing ferrous com- 
 pounds, should be oxidized to the ferric condition, by 
 free access of air, before the cyanide solution is applied, 
 
 (Basic ferrous salts resulting from oxidation of ore or 
 tailings cannot be washed out by water, but they act 
 on the potassium cyanide. By neutralizing these by 
 lime or soda (see under Acidity), ferrous oxide and 
 ferrous hydrate are formed, which should be oxidized 
 to the ferric condition, by free access of air, before the 
 cyanide solution is applied/) 
 
 Metallic Iron in a state of fine division consumes much 
 cyanide. If the ore contains fine iron (some of which 
 may be the result of crushing the ore in iron crushers 
 and other iron machinery) or magnetic iron, separate 
 such iron from the ore by magnetic separators, and, if 
 it has sufficient values to pay to treat it, roast it to 
 ferric oxide. It may need regrinding. It can then 
 be treated separately or with the ore, 
 
INTERFERING SUBSTANCES. 15 
 
 Soluble Sulphides. Soluble sulphides decompose po- 
 tassium cyanide, and form alkaline sulphides, which 
 interfere with the extraction.y^The percentage of ex- 
 traction falls with the accumulation of the alkaline 
 sulphides in the solution. The sulphur in the alkaline 
 sulphides can be removed from the solution by pre- 
 cipitation with lead salts, or changed to different com- 
 pounds by oxidizers. 
 
 Soluble sulphides should be turned into inert com- 
 pounds before the cyanide solution is applied"} Dead 
 roasting before cyaniding is probably the only^ success- 
 ful method so far applied. Roasting to sulphates and 
 washing the sulphates out by a preliminary water-wash 
 has not proved successful, on account of the difficulty 
 of turning all the sulphide into sulphates in this way. 
 
 McArthur and Ellis have covered by patent the use 
 of suitable salts or compounds which, when added to 
 the ore or solution, will form with the sulphur of the 
 sulphide an inert sulphide. For this purpose, they 
 give preference to the metallic compounds in the fol- 
 lowing order: Salts or compounds of lead, such as 
 plumbates, carbonates, acetates, or sulphates of lead; 
 sulphate or chloride of manganese, zincates, oxides, or 
 > chloride of mercury, ferric hydrate or oxide. The 
 amount to be used must be ascertained for each ore by 
 trials of a few samples. 
 
 Copper. Copper is attacked by cyanide solution, and 
 thus consumes cyanide (see Copper, under Base Metals). 
 If the gold is precipitated by zinc shavings, the copper 
 precipitates on the zinc, forming a coating which 
 prevents the precipitation of gold. An addition of 
 
16 THE CYANIDE PROCESS. 
 
 potassium cyanide solution to the gold-bearing solu- 
 tion, before it enters the zinc-boxes, or a coating of 
 lead on the zinc by dipping the zinc shavings into a 1% 
 or 2% solution of lead acetate, before they are put 
 into the zinc-boxes, are proposed remedies. 
 
 Cyanide solutions containing 0.3% or over of copper 
 yield very poor results in extraction.* To remove 
 most of the copper from the cyanide solution, by the 
 lead-zinc couple, Superintendent Higgins of the Creston- 
 Colorado plant, Minas Prietas, Sonora, Mexico, gives 
 the following description, as practiced at that plant: 
 "The solution coming from the tanks titrates about 
 0.23% KCN (potassium cyanide), and flows first 
 through' fourteen ordinary zinc launders, 18x2.5 X 2. 5 ft. 
 in size, where the fine product is collected; secondly, 
 from these launders the solution is taken through six 
 other launders with zinc-lead in each compartment. I 
 use 1.5 Ibs. lead acetate to 15 Ibs. zinc shavings; in 
 other words, about 160 Ibs. of lead acetate for 7500 tons 
 ore." The lead-zinc couple is made by dissolving in 
 distilled water, in each compartment of the zinc -boxes 
 used for this purpose, 1.5 Ibs. of lead acetate, after which 
 15 Ibs. of zinc shavings are pressed into each com- 
 partment, and allowed to stand for half an hour or 
 longer. The solution, after passing through the four- 
 teen ordinary zinc-boxes, passes through the lead- 
 zinc boxes, where a large per cent, of the copper is 
 removed. 
 
 * W. H. Virgoe, Institute of Mining and Metallurgy, December 
 1901. 
 
SUBSTANCES. 17 
 
 The removal of the copper from the ore by a prelimi- 
 nary treatment by sulphuric acid, followed by a water- 
 wash, before the cyanide solution is applied, may prove 
 satisfactory, where the value of the ore permits such 
 treatment at a profit} 
 
 Organic Matter. Organic matter precipitates gold, 
 and extracts oxygen from the solution. Leaves, chips 
 of wood, roots, and all other organic matter should be 
 kept out of the water used, and out of the ore or tailings 
 treated. 
 
 Antimony, arsenic, iron, aluminum, magnesium, 
 cobalt, manganese, zinc, interfere to a smaller or larger 
 degree, according to the physical condition and chem- 
 ical combination in which they are found. 
 
CHAPTER III. 
 THE CHEMISTRY OF THE CYANIDE PROCESS. 
 
 IT is generally accepted that oxygen is necessary to 
 dissolve metallic gold by a solution of potassium cyan- 
 ide, unless other substances are added that combine 
 with the potassium and set the cyanogen * free. Eisner's 
 equation is as follows : 
 
 2Au + 4KCN + + H 2 = 2AuK(CN) 2 + 2KOH 
 
 (Gold) (Potassium (Oxygen) (Water) (Gold-potassium (Potassium 
 cyanide) cyanide) hydrate) 
 
 The equation for the solution of metallic silver is 
 similar. There are other equations offered by different 
 persons for the solution of gold, but all such equations 
 contain oxygen. l^For the purpose of dissolving a higher 
 percentage of gold in less time, oxygen is sometimes 
 supplied by the use of chemicals, or by mechanical 
 devices/) 
 
 Among the chemicals that have been used are potas- 
 sium permanganate, barium oxide, sodium peroxide, 
 manganese dioxide, hydrogen peroxide, bleaching-pow- 
 
 By cy-an'o-gen is meant the radical (CN). 
 
 18 
 
THE CHEMISTRY OF THE CYANIDE PROCESS. 19 
 
 der, etc. The oxygen may destroy some of the potas- 
 sium cyanide: 
 
 KCN + 0=KCNO, 
 2KCNO + 3H 2 = K 2 C0 3 + C0 2 + 2NH 3 . 
 
 ->When chemicals are used that combine with the 
 potassium and set the cyanogen free, no oxygen is 
 needed to dissolve the gold. This may be illustrated 
 by the use of cyanogen bromide: 
 
 CNBr + 3KCN + 2Au = 2K Au(CN) 2 + KBr . 
 
 ~ Among the mechanical devices employed to supply 
 oxygen are the forcing of compressed air through the 
 solution and pulp (Pneumatic process), running the 
 cyanide solution, before using, through a centrifugal 
 pump which has air connection (Begeer process), and 
 allowing the solution to run through open launders. 
 
 Decomposition of Potassium Cyanide. This sub- 
 ject has been discussed to some extent under the sub- 
 ject of Interfering Substances. The mineral acids and 
 many organic acids decompose potassium cyanide. 
 Carbonic acid decomposes potassium cyanide: 
 
 2KCN + C0 2 + H 2 - 2HCN +K 2 C0 3 . 
 
 Ore containing oxidized iron pyrites usually contains 
 some sulphuric acid. With such ore the potassium 
 cyanide solution, by several reactions and contact 
 with the air, forms Prussian blue. This shows a large 
 waste of cyanide. A mixture of ferrous and ferric sul- 
 
20 THE CYANIDE PROCESS. 
 
 phates with potassium cyanide also forms Prussian 
 blue. This can be prevented by keeping the solution 
 alkaline, ^his is known as protective alkalinity. Solu- 
 tions work well on some ores with a protective alkalinity 
 up to 0.3% or more. It should be borne in mind that 
 when soluble sulphides are in the ore, the alkali will 
 form alkaline sulphides with the sulphur, which inter- 
 fere with the extraction, 
 
 The action of the potassium cyanide on the com- 
 pounds of zinc, aluminum, and other compounds has 
 already been referred to under Interfering Substances. 
 
 Strength of Solutions. Several experimenters have 
 found that the rate of the- solution of gold in potassium 
 cyanide solutions increases from very weak solutions 
 to solutions containing 0.25% potassium cyanide; after 
 which the rate decreasesT^It has been found (by 
 Maclaurin) that 0.01% potassium cyanide solution dis- 
 solves oxygen at about the same rate as ordinary 
 water, and that this power increases up to 0.25% or 
 0.3%, after which it diminishes. 
 
 Weak solutions dissolve more gold per unit of potas- 
 sium cyanide than strong solutions in the same time. 
 The weakest solution that gives the best economical 
 results, as shown lw actual experiment with the ore, 
 should be employed) 
 
 Reactions in the Zinc-boxes. The precipitation of 
 gold and silver by zinc was considered merely the sub- 
 stitution of the zinc for the gold and silver, but as free 
 potassium cyanide' must be present in the solution to 
 effect the precipitation, other equations have been 
 offered to explain the precipitation. As this subject 
 
THE CHEMISTRY OF THE CYANIDE PROCESS. 21 
 
 has not been settled, the equations have been omitted 
 here. 
 
 Determining the Strength of Solutions. 
 
 To determine the Strength of the Potassium Cyanide 
 Solutions. The determination of the potassium cyanide 
 in a solution, by silver nitrate, is based on the fact that 
 the silver cyanide, formed by the reaction of silver 
 nitrate on potassium cyanide, is dissolved as long as 
 free potassium cyanide is present, forming the double 
 cyanide of potassium and silver: 
 
 AgN0 3 + KCN = AgCN + KN0 3 , 
 
 170 65 
 
 ~KAg(CN) 2 . 
 
 65 
 
 Expressing the reactions by one equation, 
 AgN0 3 + 2KCN = KAg(CN) 2 + KN0 3 
 
 (Silver nitrate) (Potassium (Potassium (Potassium 
 
 cyanide) silver cyanide) nitrate) 
 
 170 130 
 
 When all the potassium cyanide is converted into a 
 soluble double salt of potassium and silver cyanide, 
 KAg(CN) 2 , any addition of silver nitrate will produce 
 a permanent white precipitate of the simple silver 
 cyanide : 
 
 K Ag(CN) 2 + AgN0 3 = 2AgCN + KN0 3 . 
 
 If 17 grams silver nitrate are dissolved in distilled 
 water and diluted to 1000 cubic centimeters (N/10 
 
 ^ OF THE " 
 UNIVERSITY 
 
 OF 
 
22 THE CYANIDE PROCESS. 
 
 normal solution), in 1 cubic centimeter there is 0.017 
 gram silver nitrate; and each cubic centimeter silver 
 nitrate corresponds to 0.013 gram potassium cyanide: 
 
 170 : 130:: 0.017 :x. x = 0.013 
 
 By multiplying the number of cubic centimeters of 
 silver nitrate consumed, before a permanent precipitate 
 occurs, by 0.013, the weight of the potassium cyanide 
 is found in the solution tested; from which the per- 
 centage strength * can be calculated. 
 )^ome potassium cyanide on the market contains 
 sodium cyanide. A sample containing sodium cyanide 
 reported as potassium cyanide would show the solution 
 to be stronger in cyanogen than it is. Sodium cyanide 
 contains 53 per cent, cyanogen, and potassium cyanide 
 only 40 per cent. : 
 
 AgN0 3 + 2NaCN = NaAg(CN) 2 + NaN0 3 . 
 
 170 98 
 
 170 : 98:: 0.017 :X. X = 0.0098 
 
 One cubic centimeter of a deci-normal silver nitrate 
 solution corresponds to 0.0098 gram sodium cyanide. 
 By determining the percentage of sodium in the potas- 
 sium cyanide, the per cent, of cyanogen can be calculated. 
 
 * By percentage strength is meant the amount in grams in 
 100 cubic centimeters. For example, by dissolving 1 gram pure 
 potassium cyanide in water, and diluting the solution until the 
 whole solution, containing the 1 gram potassium cyanide, measures 
 100 cubic centimeters, we have a 1 per cent, solution of ootassium 
 cyanide. 
 
THE CHEMISTRY OF THE CYANIDE PROCESS. 23 
 
 Methods to save Calculation. If 13 cubic centimeters 
 of the potassium cyanide solution to be tested are 
 titrated with the deci-normal silver nitrate solution, the 
 number of cubic centimeters of the silver nitrate solu- 
 tion consumed, divided by 10, gives the percentage of 
 the potassium cyanide in the solution. 
 
 The silver nitrate solution can be made of any strength 
 to save calculation. If 13.08 grams pure silver nitrate 
 are dissolved in distilled water and diluted to 1000 
 cubic centimeters, and 10 cubic centimeters of the 
 potassium cyanide solution are titrated by this silver 
 nitrate solution, each cubic centimeter silver nitrate 
 consumed corresponds to 0.1 per cent, potassium cya- 
 nide; or by dividing the number of cubic centimeters 
 of silver nitrate consumed by 10, the percentage 
 strength of the potassium cyanide is obtained, as above. 
 ( The action on the potassium cyanide solution of the 
 oxygen in the air, or the oxygen supplied by oxidizers, 
 may result in the formation of ammonia. } As ammonia 
 dissolves silver cyanide, and thus the titration would 
 indicate too high results, it is best to add two or three 
 drops of a 2% solution of potassium iodide to the 
 sample of potassium cyanide solution before titrating 
 it with the silver nitrate. The pale-yellow precipitate 
 which forms, after all the potassium cyanide is con- 
 sumed, is almost insoluble in ammonia. If much free 
 alkali is present, the results may be too high. 
 
 To a potassium cyanide solution containing copper, 
 two or three drops of a 2% solution of potassium iodide 
 should be added before titrating it with the silver 
 nitrate solution. Too much of the potassium iodide 
 
24 THE CYANIDE PROCESS. 
 
 affects the results when copper or much free alkali is 
 present. 
 
 In some cyanide plants the sample of potassium 
 cyanide is filtered through a little quicklime before it 
 is titrated with the silver nitrate solution. 
 
 The strength of the potassium cyanide solution may 
 be obtained by titrating it with a standard solution of 
 iodine in potassium iodide, using starch solution as an 
 indicator : 
 
 2I+KCN = KI + ICN 
 
 The iodine solution may be standardized by a sodium 
 thiosulphate solution of known strength. 
 
 To bring a Weak Potassium Cyanide Solution up to 
 Any Strength. A strong solution of potassium cyanide is 
 made by dissolving potassium cyanide in a separate tank, 
 which solution is used to bring the working solution up to 
 the required strength, after the latter has been in contact 
 with the ore, and the gold has been separated from it. 
 
 For example, suppose 50,000 gallons of working 
 solution of 0.25 per cent, strength, after having been 
 in contact with the ore and the gold having been sepa- 
 rated from it, has been reduced to 0.10 per cent, strength. 
 How much of a 10 per cent, solution will it take to 
 bring the 0.10 per cent, solution of 50,000 gallons up to 
 0.25 per cent, strength? 
 
 Let a = the strong solution, 10% strength; 
 
 b = the working solution after using, 0.10% strength ; 
 c = the working solution before using, 0.25% 
 strength; 
 
THE CHEMISTRY OF THE CYANIDE PROCESS. 25 
 
 d = the number of tons, Ibs., gallons, etc. (in this 
 example 50,000 gallons), working solution of 
 0.10% strength to be raised to 0.25% strength. 
 
 c-b 
 
 ^Xd = gallons 10 per cent, solution to be added to 
 
 the 0.10 per cent, solution to bring it up 
 to 0.25 per cent, strength. 
 
 '- X 50,000 = 769. 23 gallons 10 per cent, solution 
 1U O.Zd . iii 
 
 to be added. 
 
 - To reduce the Strength of a Solution. Suppose we 
 have 40,000 gallons of a solution of 0.24% strength, 
 and we want to reduce it to 0.10% strength: 
 
 0.10:0.24: :40,000:Z. Z = 96,000 gallons. 
 
 Add water to the 40,000 gallons until the whole 
 volume reaches 96,000 gallons, or add 56,000 gallons 
 water (96,000-40,000 = 56,000) to the 40,000 gallons 
 solution of 0.24% strength, and the strength will be 
 reduced to 0.10% strength. 
 
 To make a Definite Volume of a Weaker Solution 
 from a Stronger Solution. Suppose it is desired to 
 make 60,000 gallons solution of 0.20% strength from a 
 solution of 10% strength: 
 
 10 : 0.20 : : 60,000 : X. X = 1200 gallons. 
 
 Add water to 1200 gallons of the solution of 10% 
 strength until the whole volume reaches 60,000 gal- 
 lons, and the 60,000 gallons will have a 0.20% strength. 
 
26 THE CYANIDE PROCESS. 
 
 Danger in working the Cyanide Process. 
 
 Potassium cyanide is extremely poisonous. The 
 building in which cyaniding is carried on, or in which 
 cyanide solutions are standing, should be well ventilated. 
 If this is not done, the men suffer from headache, 
 faintness, and dizziness. It is recommended * that the 
 following be prepared for cyanide poisoning: 
 
 (1) 30 c.c. of 23 per cent, solution of ferrous sulphate. 
 
 (2) 30 c.c. of 5 per cent, solution of caustic potash. 
 
 (3) 2 grams of powdered magnesium oxide. 
 
 (4) A metal receptacle of 1 pint capacity. 
 
 (5) A stomach- tube. 
 
 Nos. 1 and 2 should be in hermetically sealed tubes, 
 which can be broken into the receptacle and powdered 
 magnesia and half a pint of water added, shaken up, 
 and administered. This amount of antidote would 
 account for 5 grams of cyanide of potassium, a quantity 
 far in excess of what is likely to be drunk accidentally, 
 but, to secure a sufficiently rapid reaction, the ferrous 
 sulphate and alkali should be in considerable excess. 
 
 F. S. Tuttle recommends the swallowing of two drops 
 of ammonia on a lump of loaf sugar; for external poison-, 
 ing a warm bath containing washing-soda and common 
 salt; and the inhalation of ammonia, when fumes are 
 accidentally inhaled. 
 
 * By Dr. C. J. Martin and Mr. R. A. O'Brien, Proceedings of 
 the Society of Chemical Industry of Victoria, Vol. I. 
 
THE CHEMISTRY OF THE CYANIDE PROCESS. 27 
 
 Methods for assaying Cyanide Solutions. 
 
 One cubic centimeter of cyanide solution weighs 
 approximately 1 gram (1 cubic centimeter water at 
 4 C. weighs 1 gram). By dividing the number of 
 cubic centimeters solution taken by the weight of 1 
 assay-ton (29.166 grams), the quotient will give approx- 
 imately the number of assay-tons taken. This makes 
 it easy to calculate the value to the ton of solution. 
 Seven hundred cubic centimeters of solution are approxi- 
 mately 24 assay-tons (700-7-29.166 = 24). When the 
 percentage of gold in the solution is small, 1000 or 
 2000 cubic centimeters solution may be taken. 
 
 1. Take 1000 cubic centimeters solution, add excess 
 of copper sulphate (the blue or green color of the filtrate 
 indicates excess). Acidify with hydrochloric, nitric, 
 or sulphuric acid, filter, wash precipitate, and scorify 
 in the usual way; or assay by crucible method. 
 
 2. Put 500 cubic centimeters solution into a casserole, 
 put under a hood with a good draft, acidify with nitric 
 acid, boil for 15 minutes, then add J gram silver dissolved 
 in nitric acid, filter, and assay the precipitate and filter- 
 paper as above. 
 
 3. Put 1000 cubic centimeters solution into a casserole 
 or enameled iron dish, sprinkle 50 grams litharge into 
 the solution, and evaporate to dryness on a sand-bath, 
 water-bath, or iron plate. Scrape out the residue, 
 mix with 7 grams potassium carbonate, 15 grams 
 sodium bicarbonate, about 15 grams silica (powdered 
 quartz or window-glass), 1 gram wheat flour, put into 
 
28 THE CYANIDE PROCESS. 
 
 a crucible, cover the charge with about 8 grams unfused 
 powdered borax, and assay in the usual way. 
 
 The litharge must be sprinkled into the solution 
 before evaporation begins. 
 
 4. To determine both Gold and Silver in a Solution. 
 Precipitate the silver with a solution of sodium sul- 
 phide, filter, dry, and assay. Precipitate the gold in 
 the filtrate by zinc chloride, filter, etc., and assay. 
 
 5. Prepare a solution of mercuric chloride, and keep 
 it in a glass-stoppered bottle. Take a measured quantity 
 of gold-bearing solution, run in, from a burette, mercuric- 
 chloride solution in excess; until no further precipi- 
 tate is produced. Assay the precipitate. 
 
 6. Add 20 drops potassium bichromate to the 
 measured gold-bearing solution. Run in strong silver 
 nitrate solution until the deep-red color of chromate 
 of silver appears. Add 100 grams zinc dust, and mix 
 thoroughly. Dissolve the remaining zinc by sulphuric 
 acid, filter, dry, etc., and assay. 
 
 A. F. Cross described 1 and 2 in JL Chem. and 
 Met. Soc. of S. Africa, May, 1902. In " Gaze's Practi- 
 cal Cyanide Operations," 5 and 6 are described. 
 
 7. Pour 4 or more assay-tons of the solution to be 
 assayed into a porcelain dish (casserole), add 10 c.c. 
 of a 10% solution of acetate of lead, then 4 grams of 
 zinc shavings, boil a minute, add 20 c.c. of hydro- 
 chloric acid. When the action has ceased, boil again, 
 wash the spongy lead with distilled water, transfer it 
 with a stirring-rod to a piece of filter-paper, squeeze 
 into a compact lump, and place it into a hot cupel. 
 The mouth of the muffle should contain a piece of dry pine 
 
THE CHEMISTRY OF THE CYANIDE PROCESS. 29 
 
 wood so that the muffle is filled with flame at the moment 
 of introducing the spongy lead. (Alfred Chiddey.) 
 
 8. Take 3 to 10 assay- tons of the solution, according 
 to richness, and bring to boiling. Acidify with hydro- 
 chloric or sulphuric acid to strong reaction with litmus 
 paper. At end of 2 or 3 minutes, add 1 gram copper 
 sulphate in solution, boil, add slight excess of either 
 sodium or potassium sulphide to precipitate the copper. 
 Continue boiling for a minute, or until evolution of 
 hydrogen sulphide ceases. Filter through an eleven- 
 centimeter filter. Remove the precipitate adhering to 
 the sides of the casserole by a little cold water and 
 rubbing. Fold filter, burn it in front of the muffle in a 
 2 J -inch scorifier, add 20 grams test-lead, a small amount 
 of borax, and scorify to 8 or 9 grams. (R. Stuart Browne.) 
 
 9. Draw off 100 to 500 c.c. of the cyanide solution. 
 Place some sawdust or porous cotton in an iron pan 
 or any convenient iron vessel. Pour the solution 
 gradually upon the sawdust and allow it some time to 
 be absorbed by the latter. Apply heat gradually to 
 the iron vessel until all the solution is evaporated and 
 the sawdust reduced to carbon. The residue, mixed 
 with the proper fluxes, is transferred into a crucible, and 
 then assayed in the ordinary way. Should the volume 
 be too large, it can be quartered down. (Robert Grauer.) 
 
 10. Take 10 A. T. solution and heat it until hot; 
 add ammoniacal copper nitrate until solution shows 
 permanent blue color; add carefully excess of sulphuric 
 acid and filter immediately; fold filter-paper and burn 
 in a scorifier; transfer to a crucible, fuse and cupel. 
 (Maurice Lineman.) 
 
30 THE CYANIDE PROCESS. 
 
 11. Sometimes it is desirable to know approximately 
 what a solution carries, before one of the above tests 
 can be made. Acidify with sulphuric acid, add excess 
 of silver nitrate (until no longer a precipitate forms), 
 filter and assay. 
 
 When t]ie gold only is to be determined, it is best to 
 add sufficient silver to the assay charge to insure 
 separation of the button. When there are no foreign 
 substances present, as sand, etc., wash the precipitate 
 of gold or gold and silver to the tip of the filter, dust 
 about 2 grams powdered lead over the inside of the 
 wet filter, allow to drain, fold the filter to as small a 
 form as possible, enclosing the precipitate with the 
 folds, bring a red-hot cupel in front of the muffle, put 3 
 grams powdered lead into the cupel, place the folded 
 filter-paper on the cupel, and allow the paper to burn 
 at a low temperature in front of the muffle. Then cover 
 the ashes with about 3 grams powdered lead, put the 
 cupel into the muffle and cupel as usual. The silver for 
 separation is added to the precipitate before folding 
 the filter, when gold only is to be determined. 
 
 Testing Cyanide Solutions containing Zinc.* 
 
 i. Total Cyanide. Add excess of sodium hydrate, 
 2 or 3 drops of a 2% potassium iodide solution, and 
 titrate with silver nitrate solution. This gives the 
 total cyanide (for reference below, we designate the 
 
 * L. W. Green, paper read before the Institute of Mining and 
 Metallurgy, Oct. 17, 1901. 
 
THE CHEMISTRY OF THE CYANIDE PROCESS. 31 
 
 number of c.c. of silver nitrate solution consumed by 
 Tc.c.). 
 
 2. Protective Alkalinity. (This includes the alkaline 
 hydrates, NaOH, KOH, the alkaline-earth hydrates, 
 mainly Ca(OH) 2 , and half the monocarbonates in 
 solution.) Add excess of potassium ferrocyanide, twice 
 the amount of silver nitrate consumed under 1, a few 
 drops of phenolthalein as indicator, and titrate with 
 decinormal nitric acid. The amount of acid used will 
 indicate the protective alkalinity (for reference as above, 
 we designate this by p). The ferrocyanide precipitates 
 the zinc, and the silver the cyanide. These precipitates 
 may be filtered off before titrating with the acid. 
 
 3. Alkaline Hydrates. Add excess of barium chloride 
 (until no further precipitate forms). Then proceed as 
 in the last test. (For reference, we designate this by 
 h). Bicarbonates may be determined by adding a 
 known quantity of standard alkali, and repeating the 
 above test. 
 
 4. Total Cyanide, Ferrocyanide, Sulphocyanides, Chlo- 
 rides, etc. Add amount of acid (as shown by 2) to 
 neutralize the alkali, a drop of potassium chromate, 
 and then titrate with silver nitrate until a permanent 
 faint- red color appears. 
 
 5. Ferrocyanides. Add 10 c.c. decinormal sodium 
 carbonate, the amount of silver nitrate consumed under 
 1, and shake well. All the ferrocyanide present will 
 be precipitated by the zinc in the solution, and any 
 excess of zinc will be thrown down as basic cabonate, 
 and there will be an excess of sodium carbonate. Add 
 phenolphthalein and neutralize slowly with decinormal 
 
32 THE CYANIDE PROCESS. 
 
 nitric acid. Add about 1 c.c. more of the nitric acid, 
 shake, and add solution of sodium carbonate drop by 
 drop till the clear solution is just faintly pink. Add 
 excess potassium ferrocyanide. The reaction between 
 the basic zinc carbonate and the potassium ferrocyanide 
 makes the solution strongly alkaline. Titrate with 
 decinormal nitric acid. This gives the amount of zinc 
 less what has been precipitated by the ferrocyanide 
 originally present (S). 
 
 6. Zinc. Add sodium carbonate as in 5, and amount 
 silver nitrate consumed in 4 to precipitate all cyanides, 
 ferrocyanides, etc., which precipitates all the zinc as 
 basic carbonate, and there will be an excess of sodium 
 carbonate in the solution. Add phenolphthalein and 
 neutralize as in 5. Add excess potassium ferrocya- 
 nide and titrate with decinormal acid. This gives the 
 amount of zinc (also the copper and cadmium, if these 
 are present) (Z). 
 
 If in each of these tests 50 cubic centimeters of the 
 cyanide solution were taken, decinormal nitric acid 
 used, and the silver nitrate solution contained 13.05 
 grams silver nitrate in 1000 cubic centimeters solution, 
 the following are the factors : 
 
 Total cyanide (as KCN) = T X 0.02% 
 
 Protective alkali (as KOH) =pX0.0112% 
 Alkaline hydrate (as KOH) - h X 0.01 12% 
 Alkaline carbonates (as K 2 C0 3 ) = (p-h) X 0.0276% 
 Ferrocyanide (as K 4 Fe(CN) 6 ) = (Z -S) X 0.0351% 
 Zinc = Zx0.0081% 
 
THE CHEMISTRY OF THE CYANIDE PROCESS. 33 
 
 One cubic centimeter of decinormal potassium ferro- 
 cyanide precipitates 0.75 c.c. decinormal zinc solution 
 from dilute neutral solutions. (Sufficiently exact for 
 technical purposes.) 
 
 When a dilute neutral zinc solution is precipitated 
 by excess of sodium carbonate, the excess of alkali being 
 afterwards neutralized with decinormal acid, a precipi- 
 tate of basic carbonate of almost constant composition 
 is obtained: 3Zn(OH) 2 ,2ZnC0 3 . 
 
 Zinc hydrate or carbonate with excess of potassium 
 ferrocyanide forms zinc ferrocyanide and potassium 
 hydrate or carbonate : 
 
 6Zn(OH) 2 +4K 4 Fe(CN) 6 
 
 =K 4 Fe(CN) 6 ,3Zn 2 Fe(CN) 6 + 12KOH, 
 
 or 
 
 6ZnC0 3 +4K 4 Fe(CN) 6 
 
 = K 4 Fe(CN) 6 ,3Zn 2 Fe(CN) 6 + 6K 2 C0 3 . 
 
 These reactions are not complete until the alkali is 
 neutralized. 
 
 Titrating Complex Solutions. On account of the 
 impurities in solutions that have been used, the silver- 
 nitrate test may not indicate the true amount of cyanide 
 in solution. For such solutions J. E. Clennell gives the 
 following method: "A measured volume of the solution 
 is made strongly alkaline by the addition of caustic 
 potash or soda. Sulphuretted hydrogen is passed into 
 the liquid until it ceases to give a precipitate, avoiding 
 a large excess, or, what is better, a concentrated solution 
 
34 THE CYANIDE PROCESS. 
 
 of pure sodium sulphide is added in slight excess. The 
 solution is then well shaken and allowed to stand until 
 the precipitate has subsided. A little lime may be 
 added to assist the settling of the precipitate, in which 
 case it can be filtered without difficulty The clear 
 nitrate is freed from excess of sulphide by agitating 
 with litharge, which is best added in small quantities at 
 a time, with constant agitation, until a drop of the liquid 
 no longer gives the slightest black or brown coloration 
 with a drop of lead acetate solution. A definite volume 
 is then filtered off and tested with nitrate of silver in 
 the ordinary way." (See also 1 above, under Testing 
 Cyanide Solutions containing Zinc.) 
 
CHAPTER IV. 
 
 DETERMINING THE APPLICABILITY OF THE 
 CYANIDE PROCESS TO AN ORE. 
 
 LABORATORY tests are made to determine the applica- 
 bility of the cyanide process to an ore. Laboratory 
 tests, of course, are not conclusive; but, if they are 
 properly conducted, they give an indication of what may 
 be expected on a large scale. Before erecting a mill 
 it is well to treat 50 to 100 Ibs. ore by the best method 
 as indicated by the laboratory experiments, which 
 should be followed by treating from 3 to 6 tons. 
 
 The percentage of extraction is usually higher, and 
 the consumption of cyanide greater in laboratory tests 
 than in a mill. It has been estimated that about one- 
 third the amount of potassium cyanide consumed in 
 laboratory tests is consumed in mill-runs, unless the 
 consumption of cyanide is due to "cyanicides." By 
 "cyanicides " is meant those substances that destroy 
 the potassium cyanide, as free acid and other substances, 
 some of which are mentioned under Interfering Sub- 
 stances (Chapter 11)7^ 
 
 It is not unusual fo get a higher percentage of extrac- 
 tion in a mill than in the laboratory. 
 
 35 
 
36 THE CYANIDE PROCESS. 
 
 A chemical analysis of the ore will give a good indica- 
 tion as to what preliminary treatment is necessary. 
 
 Extraction Tests. 
 
 1. The ore is crushed, sampled, and assayed.* 
 
 2. The ore is treated for interfering substances, such 
 as acid, etc. 
 
 3. The percentage of extraction of the assay value 
 is determined on samples of ore: (1) Crushed to differ- 
 ent sizes; (2) in contact with the solution for different 
 lengths of time; (3) for different strengths of solutions; 
 (4) by different methods (percolation, agitation, etc.; 
 roasted ore, dehydrated ore, etc.; by use of oxidizers, 
 bromo-cyanogen, etc.). 
 
 After the ore is treated, the solution is filtered off and 
 its strength determined, and the ore washed and assayed. 
 The difference between the assay value before treatment 
 and after treatment gives the extraction, or the amount 
 of gold in the solution can be determined by one of the 
 methods given under the Assay of Solutions (Chapter 
 
 in). 
 
 Acidity. Take 200 grams ore, cover with water, 
 agitate for 10 minutes, filter, wash, and titrate with 
 decinormal potassium hydrate solution (see Appendix). 
 Litmus paper may be used as an indicator. This gives 
 the soluble acidity. 
 
 Run an excess of decinormal potassium hydrate 
 solution, from a burette, on the residue, agitate, filter, 
 wash, and titrate back with decinormal acid solution. 
 
 * For the assay of ore for gold, silver, and lead, see the author's 
 Manual of Assaying, published by John Wiley & Sons, New York. 
 
ITS APPLICABILITY TO AN ORE. 37 
 
 This gives the insoluble acidity. In both cases the ore 
 must be washed until no more acid can be washed out, 
 as shown by litmus indicator. 
 
 Total Acidity. Take 200 grams ore, run an ex- 
 cess of decinormal potassium hydrate solution, from a 
 burette, on the ore, cover the ore with water, agitate, 
 filter, and wash as directed above. Add litmus solution 
 to the filtrate and wash- water, and titrate with deci- 
 normal sulphuric acid solution. 
 
 Example. Suppose 50 cubic centimeters decinormal 
 potassium hydrate solution was run on the ore, and it 
 took 8 cubic centimeters of the decinormal sulphuric 
 acid solution to neutralize the filtrate and wash-water. 
 Then it took 42 cubic centimeters of the decinormal 
 potassium hydrate solution (50-8 = 42) to neutralize 
 the acid in 200 grams ore. 
 
 One cubic centimeter decinormal potassium hydrate 
 solution contains 0.0056 gram potassium hydrate. 
 Having taken 200 grams ore, each cubic centimeter 
 decinormal potassium hydrate solution corresponds to 
 0.056 Ib. potassium hydrate to the ton (2000 Ibs.) ore. 
 (0.0056 -200 = .000028. 2000 X. 000028 = 0.056.) (If 42 
 cubic centimeters potassium hydrate were consumed, 
 it takes .056x42 = 2.35 Ibs.) 
 
 Assuming that the acid is sulphuric acid, how much 
 slaked lime will neutralize the acid in the ore? 
 
 2KOH + H 2 S0 4 = K 2 S0 4 + 2H 2 
 
 (Potassium (Sulphuric 
 
 hydrate) acid) 
 
 112 98 
 
 Ca(OH) 2 + H 2 S0 4 = CaS0 4 + 2H 2 
 
 (Slaked lime) 
 
 74 98 
 
38 THE CYANIDE PROCESS. 
 
 One cubic centimeter decinormal potassium hydrate 
 solution corresponds to 1 cubic centimeter decinormal 
 sulphuric acid solution; 1 part by weight potassium 
 hydrate (in its power to neutralize sulphuric acid) 
 corresponds to 0.66 part slaked lime (74-^112 = 0.66). 
 Hence, in the example, where 42 cubic centimeters 
 decinormal potassium hydrate solution were consumed 
 to neutralize the acid in 200 grams ore, it takes 2.35 Ibs. 
 potassium hydrate, or 1.55 Ibs. slaked lime, to the ton 
 ore to neutralize the acidity of the ore (0.056x42 = 2.35. 
 2.35X0.66 = 1.55). 
 
 To neutralize the Acid in Ore by Commercial Caustic 
 Soda. If commercial caustic soda is to be used to 
 neutralize the acid in the ore, dissolve 10 grams of the 
 soda to be used in water, and dilute to 1000 cubic 
 centimeters. Take 200 grams ore, cover with water, 
 add litmus solution, and run the soda solution, from a 
 burette, into the mixture of ore and water. Stir the 
 ore after each addition of solution. Add the solution 
 slowly until a drop gives a permanent blue color to the 
 litmus or litmus paper. Each cubic centimeter of the 
 caustic soda consumed corresponds to 0.1 Ib. of the 
 same soda to the ton (2000 Ibs.) ore. (In 1 cubic 
 centimeter of the solution there is 0.01 gram soda. 
 0.01 * 200 = 0.00005. 2000 X .00005 = 0.1 .) 
 
 Consumption of Cyanide. Put 100 cubic centi- 
 meters of a 0.25% solution of potassium cyanide on 
 200 grams of ore. After the solution has been in con- 
 tact with the ore for 24 hours (or whatever the time 
 may be for the experiment), filter off 10 cubic centi- 
 meters of the potassium cyanide solution, and titrate 
 
ITS APPLICABILITY TO AN ORE. 39 
 
 it with the decinormal silver nitrate solution (see Chap- 
 ter III). 
 
 Example. Suppose the potassium cyanide solution 
 has been reduced to 0.10% strength. This shows a 
 consumption of 1.5 Ibs. potassium cyanide to the ton 
 (2000 Ibs.) ore. (200 grams ore were used, and only 
 100 cubic centimeters solution. 200-100 = 2. 0.25- 
 0.10=0.15. 0.15-2 = 0.075%. 2000 X. 00075 = 1.5.) 
 
 By running a blank with each experiment, that is, by 
 allowing the same amount of solution and of the same 
 strength to stand in the same kind of container, for the 
 same length of time, under the same conditions (except 
 not in contact with ore), etc., as that used for the 
 experiment with the ore, the loss of cyanide not due 
 to the ore may be found. 
 
 In making the tests indicated under the heading 
 Extraction Tests, usually 200 grams ore are put into a 
 glass-stoppered bottle with 100 cubic centimeters of 
 potassium cyanide solution of 0.4% or 0.5% strength, 
 and shaken for 20 minutes or longer. Ten cubic 
 centimeters of the solution are filtered off and the 
 strength determined. If the consumption of cyanide 
 is high, the ore is treated for " cyanicides." 
 
 Subsequent experiments are carried on in percola- 
 tors, fitted up as shown in Fig. 9. A filter is made from 
 asbestos fiber, over which is placed a filter-paper, and 
 on top of this the ore is placed; or an iron-wire gauze, 
 supported on short iron-wire legs and covered with 
 duck filter-cloth, may be fitted in the bottom. Larger 
 samples can be treated in tubs, in barrels sawed in two, 
 etc. These should be fitted with false bottoms (Figs. 
 
40 
 
 THE CYANIDE PROCESS. 
 
 21-25), covered with duck filter-cloth. When wooden 
 vessels are used, they should be coated with paraffin, 
 asphalt, or coal-tar paint. 
 
 When ore is crushed to pass a 40-mesh screen or finer, 
 it may not leach in the percolators. Fine ore can bo 
 treated in 6-inch ribbed funnels, Fig. 10. 
 
ITS APPLICABILITY TO AN ORE. 
 
 41 
 
 Precipitation Tests. The solution from- the tests 
 can be passed through glass tubes rilled with zinc 
 shavings; or if larger samples are treated, a small zinc 
 
 box may be used (Figs. 1 and 2). The amount of gold 
 in a certain number of cubic centimeters of the solu- 
 tion is determined before the solution is passed through 
 
42 THE CYANIDE PROCESS. 
 
 the zinc shavings; and the amount of gold in the same 
 number of cubic centimeters of solution is determined 
 after the solution has passed through the zinc shavings, 
 by one of the methods under Methods for assaying 
 Cyanide Solutions. From these results the percentage 
 of extraction by the zinc can be calculated. 
 
 Small portions of solution may be evaporated in 
 dishes made from lead-foil, and the lead folded or 
 rolled up and cupelled; but this usually gives too low 
 results. 
 
 Coarse gold is usually amalgamated with mercury, 
 as it takes too long to dissolve it with cyanide solu- 
 tion. Ore containing coarse gold is usually crushed 
 by stamps and run over plates amalgamated with 
 mercury; and, if the concentrate or tailing contains 
 sufficient gold to pay for treatment, it may be treated 
 by the cyanide process or the chlorination process. 
 
 Amalgamation tests can be made by shaking, in a 
 bottle, for an hour or two, a pound of ore with an 
 ounce of clean mercury and sufficient water to make a 
 soft mud. Pan out the mercury; and savo the tailing 
 (and concentrate, if any), dry it, assay it, and, if it 
 contains sufficient gold to pay for treatment, make 
 cyanide tests on it as on an ore. 
 
 Amalgamation tests can also be made by panning 
 the ore with mercury OP by running the ore with water 
 over an amalgamated plate. 
 
CHAPTER V. 
 NOTES. 
 
 Strength of Solutions. In general, use the weakest 
 solution that gives the best economical results*) The 
 gold is precipitated from very weak solutions by elec- 
 tricity, zinc filaments, or the lead-zinc couple. 
 
 Temperature. The rate of the solution of gold 
 increases with rise of temperature until a maximum is 
 reached. The maximum point varies with solutions 
 of different strengths. The rate of the solution of other 
 metallic minerals also increases with the rise of tempera- 
 ture. Whether it is profitable or not to apply heat 
 must be determined for each ore?) 
 
 Calcining Ores containing hydrous silicates often 
 yield better results by giving them a preliminary cal- 
 cination at a temperature not exceeding 300 F. If an 
 ore contains lime or magnesia carbonate, and it is 
 calcined at a much higher temperature, the ore will 
 form a cement, and pack when the solution or water 
 is applied.) 
 
 Crushing. For porous ore coarse crushing is usually 
 best; and for hard, dense ore fine crushing must be 
 resorted to. At the Mercur mine, Utah, ore is crushed 
 
44 THE CYANIDE PROCESS. 
 
 to \ to J inch; and at the Republic mine, Washington, 
 ore is crushed to pass a 120-mesh screen. It should 
 be noted that a laboratory crushing gives a coarser 
 product than a mill crushing through the same size 
 screen. Laboratory tests are usually begun on ore 
 crushed to pass a 30-mesh screeiO 
 \ N Roasting. When ore' is roasted for the purpose of 
 oxidizing the sulphur, arsenic, etc., the roasting should 
 begin at a low temperature, the ore should be stirred, 
 air admitted, and the temperature slowly raised, and 
 finished at a dull-red heat. The ore should be roasted 
 "dead," or "sweet." The roasting may produce 
 soluble salts, which should be washed out of the ore 
 before the cyanide solution is applied. The wash-water 
 will contain some values, which can be recovered by 
 precipitation/) 
 
 Difficulties in the precipitation by Zinc. One of 
 these difficulties is the appearance of a white incrusta- 
 tion said to consist of zinc ferrocyanide, which covers 
 the zinc shavings and prevents further action. This 
 does not appear when much free potassium cyanide or 
 alkali is present. Formation of zinc ferrocyanide is 
 increased by soluble salts of iron in the solution. 
 
 Used Solutions Less Powerful than Fresh Solutions of 
 the Same Strength. Alfred James found by experi- 
 ment that the addition of lime to used solutions improved 
 the extraction from free gold ores having a quartz 
 gangue, but had the opposite effect on Dre containing 
 sulphur. / In the latter case he found the addition of 
 sodium sulphide (avoid excess), followed by the addi- 
 tion of a small amount of lead salt (acetate or chloride) 
 
NOTES, 45 
 
 to be effective. After such additions, time 
 must be allowed for precipitates to settle. 
 
 He also showed that the potassium-zinc oxide in the 
 used solution combines with freshly added cyanide, 
 which results in a weaker solution than the chemist had 
 intended to make: 
 
 K 2 Zn0 2 + 4KCN + 2H 2 = K 2 Zn(CN) 4 + 4KOH. 
 
 The accumulation of zinc in the solution is prevented 
 by the action of the sulphides in the ore, or by the above- 
 described treatment. 
 
 By the precipitation of gold from cyanide solution 
 by zinc, a double cyanide of potassium and zinc, 
 K 2 Zn(CN) 4 , is formed. A solution of K 2 Zn(CN) 4 dis- 
 solves gold, but more satisfactory results are obtained 
 by removing the zinc by the above treatment. 
 
 W. H. Davis has patented a process for "regenera- 
 tion of the cyanide in the solution and clarifying of 
 the latter" by " introducing into the solution an alka- 
 line hydrate and then subjecting the mixture. to the 
 action of an alternating electric current." 
 
 Silver Ores. As a general rule, potassium cyanide 
 does not extract a very large percentage of silver from 
 ore, under the same conditions that it extracts a large 
 percentage of the gold. When the silver is in the ore 
 as a chloride, bromide, or iodide, the extraction is high : 
 
 AgCl + 2KCN = KAg(CN 2 ) + KC1. 
 
 The reactions for the silver bromide and silver iodide 
 are similar. No oxygen is needed to effect the solution 
 of silver, when it is in the ore as a compound. When 
 
46 THE, CYANIDE PROCESS. 
 
 the silver is combined with sulphur, arsenic, etc., the 
 extraction is low, which is probably partly due to the 
 formation of potassium sulphide: 
 
 Ag 2 S + 4KCN = 2KAg(CN) 2 + K 2 S. 
 
 When such ore is roasted with from 0.25% to 15% 
 common salt, a silver chloride forms, which is soluble 
 in potassium cyanide. Add the salt near the end of 
 the roasting. 
 
 Low-grade ores containing both gold and silver may 
 be profitably treated by this method. Ores running 
 high in silver can be more profitably treated by other 
 methods, as much potassium cyanide is consumed in 
 the solution of silver chloride. 
 
 If roasted, the ore may need a preliminary water- 
 wash to clean the ore of soluble salts. Some values 
 will also wash out, which can be recovered by precipitat- 
 ing them. 
 
 Ore of the Dos Cabezas mines * of Sonora, Mexico, 
 assaying 29 ounces silver and 0.1 ounce gold, by com- 
 plete sliming, and treating for 24 hours by agitation by 
 compressed air, the solution being warmed, the tailing 
 assayed trace of silver and no gold. Consumption of 
 potassium cyanide, 7.3 pounds per ton of ore treated. 
 
 The Clean-up. At the end of two weeks or a month, 
 the precipitates in the zinc-boxes are collected, and 
 turned into bullion. These precipitates, in addition to 
 the gold and silver, often contain lead, zinc, iron, lime, 
 copper, etc.; and, even if they contain no copper, lead, 
 
 * M. B. Parker in the Bulletin of the International Miners' Asso- 
 ciation. 
 
NOTES. 47 
 
 etc., they contain pieces of partly used up zinc. The 
 coarse zinc is usually sieved off, and put back into the 
 zinc-boxes. The liquid is pumped or siphoned off the 
 gold slimes, and they are dried; or they are filter- 
 pressed and then dried. 
 
 In cleaning up, the zinc shavings should be exposed 
 to the air as little as possible, as they oxidize rapidly, 
 after which they are almost useless for precipitation. 
 
 There are several methods by which these slimes are 
 treated : (1) They may be melted with borax; (2) roasted, 
 then melted ; (3) treated with sulphuric acid, then melted ; 
 (4) treated with nitric acid, then melted. Alfred 
 James found that (2), (3)_, (4) occasioned an additional 
 loss to that sustained by melting with borax only, 
 and that treatment with sulphuric acid, then melting, 
 sustained the least loss among the three. His advice 
 is to handle the gold slimes as little as possible, and to 
 use lead-free zinc in the precipitation. The losses, in 
 cleaning up, have been reduced by the use of a special 
 filter- press. 
 
 Lead Smelting of Zinc-Gold Slimes. P. S. Tavener * 
 found that by fusing the precipitates with litharge, as 
 in an assay, more can be recovered than by the roast- 
 ing and acid treatment. By this process the zinc 
 slimes are dried, roughly weighed to determine the 
 amount of fluxes necessary, smelted in a reverberatory 
 furnace with the fluxes and the gold-lead cupelled. 
 The charge by weight is approximately as follows: 
 
 * Journal of the Chemical and Metallurgical Society of South 
 Africa, October, 1902. 
 
48 THE CYANIDE PROCESS. 
 
 Zinc slimes 100 parts 
 
 Litharge 60 " 
 
 Assay slag 10 to 15 " 
 
 Foul slag. 10 " 15 " 
 
 Silica 5 " 10 " 
 
 Charge for fine zinc: 
 
 Fine zinc 100 parts 
 
 Litharge 150 " 
 
 Slag 20 " 
 
 Sawdust is used as a reducing agent. One per cent, 
 of the weight of the litharge of sawdust is mixed with 
 the slime. If the proportion of litharge is in excess 
 of 60 per cent., 1.5 to 2 per cent, of sawdust is required. 
 No sawdust is added to the fine zinc. To determine the 
 amount of slag necessary to produce a fusible slag, 
 trials can be made in a crucible with a small quantity 
 of slime or fine zinc. It takes about 30 per cent, less 
 slag to make a fusible slag in the furnace than in the 
 crucible. The resulting lead should not contain more 
 than about 8 per cent, of gold, and 10 per cent, is the 
 limit. 
 
 Additional Notes. 
 
 1. Lime is used to settle slimes. 
 
 2. Lime is preferred to soda for neutralizing acidity, 
 as it does not cause formation of zinc ferrocyanide, 
 which impairs the activity of zinc for precipitation. 
 
 3. If the solution is not clear, contains suspended 
 matter, pass it through, .a sand filter before entering the 
 zinc-boxes. 
 
NOTES. 49 
 
 4. The formation of hydrogen gas in the zinc-boxes 
 is caused by the action of potassium hydrate on the 
 zinc. Excess of caustic soda or lime used in neutralizing 
 the ore, if not washed out, will act on the zinc. 
 
 5. The solutions used on ores containing no sul- 
 phides are kept slightly alkaline. "Add soda or lime, 
 a little at a time, till the solution flowing out from the 
 extractor-boxes does not rise in cyanide test." (James.) 
 
 Excess of alkali is to be avoided with sulphide ores. 
 "A little soda is necessary, and helps the zinc-box 
 reaction, but use lime generally for neutralizing purposes, 
 and keep your solutions so that they rise apparently in 
 cyanide, if soda is added." (" Cyanide Practice by 
 James.") 
 
 7. Sampling tailings in a vat by a glass tube or iron 
 pipe may result in not getting a fair sample of the 
 bottom layer. 
 
 8. From \ to 1 Ib. cyanide is consumed per ton of ore 
 treated. Some pyritic ores consume from 3 to 50 Ibs. 
 
 9. From \ to \ Ib. zinc is consumed per ton ore 
 treated. 
 
 10. One Ib. zinc should precipitate about 6 Ibs. gold, 
 but in practice it takes from 5 oz. to 1 Ib. zinc to pre- 
 cipitate 1 oz. gold. Compounds in the solution, formed 
 by the solution and the minerals in the ore, are, in a 
 large measure, the cause of the high consumption of 
 zinc. 
 
 11. Iron in contact with zinc causes solution of the 
 zinc. The use of iron trays cannot be avoided. 
 
 12. Zinc shavings weigh about 5 Ibs. per cubic foot 
 in the boxes. 
 
50 THE CYANIDE PROCESS. 
 
 13. There should be three zinc-boxes in a cyanide 
 works one for the strong solution, one for weak 
 solutions, and one for the washings. 
 
 14. Solutions rich in gold give a cleaner deposit on 
 the zinc with less consumption of cyanide, the volume 
 passing through the precipitation-boxes being less. 
 
 15. Most of the gold is precipitated in the upper com- 
 partments of the zinc-box. The zinc dissolves more 
 rapidly in the upper compartments. As the precipi- 
 tation proceeds, the zinc is transferred from the lower 
 compartments to the upper ones, and fresh zinc is 
 added at the foot of the box. 
 
 16. There are usually about ten compartments in a 
 zinc-box, and the box has a fall of about 3? inches. 
 The first and last compartments are usually left empty 
 or supplied with sand filters to clarify the solution. 
 
 17. The surface of a charge of ore should be about 
 12 inches below the rim of the vat, and the solution 
 about 3 inches above the ore. 
 
 18. Wooden vats should be coated with paraffin, 
 asphalt, or coal-tar paint. 
 
 19. A stock or strong solution is not made until 
 wanted, as it undergoes somewhat rapid decomposition. 
 
 20. Gold can not be precipitated by zinc shavings 
 from a cyanide solution which does not contain at 
 least 2 Ibs. potassium cyanide to the ton solution. 
 When the solution contains less than 0.05 per cent. 
 KCN, the solution must be in contact with the zinc for 
 an hour. 
 
 21. Zinc shavings used in the precipitation of gold 
 from cyanide solutions will weigh about 6.5 to 7 Ibs. 
 
NOTES. 51 
 
 per cubic foot when well packed. It has been found 
 advantageous to pack the precipitation boxes closely 
 and firmly, as this offers a greater surface of zinc to the 
 passing solutions than where they are loosely packed. 
 
 22. Foaming in the zinc boxes is due to excessive 
 alkalinity. 
 
 23. Some commercial cyanide contains soluble sul- 
 phides, which should be removed by adding to the 
 solution some slaked lime, and a requisite amount of lead 
 salt (acetate or chloride). Filter the solution, or allow 
 the precipitate to settle and decant the clear solution. 
 
 24. If a solution contains any reducing agents, these 
 should be removed or oxidized before the solution is 
 applied to the ore. 
 
 Useful Information. 
 
 It takes about 700 Ibs. solution to saturate and cover 
 1 ton of ore. 
 
 It requires 100 gallons water to sluice 1 ton tailings 
 out of a vat. 
 
 22 to 28 cubic feet = l ton dry raw ore. 
 
 20 to 26 cubic feet = 1 ton ore wetted down. 
 
 18 cubic feet of earth = 1 ton. 
 
 1 cubic foot of quartz in place = 165 Ibs. 
 
 1 cubic foot of quartz broken = 94 Ibs. 
 
 13 cubic feet quartz, unbroken = 1 ton. 
 
 1 cubic foot of water contains 7J gallons and weighs 
 62J Ibs. 
 
 To find the capacity of a tank in cubic feet, square 
 the diameter of the bottom in feet, multiply by 0.7854, 
 and multiply the product by the inside height in feet. 
 
CHAPTER VI. 
 
 SHORT DESCRIPTIONS OF SOME CYANIDE 
 PROCESSES. 
 
 ALL the cyanide processes, with perhaps one or two 
 exceptions, are covered by patent. The patent is on 
 the method of operating or on the method of precipita- 
 ting, or both. 
 
 The United States District Court for Idaho decided 
 (in 1901) against the patent on zinc dust for precipitating 
 gold-cyanide solutions, holding that the same had been 
 anticipated by prior publications and patents. The 
 case may be carried to a higher court for final decision. 
 
 McArthur-Forrest Process. This process consists in 
 applying dilute solutions of potassium cyanide to ore 
 (not exceeding 8 parts of cyanogen to 1000 parts of 
 water), and precipitating the gold from the solution by 
 means of zinc shavings. The zinc shavings "are cut 
 by a turning-tool from a series of zinc disks held between 
 lathe-centers and turned." The patent also covers the 
 use of an alkali or alkaline earth to neutralize the 
 acidity of the ore. 
 
 Siemens-Halske Process. By this process the gold is 
 precipitated from the solution by electricity. The 
 anodes are iron plates, 7x3xJ in. thick, covered with 
 canvas to prevent short circuits. The cathodes are 
 
 52 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 
 
 53 
 
 very thin lead sheets, stretched between two iron wires, 
 and fastened (3 in each) in light wooden frames, 2x3 ft., 
 which are suspended between the iron plates. The 
 iron anodes cause the formation of Prussian blue by 
 the reaction of ferrocyanide with iron oxide. 
 
 HAMPTON ZINC LATHE 
 
 FIG. 11. Hampton (Patent) Zinc Lathe. 
 
 Sometimes the space between the iron plates is filled 
 with lead shavings, which take the place of the lead 
 sheets, and offer a larger surface. 
 
54 THE CYANIDE PROCESS. 
 
 By this method of precipitation very weak solutions of 
 potassium cyanide can be used to leach the ore. By 
 employing very weak solutions of potassium cyanide, 
 less cyanide is lost by "cyanicides," and in the solu- 
 tion that always remains in the ore; but it requires a 
 longer contact of the solution with the ore. 
 I The Pneumatic Cyanide Process. After the cyanide 
 solution has been put on the ore, compressed air is 
 turned into the space beneath the false bottom in the 
 vat, and is evenly distributed by means of a coil of 
 perforated pipes. The air forces its way through every 
 hole in the perforated false bottom, keeps the ore 
 agitated, and supplies the oxygen for the rapid solu- 
 tion of the gold. It is claimed that nearly all sulphide 
 ores, except those containing an excess of copper and 
 antimony, can be profitably treated by this process. 
 It admits of finer crushing, and requires less time of 
 contact, than the ordinary percolation method. The 
 slimes are forced, by the compressed air, to the surface, 
 leaving the coarser and heavier portions of the ore on 
 the filter, which facilitates the leaching. \ 
 
 The Betty Cyanide Process. This process effects the 
 precipitation of gold from weak solutions. The zinc 
 shavings are completely covered with a coat of lead 
 by being moved about in a 10% solution of lead acetate. 
 When the coating is complete, they are immediately 
 transferred to the precipitation- tank, avoiding contact 
 with the air. The gold is precipitated on the lead of 
 this lead-zinc couple. This lead-zinc loses its precipita- 
 ting power in the first compartment after a ten days' 
 run, when it should be replaced by freshly prepared 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 55 
 
 zinc, and used to precipitate gold from solutions stronger 
 in cyanide. 
 The precipitating-tank is 25 feet long, 6 feet wide, 
 
 FIG. 12. Arrangement of Pneumatic Air-pipe, arranged above 
 false bottom of Leaching-tank. This illustrates the most simple 
 pipe arrangement of the "Pneumatic" Process, but sometimes it 
 is preferred to lead the main supply-pipe over the top of the Leach- 
 ing-tanks, arrange the air-pipe in sections and connect same by 
 different drop-pipes. 
 
 and 5 feet deep, divided into five compartments. Four- 
 teen to fifteen tons of solution can be treated hourly. 
 The solution enters the precipitating-tank at the top. 
 
56 
 
 THE CYANIDE PROCESS. 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 57 
 
 With the gold-bearing solution, 75 gallons of a 
 cyanide solution is allowed to run freely for four hours 
 into the tank, bringing the solution up from 0.007% 
 to 0.025%; 75 gallons of 1J% cyanide solution are now 
 run in for 6 hours. About 12 hours after this, a small 
 piece of cyanide is occasionally dropped into the gold- 
 bearing solution, to keep the strength up to about 
 0.008 per cent. 
 
 The Godbe Agitation Process. Generally, the finer 
 an ore is pulverized, the higher the percentage of extrac- 
 tion. But fine ore packs, which interferes with the 
 leaching, and a considerable amount of the gold-bearing 
 solution cannot be washed out of the ore. 
 
 The difficulties of leaching slimes are overcome by 
 introducing the cyanide solution, containing lime, 
 below the false filter-bottom, agitating the ore by stirrers 
 or compressed air, and displacing the solution by run- 
 ning the second solution in from the bottom, which is 
 displaced in the same way by water. It takes about 
 two displacements by the weaker solution, followed 
 by a water- wash, to wash all the values out. Agita- 
 tion increases the extraction. 
 
 The ore may be crushed wet, run into the vats, and 
 the water displaced by the cyanide solution. By using 
 a large amount of solution, a weaker solution of potas- 
 sium cyanide can be used, and the proper strength of 
 the solution can be kept in constant contact with the 
 ore by continuous upward percolation. 
 
 The Begeer Cyanide Process. This process differs 
 from other processes in running the cyanide solution, 
 before using, repeatedly through a centrifugal pump 
 
53 THE CYANIDE PROCESS. 
 
 which has air connections. In this way the solution 
 is saturated with oxygen, and, it is claimed, will dissolve 
 a higher percentage of gold and silver in a shorter time 
 than a solution not so treated. The power required for 
 this purpose is about one-third H.P. for 100-ton plant. 
 
 The Decantation Process. Slimes are treated by this 
 process. The slimes are agitated until the gold is 
 dissolved, when they are allowed to settle, and the 
 clear solution is drawn off from the top of the tank, 
 and run through the precipitating-boxes. The slimes 
 are washed several times with a repetition of agitation, 
 settling, and drawing off of the clear solution. Some- 
 times the slimes are agitated by a centrifugal pump 
 attached to the bottom of the tank (see Fig. 8). 
 
 Precipitation by Zinc Dust. At the Golden Gate 
 mill, Mercur, Utah, zinc dust is used to precipitate the 
 gold from the cyanide solution. The zinc dust used is 
 a blue bowder, the by-product from zinc smelting. 
 Thirty tons of solution is pumped into a precipitating- 
 tank; and, while the tank is filling, the precipitate from 
 former precipitations, which contains unconsumed zinc 
 dust, is stirred up by introducing air into the bottom 
 of the tank through a pipe, at 10 to 15 Ibs. pressure. 
 Five Ibs. fresh zinc dust is used for 30 tons solution. 
 Beginning when the tank is half full, the zinc dust is 
 sieved into the solution, at intervals, until all the zinc 
 is added. The sediment is then thoroughly stirred up 
 by moving the air-pipe about the bottom, after which 
 the pipe is removed, and the precipitate allowed to 
 settle for half an hour. The liquid is then drawn off 
 through an opening in the side of the tank,, about 8 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 59 
 
 inches above the bottom, and passed through the filter- 
 presses. The precipitation is rapid. About 1J Ibs. zinc 
 dust is consumed per ounce of gold recovered. 
 
 At the Republic mill, Washington, twenty tons of 
 solution are precipitated at each charge by sifting in 
 the necessary quantity of zinc dust, while the solution 
 is being agitated by means of compressed air, intro- 
 duced through a pipe into the bottom of the tank. 
 About 1.25 Ibs. zinc dust is consumed per ounce gold 
 precipitated, or 0.80 Ib. per ounce combined gold and 
 silver. 
 
 The Bromo-Cyanogen Process. This process consists 
 in using a mixture of cyanogen bromide and potassium 
 cyanide. It is the Sulman-Teed process, known in 
 some places as the "Diehl": 
 
 CNBr + 3KCN + 2Au = 2KAu(CN) 2 + KBr 
 
 (Cyanogen (Potassium (Gold) (Potassium- (Potasssium 
 
 bromide) cyanide) gold cyanide) bromide) 
 
 It will be noticed that by this process no oxygen is 
 necessary to dissolve the gold. 
 
 At Deloro, Canada, the mixture of potassium cyanide 
 and cyanogen bromide solution is run on the concentrates 
 to the amount of about one-third of the weight of the 
 ore. The circulating method is used. The solution 
 percolates through the ore, is brought up to strength 
 and kept in continued circulation for 24 hours, then the 
 ore is drained, turned over by shoveling, and the cir- 
 culation continued until assays show the extraction 
 complete. The ore is then given a wash by a weak 
 cyanide solution, followed by a water- wash. Consump- 
 tion per ton of concentrates: Potassium cyanide, 2 Ibs.; 
 
60 THE CYANIDE PROCESS. 
 
 cyanogea bromide, 0.5 lb.; zinc dust (precipitation), 
 0.19 lb.; treatment, 80 to 100 hours; extraction, 87% 
 to 94%. 
 
 The strength of the potassium cyanide is found by 
 the silver nitrate test. To find the amount of cyanogen 
 bromide, acidify by hydrochloric acid, add slight excess 
 of potassium iodide, starch solution as indicator, and 
 titrate the liberated iodine by decinormal sodium 
 thiosulphate. One cubic centimeter decinormal thio- 
 sulphate corresponds to 0.0052 gram cyanogen bromide: 
 
 BrCN + 2KI + 2HC1 = BrCN + 2HI + 2KC1, 
 
 BrCN + 2HI = HBr + HCN + 1 2 , 
 
 2Na 2 S 2 3 + I 2 = 2NaI 4 Na 2 S 4 O 6 . 
 
 Excess of bromo-cyanogen should be avoided, as it is 
 no longer operative after passing the zinc boxes. The 
 amount of cyanogen bromide should not be greater 
 than 25% of the potassium cyanide present in the 
 regular solution. 
 
 The Holderman Method of extracting Gold by Cyanide. 
 The main feature of this method is the Holderman 
 patented filter-tank, having its sides and ends, as well 
 as its bottom, covered with filter material, stretched 
 over A-shaped slats, giving a percolating and leaching 
 area equal to the whole surface of the interior of the 
 tank. The bottom of the tank slopes from back to 
 front, allowing an easy discharge of treated ore through 
 several front gates. The tanks are about 5x7x12 feet 
 in dimensions. About three of these tanks are arranged 
 in stair-like succession, which constitutes a plant for 
 the treatment of ore. The uppermost tank is provided 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 61 
 
 with an agitator. In this tank the ore is treated with 
 cyanide solution for from 2 to 6 hours. At the end 
 of this time the solution is drawn off through the filter, 
 the agitator being kept in motion, and the ore is then 
 washed into the next lower tank with a weak cyanide 
 solution, and allowed to stand a certain length of time, 
 then the solution is drawn off through the filter, and 
 the ore washed into the next lower tank. 
 
 The Moore Process. This process employs a peculiar 
 hollow truncated cone revolving on a horizontal axis 
 in which the ore is treated with cyanide solution, agitated, 
 aerated, and the sand is separated from the slime. The 
 slime with the solution flows down inclined troughs into 
 agitation-tanks. Agitation is accomplished by a centrif- 
 ugal sand-pump, and the slime is finally filter-pressed. 
 
 The Hendryx Process. This process is designed for 
 the rapid extraction of gold, silver, and other metals 
 from their natural ores. 
 
 The Process. The ore is first crushed in a weak 
 chemical solution containing one-fiftieth of one per cent., 
 or less, of cyanide of potassium, and the pulp passed 
 over amalgamated copper plates; then the ore-pulp 
 solution is agitated in the Hendryx Agitator, in which 
 the gold and silver from the ore pulp is dissolved and 
 precipitated by either electricity or zinc. 
 
 The solutions are now removed and returned to 
 a subsidiary tank on their way to the storage-tank, 
 hereinafter designated as " battery storage/' from which 
 the crushing and grinding machinery is supplied, an 
 additional set of plates for electrical deposition is 
 installed. (Fig. 15.) 
 
62 
 
 SHORT DESCRIPTIONS OF SOME PROCESSES. 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
 THE CYANIDE 
 
 63 
 
64 THE CYANIDE PROCESS. 
 
 In the event of there being values left in the puip, 
 owing to insoluble metallic compounds or alloys, or 
 owing to the lack of having ground the ore sufficiently 
 fine to permit of the solutions coming in contact with 
 the metals, then a further step in the process is carried 
 out, consisting of concentration (tables being shown in 
 Figs. 14 and 15). 
 
 The Hendryx Agitator (see Fig. 16) is designed for 
 the rapid extraction of gold and silver from unsepa- 
 rated sands and slimes by means of agitation and 
 aeration in weak chemical solutions containing cyanide 
 of potassium or sodium. Simultaneously the values 
 are deposited on plates by electricity, cyanide is regen- 
 erated, and the fouling of the solutions is prevented. 
 
 Essential Mechanical Feature. The essential mechan- 
 ical feature of the Agitator (Fig. 16) consists of a cylin- 
 drical tank having a conical bottom. In the center of 
 the tank is a circular well which extends nearly to the 
 top and bottom, supported by braces from the side of the 
 tank and having a circular apron at the top which 
 slopes gradually toward the circumference and per- 
 mits the ore-pulp solution, in flowing over it, to be 
 spread out into a thin sheet and to absorb an abun- 
 dance of free oxygen. In this well is a hollow shaft 
 carrying a driving-pulley near the top and a number 
 of screw propellers or pulp-solution lifting- wings. The 
 discharge-valve is connected to a screw for opening 
 and closing. Outside the well and between the apron 
 and the bottom of the tank, the anode and cathode 
 frames or the electrolytic filtering-envelope are sup- 
 ported from the side of the tank and hold the anodes 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 65 
 
 n 
 
 FiQ. 16. The Hendryx Agitator. 
 
66 THE CYANIDE PROCESS. 
 
 and cathodes which are supplied with electrical cur- 
 rent. A coil of pipe serves for raising the temperature 
 of the charge by means of steam or hot water passing 
 through it. The revolutions of the propellers in the 
 well produce a strong upward current, thus resulting in 
 a rapid and uniform circulation of the pulp upward to 
 the aerating apron, where it spreads out into a thin sheet, 
 losing its velocity and gently falling from the edge of the 
 apron into the great mass of ore-pulp solution, where its 
 velocity is again reduced, and then gently dropping down 
 through the electrically charged plates or envelopes. 
 
 Cannot scour Plates. As the violence or force ex- 
 erted by this method of agitation is within the tube 
 or well, and as the plates are outside the well, no 
 scouring of the plates is possible, thereby removing all 
 danger of scouring the deposited metals from off the 
 plates, which is so common in all of the old arm or 
 paddle stirring devices. 
 
 Agitator cannot be clogged. The charge in this 
 agitator is homogeneous and cannot be clogged. A 
 charge of 76 tons of pulp (30 tons ore, dry weight) in a 
 16-foot agitator was settled 48 hours on account of the 
 breaking of a countershaft. Upon starting up, the 
 pump was throwing its full capacity in three minutes, 
 and the charge was in perfect agitation in ten minutes. 
 
 Power required. The power required to operate a 
 machine of 80 to 100 tons of ore pulp, containing one 
 or two tons of solution to one of ore, is about eight 
 horse-power, and the whole contents of the tank are 
 brought up and over the aerating or distributing plate 
 once in five or ten minutes, at the pleasure of the opera- 
 tor, by an increased or decreased speed of the pump. 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 
 
 67 
 
 Sample Specifications and Prices of Cyanide Plants for 
 48 Hours' Contact. 
 
 SPECIFICATIONS. 
 
 2 Solution-tanks. 
 
 4 Leaching-tanks, including false bottom, style A or 
 B, Duck Filters and Bottom Discharge-doors. 
 
 2 Gold-solution Tanks. 
 
 3 Zinc Precipitation-boxes (2 for strong solution and 
 
 1 for weak solution). 
 2 Sump-tanks. 
 1 Solution-pump. 
 Acid-proof Paint in sufficient quantity to coat all tanks 
 
 on the inside. 
 Tank-connections . 
 Cyanide Stop-cocks. 
 And all necessary Pipe and Pipe Fittings. 
 
 Plants up to and including 25-ton capacity are fur- 
 nished with 100 pounds of Zinc Shavings, and larger 
 plants with a Zinc Lathe. 
 
 (These specifications do not include crushing machinery, furnaces, 
 etc.) 
 
 Price. 
 
 Daily Capacity at 25 
 Cubic Feet per Ton. 
 
 Approximate Weight. 
 
 Cost. 
 
 10 tons 
 
 16,780 Ibs. 
 
 $1,000 00 
 
 15 
 
 
 18,760 
 
 
 1,140 00 
 
 20 
 
 
 22,290 
 
 
 1,335 00 
 
 25 
 
 
 26,430 
 
 
 1,460 00 
 
 40 
 
 
 43,655 
 
 
 2,155 00 
 
 50 
 
 
 50,570 
 
 
 2,535 00 
 
 60 
 
 
 57,150 
 
 
 2,720 00 
 
 75 
 
 
 63,260 
 
 
 3,040 00 
 
 100 
 
 
 . 77,485 
 
 
 3,800 00 
 
 125 
 
 
 101,320 
 
 
 4,300 00 
 
 150 
 
 
 113,000 
 
 
 4,940 00 
 
 200 
 
 
 134,150 
 
 
 6,080 00 
 
68 
 
 THE CYANIDE PROCESS. 
 
 "iito^ 
 
 FIG. 17. Leaching- tanks 
 
 FIG. 18. Bottom Discharge-doors. Size of opening 10X10 in., 
 or 16 X 16 in. These sluice-doors consist of heavy cast-iron frames 
 with iron doors attached by bolt hinges. They are kept water- 
 tight by means of rubber gaskets placed around the edge oi the 
 door proper. Bottom discharge-plugs are used where it i 
 desirable to open doors from below a tank. These plugs are 
 removed from inside by means of a handle extending to top of tank. 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 69 
 
 Size. 
 
 8X13 in. 
 8X 8 " 
 
 Weight. 
 115 Ibs. 
 , 90 " 
 
 FIG. 19. Side Discharge-doors. 
 
70 THE CYANIDE PROCESS. 
 
 FIG. 20. Bottom Discharge-gate. 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 
 
 71 
 
 FILTER BOTTOM 
 STYLE A. 
 
 FIG. 21. False Bottom for Leaching-tanks. This bottom con- 
 sists of a grating built of Oregon-pine strips laid about 1J inches 
 apart, and for the protection of the filter a thin band is placed 
 around the outer edge of these strips. Each strip is crozed to 
 allow of free flow of solution. 
 
72 
 
 THE CYANIDE PROCESS. 
 
 FIG. 22. False Bottom for Leaching-tank. The bottom slats 
 of this filter bottom are similar to style "A," but placed farther 
 apart on which a grating is placed, consisting of 1-inch Oregon- 
 pine strips, laid 1 inch apart, with a suitable strip around the outer 
 edge of slats to prevent filter-cloth from being cut. 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 73 
 
 FIG. 23. This filter is constructed of 3 X 4-inch segments, 
 forming a complete circle; within this circle are placed' the sill- 
 pieces which support a 1-inch Oregon-pine floor provided with 
 holes bored at equal distances. 
 
74 
 
 THE CYANIDE PROCESS. 
 
 Sand Filter 
 
 FIG. 24. Sand Filters. In some localities this filter is very 
 much in use. It consists of triangular slats resting on regular sill- 
 pieces. The spaces between the slats are filled with gravel and 
 sand, level with the upper edge, and no filter-cloth is used in con- 
 nection with them. 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 
 
 75 
 
 FIG. 25. False Bottom, Style D, sloping 5 to center. 
 
 This Filter Bottom consists of 1-inch Oregon pine, perforated 
 with ^-inch holes, 1 inch center to center. 
 
 The bottom rests upon circles 3 ft. apart. The circles are built 
 up to different heights, with openings crozed in lower part for free 
 flow of solution. 
 
 Tailings Discharge is placed in center of tank, but tanks above 
 36 ft. diameter have special arrangement for four bottom doors. 
 
76 
 
 THE CYANIDE PROCESS. 
 
 FIG. 26. Fairfax Exploration Co.'s Cyanide Plant. 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 77 
 
 FIG. 27. Cyanide Works, "Myall United" Gold-mine, 
 McPhail, N. S. W. 
 
SHORT DESCRIPTIONS OF SOME PROCESSES. 
 
 79 
 
 FIG. 29. Clean-up Room at the Cyanide Plant of Liberty Bell 
 Mine, showing Iron Vacuum-tanks, Zinc Precipitating-boxee, Vac- 
 uum-pumps, Solution-pumps, Acid-tanks. 
 
APPENDIX. 
 
 Volumetric Analysis. 
 
 By volumetric analysis the quantity of a substance 
 in a solution is determined by another solution of known 
 strength, with which the solution to be determined 
 reacts. When the reaction is complete, a precipitate 
 forms, or ceases to form; a color appears, or dis- 
 appears; a change of color occurs, or a change of color 
 is produced in an indicator put into the solution for this 
 purpose. 
 
 End Reaction. The point in the operation where the 
 reaction is complete, as indicated by change of color, 
 etc., is called the end reaction. 
 
 Titration is the operation of running a standard solu- 
 tion into the solution to be determined, and observing 
 the end reaction: the operation of volumetric analysis, 
 
 Normal Factor. The amount in grams of the reagent 
 in \ cubic centimeter of a normal solution is called 
 the normal factor. 
 
 80 
 
STANDARD SOLUTIONS. 81 
 
 Indicators. 
 
 Litmus. Grind litmus in a porcelain mortar with a 
 little alcohol. Transfer to a flask or beaker, and pour 
 some boiling alcohol on the litmus. After standing 
 for some time, pour off the alcoholic solution, which is 
 of no value. Pour distilled water on- the litmus, let 
 stand for some time, and then filter the solution. Add 
 dilute hydrochloric acid, drop by drop, to the blue 
 solution until it turns violet (not red). Keep the 
 solution in a loosely covered vessel. Alkalies turn the 
 solution blue, and acids red. Free carbonic acid, C0 2 , 
 interferes with the production of the blue color : it must 
 be boiled out of the solution. It cannot be used by 
 gaslight. 
 
 Methyl Orange. Dissolve 1 gram in 1000 cubic 
 centimeters of distilled water. It is colorless, or faint 
 yellow with excess of alkalies, and red, or pink, with 
 acids. It is not affected by carbonic acid or sulphuretted 
 hydrogen. It cannot be used in organic acids or hot 
 solutions. 
 
 Phenacetolin. Dissolve in alcohol, in proportion of 
 2 grams per 1000 cubic centimeters of alcohol. It is 
 used in titrating potassium hydrate, sodium hydrate, 
 or calcium oxide in the presence of their respective 
 carbonates. Alkalies turn it pink, and acids yellow. 
 
 Starch Solutions. Mix 1 gram starch with a little 
 cold water, then pour 100 cubic centimeters boiling 
 water on the starch. Mix and filter. The solution 
 should be cold when used. It must be made fre- 
 quently, as it will not keep for a long time. If a little 
 
82 APPENDIX. 
 
 salicylic acid or pure common salt is added, the solution 
 will keep for a long time. It is used in titrating with 
 iodine. Iodine colors starch blue. 
 
 Phenolphthalein. Dissolve 1 gram in a liter of 50% 
 alcohol. It is used in titrating organic acids, and 
 fixed caustic alkalies in presence of carbonates. It 
 gives no color with bicarbonates, and cannot be used 
 for the titration of free ammonia and its compounds, 
 or for the fixed alkalies, \vhen salts of ammonia are 
 present. It is purple in alkaline solutions, and color- 
 less in acids. 
 
 Standard Solutions. 
 
 Standard Solutions. When a solution of definite 
 strength of a chemical is made, by means of which the 
 strength of other solutions is determined, it is a standard 
 solution. The strength of which to make a standard 
 solution depends on the peculiar reaction such a solu- 
 tion has with the solution to be tested. 
 
 Write the equation for the reaction between the 
 standard solution and the solution to be titrated, 
 from which the value of the standard solution to the 
 solution to be determined will be seen. 
 
 Normal Solutions contain the hydrogen equivalent 
 of the reacting element in grams in 1 liter (1000 cubic 
 centimeters, at 16 C. or 60 F.) . A normal solution 
 is indicated by the letter N. Solutions of less strength 
 are indicated as N/10 (1/10 normal, or decinormal), 
 etc. If a substance is univalent (example, HC1), the 
 full molecular weight is taken. If bivalent (example, 
 
STANDARD SOLUTIONS. 83 
 
 H2S04), half the molecular weight is taken, etc. This 
 rule does not hold good in all cases. (Read paragraph 
 above beginning, Write the equation for the reaction. . .) 
 
 All standard solutions should be made with the 
 greatest care and accuracy, and should be kept in 
 well-stoppered bottles. Before using a solution, the 
 bottle containing the same should be well shaken, to 
 take up the liquid that may have evaporated and con- 
 densed on the sides of the bottle, and to mix the solu- 
 tion thoroughly. Burettes and all other measuring- 
 vessels must be clean and dry before a standard solution 
 is measured by them. 
 
 Vessels in which weighed or determined samples for 
 standard solutions are dissolved must be thoroughly 
 rinsed into the measuring-cylinder before the solution 
 is diluted to the determined volume. 
 
 Bottles with glass stoppers and burettes with glass 
 stop-cocks should not be used for caustic-alkali solutions, 
 as they are liable to stick fast. 
 
 To make a Decinormal Potassium Hydrate, KOH, 
 Solution. Potassium hydrate cannot be accurately 
 weighed. The solution must be standardized against 
 an acid which can be accurately weighed. 
 
 Weigh out exactly 6.300 grams perfectly pure crystals 
 of oxalic acid (H*CaO 4 .2B20126; 126^2 = 63; 
 63^10 = 6.300), dissolve in distilled water, and dilute 
 to exactly 1 liter (1000 cubic centimeters*). This 
 is a decinormal oxalic acid solution. Each cubic centi- 
 meter contains 0.0063 gram of the acid. 
 
 * Cubic centimeters is usually abbreviated to c.c. 
 
84 APPENDIX. 
 
 Weigh out, approximately, 5.600 grams pure potas- 
 sium hydrate (KOH = 56; 56-^-10 = 5.600), dissolve in 
 distilled water, and dilute to about 800 cubic centi- 
 meters. 
 
 Take 10 cubic centimeters of the potassium hydrate 
 solution, to which add several drops of litmus solution 
 (or methyl orange), and titrate from a burette by the 
 decinormal oxalic acid solution, until the litmus (or 
 the methyl orange, if used) turns red. Note the number 
 of cubic centimeters of oxalic acid consumed. Make a 
 duplicate titration. Do the same with 20 cubic centi- 
 meters of the potassium hydrate solution. If the results 
 agree closely, take the average. 
 
 Example. Suppose it took 12 cubic centimeters of 
 the oxalic acid solution to neutralize 10 cubic centi- 
 meters of the potassium hydrate solution. The potas- 
 sium hydrate solution must be diluted until 1 cubic 
 centimeter of the oxalic acid solution will exactly 
 neutralize 1 cubic centimeter of the potassium hydrate 
 solution. 
 
 Suppose there are 740 cubic centimeters of the 
 potassium hydrate solution remaining after the above 
 trials : 
 
 10:12::740:z. z = 888. 
 
 Add distilled water to the 740 cubic centimeters of 
 potassium hydrate solution, until the whole volume 
 reaches 888 cubic centimeters; or add 148 cubic centi- 
 meters water to the 740 cubic centimeters potassium 
 hydrate solution (888-740 = 148). 
 
STANDARD SOLUTIONS. 85 
 
 Now titrate again. One cubic centimeter of the acid 
 should exactly neutralize 1 cubic centimeter of the 
 potassium hydrate solution. Each cubic centimeter 
 contains 0.0056 gram potassium hydrate. 
 
 To make a Decinormal Sulphuric Acid, H^SCU, Solu- 
 tion. Take 2.8 cubic centimeters strong sulphuric 
 acid (1.84 sp. gr.), and pour it into about 800 cubic 
 centimeters distilled water (pour the acid into the 
 water, not the water into the acid) . After the mixture 
 is cool, take 10 cubic centimeters of the acid and titrate 
 from a burette with the decinormal potassium hydrate 
 solution (use litmus or methyl orange as an indicator). 
 Note the number of cubic centimeters of potassium 
 hydrate consumed to neutralize the acid. Make a 
 duplicate titration. 'Do the same with 20 cubic centi- 
 meters. If the results agree closely, take the average. 
 
 Example Suppose it took 12 cubic centimeters of 
 the decinormal potassium hydrate solution to neu- 
 tralize 10 cubic centimeters of the sulphuric-acid 
 solution, and suppose there are 768 cubic centimeters 
 of the sulphuric acid solution remaining, after the above 
 trials: 
 
 10:12: :768:z. a =921.6. 
 
 Add distilled water to the 768 cubic centimeters 
 sulphuric acid until the whole volume reaches 921.6 
 cubic centimeters, or add 153.6 cubic centimeters 
 water to the 768 cubic centimeters sulphuric acid 
 (921.6-768 = 153.6). After the mixture is cool, titrate 
 again. One cubic centimeter decinormal potassium 
 
86 APPENDIX. 
 
 hydrate solution should exactly neutralize 1 cubic cen- 
 timeter of the sulphuric acid solution. Each cubic 
 centimeter contains 0.0049 gram sulphuric acid. 
 
 To make a Decinormal Nitric Acid, HNOs, Solution. 
 Take pure nitric acid and standardize it against deci- 
 normal potassium hydrate solution, in the same way 
 as directed for sulphuric acid. In 1 cubic centimeter 
 decinormal nitric acid solution there is 0.0063 gram of 
 the acid. 
 
 To make a Decinormal Iodine Solution. Procure 
 three watch-glasses (accurately fitting on one another) 
 of convenient size. Weigh two glasses accurately. 
 Take about 12 grams iodine, and mix it with about 
 one-fourth its weight potassium iodide on the third 
 glass. Cover this glass with one of the weighed glasses, 
 which should not touch the mixture. Apply heat to 
 the glass containing the mixture. After the iodine 
 has sublimed on the upper glass, remove it and cover it 
 with the other weighed glass, cool, and weigh. 
 
 Example: 
 
 Grams. 
 
 Weight of glasses and iodine 32 . 000 
 
 Weight of glasses only 20.000 
 
 Iodine 12.000 
 
 A decinormal iodine solution contains 12.685 grams 
 iodine per 1000 cubic centimeters. 
 
 12.685:12: :1000:z. x = 945.99. 
 
 After weighing the glasses containing the iodine, 
 place them immediately in a beaker containing a solu- 
 
STANDARD SOLUTIONS. 87 
 
 tion of nearly twice as much potassium iodide as there 
 is iodine by weight (the potassium iodide must give no 
 blue color to starch, when dilute sulphuric acid is 
 added to a solution of the potassium iodide used for 
 this purpose). 
 
 Now transfer the solution to a graduated cylinder, 
 and fill it up to the required volume, 945.99 cubic centi- 
 meters. Each cubic centimeter contains 0.012685 
 gram iodine. 
 
 Second Method. Put some pure iodine in a weighed, 
 glass-stoppered, weighing-bottle, and weigh the bottle 
 and iodine (the bottle must be kept tightly stoppered, 
 as iodine is very volatile). 
 
 Make a solution of nearly twice as much potassium 
 iodide by weight as iodine taken, as in the first method. 
 With this solution wash the iodine out of the weighing- 
 bottle into a graduated cylinder. Be careful that all 
 the iodine is transferred to the graduated cylinder. 
 
 Example. Suppose the iodine (less the weight of 
 the bottle) weighed 6.000 grams. 
 
 12.685:6: :1000:z. z = 472.99. 
 
 Add distilled water to the cylinder until the whole 
 volume reaches 472.99 cubic centimeters. This is a 
 decinormal iodine solution, the same as under the first 
 method. 
 
 Third Method. Powder pure crystals of -sodium 
 thiosulphate, dry by pressing between folds of blotting- 
 paper, and weigh out exactly 24.8 grams (Na2S 2 03.5H 2 
 =248. 248-*- 10 = 24.8). Dissolve in distilled water 
 
88 APPENDIX. 
 
 and dilute to exactly 1000 cubic centimeters. This 
 is a decinormal solution of sodium thiosulphate. Each 
 cubic centimeter contains 0.0248 gram sodium thio- 
 sulphate. As only half the sodium reacts with iodine^ 
 the whole molecular weight of the sodium thiosulphate 
 will be contained in a liter of a normal solution: 
 
 2Na 2 S 2 3 + 1 2 = 2NaI + Na 2 S 4 6 
 
 Dissolve iodine in distilled water containing potassium 
 iodide, as directed in the first method. Have the iodine 
 solution stronger in iodine than decinormal (by not 
 diluting to that point). Draw 10 cubic centimeters of 
 the sodium thiosulphate solution from a burette, add 
 a little starch solution, and run in, from a burette, the 
 iodine solution. As soon as the iodine is in excess, it 
 blues the starch solution. Make a duplicate, etc., as 
 directed in other examples. 
 
 Suppose it took 8 cubic centimeters of the iodine 
 solution to neutralize 10 cubic centimeters of the 
 sodium thiosulphate solution, and there are 500 cubic 
 centimeters of the iodine solution remaining: 
 
 8:10::500:z. z = 
 
 Add distilled water to the iodine solution until the 
 whole volume reaches 625 cubic centimeters, or add 
 125 cubic centimeters water to the 500 cubic centi- 
 meters iodine solution (625-500 = 125). This is a 
 decinormal solution of iodine, the same as under the 
 first and the second method. 
 
STANDAKD SOLUTIONS. . 89 
 
 Iodine solutions should be occasionally tested, as they 
 change after standing for some time. In a well- 
 stoppered bottle wrapped in brown paper to exclude the 
 light, the solution remains unchanged for a long time. 
 
 To determine the Strength of a Potassium Cyanide 
 Solution by a Decinormal Iodine Solution. In titrat- 
 ing potassium cyanide with iodine, the reaction is: 
 
 21 + KCN = KI+ICN. 
 
 253.70 65 
 
 253.70:65: : 0.012685: x. z = 0.00325. 
 
 Each cubic centimeter of a decinormal iodine solu- 
 tion corresponds to 0.00325 gram potassium cyanide. 
 Use starch solution as an indicator. By multiplying 
 the number of cubic centimeters of a decinormal iodine 
 solution consumed before the blue color in the solution 
 appears, by 0.00325, the weight of the potassium 
 cyanide is found in the solution tested: from which 
 the percentage strength can be calculated. 
 
ATOMIC WEIGHTS. 
 
 Aluminum .............................. Al 27.1 
 
 Antimony .............................. Sb 120.4 
 
 Arsenic ................................ As 75.0 
 
 Barium ................................ Ba 137.40 
 
 Bismuth ............................... Bi 208.1 
 
 Boron .................................. B 11.0 
 
 Bromine ............................... Br 79.95 
 
 Cadmium ............................... Cd 112.4 
 
 Carbon ................................ C 12.0 
 
 Calcium ................................ Ca 40.1 
 
 Chlorine ........... .' .................... Cl 35.45 
 
 Chromium ........... ................... Cr 52.1 
 
 Cobalt ................................. Co 59.0 
 
 Copper ................................ Cu 63.60 
 
 Fluorine ....... ......................... Fl 19.05 
 
 Gold ................................... Au 197.2 
 
 Hydrogen .............................. H 1.008 
 
 Iodine ................................. I 126.85 
 
 Iron ................................... Fe 55.9 
 
 Lead ................................... Pb 206.92 
 
 Magnesium ............................. Mg 24.3 
 
 Manganese ............................. Mn 55.0 
 
 Mercury ................................ Hg 200.0 
 
 Molybdenum ............................ Mo 96.0 
 
 Nickel ................................. Ni 58.70 
 
 Nitrogen ............................... N 14.04 
 
 Oxygen ................................ O 16.0 
 
 Phosphorus. . . . ......................... P 31.0 
 
 Platinum ............................... Pt 194.9 
 
 Potassium .............................. K 39.11 
 
 Selenium ............................... Se 79.2 
 
 Silicon ................................. Si 28.4 
 
 Silver .................................. Ag 107.92 
 
 Sodium ................................ Na 23.05 
 
 Strontium .............................. Sr 87.60 
 
 Sulphur. . .............................. S 32.07 
 
 Tellurium .............................. Te 127.7 
 
 Tin .................................... Sn 119.0 
 
 Titanium ............................... Ti 48.15 
 
 Zinc ................................... Zn 65.4 
 
 90 
 
INDEX. 
 
 A 
 
 PAGE 
 
 Acidity 12 
 
 Agitation Method 8 
 
 Amalgamation Tests 42 
 
 Applicability of Cyanide Process to an Ore 35 
 
 Assaying Cyanide Solutions 27 
 
 Atomic Weights 90 
 
 B 
 
 Base Metals 12 
 
 Begeer Process 57 
 
 Betty Process 54 
 
 Bottom, false 71 
 
 C 
 
 Calcining 43 
 
 Calculation, Methods to save 23 
 
 Chemical Means of Supplying Oxygen 18 
 
 Chemistry of the Cyanide Process 18 
 
 Chloridizing Roasting 44 
 
 Circulating Method 10 
 
 Clean-up 46 
 
 Complex Solutions, Titration of 33 
 
 Consumption of Cyanide 38 
 
 Crushing 43 
 
 91 
 
92 INDEX. 
 
 PAGE 
 
 Cyanide Process 8 
 
 Begeer 57 
 
 Betty ; 54 
 
 Bromo-Cyanogen 59 
 
 Decantation 58 
 
 General Description 3 
 
 Godbe 57 
 
 Hendryx 61 
 
 Holderman 60 
 
 McArthur-Forest 52 
 
 Moore 61 
 
 Pneumatic 54 
 
 Siemen-Halske 52 
 
 Zinc-dust Precipitation 58 
 
 D 
 
 Decantation Process 58 
 
 Decomposition of Potassium Cyanide 19 
 
 Definite Volume of Solution 25 
 
 Door, bottom 68 
 
 side 69 
 
 Double-treatment Method 10 
 
 E 
 
 Extraction Tests 36 
 
 G 
 
 Godbe Process 57 
 
 H 
 
 Hendryx Cyanide Process 61 
 
 Holderman Cyanide Process 60 
 
INDEX. 93 
 
 PAGE 
 
 Interfering Substances, Acidity 12 
 
 Aluminum 17 
 
 Antimony 17 
 
 Arsenic 17 
 
 Base Metals 12 
 
 Cobalt 17 
 
 Copper 15 
 
 Iron 14 
 
 Iron Sulphides 17 
 
 Magnesium 17 
 
 Manganes 17 
 
 Organic Matter 17 
 
 Introductory 1 
 
 Iodine, Decinormal Solution 86 
 
 M 
 
 McArthur-Forest Process 52 
 
 Mechanical Means to supply Oxygen 18 
 
 Methods of operating the Cyanide Process 8 
 
 Methods to save Calculations 23 
 
 Moore Cyanide Process 61 
 
 N 
 
 Nitric acid 86 
 
 O 
 
 Operating, Methods of 8 
 
 Oxygen, Means of Supplying 18 
 
 P 
 
 Percolation Method 8 
 
 Pneumatic Process 54 
 
94 INDEX. 
 
 PAGE 
 
 Potassium Cyanide, Decomposition of 19 
 
 Potassium Hydrate, Decinormal Solution 83 
 
 Precipitating Gold from Cyanide Solution, Methods of. ... 11 
 
 Precipitation Tests 41 
 
 R 
 
 Reactions in the Zinc Boxes 20 
 
 Roasting 44 
 
 S 
 
 Solutions, Determination of Strength. 21 
 
 Strength of 20, 43 
 
 Siemens-Halske Process 52 
 
 Silver Ores 45 
 
 Specifications and Prices of Cyanide Plants 67 
 
 Sulphuric Acid, Decinormal Solution 85 
 
 T 
 
 Testing Cyanide Solutions containing Zinc 30 
 
 Tests, Extraction ' 36 
 
 Titrating Complex Solutions 33 
 
 U 
 
 Useful Information 51 
 
 Vats 63 
 
 Volumetric Analysis 80 
 
 Decinormal Iodine Solution 86 
 
 Nitric Acid Solution 86 
 
 Potassium Hydrate Solution 83 
 
 Sulphuric Acid Solution 85 
 
. INDEX. 
 
 95 
 
 W 
 
 PAGE 
 
 Weak Solutions, to bring to Strength ................... 24 
 
 Zinc Boxes, Reactions in .............................. 20 
 
 Zinc-dust Precipitation. ............................. 58 
 
SHORT-TITLE CATALOGUE 
 
 OF THE 
 
 PUBLICATIONS 
 
 OF 
 
 JOHN WILEY & SONS, 
 
 NEW YORK. 
 LONDON: CHAPMAN & HALL, LIMITED. 
 
 ARRANGED UNDER SUBJECTS. 
 
 Descriptive circulars sent on application. Books marked with an asterisk (*) are sold 
 at net prices only, a double asterisk (**) books sold under the rules of the American 
 Publishers' Association at net prices subject to an extra charge for postage. All books 
 are bound in cloth unless otherwise stated. 
 
 AGRICULTURE. 
 
 Armsby's Manual of Cattle-feeding zzmo, Si 75 
 
 Principles of Animal Nutrition 8vo, 4 oo 
 
 Budd and Hansen's American Horticultural Manual: 
 
 Part I. Propagation, Culture, and Improvement izmo, 50 
 
 Part IL Systematic Pomology. i2mo, 59 
 
 Downing's Fruits and Fruit-trees of America 8vo, oo 
 
 Elliott's Engineering for Land Drainage I2mo, 50 
 
 Practical Farm Drainage I2mo, oo 
 
 Green's Principles of American Forestry 121110, 50 
 
 Grotenfelt's Principles of Modern Dairy Practice. (Wo 11.) 121110, oo 
 
 Kemp's Landscape Gardening i2mo, 50 
 
 Maynard's Landscape Gardening as Applied to Home Decoration i2mo, so 
 
 Sanderson's Insects Injurious to Staple Crops I2mo, 50 
 
 Insects Injurious to Garden Crops. (In preparation.) 
 Insects Injuring Fruits. (In preparation.) 
 
 Stockbridge's Rocks and Soils 8vo, 50 
 
 Woll's Handbook for Farmers and Dairymen i6mo, 50 
 
 ARCHITECTURE. 
 
 Baldwin's Steam Heating fr Buildings I2mo, 2 30 
 
 Berg's Buildings and Structures of American Railroads 4to, 5 oo 
 
 Birkmire's Planning and Construction of American Theatres 8vo, 3 oo 
 
 Architectural Iron and Steel 8vo, 3 50 
 
 Compound Riveted Girders as Applied in Buildings 8vo, 2 oo 
 
 Planning and Construction of High Office Buildings 8vo 3 50 
 
 Skeleton Construction in Buildings 8vo, 3 oo 
 
 Brigg's Modern American School Buildings. . 8vo, 4 oo 
 
 Carpenter's Heating and Ventilating of Buildings 8vo, 4 oo 
 
 Freitag's Architectural Engineering 8vo, 3 50 
 
 Fireproofing of Steel Buildings 8vo, 2 50 
 
 French and Ives's Stereotomy. . , 8vo, 2 50 
 
 Gerhard's Guide to Sanitary House-inspection i6mo, i oo 
 
 Theatre Fires and Panics. i2mo, i 50 
 
 Holly's Carpenters' and Joiners' Handbook i8mo, 75 
 
 Johnson's Statics by Algebraic and Graphic Methods 8vo, 2 oo 
 
 1 
 
Kidder's Architects' and Builders' Pocket-book. Rewritten Edition. i6mo,mor. f 5 oo 
 
 Merrill's Stones for Building and Decoration 8vo, 5 oo 
 
 Non-metallic Minerals: Their Occurrence and Uses 8vo, 4 oo 
 
 Monckton's Stair-building 4 to, 4 03 
 
 Patton's Practical Treatise on Foundations 8vo, 5 oo 
 
 Peabody's Naval Architecture 8vo, 7 50 
 
 Richey's Handbook for Superintendents of Construction i6mo, mor. , 4 oo 
 
 Sabin's Industrial and Artistic Technology of Paints and Varnish 8vo, 3 oo 
 
 Siebert and Biggin's Modern Stone-cutting and Masonry 8vo, i 50 
 
 Snow's Principal Species of Wood 8vo, 3 50 
 
 Sondericker's Graphic Statics with Applications to Trusses, Beams, and Arches. 
 
 8vo, 2 oo 
 
 Towne's Locks and Builders' Hardware i8mo, morocco, 3 oo 
 
 Wait's Engineering and Architectural Jurisprudence 8vo, 6 oo 
 
 Sheep, 6 50 
 
 Law of Operations Preliminary to Construction in Engineering and Archi- 
 tecture 8vo, 5 oo 
 
 Sheep, 5 50 
 
 Law of Contracts 8vo, 3 oo 
 
 Wood's Rustless Coatings: Corrosion and Electrolysis of Iron and Steel. .8vo, 4 oo 
 
 Woodbury's Fire Protection of Mills 8vo, 2 50 
 
 Worcester and Atkinson's Small Hospitals, Establishment and Maintenance, 
 Suggestions for Hospital Architecture, with Plans for a Small Hospital. 
 
 i2mo, i 25 
 
 The World's Columbian Exposition of 1893 Large 4to, i oo 
 
 ARMY AND NAVY. 
 
 Bernadou's Smokeless Powder, Nitro-cellulose, and the Theory of the Cellulose 
 
 Molecule i2mo, 2 50 
 
 * Bruff's Text-book Ordnance and Gunnery 8vo, 6 oo 
 
 Chase's Screw Propellers and Marine Propulsion 8vo, 3 oo 
 
 Cloke's Gunner's Examiner. (In press.) 
 
 Craig's Azimuth 4to, 3 50 
 
 Crehore and Squier's Polarizing Photo-chronograph 8vo, 3 oc 
 
 Cronkhite's Gunnery for Non-commissioned Officers 241110, morocco, 2 oa 
 
 * Davis's Elements of Law 8vo, 2 se 
 
 * Treatise on the Military Law of United States 8vo, 7 ec 
 
 Sheep, 7 50 
 
 De Brack's Cavalry Outposts Duties. (Carr.) 24mo, morocco, 2 oo 
 
 Dietz's Soldier's First Aid Handbook i6mo, morocco, i 25 
 
 * Dredge's Modern French Artillery. 4to, half morocco, 15 oe 
 
 Durand's Resistance and Propulsion of Ships 8vo, 5 oc 
 
 * Dyer's Handbook of Light Artillery i2mo, 3 oc 
 
 Eissler's Modern High Explosives 8vo, 4 oc 
 
 * Fiebeger's Text-book on Field Fortification Small 8vo, 2 oc 
 
 Hamilton's The Gunner's Catechism i8mo, i oc 
 
 * Hoff' s Elementary Naval Tactics 8vo, i sc 
 
 Ingalls's Handbook of Problems in Direct Fire 8vo, 4 oc 
 
 * Ballistic Tables 8vo, i sc 
 
 * Lyons's Treatise on Electromagnetic Phenomena. Vols. I. and II. . 8vo, each, 6 oe 
 
 * Mahan's Permanent Fortifications. (Mercur.) 8vo, half morocco, 7 sc 
 
 Manual for Courts-martial i6mo, morocco, i sc 
 
 * Mercur's Attack of Fortified Places i2mo, 2 oc 
 
 * Elements of the Art of War 8vo, 4 o( 
 
 Metcalf's Cost of Manufactures And the Administration of Workshops. .8vo, 5 o< 
 
 * Ordnance and Gunnery. 2 vols i2mo, 5 o< 
 
 Murray's Infantry Drill Regulations i8mo, paper, i< 
 
 Nixon's Adjutants' Manual 24010, i o< 
 
 Peabody's Naval Architecture 8vo, 7 5< 
 
* Phelps's Practical Marine Surveying 8vo, 2 50 
 
 Powell's Army Officer's Examiner i2mo, 4 oo 
 
 Sharpe's Art of Subsisting Armies in War iSmo^ morocco, i 50 
 
 * Walke's Lectures on Explosives 8vo, 4 oo 
 
 * Wheeler's Siege Operations and Military Mining 8vo, 2 oo 
 
 Winthrop's Abridgment of Military Law .- i2mo, 2 50 
 
 Woodhull's Notes on Military Hygiene i6mo, i 50 
 
 Young's Simple Elements of Navigation i6mo, morocco, i oo 
 
 Second Edition, Enlarged and Revised i6mo, morocco, 2 oo 
 
 ASSAYING. 
 
 Fletcher's Practical Instructions in Quantitative Assaying with the Blowpipe. 
 
 i2mo, morocco, i 50 
 
 Furman's Manual of Practical Assaying 8vo, 3 oo 
 
 Lodge's Notes on Assaying and Metallurgical Laboratory Experiments. . . .8vo, 3 oo 
 
 Miller's Manual of Assaying I2mo, i oo 
 
 O'Driscoll's Notes on the Treatment of Gold Ores 8vo, 2 oo 
 
 Ricketts and Miller's Notes on Assaying 8vo, 3 oo 
 
 Ulke's Modern Electrolytic Copper Refining 8vo, 3 oo 
 
 Wilson's Cyanide Processes i2mo, i 50 
 
 Chlorination Process * i2mo, i 50 
 
 ASTRONOMY. 
 
 Comstock's Field Astronomy for Engineers 8vo, 2 50 
 
 Craig's Azimuth 4to, 3 50 
 
 Doolittle's Treatise on Practical Astronomy 8vo, 4 oo 
 
 Gore's Elements of Geodesy 8vo, 2 50 
 
 Hayford's Text-book of Geodetic Astronomy 8vo, 3 . oo 
 
 Merriman's Elements of Precise Surveying and Geodesy 8vo, 2 50 
 
 * Michie and Harlow's Practical Astronomy 8vo, 3 oo 
 
 * White's Elements of Theoretical and Descriptive Astronomy I2mo, 2 oo 
 
 BOTANY. 
 
 Davenport's Statistical Methods, with Special Reference to Biological Variation. 
 
 i6mo, morocco, i 25 
 
 Thome' and Bennett's Structural and Physiological Botany i6mo, 2 25 
 
 Westermaier's Compendium of General Botany. (Schneider.) 8vo, 2 oo 
 
 CHEMISTRY. 
 
 Adriance's Laboratory Calculations and Specific Gravity Tables I2mo, i 25 
 
 Allen's Tables for Iron Analysis 8vo, 3 oo 
 
 Arnold's Compendium of Chemistry. (Mandel.) Small 8vo, 3 50 
 
 Austen's Notes for Chemical Students i2mo, i 50 
 
 Bernadou's Smokeless Powder. Nitro-cellulose, and Theory of the Cellulose 
 
 Molecule I2mo, 2 50 
 
 Bolton's Quantitative Analysis 8vo, i 50 
 
 * Browning's Introduction to the Rarer Elements. 8vo, i 50 
 
 Brush and Penfield's Manual of Determinative Mineralogy 8vo, 4 oo 
 
 Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.). .8vo, 3 oo 
 
 Cohn's Indicators and Test-papers i2mo, 2 oo 
 
 Tests and Reagents 8vo, 3 oo 
 
 Crafts's Short Course in Qualitative Chemical Analysis. (Schaeffer.). . .i2mo, i 50 
 Dolezalek's Theory of the Lead Accumulator (Storage Battery). (Von 
 
 Ende.) I2mo, 2 50 
 
 Drechsel's Chemical Reactions. (Merrill.) i2mo, i 25 
 
 Duhem's Thermodynamics and Chemistry. (Burgess.) .8vo, 4 oo 
 
 Eissler's Modern High Explosives 8vo, 4 oo 
 
 Effront's Enzymes and their Applications. (Prescott.) 8vo, 3 oo 
 
 Efdmann's Introduction to Chemical Preparations. (Dunlap.) I2mo, i 25 
 
Fletcher's Practical Instructions in Quantitative Assaying with the Blowpipe. 
 
 i2mo, morocco, i 50 
 
 Fowler's Sewage Works Analyses: i2mo, 2 oc 
 
 Fresenius's Manual of Qualitative Chemical Analysis. (Wells.) 8vo, 5 oc 
 
 Manual of Qualitative Chemical Analysis. Part I. Descriptive. (Wells.) 8vo, 3 o 
 System of Instruction in Quantitative Chemical Analysis. (Cohn.) 
 
 2 vols 8vo, 12 50 
 
 Fuertes's Water and Public Health i2mo, i 50 
 
 Furman's Manual of Practical Assaying 8vo, 3 oo 
 
 * Getman's Exercises in Physical Chemistry I2mo, 2 oo 
 
 Gill's Gas and Fuel Analysis for Engineers i2mo, i 25 
 
 Grotenfelt's Principles of Modern Dairy Practice. (Woll.) i2mo, 2 oo 
 
 Hammarsten's Text-book of Physiological Chemistry. (Mandel.) 8vo, 4 oo 
 
 Helm's Principles of Mathematical Chemistry. (Morgan.) i2mo, i 50 
 
 Bering's Ready Reference Tables (Conversion Factors) i6mo, morocco, 2 50 
 
 Hind's Inorganic Chemistry 8vo, 3 oo 
 
 * Laboratory Manual for Students 12010, 75 
 
 Holleman's Text-book of Inorganic Chemistry. (Cooper.) 8vo, 2 50 
 
 Text-book of Organic Chemistry. (Walker and Mott.) 8vo, 2 50 
 
 * Laboratory Manual of Organic Chemistry. (Walker.) i2mo, i oo 
 
 Hopkins* s Oil-chemists' Handbook 8vo, 3 oo 
 
 Jackson's Directions for Laboratory Work in Physiological Chemistry. .8vo, i 25 
 
 Keep's Cast Iron 8vo, 2 50 
 
 Ladd's Manual of Quantitative Chemical Analysis i2mo, i oo 
 
 Landauer's Spectrum Analysis. (Tingle-.) 8vo, 3 oo 
 
 * Langworthy and Austen. The Occurrence of Aluminium in Vegetable 
 
 Products, Animal Products, and Natural Waters 8vo, 2 oo 
 
 Lassar-Cohn's Practical Urinary Analysis. (Lorenz.) i2mo, i oo 
 
 Application of Some General Reactions to Investigations in Organic 
 
 Chemistry. (Tingle.) i2mo, i oo 
 
 Leach's The Inspection and Analysis of Food with Special Reference to State 
 
 Control. 8vo, 7 50 
 
 Lob's Electrolysis and Electrosynthesis of Organic Compounds. (Lorenz. ).i2mo, i oo 
 
 Lodge's Notes on Assaying and Metallurgical Laboratory Experiments. .. .8vo, 3 oo 
 
 Lunge's Techno-chemical Analysis. (Cohn.) i2mo, i oo 
 
 Mandel's Handbook for Bio-chemical Laboratory i2mo, i 50 
 
 * Martin's Laboratory Guide to Qualitative Analysis with the Blowpipe . . i2mo, 60 
 Mason's Water-supply. (Considered Principally from a Sanitary Standpoint.) 
 
 3d Edition, Rewritten 8vo, 4 oo 
 
 Examination of Water. (Chemical and Bacteriological.) i2mo, i 25 
 
 Matthew's The Textile Fibres 8vo, 3 5<> 
 
 Meyer's Determination of Radicles in Carbon Compounds. (Tingle.). . i2mo, i oo 
 
 Miller's Manual of Assaying i2mo, i oo 
 
 Mixter's Elementary Text-book of Chemistry. i2mo, i 50 
 
 Morgan's Outline of Theory of Solution and its Results i2iiio, i oo 
 
 Elements of Physical .Chemistry i2mo, 2 oo 
 
 Morse's Calculations used in Cane-sugar Factories i6mo, morocco, i 50 
 
 Mulliken's General Method for the Identification of Pure Organic Compounds. 
 
 Vol. I Large 8vo, 5 oo 
 
 O'Brine's Laboratory Guide in Chemical Analysis 8vo, 2 oo 
 
 O'Driscoll's Notes on the Treatment of Gold Ores 8vo, 2 oo 
 
 Ostwald's Conversations on Chemistry. Part One. (Ramsey.) i2mo, 150 
 
 Ostwald's Conversations on Chemistry. Part Two. (Turnbull.). (In Press.) 
 
 * Penfield's Notes on Determinative Mineralogy and Record of Mineral Tests. 
 
 8vo, paper, 50 
 
 Pictet's The Alkaloids and their Chemical Constitution. (Biddle.) 8vo, 5 oo 
 
 Pinner's Introduction to Organic Chemistry. (Austen.) i2mo, i 50 
 
 Poole's Calorific Power of Fuels 8vo, 3 oo 
 
 Prescott and Winslow's Elements of Water Bacteriology, with Special Refer- 
 ence to Sanitary Water Analysis i2mo, i 25 
 
* Reisig's Guide to Piece-dyeing. . . v 8vo, 25 oo 
 
 Richards and Woodman's Air, Water, and Food from a Sanitary Standpoint 8vo, 2 oo 
 
 Richards's Cost of Living as Modified by Sanitary Science i2mo, i oo 
 
 Cost of Food, a Study in Dietaries I2mo, i oo 
 
 * Richards and Williams's The Dietary Computer 8vo, i 50 
 
 Ricketts and Russell's Skeleton Notes upon inorganic Chemistry. (Part I. 
 
 Non-metallic Elements.) 8vo, morocco, 75 
 
 Ricketts and Miller's Notes on Assaying 8vo, 3 oo 
 
 Rideal's Sewage and the Bacterial Purification of Sewage 8vo, 3 50 
 
 Disinfection and the Preservation of Food 8vo, 4 oo 
 
 Rigg's Elementary Manual for the Chemical Laboratory 8vo, i 25 
 
 Rostoski's Serum Diagnosis. (Bolduan.) i2mo, i oo 
 
 Ruddiman's Incompatibilities in Prescriptions 8vo, 2 oo 
 
 Sabin's Industrial and Artistic Technology of Paints and Varnish 8vo, 3 oo 
 
 Salkowski's Physiological and Pathological Chemistry. (Orndorff.) 8vo, 2 50 
 
 Schimpf's Text-book of Volumetric Analysis i2mo, 2 50 
 
 Essentials of Volumetric Analysis i2mo, i 25 
 
 Spencer's Handbook for Chemists of Beet-sugar Houses i6mo, morocco, 3 oo 
 
 Handbook for Sugar Manufacturers and their Chemists. . i6mo, morocco, 2 oo 
 
 Stockbridge's Rocks and Soils 8vo, 2 50 
 
 * Tillman's Elementary Lessons in Heat 8vo, i 50 
 
 * Descriptive General Chemistry 8vo, 3 oo 
 
 Treadwell's Qualitative Analysis. (Hall.) 8vo, 3 oo 
 
 Quantitative Analysis. (Hall.) 8vo, 4 oo 
 
 Turneaure and Russell's Public Water-supplies 8vo, 5 oo 
 
 Van Deventer's Physical Chemistry for Beginners. (Boltwood.) i2mo, i 50 
 
 * Walke's Lectures on Explosives 8vo, 4 oo 
 
 Washington's Manual of the Chemical Analysis of Rocks 8vo, 2 oo 
 
 Wassermann's Immune Sera : Haemolysins, Cytotoxins, and Precipitins. (Bol- 
 duan.) i2mo, i oo 
 
 Well's Laboratory Guide in Qualitative Chemical Analysis 8vo, i 50 
 
 Short Course in Inorganic Qualitative Chemical Analysis for Engineering 
 
 Students i2mo, i 50 
 
 Text-book of Chemical Arithmetic. (In press.) 
 
 Whipple's Microscopy of Drinking-water 8vo, 3 50 
 
 Wilson's Cyanide Processes i2mo, i 50 
 
 Chlorination Process i2mo, i 50 
 
 Wulling's Elementary Course in Inorganic, Pharmaceutical, and Medical 
 
 Chemistry i2mo, 2 oo 
 
 CIVIL ENGINEERING. 
 
 BRIDGES AND ROOFS. HYDRAULICS. MATERIALS OF ENGINEERING.' 
 RAILWAY ENGINEERING. 
 
 Baker's Engineers' Surveying Instruments i2mo, 3 oo 
 
 Bixby's Graphical Computing Table Paper 19^X24! inches. 25 
 
 ** Burr's Ancient and Modern Engineering and the Isthmian Canal. (Postage, 
 
 27 cents additional.) 8vo, 3 50 
 
 Comstock's Field Astronomy for Engineers 8vo, 2 50 
 
 Davis's Elevation and Stadia Tables 8vo, i oo 
 
 Elliott's Engineering for Land Drainage i2mo, i 50 
 
 Practical Farm Drainage i2mo, i oo 
 
 Fiebeger's Treatise on Civil Engineering. (In press.) 
 
 Folwell's Sewerage. (Designing and Maintenance.) 8vo, 3 oo 
 
 Freitag's Architectural Engineering. 2d Edition, Rewritten 8vo, 3 50 
 
 French and Ives's Stereotomy 8vo, 2 50 
 
 Goodhue's Municipal Improvements *. I2mo, I 75 
 
 Goodrich's Economic Disposal of Towns' Refuse 8vo, 3 50 
 
 Gore's Elements of Geodesy 8vo, 2 50 
 
 Hayford's Text-book of Geodetic Astronomy vo, 3 oo 
 
 Bering's Ready Reference Tables (Conversion Factors) i6mo, morocco, 2 50 
 
 5 
 
Howe's Retaining Walls for Earth izmo, i 35 
 
 Johnson's (J. B.) Theory and Practice of Surveying Small 8vo, 4 oo 
 
 Johnson's (L. J.) Statics by Algebraic and Graphic Methods 8vo, 2 oo 
 
 Laplace's Philosophical Essay on Probabilities. (Truscott and Emory.) . i2mo, 2 oo 
 
 Mahan's Treatise on Civil Engineering. (1873.) (Wood.) 8vo, 5 oo 
 
 * Descriptive Geometry 8vo, i 50 
 
 Merriman's Elements of Precise Surveying and Geodesy 8vo, 2 50 
 
 Elements of Sanitary Engineering 8vo, 2 oo 
 
 Merriman and Brooks's Handbook for Surveyors i6mo, morocco, 2 oo 
 
 Nugent's Plane Surveying '. 8vo, 3 50 
 
 Ogden's Sewer Design : i2mo, 2 oo 
 
 Patton's Treatise on Civil Engineering 8vo half leather, 7 50 
 
 Reed's Topographical Drawing and Sketching 4to, 5 oo 
 
 Rideal's Sewage and the Bacterial Purification of Sewage 8vo, 3 50 
 
 Siebert and Biggin's Modern Stone-cutting and Masonry , 8vo, i 50 
 
 Smith's Manual of Topographical Drawing. (McMillan.) 8vo, 2 50 
 
 Sondericker's Graphic Statics, with Applications to Trusses, Beams, and Arches. 
 
 8vo, 2 oo 
 
 Taylor and Thompson's Treatise on Concrete, Plain and Reinforced 8vo, 5 oo 
 
 * Trautwine's Civil Engineer's Pocket-book i6mo, morocco, 5 oo 
 
 Wait's Engineering and Architectural Jurisprudence 8vo, 6 oo 
 
 Sheep, 6 50 
 
 Law of Operations Preliminary to Construction in Engineering and Archi- 
 tecture 8vo, 5 oo 
 
 Sheep, 5 50 
 
 Law of Contracts 8vo, 3 oo 
 
 Warren's Stereotomy Problems in Stone-cutting 8vo, 2 50 
 
 Webb's Problems in the Use and Adjustment of Engineering Instruments. 
 
 i6mo, morocco, i 25 
 
 * Wheeler s Elementary Course of Civil Engineering 8vo, 4 oo 
 
 Wilson's Topographic Surveying 8vo, 3 50 
 
 BRIDGES AND ROOFS. 
 
 Boiler's Practical Treatise on the Construction of Iron Highway Bridges . 8vo, 2 oo 
 
 * Thames River Bridge 4to, paper, 5 oo 
 
 Burr's Course on the Stresses in Bridges and Roof Trusses, Arched Ribs, and 
 
 Suspension Bridges 8vo, 3 50 
 
 Burr and Falk's Influence Lines for Bridge and Roof Computations. . . .8vo, 3 oo 
 
 Du Bois's Mechanics of Engineering. Vol. II Small 4to, 10 oo 
 
 Foster's Treatise on Wooden Trestle Bridges 4to, 5 oo 
 
 Fowler's Ordinary Foundations 8vo, 3 50 
 
 Greene's Roof Trusses 8vo, i 25 
 
 Bridge Trusses 8vo, 2 50 
 
 Arches in Wood, Iron, and Stone 8vo, 2 50 
 
 Howe's Treatise on Arches 8vo, 4 oo 
 
 Design of Simple Roof-trusses in Wood and Steel 8vo, 2 oo 
 
 Johnson, Bryan, and Turneaure's Theory and Practice in the Designing of 
 
 Modern Framed Structures Small 4to, 10 oo 
 
 Merriman and Jacoby's Text-book on Roofs and Bridges: 
 
 Part I. Stresses in Simple Trusses 8vo, 2 50 
 
 Part n. Graphic Statics 8vo, 2 50 
 
 Part III. Bridge Design 8vo, 2 50 
 
 Part IV. Higher Structures 8vo, 2 50 
 
 Morison's Memphis Bridge .^ 4to, 10 oo 
 
 Waddell's De Pontlbus, a Pocket-book for Bridge Engineers. . i6mo, morocco, 3 oo 
 
 Specifications for Steel Bridges i2mo, i 25 
 
 Wood's Treatise on the Theory of the Construction of Bridges and Roofs . . 8vo, 2 c ^ 
 Wright's Designing of Draw-spans : 
 
 Part I. Plate-girder Draws 8vo, 2 50 
 
 Part H. Riveted-truss and Pin-connected Long-span Draws 8vo, 2 50 
 
 Two parts in one volume. 8vo, 3 So 
 
HYDRAULICS. 
 
 Bazin's Experiments upon the Contraction of the Liquid Vein Issuing from 
 
 an Orifice. (Trautwine.) 8vo, 2 oo 
 
 Bovey's Treatise on Hydraulics 8vo, 5 oo 
 
 Church's Mechanics of Engineering 8vo, 6 oo 
 
 Diagrams of Mean Velocity of Water in Open Channels payer, i 50 
 
 Coffin's Graphical Solution of Hydraulic Problems i6mo, morocco, 2 50 
 
 Flather's Dynamometers, and the Measurement of Power 12010, 3 oo 
 
 Polwell's Water-supply Engineering 8vo, 4 oo 
 
 Frizell's Water-power 8vo, 5 o^ 
 
 Fuertes's Water and Public Health i2mo, i 50 
 
 Water-filtration Works i2mo, 2 50 
 
 Ganguillet and Kutter's General Formula for the Uniform Flow of Water in 
 
 Rivers and Other Channels. (Hering and Trautwine.) 8vo 4 oo 
 
 Hazen's Filtration of Public Water-supply 8vo, 3 oo 
 
 Hazlehurst's Towers and Tanks for Water-works 8vo, 2 50 
 
 Herschel's 115 Experiments on the Carrying Capacity of Large, Riveted, Metal 
 
 Conduits 8vo, 2 oo 
 
 Mason's Water-supply. (Considered Principally from a Sanitary Standpoint.) 
 
 8vo, 4 oo 
 
 Merriman's Treatise on Hydraulics 8vo, 5 oo 
 
 * Michie's Elements of Analytical Mechanics . .8vo, 4 oo 
 
 Schuyler's Reservoirs for Irrigation, Water-power, and Domestic Water- 
 supply Large 8vo, 5 oo 
 
 ** Thomas and Watt's Improvement of Rivers. (Post., 440. additional. ).4to, 6 oo 
 
 Turneaure and Russell's Public Water-supplies 8vo, 5 oo 
 
 Wegmann's Design and Construction of Dams 4to, 5 oo 
 
 Water-supply of the City of New York from 1658 to 1895 4to, 10 oo 
 
 Wilson's Irrigation Engineering , .Small 8vo, 4 oo 
 
 Wolff's Windmill as a Prime Mover 8vo, 3 oo 
 
 Wood's Turbines 8vo, 2 50 
 
 Elements of Analytical Mechanics 8vo, 3 oo 
 
 MATERIALS OF ENGINEERING. 
 
 Baker's Treatise on Masonry Construction , . . . .8vo, 5 oo 
 
 Roads and Pavements 8vo, 5 oo 
 
 Black's United States Public Works Oblong 4to, 5 oo 
 
 Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 
 
 Burr's Elasticity and Resistance of the Materials of Engineering 8vo, 7 50 
 
 Byrne's Highway Construction 8vo, 5 oo 
 
 Inspection of the Materials and Workmanship Employed in Construction. 
 
 i6mo, 3 oo 
 
 Church's Mechanics of Engineering 8vo, 6 oo 
 
 Du Bois's Mechanics of Engineering. Vol. I Small 4to, 7 50 
 
 Johnson's Materials of Construction Large 8vo, 6 oo 
 
 Fowler's Ordinary Foundations 8vo, 3 50 
 
 Keep's Cast Iron 8vo, 2 50 
 
 Lanza's Applied Mechanics 8vo, 7 50 
 
 Marten's Handbook on Testing Materials. (Henning.) 2 vols 8vo, 7 50 
 
 Merrill's Stones for Building and Decoration 8vo, 5 oo 
 
 Merriman's Text-book on the Mechanics of Materials 8vo, 4 oo 
 
 Strength of Materials izmo, i oo 
 
 Metcalf's Steel. A Manual for Steel-users i2mo, 2 oo 
 
 Patton's Practical Treatise on Foundations .. 8vo, 5 09 
 
 Richardson's Modern Asphalt Pavements 8vo, 3 oo 
 
 Richey's Handbook for Superintendents of Construction lOmo, mor., 4 oo 
 
 Rockwell's Roads and Pavements in France I2mo, i 35 
 
 7 
 
Sabin's Industrial and Artistic Technology of Paints and Varnish 8vo, 3 oo 
 
 Smith's Materials of Machines i2mo, i oo 
 
 Snow's Principal Species of Wood. 8vo, 3 50 
 
 Spalding's Hydraulic Cement i2mo, 2 oo 
 
 Text-book on Roads and Pavements I2mo, 2 oo 
 
 Taylor and Thompson's Treatise on Concrete, Plain and Reinforced 8vo, 5 oo 
 
 Thurston's Materials of Engineering. 3 Parts 8vo, 8 oo 
 
 Part I. Non-metallic Materials of Engineering and Metallurgy 8vo, 2 oo 
 
 Part II. Iron and SteeL . ; 8vo, 3 50 
 
 Part in. A Treatise on Brasses, Bronzes, and Other Alloys and their 
 
 Constituents 8vo, 2 50 
 
 Thurston's Text-book of the Materials of Construction 8vo, 5 oo 
 
 Tillson's Street Pavements and Paving Materials 8vo, 4 oo 
 
 WaddelPs De Pontibus. C A Pocket-book for Bridge Engineers.). .i6mo, mor., 3 oo 
 
 Specifications for Stc i Bridges i2mo, i 25 
 
 Wood's (De V.) Treatise on the Resistance of Materials, and an Appendix on 
 
 the Preservation of Timber 8vo, 2 oo 
 
 Wood's (De V.) Elements of Analytical Mechanics 8vo, 3 oo 
 
 Wood's (M. P.) Rustless Coatings: Corrosion and Electrolysis of Iron and 
 
 SteeL 8vo, 4 oo 
 
 RAILWAY ENGINEERING. 
 
 Andrew's Handbook for Street Railway Engineers 3x5 inches, morocco, i 25 
 
 Berg's Buildings and Structures of American Railroads 4to, 5 oo 
 
 Brook's Handbook of Street Railroad Location i6mo, morocco, i 50 
 
 Butt's Civil Engineer's Field-book i6mo, morocco, 2 50 
 
 Crandall's Transition Curve i6mo, morocco, i 50 
 
 Railway and Other Earthwork Tables 8vo, i 50 
 
 Dawson's "Engineering" and Electric Traction Pocket-book. . i6mo, morocco, 5 oo 
 
 Dredge's History of the Pennsylvania Railroad: (1879) Paper, 5 oo 
 
 * Drinker's Tunnelling, Explosive Compounds, and Rock Drills. 4to, half mor., 25 oo 
 
 Fisher's Table of Cubic Yards Cardboard, 25 
 
 Godwin's Railroad Engineers' Field-book and Explorers' Guide. . . i6mo, mor., 2 50 
 
 Howard's Transition Curve Field-book i6mo, morocco, i 50 
 
 Hudson's Tables for Calculating the Cubic Contents of Excavations and Em- 
 bankments 8vo, i oo 
 
 Molitor and Beard's Manual for Resident Engineers i6mo, i oo 
 
 Wagle's Field Manual for Railroad Engineers i6mo, morocco, 3 oo 
 
 Philbrick's Field Manual for Engineers i6mo, morocco, 3 oo 
 
 Searles's Field Engineering i6mo, morocco, 3 oo 
 
 Railroad Spiral i6mo, morocco, i 50 
 
 Taylor's Prismoidal Formulae and Earthwork 8vo, i 50 
 
 * Trautwine's Method of Calculating the Cube Contents of Excavations and 
 
 Embankments by the Aid of Diagrams 8vo, 2 oa 
 
 The Field Practice of Laying Out Circular Curves for Railroads. 
 
 I2mo, morocco, 2 50 
 
 Cross-section Sheet Paper, 25 
 
 Webb's Railroad Construction i6mo, morocco, 5 oo 
 
 Wellington's Economic Theory of the Location of Railways Small 8vo, 5 oo 
 
 DRAWING. 
 
 Barr's Kinematics of Machinery 8vo, 2 50 
 
 * Bartlett's Mechanical Drawing 8vo, 3 oo 
 
 * " " " Abridged Ed 8vo, 150 
 
 Coolidge's Manual of Drawing 8vo, paper i oo 
 
 Coolidge and Freeman's Elements of General Drafting for Mechanical Engi- 
 neers \ Oblong 4to, 2 50 
 
 Durley's Kinematics of Machines 8vo, 4 oo 
 
 Emch's Introduction to Projective Geometry and its Applications 8vo. 2 50 
 
 R 
 
Hill's Text-book on Shades and Shadows, and Perspective 8vo, 2 oo 
 
 Jamison's Elements of Mechanical Drawing , 8vo, 2 50 
 
 Jones's Machine Design: 
 
 Part I. Kinematics of Machinery 8vo, i 50 
 
 Part II. Form, Strength, and Proportions of Parts 8vo, 3 oo 
 
 MacCord's Elements of Descriptive Geometry 8vo, 3 oo 
 
 Kinematics; or, Practical Mechanism 8vo, 5 oo 
 
 Mechanical Drawing 4to, 4 oo 
 
 Velocity Diagrams 8vo, i 50 
 
 * Mahan's Descriptive Geometry and Stone-cutting 8vo, i 50 
 
 Industrial Drawing. (Thompson.) 8vo, 3 50 
 
 Moyer's Descriptive Geometry 8vo, 2 oo 
 
 Reed's Topographical Drawing and Sketching 4to, 5 oo 
 
 Reid's Course in Mechanical Drawing 8vo, 2 oo 
 
 Text-book of Mechanical Drawing and Elementary Machine Design. 8vo, 3 oo 
 
 Robinson's Principles of Mechanism 8vo, 3 oo 
 
 Schwamb and Merrill's Elements of Mechanism 8vo, 3 oo 
 
 Smith's Manual of Topographical Drawing. (McMillan.) 8vo, 
 
 Warren's Elements of Plane and Solid Free-hand Geometrical Drawing. i2mo, 
 
 Drafting Instruments and Operations i2mo : 
 
 Manual of Elementary Projection Drawing I2mo, 
 
 Manual of Elementary Problems in the Linear Perspective of Form and 
 
 Shadow i2mo, 
 
 Plane Problems in Elementary Geometry I2mo, 
 
 50 
 oo 
 
 25 
 
 oo 
 25 
 
 Primary Geometry ................ . ......................... I2mo, 75 
 
 Elements of Descriptive Geometry, Shadows, and Perspective ....... 8vo, 3 50 
 
 General Problems of Shades and Shadows ........................ 8vo, 3 oo 
 
 Elements of Machine Construction and Drawing .................. 8vo, 7 50 
 
 Problems, Theorems, and Examples in Descriptive Geometry ....... 8vo, 2 50 
 
 Weisbach's Kinematics and Power of Transmission. (Hermann and Klein)8vo, 5 oo 
 
 Whelpley's Practical Instruction in the Ait of Letter Engraving ....... i2mo, 2 oo 
 
 Wilson's (H. M.) Topographic Surveying ............................. 8vo, 3 50 
 
 Wilson's (V. T.) Free-hand Perspective .............................. 8vo, 2 50 
 
 Wilson's (V. T.) Free-hand Lettering ............................... 8vo, i oo 
 
 Woolf's Elementary Course in Descriptive Geometry ............. Large 8vo, 3 oo 
 
 ELECTRICITY AND PHYSICS. 
 
 Anthony and Brackett's Text-book of Physics. (Magie.) Small 8vo, 3 oo 
 
 Anthony's Lecture-notes on the Theory of Electrical Measurements I2mo, i oo 
 
 Benjamin's History of Electricity 8vo, 3 oo 
 
 Voltaic Cell 8vo, 3 oo 
 
 Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.).Svo, 3 oo 
 
 Crehore and Squier's Polarizing Photo-chronograph 8vo, 3 oo 
 
 Dawson's "Engineering" and Electric Traction Pocket-book. i6mo, morocco, 5 oo 
 Dolezalek's Theory of the Lead Accumulator (Storage Battery). (Von 
 
 Ende.) i2mo, 2 50 
 
 Duhem's Thermodynamics and Chemistry. (Burgess.) 8vo, 4 oo 
 
 Flather's Dynamometers, and the Measurement of Power I2mo, 3 oo 
 
 Gilbert's De Magnete. (Mottelay.) 8vo, a 50 
 
 Hanchett's Alternating Currents Explained I2mo, i oo 
 
 Bering's Ready Reference Tables (Conversion Factors) i6mo, morocco, 2 50 
 
 Holman's Precision of Measurements 8vo, 2 oo 
 
 Telescopic Mirror-scale Method, Adjustments, and Tests. . . .Large 8vo, 75 
 
 Kinzbrunner's Testing of Continuous-Current Machines ' 8vo, 2 oo 
 
 Landauer's Spectrum Analysis. (Tingle.) 8vo, 3 oo 
 
 Le Chatelien's High-temperature Measurements. (Boudouard Burgess.) 12010, 3 oo 
 
 Lob's Electrolysis and Electrosynthesis of Organic Compounds. (Lorenz.) i2mo i oo 
 
 9 
 
50 
 50 
 50 
 50 
 
 00 
 
 ' Lyons's Treatise on Electromagnetic Phenomena. Vols. I. and II. 8vo, each, 6 oo 
 
 * Michie's Elements of Wave Motion Relating to Sound and Light 8vo, 4 oo 
 
 Niaudet's Elementary Treatise on Electric Batteries. (Fishback.) lamo, 2 50 
 
 * Rosenberg's Electrical Engineering. (Haldane Gee Kinzbrunner.). . .8vo, 
 
 Ryan, Norris, and Hoxie's Electrical Machinery. Vol. 1 8vo, 
 
 Thurston's Stationary Steam-engines 8vo, 
 
 * Tillman's Elementary Lessons in Heat 8vo, 
 
 Tory and Pitcher's Manual of Laboratory Physics Small 8vo, 
 
 Hike's Modern Electrolytic Copper Refining 8vo, 3 oo 
 
 LAW. 
 
 * Davis's Elements of Law 8vo, 2 50 
 
 * Treatise on the Military Law of United States 8vo, 7 oo 
 
 Sheep, 7 50 
 
 Manual for Courts-martial i6mo, morocco, i 50 
 
 Wait's Engineering and Architectural Jurisprudence 8vo, 6 oo 
 
 Sheep, 6 50 
 
 Law of Operations Preliminary to Construction in Engineering and Archi- 
 tecture 8vo, 5 oo 
 
 Sheep, 5 50 
 
 Law of Contracts 8vo, 3 oo 
 
 Winthrop's Abridgment of Military Law i2mo, 2 50 
 
 MANUFACTURES. 
 
 Bernadou's Smokeless Powder Nitro-cellulose and Theory of the Cellulose 
 
 Molecule .' i2mo, 2 50 
 
 Holland's Iron Founder i2mo, 2 50 
 
 ".The Iron Founder," Supplement i2mo, 2 50 
 
 Encyclopedia of Founding and Dictionary of Foundry Terms Used in the 
 
 Practice of Moulding ' i2mo, 3 oo 
 
 Eissler's Modern High Explosives 8vo, 4 oo 
 
 Effront's Enzymes and their Applications. (Prescott.) 8vo, 3 oo. 
 
 Fitzgerald's Boston Machinist i2mo, i oo 
 
 Ford's Boiler Making for Boiler Makers i8mo, i oo 
 
 Hopkin's Oil-chemists' Handbook 8vo, 3 oo 
 
 Keep's Cast Iron 8vo, 2 50 
 
 Leach's The Inspection and Analysis of Food with Special Reference to State 
 
 Control Large 8vo, 7 50 
 
 Matthews's The Textile Fibres 8vo, 3 50 
 
 Metcalf's Steel. A Manual for Steel-users i2mo, 2 oo 
 
 Metcalfe's Cost of Manufactures And the Administration of Workshops. 8vo, 5 oo 
 
 Meyer's Modern Locomotive Construction 4to, 10 oo 
 
 Morse's Calculations used in Cane-sugar Factories i6mo, morocco, i 50 
 
 * Reisig's Guide to Piece-dyeing 8vo, 25 oo 
 
 Sabin's Industrial and Artistic Technology of Paints and Varnish 8vo, 3 oo 
 
 Smith's Press-working of Metals 8vo, 3 oo 
 
 Spalding's Hydraulic Cement i2mo, 2 oo 
 
 Spencer's Handbook for Chemists of Beet-sugar Houses. .. . i6mo, morocco, 3 o^ 
 
 Handbook for Sugar Manufacturers and their Chemists. . i6mo, morocco, -j. oo 
 
 Taylor and Thompson's Treatise on Concrete, Plain and Reinforced 8vo, 5 oo 
 
 Thurston's Manual of Steam-boilers, their Designs, Construction and Opera- 
 tion 8vo, 5 oo 
 
 * Walke's Lectures on Explosives 8vo, 4 oo 
 
 Ware's Manufacture of Sugar. (In press.) 
 
 West's American Foundry Practice i2mo, 2 50 
 
 Moulder's Text-book i2mo, 2 50 
 
 1 A 
 
Wolff's Windmill as a Prime Mover '. 8vo, 3 oo 
 
 Wood's Rustless Coatings: Corrosion and Electrolysis of Iron and Steel. .8vo, 4 oo 
 
 MATHEMATICS. 
 
 Baker's Elliptic Functions ; 8vo, i S 
 
 * Bass's Elements of Differential Calculus i2mo, 4 oo 
 
 Briggs's Elements of Plane Analytic Geometry i2mo, ioo 
 
 Compton's Manual of Logarithmic Computations i2mo, 
 
 Davis's Introduction to the Logic of Algebra 8vo, 
 
 * Dickson's College Algebra Large i2mo, 
 
 * Introduction to the Theory of Algebraic Equations . .Large i2mo, 
 
 Emch's Introduction to Projective Geometry and its Applications 8vo, 
 
 Halsted's Elements of Geometry 8vo, 
 
 Elementary Synthetic Geometry , 8vo, 
 
 Rational Geometry . i2mo, 
 
 ^.Johnson's (J. B.) Three-place Logarithmic Tables: Vest-pocket size. paper, 15 
 
 ipo copies for 5 oo 
 
 * Mounted on heavy cardboard, 8X 10 inches, 25 
 
 10 copies for 2 oo 
 
 Jehnson's (W. W.) Elementary Treatise on Differential Calculus . . Small 8vo, T; oo 
 
 Johnson's (W. W.) Elementary Treatise on the Integral Calculus. Small 8vo, i 50 
 
 Johnson's (W. W.) Curve Tracing in Cartesian Co-ordinates i2mo, i oo 
 
 Johnson's (W. W.) Treatise on Ordinary and Partial Differential Equations. 
 
 Small 8vo, 3 50 
 
 Johnson's (W. W.) Theory of Errors and the Method of Least Squares. i2mo, i 50 
 
 * Jehnson's (W. W.) Theoretical Mechanics i2mo, 3 oo 
 
 Laplace's Philosophical Essay on Probabilities. (Truscott and Emory.) . i2mo, 2 oo 
 
 * Ludlow and Bass. Elements of Trigonometry and Logarithmic and Other 
 
 Tables 8vo, 3 oo 
 
 Trigonometry and Tables published separately Each, 2 oo 
 
 * Ludlow's Logarithmic and Trigonometric Tables 8vo, i oo 
 
 Maurer's Technical Mechanics 8> _ , 4 oo 
 
 Merriman and Woodward's Higher Mathematics 8vo, 5 oo 
 
 Merriman's Method of Least Squares 8vo, 2 oo 
 
 Rice and Johnson's Elementary Treatise on the Differential Calculus. . Sm. 8vo, 3 oo 
 
 Differential and Integral Calculus. 2 vols. in one Small 8vo, 2 50 
 
 Wood's Elements of Co-ordinate Geometry 1 8vo, 2 oo 
 
 Trigonometry: Analytical, Plane, and Spherical i2mo, i oo 
 
 MECHANICAL ENGINEERING. 
 
 MATERIALS OF ENGINEERING, STEAM-ENGINES AND BOILERS. 
 
 Bacon's Forge Practice tamo, 50 
 
 Baldwin's Steam Heating for Buildings I2mo, 50 
 
 Barr's Kinematics of Machinery 8vo, 50 
 
 * Bartlett's Mechanical Drawing 8vo, oo 
 
 * " " Abridged Ed 8vo, 50 
 
 Benjamin's Wrinkles and Recipes i2mo, oo 
 
 Carpenter's Experimental Engineering- 8vo, 6 oo 
 
 Heating and Ventilating Buildings 8vo, 4 oo 
 
 Gary's Smoke Suppression in Plants using Bituminous Coal. (In Prepara- 
 tion.) 
 
 Clerk's Gas and Oil Engine Small 8vo, 4 oo 
 
 Coolidge's Manual of Drawing 8vo, paper, i oo 
 
 Coolidge and Freeman's Elements of General Drafting for Mechanical En- 
 gineers. ,,.... Oblong 4to, 2 50 
 
 11 
 
Cromwell's Treatise on Toothed Searing i2mo, i 50 
 
 Treatise on Belts and Pulleys i2mo, i 50 
 
 Durley's Kinematics of Machines. 8vo, 4 oo 
 
 Flather's Dynamometers and the Measurement of Power. i2mo, 3 oo 
 
 "* Rope Driving i2mo, 2 oo 
 
 Gill's Gas and Fuel Analysis for Engineers i2mo, i 25 
 
 Hall's Car Lubrication. . I2mo, i oo 
 
 Bering's Ready Reference Tables (Conversion Factors) i6mo, morocco, 2 50 
 
 Button's The Gas Engine 8vo, 5 oo 
 
 Jamison's Mechanical Drawing 8vo, 2 50 
 
 Jones's Machine Design: 
 
 Part I. Kinematics of Machinery 8vo, i 50 
 
 Part II. Form, Strength, and Proportions of Parts 8vo, 3 oo 
 
 Kent's Mechanical Engineers' Pocket-book i6nio, morocco, 5 oo 
 
 Kerr's Power and Power Transmission 8vo, 2 oo 
 
 Leonard's Machine Shop, Tools, and Methods. (In press.) 
 
 Lorenz's Modern Refrigerating Machinery. (Pope, Haven, and Dean.) (In press.) 
 
 MacCord's Kinematics; or, Practical Mechanism 8vo, 5 oo 
 
 Mechanical Drawing 4to, 4 oo 
 
 Velocity Diagrams 8vo, i 50 
 
 Mahan's Industrial Drawing. (Thompson.) 8vo, 3 50 
 
 Poole's Calorific Power of Fuels 8vo, 3 oo 
 
 Reid's Course in Mechanical Drawing 8vo, 2 oo 
 
 Text-book of Mechanical Drawing and Elementary Machine Design. 8vo, 3 oo 
 
 Richard's Compressed Air I2mo, i 50 
 
 Robinson's Principles of Mechanism 8vo, 3 oo 
 
 Schwamb and Merrill's Elements of Mechanism 8vo, 3 oo 
 
 Smith's Press-working of Metals. . . 8vo, 3 oo 
 
 Thurston's Treatise on Friction and Lost Work in Machinery and Mill 
 
 Work.. 8vo, 3 oo 
 
 Animal as a Machine and Prime Motor, and the Laws of Energetics . i2mo, i oo 
 
 Warren's Elements of Machine Construction and Drawing , . . . 8vo, 7 50 
 
 Weisbach's Kinematics and the Power of Transmission. (Herrmann 
 
 Klein.) 8vo, 5 oo 
 
 Machinery of Transmission and Governors. (Herrmann Klein.). .8vo, 5 oo 
 
 Wolff' s Windmill as a Prime Mover 8vo, 3 oo 
 
 Wood's Turbines 8vo, 2 50 
 
 MATERIALS OF ENGINEERING. 
 
 Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 
 
 Burr's Elasticity and Resistance of the Materials of Engineering. 6th Edition. 
 
 Reset 8vo, 7 50 
 
 Church's Mechanics of Engineering 8vo, 6 oo 
 
 Johnson's Materials of Construction 8vo, 6 oo 
 
 Keep's Cast Iron 8vo, 2 50 
 
 Lanza's Applied Mechanics 8vo, 7 50 
 
 Martens's Handbook on Testing Materials. (Henning.) 8vo, 7 50 
 
 Merriman's Text-book on the Mechanics of Materials 8vo, 4 oo 
 
 Strength of Materials I2mo, i oo 
 
 Metcalf's Steel. A manual for Steel-users I2mo. 2 oo 
 
 Sabin's Industrial and Artistic Technology of Paints and Varnish 8vo, 3 oo 
 
 Smith's Materials of Machines I2mo, i oo 
 
 tthurston's Materials of Engineering 3 vols., 8vo, 8 oo 
 
 Part II. Iron and Steel 8vo, 3 So 
 
 Part HI. A Treatise on Brasses, Bronzes, and Other Alloys and their 
 
 Constituents 8vo, 2 50 
 
 Text-book of the Materials of Construction 8vo, 5 o 
 
 12 
 
Wood's (De V.) Treatise on the Resistance of Materials and an Appendix on 
 
 the Preservation of Timber 8vo, 2 oo 
 
 Wood's (De V.) Elements of Analytical Mechanics. 8vo, 3 oo 
 
 food's (M. P.) Rustless Coatings: Corrosion and Electrolysis of Iron and 
 
 SteeL ' 8vo, 4 oo 
 
 STEAM-ENGINES AND BOILERS. 
 
 Berry's Temperature-entropy Diagram. I2mo, i 25 
 
 Carnot's Reflections on the Motive Power of Heat. (Thurston.) i2mo, i 50 
 
 Dawson's " Engineering " and Electric Traction Pocket-book. . . . i6mo, mor., 5 oo 
 
 Ford's Boiler Making for Boiler Makers i8mo, i oo 
 
 Goss's Locomotive Sparks 8vo, 2 oo 
 
 Hemenway's Indicator Practice and Steam-engine Economy i2mo, 2 oo 
 
 Hutton's Mechanical Engineering of Power Plants 8vo, 5 oo 
 
 Heat and Heat-engines 8vo, 5 oo 
 
 Kent's Steam boiler Economy 8vo, 4 oo 
 
 Kneass's Practice and Theory of the Injector 8vo, i 50 
 
 MacCord's Slide-valves 8vo, 2 oo 
 
 Meyer's Modern Locomotive Construction, . ., 4to, 10 oo 
 
 Peabody's Manual of the Steam-engine Indicator I2mo. i 50 
 
 Tables of the Properties of Saturated Steam and Other Vapors 8vo, i oo 
 
 Thermodynamics of the Steam-engine and Other Heat-engines 8vo, 5 oo 
 
 Valve-gears for Steam-engines 8vo, 2 50 
 
 Peabody and Miller's Steam-boilers. , 8vo, 4 oo 
 
 Pray's Twenty Years with the Indicator Large 8vo, 2 50 
 
 Pupin's Thermodynamics of Reversible Cycles in Gases and Saturated Vapors. 
 
 (Osterberg.) i2mo, i 25 
 
 Reagan's Locomotives: Simple Compound, and Electric i2mo, 2 50 
 
 Rontgen's Principles of Thermodynamics. (Du Bois.) 8vo, 5 oo 
 
 Sinclair's Locomotive Engine Running and Management i2mo, 2 oo 
 
 Smart's Handbook of Engineering Laboratory Practice i2mo, 2 50 
 
 %iow's Steam-boiler Practice 8vo, 3 oo 
 
 Spangler's Valve-gears 8vo, 2 50 
 
 Notes on Thermodynamics i2mo, i oo 
 
 Spangler, Greene, and Marshall's Elements of Steam-engineering 8vo, 3 oo 
 
 Thurston's Handy Tables 8vo, i 50 
 
 Manual of the Steam-engine 2 vols., 8vo, 10 oo 
 
 Part I. History, Structure, and Theory 8vo, 6 oo 
 
 Part II. Design, Construction, and Operation 8vo, 6 oo 
 
 Handbook of Engine and Boiler Trials, and the Use of the Indicator and 
 
 the Prony Brake 8vo, 5 oo 
 
 Stationary Steam-engines 8vo, 2 50 
 
 Steam-boiler Explosions in Theory and in Practice i2mo, i 50 
 
 Manual of Steam-boilers, their Designs, Construction, and Operation 8vo, 5 oo 
 
 Weisbach's Heat s Steam, and Steam-engines. (Du Bois.) 8vo, 5 oo 
 
 Whitham's Steam-engine Design 8vo, 5 oo 
 
 Wilson's Treatise on Steam-boilers. (Flather.) i6mo, 2 50 
 
 Wood's Thermodynamics! Heat Motors, and Refrigerating Machines. . .8vo, 4 oo 
 
 MECHANICS AND MACHINERY. 
 
 Barr's Kinematics of Machinery 8vo, 2 50 
 
 Bovey's Strength of Materials and Theory of Structures 8vo, 7 50 
 
 Chase's The Art of Pattern-making I2mo, 2 50 
 
 Church's Mechanics of Engineering 8vo, 6 oo 
 
 13 
 
Church's Notes and Examples in Mechanics 8vo, 2 GJ 
 
 Compton's First Lessons in Metal-working i2n:o.. i Sc. 
 
 Compton and De Groodt's The Speed Lathe i2mo, i 50 
 
 Cromwell's Treatise on Toothed Gearing i2mo, i 50 
 
 Treatise on Belts and Pulleys. i2mo, i 50 
 
 Dana's Text-book of Elementary Mechanics for Colleges and Schools. . i2mo, i 50 
 
 Dingey's Machinery Pattern Making i2mo, 2 oo 
 
 Dredge's Record of the Transportation Exhibits Building of the World's 
 
 Columbian Exposition of 1893 4to half morocco, 5 oo 
 
 Du Bois's Elementary Principles of Mechanics : 
 
 Vol. I. Kinematics 8vo, 3 50 
 
 Vol. II. Statics 8vo, 4 oo 
 
 Vol. HI. Kinetics 8vo, 3 50 
 
 Mechanics of Engineering. Vol. I Small 4to, 7 50 
 
 Vol. II Small 4to, 10 oo 
 
 Durley's Kinematics of Machines 8vo, 4 oo 
 
 Fitzgerald's Boston Machinist i6mo, i oo 
 
 Flather's Dynamometers, and the Measurement of Power i2mo, 3 oo 
 
 Rope Driving i2mo, 2 oo 
 
 Goss's Locomotive Sparks 8vo, 2 oo 
 
 Hall's Car Lubrication I2mo, i oo 
 
 Holly's Art of Saw Filing i8mo, 75 
 
 James's Kinematics of a Point and the Rational Mechanics of a Particle. Sm.8vo,2 oo 
 
 * Johnson's (W. W.) Theoretical Mechanics i2mo, 3 oo 
 
 Johnson's (L. J.) Statics by Graphic and Algebraic Methods 8vo, 2 oo 
 
 Jones's Machine Design: 
 
 Part I. Kinematics of Machinery 8vo, i 50 
 
 Part II. Form, Strength, and Proportions of Parts 8vo, 3 oo 
 
 Kerr's Power and Power Transmission 8vo, 2 oo 
 
 Lanza's Applied Mechanics. 8vo, 7 50 
 
 Leonard's Machine Shop, Tools, and Methods. (In press.) 
 
 Lorenz's Modern Refrigerating Machinery. (Pope, Haven, and Dean.) (In press.) 
 
 MacCord's Kinematics; or, Practical Mechanism 8vo, 5 oo 
 
 Velocity Diagrams 8vo, i 50 
 
 Maurer's Technical Mechanics 8vo, 4 oo 
 
 Merriman's Text-book on the Mechanics of Materials 8vo, 4 oo 
 
 * Elements of Mechanics i2mo, i oo 
 
 * Michie's Elements of Analytical Mechanics 8vo, 4 oo 
 
 Reagan's Locomotives: Simple, Compound, and Electric i2mo t 2 50 
 
 Reid's Course in Mechanical Drawing 8vo, 2 oo 
 
 Text-book of Mechanical Drawing and Elementary Machine Design. 8vo. 3 oo 
 
 Richards's Compressed Air i2mo, i 50 
 
 Robinson's Principles of Mechanism 8vo, 3 oo 
 
 Ryan, Norris, and Hoxie's Electrical Machinery. Vol. 1 8vo, 2 50 
 
 Schwamb and Merrill's Elements of Mechanism 8vo, 3 oo 
 
 Sinclair's Locomotive-engine Running and Management i2mo, 2 oo 
 
 Smith's (O.) Press-working of Metals- 8vo, 3 oo 
 
 Smith's (A. W.) Materials of Machines ,. I2mo, i oo 
 
 Spangler, Greene, and Marshall's Elements of Steam-engineering 8vo, 3 oo 
 
 Thurston's Treatise on Friction and Lost Work in Machinery and Mill 
 
 Work 8vo, 3 oo 
 
 Animal as a Machine and Prime Motor, and the Laws of Energetics. 
 
 i2mo, i oo 
 
 Warren's Elements of Machine Construction and Drawing 8vo, 7 50 
 
 Weisbach's Kinematics and Power of Transmission. ( Herrmann Klein. ) . 8vo , 5 oo 
 
 Machinery of Transmission and Governors. (Herrmann Klein. ).8vo, 5 oo 
 
 Wood's Elements of Analytical Mechanics 8vo, 3 oo 
 
 Principles of Elementary Mechanics I2mo, i 25 
 
 Turbines 8vo. 2 50 
 
 The World's Columbian Exposition of 1893 4to, i oo 
 
 14 
 
METALLURGY. 
 
 Fgleston's Metallurgy of Silver, Gold, and Mercury: 
 
 Vol. I. Silver 8vo t 7 50 
 
 Vol. II. Gold and Mercury 8vo, 7 50 
 
 ** Iles's Lead-smelting. (Postage 9 cents additional) i2mo, 2 50 
 
 Keep's Cast Iron 8vo, 2 50 
 
 Kunhardt's Practice .of Ore Dressing in Europe 8vo, i go 
 
 Le Chatelier's High-temperature Measurements. (Boudouard Burgess. )i2mo, 3 oo 
 
 Metcalf's Steel. A Manual for Steel-users- , i2mo, 2 oo 
 
 Smith's Materials of Machines I2mo, i oo 
 
 Thurston's Materials of Engineering. In Three Parts 8vo, 8 oo 
 
 Part II. Iron and Steel 8vo, 3 50 
 
 Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their 
 
 Constituents 8vo, 2 50 
 
 Ulke's Modern Electrolytic Copper Refining 8vo, 3 oo 
 
 MINERALOGY. 
 
 Barringer's Description of Minerals of Commercial Value. Oblong, morocco, 2 50 
 
 Boyd's Resources of Southwest Virginia 8vo, 3 oa 
 
 Map of Southwest Virignia. . . .' Pocket-book form. 2 oo 
 
 Brush's Manual of Determinative Mineralogy. (Penfield.) 8vo, 4 oo 
 
 Chester's Catalogue of Minerals 8vo, paper, i oo 
 
 Cloth, i 25 
 
 Dictionary of the Names of Minerals .8vo, 3 50 
 
 Dana's System of Mineralogy Large 8vo, half leather, 12 50 
 
 First Appendix to Dana's New " System of Mineralogy.'* Large 8vo, i oo 
 
 Text-book of Mineralogy 8vo, 4 oo 
 
 Minerals and How to Study Them I2mo, i 50 
 
 Catalogue of American Localities of Minerals Large 8vo, i oo 
 
 Manual of Mineralogy and Petrography i2mo- 2 oo 
 
 Douglas's Untechnical Addresses on Technical Subjects i2mo, i oo 
 
 Eakle's Mineral Tables 8vo, i 25 
 
 Egleston's Catalogue of Minerals and Synonyms 8vo, 2 50 
 
 Hussak's The Determination of Rock-forming Minerals. (Smith. ). Small 8vo, 2 oo 
 
 Merrill's Non-metallic Minerals: Their Occurrence and Uses 8vo, 4 oo 
 
 * Ponfield's Notes on Determinative Mineralogy and Record of Mineral Tests. 
 
 8vo. paper, o 50 
 Roseabusch's Microscopical Physiography of the Rock-making Minerals. 
 
 (Iddings.) 8vo. 5 oo 
 
 * Tillman's Text-book of Important Minerals and Rocks , .8vo. 2 oo 
 
 Williwns's Manual of Lithology 8vo, 3 oo 
 
 MINING. 
 
 fceard'a Ventilation of Mines I2mo. 2 50 
 
 Boyd's Resources of Southwest Virginia 8vo, 3 oo 
 
 Map of Southwest Virginia Pocket book form, 2 oo 
 
 Douglas's Untechnical Addresses on Technical Subjects i2mo. i oo 
 
 * Drici;er's Tunneling, Explosive Compounds, and Rock Drills. .4to,hf. mor 25 oo 
 
 Eissler's Modern High Explosives 8vo 4 oo 
 
 Fowler's Sewage Works Analyses i2mo 2 oo 
 
 Goodyear's Coal-mines of the Western Coast of the United States i2mo. 2 50 
 
 Ihlseng's Manual of Mining 8vo, 5 oo 
 
 ** Iles's Lead-smelting. (Postage QC. additional.) I2mo. 2 50 
 
 Kunhardt's Practice of Ore Dressing in Europe 8vo. i 50 
 
 O'DriscoU's Notes on the Treatment of Gold Ores 8vo, 2 oo 
 
 * Walke's Lectures on Explosives 8vo, 4 oo 
 
 Wilson's Cyanide Processes I2mo[ i 50 
 
 Chlertnation Process i j mo i 5O 
 
 15 
 
Wilson's HydrauLw and Placer Mining i2mo, 2 oo 
 
 Treatise on Practical and Theoretical Mine Ventilation i2mo, i as 
 
 SANITARY SCIENCE. 
 
 Folwell's Sewerage. (Designing, Construction, and Maintenance.) 8vo, 
 
 Water-supply Engineering 8vo, 
 
 Fuertes's Water and Public Health i2mo, 
 
 Water-filtration Works iamo, 
 
 Gerhard's Guide to Sanitary House-inspection i6mo, 
 
 Goodrich's Economic Disposal of Town's Refuse Demy 8vo, 
 
 Hazen's Filtration of Public Water-supplies 8vo, 
 
 Leach's The Inspection and Analysis of Food with Special Reference to State 
 
 Control 8vo, 7 
 
 Masou's Water-supply. (Considered principally from a Sanitary Standpoint) 8vo, 4 
 
 Examination of Water. (Chemical and Bacteriological.) i2mo, i 
 
 Merriman's Elements of Sanitary Engineering 8vo, 2 
 
 Ogden's Sewer Design i2mo, 2 
 
 Prescott and Winslow's Elements of Water Bacteriology, with Special Refer- 
 ence to Sanitary Water Analysis I2mo, i 
 
 * Price's Handbook on Sanitation i2mo, i 
 
 Richards's Cost of Food. A Study in Dietaries I2mo, i 
 
 Cost of Living as Modified by Sanitaiy Science i2mo, i 
 
 Richards and Woodman's Air, Water, and Food from a Sanitary Stand- 
 point 8vo, 
 
 * Richards and Williams's The Dietary Computer 8vo, 
 
 Rideal's Sewage and Bacterial Purification of Sewage 8vo, 
 
 Turneaure and Russell's Public Water-supplies 8vo, 
 
 Von Behring's Suppression of Tuberculosis. (Bolduan.) i2mo, 
 
 Whipple's Microscopy of Drinking-water 8vo, 
 
 Woodhull's Notes on Military Hygiene i6mo, 
 
 MISCELLANEOUS. 
 
 De Fursac's Manual of Psychiatry. (Rosanoff and Collins.). . . .Large 12 mo, 2 
 Emmons's Geological Guide-book of the Rocky Mountain Excursion of the 
 
 International Congress of Geologists, i Large 8vo, i 
 
 Fen-el's Popular Treatise on the Winds 8vo. 4 
 
 Haines's .American Railway Management i2mo, 2 
 
 Mott's Composition, Digestibility, and Nutritive Value of Food. Mounted chart, i 
 
 Fallacy of the Present Theory of Sound i6mo, i 
 
 Ricketts's History of Rensselaer Polytechnic Institute, 1824-1894.. Small 8vo, 
 
 Rostoski's Serum Diagnosis. (Bolduan.) i2mo k 
 
 Rotherham's Emphasized New Testament Large 8vo, 
 
 Steel's Treatise on the Diseases of the Dog 8vo, 
 
 Totten's Important Question in Metrology. 8vo, 
 
 The World's Columbian Exposition of 1893 4*o, 
 
 Von Behring's Suppression of Tuberculosis. (Bolduan.) i2mo, 
 
 Winslow's Elements of Applied Microscopy i2mo, 
 
 Worcester and Atkinson. Small Hospitals, Establishment and Maintenance; 
 Suggestions for Hospital Architecture : Plans for Small Hospital . 12 mo, 
 
 HEBREW AND CHALDEE TEXT-BOOKS. 
 
 Green's Elementary Hebrew Grammar iamo, 
 
 Hebrew Chrestomathy 8vo 
 
 Gesenius's Hebrew and Chaldee Lexicon te the Old Testament Scriptures. 
 
 (Tregelles.) . t *fffz*rz=z=s esa!a .. .Small 4*0, half morocco, 
 
 Letter's Hebrew Bible ^^^^A^^. 8vo, 
 
1 
 
 UNIVERSITY OF CALIFORNIA LIBRARY 
 
 THIS BOOK IS DUE ON THE LAST DATE 
 STAMPED BELOW 
 
 - 
 
 
 
 i^J9Rtf*Z 
 
 30m-6,'14 
 
/oo 
 
 /