Technical Chemistry.
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Vite gave a loss of I O per cent. on pure caffeine, and a loss of a s much as 42 per cent. when working with tea. T h e other three methods gave good results with pure caffeine. T h e percentages of caffeine found in three samples of tea are given in the following table : Method.
Congo tea.
.............. 0.843 .......... 0.919
Peligot Crosschoff Gomberg
........... 1.542
Green tea.
Gunpowder tea.
2.061 2.031 2.386
3.680 3.200
3.986
T h e higher results given by Gomberg’s method, together with its simplicity, make it the most desirable method for the rapid determination of caffeine.
nethods for the Determination of Color and the Relation of the Color to the Character of the Water. BY FREDERICK S. HOLLIS.J . N. E. Water Works Assoc., 13, g4-111.-The author shows by a series of analyses, extending over a year, that in an unpolluted surface water the variations in oxygen consumed, loss on ignition, and albuminoid ammonia, in general, follow the changes in color. Among the methods for the determination of color are described the Tidy colorimeter, the Nessler scale of Leeds, the method based on a comparison of the natural waters with the Lovibond tintometer (erroneously spelled Lovibard), the platinum scale of Hazen, and the special form of colorimeter used a t the Experimental Filter Station of the Boston Water Works. A table is given for the conversion of color readings from the Nessler and natural water standard to the platinum standard. TECHNICAL CHEnISTRY. F.H. THORP,REVIEWER.
The Influence of Bismuth on Brass and Its Relation to Firecracks. BY EDWIN s. SPERRY.American Machinist, 21, 6906g2.-The author investigated the truth of the niaxim common among brass founders that bismuth is injurious in brass. Five experiments were made in which a pure Lake Superior copper was melted and a certain quantity of a definite alloy of copper and bismuth introduced. Pure refined zinc was then added and the brass cast in a mold. It was then rolled cold. T h e presence or absence of cracks on the edges and surface of the plate was noted. T h e plate was then annealed and again examined for fire-cracks ; if these were not sufficiently deep to prevent further treatment, the plate was again rolled and examined. T h e amount of bismuth introduced varied from 0.5 per cent. to 0.02 per cent., and in all cases the amount of cracking was proportional to the quantity of bismuth present. Less than 0 . 0 2
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Review of AmeriLan Chemical Research.
per cent. bismuth would produce a satisfactory brass. T h e author believes h e has demonstrated that bismuth is a cause of fire-cracks in brass, but it is not commonly present in sufficient quantities to be considered the oizly cause of them. His results in brief are : Bismuth renders brass cold-short, but has less effect than antimony in this respect ; it causes fire-cracks, and brass for cold rolling should not contain over 0.01per cent. of bismuth ; it also causes hot-shortness and latent fire-cracks, i. E . , lines of inferior cohesion after annealing which develop into cracks when t h e brass is rolled.
The Variation in the Composition of 6' Paris Green," with a Scheme for Its Analysis. BY T ~ o a r a sB. STILLMAN.Stevens Indicator, 15, 233-24o.-The composition of a pure Paris green is given a s a n aceto-arsenite of copper containing in per cent. CuO, 31.29 ; As,O,, 58.65 ; C,H,O,, 10.06. Adulteration as such is rare in this country, but many samples show an excessive amount of arsenious acid, and the commercial material fails to give uniform results when used as an insecticide. Foreign samples are often found adulterated with barium sulphate, calcium carbonate, lead chromate, or gypsuni ; but these may be added to alter the shade when the material is designed for use as a pigment. A simple scheme for t h e analysis of Paris greens, containing t h e above impurities, is given. Producing Illuminating Gas and Coke in By-product CokeOvens. BY H. 0. HOFMIAW. Eng. Min. ]., 66,428-430 ; 458460.-A study of the working of ten Seniet-Solvay coke-ovens a t Halifax, N . S . , was made by the author. Since 1897 these ovens have supplied 18 candle-power gas to the city for illuminating purposes, while a fuel gas of 8; candle-power is also obtained. Of the gas made, 32.26 per cent. is illuminating gas and 67.74 per cent. fuel gas ; the latter is used to heat the retorts, and 54.84 per cent. of the total gas made is thus utilized ; t h e remainder is sold for heating gas. Every 24 hours 37 tons (of 2 , 0 0 0 lbs.) are coked and yield 310,000 cubic feet of gas, while 7 j per cent. of the weight of the coal charged is obtained as coke. Each ton of coal also yields about 5 lbs. of ammonia gas and I Z gallons of t a r (120 lbs.). An abstract of a report on a n Otto-Hoffmann oven, worked at Glassport, P a . , is also included. T h e coal used mas a washed slack from the Dominion Coal Co., Cape Breton. W i t h an average charge of 14591 lbs. of coal containing 9.9 per cent. moisture, t h e time of coking was 33 hours and 56 minutes. T h e yield of products per long ton of coal was: coke, 1593.4 lbs. (71.13 per cent.) ; tar, 75.7 lbs. (3.38 per cent.) ; ammonia 7.6 Ibs. (0.34 per cent.) ; gas, 10,390 cu. ft. (16.43 per cent.). Of t h e gas 49.5 per cent. was
Technical Ckemistry.
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of 14.7 candle-power, and 50.5 per cent. of CJ candle-power, only available a s fuel gas. Carbon disulphide, hydrogen sulphide, gas liquor, and loss, amounted to 8.72 per cent. Numerous tables of analyses of the products and calculations of the heating value of the gas, coal, and coke are given. I t is determined that 10.9 per cent. of the calorific value of the coal is consumed in the coking operation. I t is shown that the production of illuminating and fuel gas and coke in these ovens rests on a sound theoretical and economic basis. The Le Sueur Process for the Electrolytic Production of Sodium Hydroxide and Chlorine. BY CHAS. I,. PARSONS./, A m . Ckenz. SOL.,2 0 , 868-878.-A short history of the original process is given in which it is shown that some of the criticisms made by Lunge and others are unfounded. A detailed description of the process as carried on a t Rumford Falls, Me., follows, in which it appears that the original apparatus has been greatly modified, although the essential features of the process are said to be unaltered. T h e chief difficulty has always been the diffusion of the caustic solution into the anode compartment. This is combatted by adding hydrochloric acid to the anode compartment, thus decomposing any hypochlorite formed. T h e amount of acid required is, by the table given, somewhat less than onesixth of the total weight of salt decomposed. A sketch and a description of the improved cell are given, together with a discussion of the practical working and cost of the process.
Sulphuric Acid and the By-products from Iron Pyrites. BY R. G. EWER. /. Assoc. Eng. SOL.,21, 160-171.--After a historical sketch of the sulphuric acid industry, tracing the improvements down to the present, the author describes a modern plant, showing a plan and details of a set of chambers of his own design. T h e process described shows the working of Spanish pyrites, with recovery of copper, silver, and gold and utilization of the iron oxides by blast-furnaces. Turf Briquettes in Germany. BY JOHN E. KEHL. U. S. Consular Rep., 59, g8.-The preparation of this new fuel is described briefly, and the success of the new venture predicted. T h e turf (peat) is cariied directly from the bog to a breaker from which it goes to a steam dryer, and is thus obtained a s a fine dry dust. T h i s is heavily pressed to form briquettes, which furnish a cheap, clean, and easily handled fuel.
Refining Petroleum with Silicate of Sodium. BY R. p. ROTHWELL. Eng. Min. I , ,66, 338.--This article is in the main a condensed statement of the proposition of J. R . Michler to substitute sodium silicate solution for caustic soda in neutralizing the excess of acid left in heavy petroleum oils after the re-
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Review of Amcrican Chemical Reseayeh.
moval of the acid tar. T h e separation of the silicic acid is claimed to decolorize the oil, as well as to cause the sludge to settle quickly.
Colored Glazes. BY S. GEYSBECK. Brick, 9, 66.-This is a popular article in which is explained the causes of crazing” and “shivering” in glazes for pottery. Methods of modifying the glazes to overcome these difficulties are given. Analyses of Commercial Fertilizers. Agr. E x p t . Sta, Bull. Me., LVO. 38; N. 7 , N o . 124; A?.k., No. 47 ; W i s . , No. 6 6 ; Ar. Y., No. 129; Md., No. 52; Miss., N o . 48; ?V. Vu.,No. 51 ; Conn. zrst Ann. Rep., Pt. 11; Cal. Ann. Rep., 1695-1897; Wis. 15th .4nn. Rep. ; W. Vu. Special Bull.. May I , r898. Crude Caustic Soda Sold in the Market as Caustic Potash. BY CARL E. SRIITH.A n t . /. Pharm., 70, 392-398.-111 the course of an investigation of the purity of commercial caustic potash, t h e author found five samples that were nothing else than caustic soda. I t is supposed that they represent the supply furnished to grocers a r d other consumers who are not e x pected to test their purchases. T h e products were of good appearance, and niight easily deceive their purchasers. Simple methods of testing crude alkali for sodium and potassium, and also quantitative methods for estimating socla and potash, caustic and carbonate, chlorides, sulphates, and silica in crude alkali, are given. T h e sensitiveness of sodium cobaltic nitrite as a test for potassium was also determined. X solution containing 0 . 2 per cent. of potassium hydrate showed turbidity in four minutes, but a weaker solution failed to react after many hours. Sodium Aluminate a s a ileans for the Removal of Lime and Suspended Ilatter from Water for Use in Boilers. BY CHAS. F. h f h B E R Y A N D EDWINB. BA4I,T~~E\’./. A w ~Chent. . SOL., 21,23-27.--The authors first studied a method of making sodiuni aluminate, which consistecl in adding sodiuni hydroxide to aluminum sulphate solution of known strength. T h e solution of sodium aluminate so formed was then added iii definite quantity to the water to be purified. T h e reactions involved in t h e precipitation are : CaH,(CO,),+Al,O,Na,+H,O=CaC0,+2X1(OH )3+Na,C0,, and CaS0,+Na,C03=CaC0,+Na,S0,. Seven different waters were tested by this method and also by sodium hydroxide alone, but in each case the latter removed only about one-half the quantity of lime that was thrown ont by the aluminate. T h e precipitated alumina also removed suspended matter most co npletely.
Techzical Chemistry.
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Theory and Practice of Asphalt Mixtures. BY A. W . Dow. A m . Gas-Lightj., 69, 862-863.-1n testing asphalt for paving, it is often true that the investigator overlooks the physical laws involved, especially those relating to the attraction and adhesion of liquids to solids. Asphalt cement is properly a liquid, and the author showed by a simple experiment that one used in a Washington pavement flowed perceptibly at temperatures of 26', 75', and 140' F. A smooth block of asphalt was placed directly over a small hole in a board, and kept a t these temperatures for some time. T h e amount of flow of the asphalt into the hole was measured. T h e hardness of a pavement mixture is largely dependent on the character of the sand used, very fine, sharp sand forming a much harder mass than coarse sand whose grains were rounded. With rounded grains it was found possible to make a very soft pavement mixture from asphalt which yielded a very hard mass with sharp sand. Tanning Leather with the Aid of Electrolysis. BY CHAS. F. MABERYA N D K. L. LANDGREBE. Proc. Am. Assoc. A d v . Sa*., 1898; Abstract Leather Manufacturer, 9, 138-13g.-Early attempts to apply electric currents to tanning date back to 1849 and 1883. T h e purpose of this investigation was to study the influence of the current on the chemical change and in hastening the process. T h e action of sodium sulphide as a depilatory was also studied. Samples of sheep, calf, and steer hides were treated in a bath made by mixing one liter of sodium sulphide solution containing 5 0 grams of the salt with four liters of lime water. After twenty minutes' agitation, the strongly alkaline bath reduced the hair to a pulp, which was easily scraped off, leaving the skin, after washing, ready for the tan. No bate was necessary, a n d the skin was soft and plump. This prepared skin was placed in a bark extract liquor between carbon plates and subjected to currents varying from three to six amperes, the potential difference varying from six to twelve volts, according to the strength of the tannin solution. A current of air was blown into the bath for agitation. A solution of 240 grams oak extract in three liters of water, with a current of 3.5 amperes (six volts potential), tanned the skin samples completely in I .5 days. A similar experiment without electricity required six days to tan the skins. T h e current is supposed to assist in the intimate contact between the inner hide substance and oxygen, and also in precipitating coloring-matter, leaving only a clear tannin solution to permeate the skin. T h e determination of nitrogen in the hide substance shows that the hydrogen liberated exerts some action on the nitrogenous bodies, probably forming ammonia. T h e proportion of nitrogen in dry and fatfree hide from the same animals is constant : hence this enables
20
Review of American Chemical Research.
t h e proportion of tannin taken up by the hide substance to be calculated. A table of nitrogen determinations in sheep and calf skins, with and without electrical tannage, is given, showing that nitrogen is removed in the electric bath.
BIOLOGICAL CHEMISTRY. A G . WoODnrAN. R E I I F \ \ F X .
A Chemico-Physiological Study of Certain Derivatives of the Proteids. BY R. H . CHITTENDEN,LAFAYETTE B. MENDEL, A N D TANDELL HENDERSON. A m . /. Phys.. 2, 142-18r.--In t h e first part of their paper the authors have recorded the results of a study of the physiological effect of a number of cleavage products of proteids, observations having been made as to their influence on blood pressure, on blood coagulation, on lymph flow, flow of urine, and on the apparent immunity conferred upon animals by a n intravenous injection of propeptone against subsequent injections of the same substance. T h e second part of the paper is devoted to a description of the method of preparation of the proteid derivatives used and to a presentation of analyses of ( I ) antipeptone, which was formed by t h e action of trypsin on pure antialbumid and was dried a t 110"C. ; ( 2 ) of deuterogelatose, formed by the action of trypsin on gelatine and dried at IOj' C. to constant weight ; and ( 3 ) of the gelatine-peptone separated from the deuterogelatose by ammonium sulphate.
The Effect of Aqueous Solutions upon the Germination of Fungus Spores. BY F. L. STEVENS.Botazical Gazette, 26, 377-406.-1n order to determine the strengths of various solutions which just suffice to prevent the growth of fungus spores, the author has made cultures of various fungi in salt solutions of varying degrees of dilution, using the van Tieghem hanging-drop method. Of t h e salts used. mercuric chloride had the most marked toxic effect, while potassiuni cyanide was remarkably weak, although it was found that various fungi differ in their resistance to poisons, and that the limits of resistance even vary in the same species. T h e cathions Hg, H, and Cu, atid the anions C N , CrO,, Cr,O, and O H are poisonous, while the halogen ions are not poisonous. I n general, the results were found to be in accord with the dissociation theory. The Physiological Action of Certain Plasmolyzing Agents. BY RODXEYH. TRUE. Rolaalzical Gazelie. 26, 407--416.-The author has studied in the case of spirogyra the physiological action of t h e substances most used as plasmolyzing agents. canesugar, glycerine, sodium chloride and potassium nitrate. H e is
