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T H E JOURNAL OF I N D U S T R I A L A K D EAVGISEERIiYG C H E 3 I I S T R l ’ .
Fifth.-“They advise the use of aluminum for the reduction of iron, but do not mention that commercial aluminum usually contains enough iron t o cause a serious error.” More careful revieTying would have made it evident t h a t the authors specifically mention this fact under Iron, page 83, line I : “To the solution in the six-oz. flask, .add 2 grams of pure aluminum sheet or drillings. Weigh this fairly accurately, as ell aluminum contaitzs a littb iron which must be deducted jrom the total iroit found,” and, again, on page 84, line 8: “A small correction must be applied t o the burette reading to allow for the amount of permanganate used to produce a pink tint in a blank solution containing the same amount of aluminum and the same amount of acids and water used but without any iron wire.” “Dissolve two grams of aluminum, etc.;” “Subtract the correction thus obtained from every burette reading.” Sixth.--“In the description of the volumetric method for zinc, they do not lay enough stress on the necessity of keeping all conditions uniform. Variations in the temperature, acidity, and amount of ammonium chloride present, all affect the end point.” In this connection, i t did not seem necessary to burden the reader with all of Waring’s different experiments and results connected with the temperature, acidity, and amount of ammonium chloride present, especially as the amounts of hydrochloric acid, ammonium chloride and temperature, as given on pages 141 t o 145,inc., are exactly the same as the conditions given by Waring to insure accurate results after he had investigated the effect of temperature, acidity, and amounts of ammonium chloride on the end point. It is to be regretted that this book could not have been reWnf. B. PRICE. vielved with more care.
June,
1912
iridium; the other end of the silica tube was drawn out for connecting Tvith the pump and sealing. It was exhausted to a high vacuum and heated to near redness along its whole length till all moisture and occluded gases had been removed; it was then sealed off, and placed in the furnace in such a position t h a t the iridium would be a t the point of greatest heat. The bulb was kept a t a temperature of 1,300’ for 30 hours. On examining the silica tube when cold it was seen that the longcontinued high temperature had caused the bulb and the upper part of the tube to devitrify and become white and translucent and that it had a n irregular black deposit on the lower part, which proved to be metallic iridium. LONDON, March 13, 1912.
CHEMISTRY AND THE LITHOGRAPHIC INDUSTRY
I
Edztor Journal 0) Industrial and Engtneeving Chemistrj : The article in the January number by Nr. W. H. Watkins strongly appealed t o the writer, who may be classed as a chemist in one of the industries in which “there are almost no chemists.” A few years ago my attention was directed t o the lithographic industry as one involving chemical processes to a large extent. These processes, almost without exception, had developed by rule-of-thumb methods and were entirely without technical control. A given operation would be successful one day and unsuccessful the next, depending on the “luck” of the operator. After carrying on research work for some time to convince myself that the rule-of-thumb man was not always correct in his methods and deductions, I laid some of the laboratory results before a lithographic firm for its consideration. The SCOVILL~IA~XUFACTURING Co. work of demonstrating the advantages of chemical control in May, 1912. this particular line of manufacture, although somewhat slow a t the beginning, was eventually convincing. A laboratory VOLATILITY OF METALS O F THE PLATINUM GROUP. was installed in the plant, and actual work begun. Changes During the reading of a paper on “The Volatility of Metals of the Platinum Group,” read before the members of the British were made in the processes one after another. Not only in the Royal Society in March, Sir William Crookes narrated some testing of raw materials but more especially in modifying some observations which indicate t h a t platinum is not so entirely of the time-honored practices, the work met with considerable fixed a t temperatures well below its melting point as has been opposition from the “practical” man who had done it the old way for so many years. The attitude of some of the men conuniversally accepted by chemists and physicists. cerned in these changes was well described by Mr. A. D. Little I n using an electric furnace consisting of a coil of platinum ribbon contained in a porcelain tube he found t h a t in time the in his recent lecture on “The Earning Power of Chemistry.” ribbon grew thinner till it melted a t the weakest part. When They certainly took no pains t o conceal their “militant skeptit h a t happened he noticed that the porcelain tube was coated cism.” To-day this laboratory, with its system of control, is a n integral part of the factory and is regarded as one of the with a fine dust of beautifully formed crystals of brilliant metallic luster, which on analysis proved to be platinum. It essential departments. It is of the utmost importance in work of this character for therefore seemed of interest to subject a platinum crucible to a temperature approaching t h a t to which the platinum resist- the chemist to familiarize himself as rapidly and as completely ance coil had been exposed. A crucible was heated to 1 , 3 0 0 ~ as possible with the details of the manufacturing prxesses. C. in the electric furnace for 30 hours when the loss of weight While often wrong from the standpoint of the theory-shrouded amounted to 0.245 per cent. Palladium, treated in the same technical graduate, the practical man may be nearly correct way, lost 0.745 per cent. in 30 hours. An iridium crucible lost as far as he goes, but the chemist, or chemical engineer, can over 7 per cent. in weight after 2 2 hours a t 1,300°, and a t greater investigate the problem more thoroughly and by properly heat, loss of weight for equal periods of time was proportional classifying the data a t his disposal obtain the desired results. to temperature. After this severe treatment, the crucible, The work of both these men can be materially lightened by which had taken on a crystalline appearance over the whole consistent cooperation. I n the lithographic industry, as well surface ivhen the series commenced, began to show disinte- as in industries where chemists are more generally employed, gration along its edges and pieces began to crumble when touched the chemist should bear in mind t h a t in addition to his more with the forceps. With rhodium, a metal intermediate in specific duties he must endeavor to become an efficiency expert. fusibility between platinum and iridium, the loss in 30 hours This feature of his work is sure to attract the attention of the manager of the varnish, ink, or paint works, as the case may be, was 0.13 per cent., not far from t h a t of platinum. Experiments were then made a t 900’ by heating the metals whereas the more technical details would pass unnoticed. in a flame of a good Mkker burner. Platinum and rhodium Whether i t be the mere routine testing of finished products or after heating for 20 hours showed no loss of weight, but pal- the perfection of methods for the profitable utilization of waste, ladium in I O hours lost 0.0919, and iridium in 20 hours lost the progressive manufacturer is not going to rely upon “the fellow who doesn’t know any better.” He is realizing more 0.091 per cent. I n an experiment to see whether iridium would volatilize a t each year the need for technically trained men. Men trained a high temperature in a vacuum, a fused silica tube had a bulb in chemistry should force their way into w . z e industries if this blown on the end. In the bulb were put 27.619 grains of clean “century of chemistry” is to be realized. To use an expression
