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By L. G. Huntley

In view of the recent advance made in the knowledge of the nature and conditions accompanying the occurrence of oil and gas, and of the recent activity in drilling in Wyoming, Montana, and western Canada, a discussion of the probabilities of obtaining production in such a reservoir as the Dakota sand in general, and in particular districts, is thought by the author to be timely and likely to result in more intelligent operating in certain parts of the territory underlain by this sand. In Canada particularly it is thought that these general considerations have equal if not more significance in a consideration of the oil and gas possibilities of the formations than have the various local conditions. Age and Nature of Deposition of the Dakota Sand The Dakota is distinctive in that it is known to form a generally continuous sheet of sand underlying the greater part of Alberta, Saskatchewan, Manitoba, North and South Dakota, Montana, and large areas in Nebraska, Colorado, and Wyoming. It does not seem to have been laid down in more or less isolated lenses, as has been the case with most oil-sand horizons. Except in northern Alberta, the Dakota sand contains fresh-water fauna, having been deposited very uniformly over these wide areas in shallow water with prevailing strong currents. In northern Alberta marine and brackish water conditions prevailed. In this district it forms the basal member of the Cretaceous sediments, directly overlying beds of Devonian limestone along a great unconformity in the Athabasca River valley and eastward. In southern and western Alberta it is underlain unconformably by the Kootenay shales (Lower Cretaceous), and by Jurassic and Carboniferous rocks. In the United States in South Dakota it was in places deposited upon Cambrian quartzites, and in other places directly upon the granite. In the State of Dakota, and in the

Jan 1, 1916

By L. G. Huntley

The occurrence of oil or "tar" in Mexico was mentioned as early as the seventeenth century by Friar Sagahun, who gives the Indian name "chapopote," by which these asphalt seepages are still called. This asphalt was apparently used, as it has been used by primitive people in many parts of the world, in religious ceremonies and for medicinal purposes. Travellers also report that the ruins in Yucatan and the pyramids in southern Mexico show traces of the use of "chapopotel' as a building cement.l DeGolyer says that the first attempt to exploit oil or gas in Mexico in a commercial way is shown by the records of the Memoria de Fomento of 1865, when permission was granted to a Senor Ildefonso Lopez to exploit the deposits of petroliferous substances in the San Jose de las Rusias area in the State of Tamaulipas. Other concessions follow, and probably refer to surface seepages which occur in that district. This was several years after the discovery of oil in Pennsylvania. In 1868, a well 125 it. deep was :drilled by a company organized in Mexico City, in what is now known as the,, Furbero district, and a little oil was refined there. In 1873, residents of Tampico denounced seepages along the Tamesi River, and asphalt was mined near Tempoal in the Canton of Tantoyuca. No drilling was attempted. But between 1880 and 1883 several shallow wells were drilled for oil in Mexico, two of them being near the present Potrero de Llano field west of Tuxpam. The wells were drilled by a Boston company with Canadian rigs, and are said to have reached a depth of about 400 ft., while one is reported to have flowed. Several other abortive attempts were made to drill for oil between 1885 and the beginning of the present century, about which time the Mexican Petroleum & Liquid Fuel Co., Ltd., in which Cecil Rhodes was interested drilled 24 wells unsuccessfully, several of them as deep as 1,500 ft., in the State of Vera Cruz. Also Messrs. Doheny and Canfield of California pur-

Jan 1, 1916

By Charles E. Weaver

During the past few years there has been considerable activity in prospecting for oil and gas in several parts of western washington. From time to time seepages of oil or emanations of gas have been reported from various places. Several companies have been organized for the purpose of drilling, but only a part of these have actually begun operations. In certain localities very small seepages of oil occur, but up to the present time no oil or gas in commercial quantities has been obtained. In order to determine the conditions which may be favorable or unfavorable to the occurrence of petroleum it becomes necessary to know the character and extent of the geological formations in which such deposits might occur. In other regions where producing wells have been developed it is possible to know what formations contain the oil and what structural conditions influence its concentration in reservoirs or zones. It is usually possible to determine those strata which contained the materials from which the petroleum may have been derived and also the position and distribution of the more porous sandstone belts into which it may have collected. Detailed stratigraphic surveys may even determine the depth at which a certain known oil-bearing zone may be tapped at any particular place. It is also possible to recognize those formations which are presumably barren of oil, as well as those which are absolutely so. In new regions far distant from any of those which are now producing or have produced in the past, it becomes absolutely impossible to foretell whether oil may exist in commercial quantities or not. Assuming that such deposits do exist, it is extremely difficult to predict at what depth the produciqg zone or zones occur. However, in prospecting in a new and unexplored region, use should be made of such laws as have been found to govern the occurrence of petroleum deposits in other well-developed fields. Such deposits in their world-wide distribution are found almost exclusively associated with sedimentary rocks. Areas composed predominatingly of igneous and metamorphosed rocks are to be rcgarded as extremely unfavorable localities for the occurrence of commercial deposits of oil or gas. Assuming that such oil deposits are

Jan 1, 1916

By Dorsey A. Lyon, Robert M. Keeney

The utilization of hydro-electriic power in electro-metallurgical industries, aside from purely mechanical operations, may be of two kinds. The electric energy may be used to supply the heat necessary for the performance of the chemical reactions of a metallurgical process, or the electrolytic action of a direct current may be employed for extraction of metals, either in a reduction process or a refining process. In discussing this subject, it is well to distinguish between established industries, which are producing metals and alloys at a, profit by use of the electric current, and the many processes which are either still in the experimental stage or have not even passed the paper stage of development of a patent. That is, we consider electro-metallurgical industries as commercial operations which are now consuming large blocks of electric energy, while processes which are not in commercial operation are only prospective consumers. Also, owing to the difliculty and risk of any attempt to foresee the effect of the European war upon electro-metallurgical industries, we have felt obliged to disregard the war entirely, and state our opinions regardless of its existence. Application of Electric Energy to Metallurgy Disregarding electrolytic refining processes, the applications of electric energy to metallurgy, when considered from a commercial viewpoint, may be classified as follows: Industries Experimental Processes Manufacture of aluminum Electric-furnace smelting of: Electric-furnace manufacture of: Ferro-alloys Copper ore Pig iron Zinc ore Steel In this paper only the above industries and experimental processes will be considered as possible consumers of hydro-electric power in large quan-

Jan 1, 1916

By W. McA. Johnson

The work of J. E. Johnson, Jr., on the effect of small amounts of oxygen in cast iron in increasing its strength and resistance to shock, is of interest from the technical and scientific standpoints. The following exposition of the theory carries Mr. Johnson's explanation further and, in my opinion, will disclose certain related phenomena and perhaps shed further light on the subject. Some facts, so novel in character as to excite incredulity, have been accepted finally by many metallurgical authorities. One of these is that oxygen to the amount of 0.060 per cent. in cast iron gives it a breaking strength of 3,500 Ib. per square inch, compared with a breaking strength of 2,500 lb. per square inch in cast iron of the same composition with respect to elements other than oxygen, but having only 0.010 per cent, oxygen. The "oxygenated" cast iron, even if made in a coke furnace, has properties equivalent to the best charcoal pig iron. Mr. Johnson has also established the fact that the variations in combined carbon cannot account for the results. By microphotographic evidence he has shown that in oxygenated cast iron the graphite particles are dense and spherical, while in well-deoxidized cast iron the graphite particles are flaky and leaf-like. It is just a matter of common sense that iron of the latter structure is much weaker than the former. The analytical and microscopical work has been done with care and there is no doubt in my mind about the accuracy of the experimental results. In this paper then, we shall consider it as accepted that small amounts (0.060 per cent.) of oxygen increase the strength of cast iron by producing a structure in which the round and solid particles of graphite are surrounded firmly by a principal matrix of ferrite. The purpose of this paper is to show that the reason why the graphite particles are round is founded on the fact that the particles of any precipitate are made denser and harder by the presence of a reagent having a solvent action on the precipitate. This can be stated as a law, although I have never seen it so given in any textbook. Let us then, for purposes of illustration, give a concrete example and develop the theory of such mechanical and chemical actions as occur: It is well known that, by a soluble sulphate, a barium salt in solution is precipitated in a dense and easily filtered body when the solution is

Jan 1, 1916

By F. D. Weeks

The Salida smelting plant, owned by the Ohio & Colorado Smelting & Refining Co., is situated at an altitude of 7,000 ft., about 2 miles west of Salida, Colo., and 215 miles southwest of Denver. Salida is a division point on the Denver & Rio Grande R. R. where the narrow-gage line serving the San Juan region joins the through standard gage. This narrow-gage road also serves the coal and coke companies at Crested Butte and the lime quarries and mines at Monarch and Garfield, which are only 20 miles distant. These facts, together with the possibility of an appropriate site, doubtless influenced the builders to locate at this point. The smelting plant and yard occupy 80 acres of land on the northeast side of the Arkansas River. The slope of the ground is such as to permit of the ore being delivered by cars at a point 25 ft. above the feed floor; and in front of the furnaces there is a fall of 50 ft. for the slag dump. A recent purchase of river bottom has provided slag room for 20 years. As originally constructed, the plant consisted of four blast furnaces, 40 by 144 in. at tuyéres, two copper-matting furnaces, dust chamber, stack, power plant, blowers, sampling works, and one railroad trestle about 16 ft. from bed floor to rails. Later 12 hand roasters of excellent design were added and the practice of smelting leady matte in a copper-matting furnace was abandoned. Since the plant passed under the present management the equipment has been increased so that the following is a brief description of the same at this date: Two lead blast furnaces, 48 by 180 in. at tuyéres, 17 ft. 6 in. tuyéres to feed floor; four lead blast furnaces, 40 by 144 in. at tuyéres, 17 ft. 6 in. tuyéree to feed floor; two copper-matting furnaces, not used; blast-furnace flue, 900 ft.; area 245 sq. ft.; blast-furnace stack, 150 ft.; above furnace floor, 190 ft. When smelting a 500-ton charge per day, the gases approximate 63,700 cu. ft. per minute and travel at a speed of 260 ft. per minute. The slag is hauled by a 10-ton electric locomotive; the slag shells and settler refuse are elevated to a bin on the feed floor by an electric hoist. The matte is tapped in 1,600-lb. cakes and loaded into cars

Jan 1, 1916

By John Blatchford, William T. Hall

The product obtained by roasting stibnite is likely to contain some unoxidized antimony trisulphide and a mixture of antimony trioxide and antimony tetroxide. It was desired to determine, as accurately as possible, the condition of the antimony as well as the total quantity present. Attempts were made to separate the trisulphide and the two oxides by methods based upon their varying solubilities in different solvents, but no satisfactory results were obtained in this way. It was found, however, that by determining the total antimony content, the antimony present as trioxide, and the antimony present as trisulphide, a good idea of the chemical composition of the roasted product could be obtained. The total antimony was determined by dissolving the sample in concentrated hydrochloric acid, reducing the antimony entirely to the trivalent condition by means of hydriodic acid and eventually titrating the antimony back to the pentavalent condition by means of iodine in the presence of sodium bicarbonate1* The details of the procedure are as follows: Weigh out 0.25 gram of the roasted product into a trapped flask (Fig. I), add 4 grams of powdered tartaric acid, 2 grams of potassium iodide and 40 c.c. of concentrated hydrochloric acid. Boil the solution gently f;r 5 min. and then cool to room temperature by shaking the flask while holding it under running water. Then, very carefully discharge the iodine color by the cautious addition of 0.05-normal sodium thiosulphate solution, adding a little starch toward the last. Nearly neutralize the acid with ammonia solution, but leave the solution distinctly acid. Pour the slightly acid solution into 200 c. c. of water containing an excess of sodium bicarbonate and titrate to a permanent blue color with standard 0.1-normal iodine solution.

Jan 1, 1916

By James F. Kemp

The iron ores of southeastern Cuba present a subject of exceptional geological interest. Their relations to the inclosing rocks are varied and in some cases unusual. The problem of their geological origin is not a simple one and for this reason has occasioned some divergence of views among previous observers. Profiting, however, by these earlier studies and by more detailed field and laboratory observations as well as by the experience of added years of mining, much more satisfactory descriptions and interpretations can now be prepared. Previous Work In 1884, interest in the southeastern coast of Cuba became active among the consumers of iron ore along the Atlantic seaboard of the United States. Active development was undertaken by the Juragua Iron Co., Ltd., a corporation affiliated with the Bethlehem Steel Co., and the Pennsylvania Steel Co. The property of the Juragua company, which is situated about 15 miles east of Santiago, was studied in June and July, 1884, by Dr. James P. Kimball, at the time Professor of Economic Geology in Lehigh University and one of the best known of American mining geologists. Dr. Kimball published on his return two papers, the first important descriptions which we have of the local geology.1 It is

Jan 1, 1916

By W. L. Honnold

Owing to a unique labor situation and other unusual circumstances, the mining methods of the Rand are hardly comparable with practice elsewhere. They are of considerable interest, however, and their importance is increased by the magnitude of the' industry with which they are identified, gold of $166,186,000 value, say 40 per cent. of the world's production, having been recovered from 25,701,954 tons of ore milled in 1914. In the sketchy remarks to follow, attention will first be drawn to some influential factors of general bearing, after which certain features at two mines of the writer's group will be referred to. It is hoped that engineers associated with similar or different conditions and practice will contribute to broaden the discussion. Before proceeding, recognition is due the generous assistance of C. E. Knecht and F. A. Unger. General Observations The principal mines are situated along the northern limit of an irregularly shaped geological basin, and extend in almost unbroken continuity over a distance of about 60 miles. As the boundaries are defined by vertical planes there are both "outcrop" and "deep-level" properties, all differing in size and in technical features. So much has been written in regard to the geology of the Rand that only a few pertinent features need here be recalled. Briefly, the ore deposits are profitably enriched portions of certain conglomerate beds or "reefs," rarely more than three, which are interposed between quartzite, or quartzite and slate, and lie so closely together that where more than one are mined they are dealt with as a working unit, although they may be stoped separately. Their collective extension is locally referred to as " the Reef." Along the outcrop the series dips more or less steeply, and in depth it flattehs, the latter tendency being most marked in the Far East Rand, where the bottom of the basin is nowhere so deep as to be inaccessible. Dikes and faults are a common feature throughout. They are,

Jan 1, 1916

By Frank Fahrenwald

I. INTRODUCTORY METALLURGICAL research has discovered many an alloy possessing properties not combined in any single metal, and progress still consists chiefly in the investigation and utilization of alloys. In the case of iron, the demands of automobiles, high-speed machines and high-duty engines have led to the production of special iron alloys which will meet any reasonable specifications in that field. In like manner, the bronzes, brasses and other alloys of copper have been brought to remarkable perfection, and for nearly every industrial purpose some alloy has been found more suitable than the pure metal. Less complete success has attended the attempt to find substitutes for gold, platinum, and the other precious metals. Indeed, it is not likely that a material can be produced which will possess all the properties of any one of them; yet it is reasonable to hope that, for any given use, the properties required may, be found in some less expensive material. Thus, in incandescent electric lamps, the wire passing through the thick glass neck of the bulb was, until recently, almost universally made of platinum, for the single reason that no other known material, suitable as a conductor, had the same coefficient of expansion as glass. But a comparatively recent investigation of the iron-nickel series' has shown that alloys of those metals may be produced, the coefficient of expansion of which can be accurately controlled between that of iron or nickel and zero. Thus, in that particular industry, a substitute for platinum has been found. According to statistical reports, not only considerable quantities of gold and iridium, but also more than one-third of the annual supply of platinum, are used (and, in the nature of the case, irrevocably lost) by dentists. Platinum is thus employed in several forms. As a thin foil, it serves various purposes for which its high melting point, pliability, chemical resistance, and other properties-including the ease with which

Jan 1, 1916

By Hugh P. Tiemann

The desirability of employing the centigrade scale for the measurement of temperatures is becoming more and more recognized in this country, particularly in view of the fact that this scale is used almost exclusively in technical papers and publications—exclusively in those published in French or German. There are, however, a large number of factories and laboratories which still employ the Fahrenheit scale. It therefore frequently becomes necessary to convert one into the other and the accompanying chart (Fig. I) has been found very convenient for this purpose. The formulas for conversion follow: (1) °F. = 9o /5+ 32 (2) oC = 5 (oF - 32 ) (1) 100° C X 9 900/5 =180 .'. 180 + 32 = 212° F. 5 (2) 5 (212° F - 32) = 5 X 180 =100o C 9 9

Jan 1, 1916

By J. Norman Bulkley

As electrical power is used to a greater extent on the Rand than in any other mining center, it is thought that a short description of the methods used and results obtained may be of interest. In comparing Rand practice with that on other fields, several general factors should be borne in mind: First, the mines are all working on large tonnages of low-grade ore (average $6.50). The annual crushing rate is about 27,000,000 tons. Second, the mines are all grouped under the financial and engineering control of mining houses, so that the results of a group, rather than an individual mine, are open for study, and practice follows more uniform lines. Third, coal of fair quality (about 12,000 B.t.u.) can be obtained for $2 to $3 per ton. Good supplies of condensing water are, however, scarce, and have to be carefully stored. Power Supply Power is supplied by the Victoria Falls & Transvaal Power Co., Ltd., and its subsidiary, the Rand "Mincs Power Supply Co. Both companies, which are practically one from an engineering point of view, operate the following stations, all fecding into the same system. Capacity Installed Turbo Capacity Installed Steam-Tur- Station Alternators bine Dliven Centrifugal Compressors Brakpan............... Two 12,500-kw. sets Two 3,000-kw. sets Simmer Pan............... Six 3,000-kw. sets Rosherville................ Two 11,000-kw. sets Six 3,500-kw. machines Five 9,600-kw. sets Three 7,000-kw. machines Verckniging ............. Two 9,600-kw. sets Two 12,000-kw. sets 162,200-kw. sets Total steam-tkbine capacity installed, 204,200 kw. There are also at the Robinson Central air station six motor-driven centrifugal compressors, each of 3,500 kw., equal to 22,000 cu. ft. per minute at 120 Ib. capacity at 3,000 r.p.m. Power is supplied from these stations as 50-cycle, three-phase current generally at 40,000 volts,

Jan 1, 1916

Jan 1, 1916

By Frederic K. Bunton

The smelting plant of the British Columbia Copper Co. at Greenwood, B. C., now closed because of the decline in the price of copper due.to the European war, is of special interest to metallurgists for several reasons. It was successfully smelting in blast furnaces the lowest grade copper ore of all plants in America. In order to do so, it had to run at very hig~; efficiency, which necessarily required a large tonnage per square foot of hearth area, together with the minimum amount of labor and other costs. The furnaces smelted daily 2,250 tons of ore (6.62 tons per sq. ft. of hearth area), carrying 0.85 per cent. of copper, at a smelting cost of 81.18 per ton. The entire plant required 130 men to operate it and keep up repairs, showing a labor efficiency of about 17.5 Dons per man per day. In the present paper, the method of obtaining these results is shown. Most of the information contained in this description I obtained as Assistant Superintendent, during the two years preceding the present shutdown. Other sources of information to which I am indebted are: The British Columbia Copper Co., Ltd., by ALfred W. G. Wilson, in The Copper Smelting Industry of Canada; Greenwood Smelting Worlrs, by J. E. McAllister, Engineering and Mining Journal, vol. xci, pp. 1011 to 1015 (May 20, 1911); and Description of the Copper Smelter of The British Columbia Copper Co., by W. L. Bell, in Transactions of the Canadian Mining Institute, vol. xvi, pp. 151 to 154 (1913). II. Location and Connections The smelter of this company is about half a mile south of GreenGood, in the Boundary district of British Columbia, on the Columbia & Westerg branch of the Canadian Pacific Railway. It was originally built in 1900 by Paul Johnson, to handle 600 tons of ore a day in two small furnaces of 300 tons capacity; but in 1907 the old furnaces were torn out, the plant was remodeled, and three blast furnaces, 48 by 240 in. at) the tuyéres, were installed. In 1910, two of these were enlarged to 51 by

Jan 1, 1916

By Walter O. Snelling

Continuation of the discussion of the paper of WaltER o. SnelLIng, presented at the New York and San Francisco meetings, February and September, 1915, respectively, and printed in Bulletin No. 100, April, 1915, pp. 695 to 704 and Trans., li, pp. 657 to 671. A. C. McLaUghlin, San Francisco, Ca1.—It seems to me that Mr. Snelling's work, if it is what it appears to be, is one of the most important contributions to petroleum technology that has been brought out in the last 25 years. If his end products are what they seem to be, he has made. a discovery, which, in my judgment, will revolutionize the petroleum industry. As to industrially carrying out these processes I do not think there is the slightest difficulty, for I have had some work recently where crude oils were handled successfully at a temperature of 750" F, and pressure of 750 lb. per square inch. William A. WillIams, San francisco, Ca1.—What metal did you use, Mr. McLaughlin? A. C. McLauGHILIN.—Ordinaly seamless tubing, extra strong. William A. Williams.—Tests were made in Dr. Rittman's experimental plant at Pittsburgh, upon samples of residuum furnished by Mr. Bell, the residuum being the remainder of the crude oil after the lighter fractions had been removed. After the material had been run through Dr. Bittman's plant, yields of from 43 to 58 per cent. of material, boiling under 150" C. were obtained. The distillate had a peculiar odor, due to the presence of benzene, toluene, and other unsaturated hydrocarbons. W. N. Best, New York, N. Y.—What is the difference between the Rittman and the Snelling process or system? William A. Williams.—he fundamental difference is that reactions take place under relatively higher temperatures and pressures and with none of the oil present in its original or liquid state, while the reactions secured by Mr. Snelling and other investigators have been from the liquids in the presence of some vapors. Under such conditions as Mr. Snelling operates, the temperatures and pressures used are limited and the flexibility in the control of these variables is extremely limited when compared with the Rittman process.

Jan 1, 1916

By Arthur F. Taggart

The following conclusions on the work of the Hardinge mill are based on data furnished to the writer by the Hardinge Conical Mill Co. in the form of the mesh cards hereto appended. Energy units (E. U.) and relative mechanical efficiencies (R. M. E.) are computed by the "volume method" of Stadler.' Screen apertures used are the average apertures of testing screeps of the meshes given. i . Card 122. June 28, 1912. Vipond Porcupine Mines Co., Ltd., Schumacher, Ont., Canada. Ore from mill bin. Gangue, quartz and basalt. 4.5 ft. by 13 in. ball mill, Capacity, 48 tons per 24 hr. Charge, 4,000 lb. balls. Speed, 33 rev. per minute. Horsepower, 15 to 17. Water, 100 per cent. by weight. (50 per cent. ?) Product deslimed and oversise reground in pebble mill, see Card 113. Feed to mill through 2-in. mesh. Mesh Feed, Per Cent. Discharge, Per Cent.. + 1in. 5.50 ....... + 3/4. 28.00 + in. 30.00 ...... + 1/4in. 19.72 ....... + 10 10.87 2.10 + 20 2.42 8.00 -20 3.51 .....,. + 40 ....... 22.68 + 60 ...___ 10.50 4-80 ....... 11.80 + 100 ....... 3.90 -100 ....... 40.15

Jan 1, 1916

By James A. Barr

When phosphate mining operations first commenced in Tennessee the loss of both high- and low-grade material was large, because of the crude hand methods employed. Practically all rock smaller than 2 in. was thrown back into the pits and covered with the overburden of subsequent openings. With the advent of mechanical washers and other mining machinery, together with the abolishing of the contract system, the waste has been steadily diminished, until at present only the finest sand is being rejected; and even this is not lost, for in the majority of cases the water, slime, and sand from the washers are run into large settling ponds where practically all of the phosphate-bearing material is caught and stored for future use, or until it is profitable to ship lower grades. The latest equipment used to recover the fine and lower-grade phosphate sand includes Dorr thickeners, settling tanks, Dorr classifiers and settling ponds served by locomotive cranes with clam-shell buckets, making it possible to save material averaging as fine as 200 mesh. TO attempt saving finer material would necessitate a different type of drier, which might be patterned after the multiple-deck roasters. The present tailing runs from 15 to 25 per ccnt. of available phosphate, which, howrever, as mentioned before, does not represent a total loss to possible future operations. The demand of the consumer is the greatest factor in regulating the recovery at present. In the mining of blue rock, which does not require washing treatment, the main waste material is the capping of low-grade kidney formation, generally used for backfilling of the rooms. By reason of the introduction of improved methods in the early stages and the re-mining of territory skimmed over at the start, at the present time the net result of all operations is a comparatively small loss. One of the largest temporary losses in the industry occurs in the Florida pebble district where the recovery of phosphate runs about 25 per cent. The loss is classed as temporary because most of the tailing has been collected in ponds and piles, where it may be reclaimed in the future should developments or improved processes warrant. In cleaning the Florida pebble phosphate, aside from the elutriatisn

Jan 1, 1916

Jan 1, 1916

Jan 1, 1916

By William Hall

THE product obtained by roasting stibnite is likely to contain some unoxidized antimony trisulphide and a mixture of antimony trioxide and antimony tetroxide. It was desired to determine, as accurately as possible, the condition of the antimony as well as the total quantity present. Attempts were made to separate the trisulphide and the two oxides by methods based upon their varying solubilities in different solvents, but no satisfactory results were obtained in this way. It was found, however, that by determining the total antimony content, the antimony present as trioxide, and the antimony present as trisulphide, a good idea of the chemical composition of the roasted product could be obtained. The total antimony was determined by dissolving the sample in concentrated hydrochloric acid, reducing the antimony entirely to the trivalent condition by means of hydriodic acid and eventually titrating the antimony back to the pentavalent condition by means of iodine in the presence of sodium bicarbonate.' The details of the procedure are as follows: Weigh out 0.25 gram of the roasted product into a trapped flask (Fig. 1), add 4 grams of powdered tartaric acid, 2 grams of potassium iodide and 40 c.c. of concentrated hydrochloric acid. Boil the solution gently for 5 min. and then cool to room temperature by shaking the flask while holding it under running water. Then, very carefully discharge the iodine color by the cautious addition of 0.05-normal sodium thiosulphate solution, adding a little starch toward the last. Nearly neutralize the acid with ammonia solution, but leave the solution distinctly acid. Pour the slightly acid solution into 200 c.c. of water con-

Jan 1, 1916