4 so
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theory, however brilliant its success may be in its first qualitative and roughly quantitatjve garb, must, in order to survive and prove its permanent justification, conform ultimately t o the test of minutely accurate quantitative measurement. This necessary and vital service t o the theory of ionization was undertaken by Dr. Noyes and his associates and has been brilliantly carried out. Last year, in his Faraday address in London, Arrhenius again and again referred gratefully to the value of this work. I t is interesting t o note that this insistence on the utmost limits of accuracy is becoming the most striking characteristic of the genius of our best American scientists: to mention only a few names familiar to all of us. We saw i t in Gibbs in his far-going mathematical analysis of chemical and physical changes; we find i t in Michelson, in Richards, in Morley, in Millikan-and again, tonight, in our medalist. This insistence on accuracy is evident in all of the contributions of Dr. Noyes to chemistry: van’t Hoff developed a method for determining the order of a given chemical reaction, but van’t Hoff’s formula was, after all, not a rigorous one and sometimes left one in doubt as t o the result: a more reliable formula, based on rigorous analysis, was developed by Dr. Noyes and is displacing van’t Hoff’s. Accuracy again characterized the searching work of Dr. Noyes on the sensitiveness of indicators, on the correct use and understanding of which the reliability of so much of our technical and scientific research and practice depends. Undoubtedly it was this same pressing need of accuracy that led Dr. hToyes into the monumental work on which we shall hear him speak tonight: his work on the revision of the methods of qualitative analysis. Bringing to this labor the ardor for exactness combined with a masterly knowledge of the laws of physical chemistry-an advantage not held by his greatest predecessor in this field, Fresenius-Dr. Noyes could be content with nothing less than methods which approach quantitative analysis in accuracy, content with nothing less than a system broad enough t o include ultimately the rare as well as the common elements in its scope. He thus escaped the chance for error inherent in older methods, which results from the setting of limitations not recognized by nature. I cannot close this short review of some of the contributions of our medalist to our science without a grateful recognition of two other important forms of service other than original investigation: Dr. Noyes has been uniquely successful in associating with himself a group of great chemists: Lewis, Whitney, Washburn, Kraus, Bray, Tolman, Harkins are carrying the traditions of accuracy and thoroughness of his laboratory into all parts of our country, in technical as well as scientific fields, in work fertilized by their own brilliant ideas, characterized by the standards of the research laboratory of the Massachusetts Institute of Technology. I n the second place, Dr. Noyes has been and is a great teacher of the young, the undergraduate chemist-to-be: like A. W. Hofmann, in his day the greatest teacher of chemistry in the world, Dr. Noyes has insisted on presenting to the beginners in chemistry the new physicochemical theories in lucid, transparent terms, and, in pursuance of this ideal, he has invented a long series of beautiful lecture experiments on physico-chemical relations-the best we have, which, like Hofmann’s, are now incorporated, more or less consciously or unconsciously, into our best elementary courses. These lecture experiments, like the work on the theory of ionization, like the work on qualitative analysis, have already become classics of American chemical endeavor. To DR. NOYES: In consideration of these great contributions to chemistry by you, Dr. Arthur Amos Noyes, as a n investigator and as a teacher, the Chicago Section of the American Chemical Society decided t o bestow upon you its highest honor, the Willard Gibbs Medal, founded by our service-loving fellow member, Mr. William’ A. Converse. In the name of the Section, I have the
Vol. 7 , No. 5
honor t o present t o you this, the Fifth Willard Gibbs Medal, with the best wishes for, and confidence in, further great productive work on your part on behalf of our common science and country.
ADDRESS OF ACCEPTANCE’ B y ARTHURAMOSN O Y E S
I n replying t o the address of presentation, Dr. Noyes expressed his deep appreciation of the honor conferred upon him, particularly in being placed in a group with the four great chemists to whom the award has been given on previous occasions, and most of all in being presented with a medal given in the name of America’s greatest chemist, Willard Gibbs. He also wished the Section t o know how much more h e valued such an honor on account of the fact that i t came as a token of appreciation from his fellow chemists, of work done in the past. On account of the fact t h a t the work which he described in his address is still incomplete, even although it is finished in all its essential parts, Dr. Noyes has decided that it will be best at this time to publish only a short abstract written by one of the members of the Section. The work when completed will be published in full. The driving force which kept him a t work during fifteen years of investigation was his feeling of the great need of chemists for a systematic scheme of qualitative analysis to include all of the elements. The lack of such a scheme was most vividly impressed upon his mind when twenty years ago he received from Colorado a n ore said to contain uranium. Even by making use of the best methods then available it took three weeks t o determine that the rare element present was not uranium but vanadium. This incident he cited t o illustrate the difficulties which then lay in the path of chemists when they started out to make analyses for the rare elements by using the isolated statements which were all that could be found in the literature a t that time. Now many of the so called rare elements have been found in such large quantities that they are no longer rare. The reason for the omission of these elements from the ordinary scheme for a qualitative analysis is twofold: ( I ) the historical development of analytical chemistry; ( 2 ) the fact that they are more difficult t o detect than most of the common elements. On the other hand, many of these so-called rare elements have come to play an enormously important part in science and industry, and some of them, for example titanium, have been found to be much more abundant in nature than some of the members of t h e group of the 2 1 common elements. I n steel, tungsten, vanadium, and uranium have found a n extensive use; thorium and cerium have come t o be enormously important in the making of mantles for gas lighting, while tantalum, and to a greater extent tungsten, have rendered the same service in connection with lighting by electricity. I n papers already published in the Journal of the American Chemical Society a revision of the usual scheme of analysis for the common elements has been described, and in this a few of the rare elements have been included. In the present scheme the aim has been to provide for the detection of nearly all of the rare elements as well as the common ones, and a t the same time t o develop such detailed and explicit instructions that the results of a n analysis may be certain if carried out by a chemist of ordinary skill. The aim has been to provide a method which will detect the presence of I mg. of any element in a mixture with 500 mg. of any common element or elements, or with roo mg. of any rare element, It is often stated that a qualitative analysis is unnecessary if a quantitative analysis is to be made, and that the former is only a waste of time. That this is not in general true is proved by the fact that many quantitative analyses are made inexact by a failure t o realize the presence of a n ele1 Abstracted, by consent of the author, b y Professor William D. Harkins. of Chicago University.
M a y , 1915
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ment which would have been detected easily by the use of the proper methods of qualitative analysis, while on the other hand a qualitative analysis can be so conducted as to enable the proportions of the various elements to be estimated roughly, thus making in many cases a quantitative analysis superfluous. A former president of the society, Mr. Dudley, spoke on the dignity of analytical chemistry, and now it is necessary that the dignity ofqualitative analysis in particular should be upheld. Why is qualitative analysis so much discredited? This is due to the slack methods usually used in teaching the subject. Thus the manipulation is not given such painstaking attention as is considered necessary in the teaching of quantitative analysis. I n general, in making a qualitative analysis according to the system advocated, I g. of the sample is used, since in this case I mg. is equal to I per cent. However, the strict adherence to the rule that I mg. should be detected, is somewhat irrational, since the results of a test depend upon the number of atomic weights of an element present, rather than upon its weight in grams. The idea of the present presentati’on of the subject is not to give a method for making a qualitative analysis, but to show rather the character of the research. The systematic treatment of the analytical schemes must be left for the final papers. A great deal of attention has been paid t o an investigation of the methods for the preparation of the solution. hTitric acid is used for the solution of the substance rather than hydrochloric since the latter gives the volatile chlorides or arsenic, germanium, and selenium, and also mercuric chloride, which is somewhat volatile. For the solution of the insoluble residue, hydrofluoric acid is used rather than fusion with carbonates, since the former method not only introduces less foreign sub-
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stance, but a t the same time it removes silicon. This residue is treated with hydrofluoric acid, and then evaporated with nitric acid. After this nitric acid treatment, tin, antimony, tantalum, columbium, titanium, and tungsten are left in the form of insoluble compounds, and the platinum metals and certain iron alloys are found to remain largely undissolved. The residue is heated with hydrofluoric acid, and after filtration the residue of metal is fused with sodium peroxide, which may now be obtained pure, and osmium is distilled off as 0~01. The solution is evaporated, concentrated hydrobromic acid is added, and arsenic, selenium, and germanium are distilled off as bromides. This process of distillation is, contrary to the usual opinion, somewhat quicker than the application of methods of filtration. Silver is left in the form of bromide. Some of the most marked deviations from the usual method of procedure may be mentioned. Thus for the precipitation with hydrogen sulfide the solution is first saturated with the gas in a bottle, a cork is inserted tightly, and the corked bottle is heated for ‘/2 to I hour in boiling water. Arsenic, antimony, and tin have been removed before this; the platinum metals cannot be completely removed by ammonium sulfide, so the treatment with this latter substance is not used. I n a later part of the analysis, T i 0 2 is removed from a residue containing Ta20j,and CbnOs, by boiling with potassium salicylate. The work has now proceeded so far that fairly good separations have been devised for almost every group, and considerable success has been attained in separations of certain of the rare earth elements. Those who have worked on the rare earths have neglected too much methods of separation which depend upon the fact that a number of these elements are capable of existence in several stages of oxidation.
NOTES AND CORRESPONDENCE NOTE ON REVIEW OF DR. THOMPSON’S “OCCUPATIONAL DISEASES”
Editor of the Journal of Industrial and Engineering Chemistry: M y attention has been called to a review,’ by W. A . Hamor, of Dr. W. Gilman Thompson’s recent work on “Occupational Diseases, etc.” In this review the statement is made that ‘‘ ‘Brass Founders’ Ague’ is more likely due t o the inhalation of zinc oxide and not zinc fume.” This statement is based on visits made t o brass foundries, but zinc works, where this metal is handled in large quantities, were not visited, and those connected with such works, whose opinions and experiences would have been of value, were not consulted. For the past seven years I have been surgeon to one of the largest zinc plants in the country, and have just finished making a thorough physical examination of all of the employees. With this experience I have no hesitation in saying that I have never seen a case of illness which could be directly attributed to zinc. Sir Thomas Oliver2 states that zinc is non-toxic and described symptoms seen among brass founders which resemble those which he has seen in workers in copper, especially gastro-intestinal symptoms. Though he states that copper workers seem t o be “as healthy as persons following other occupations elsewhere,” he distinctly states that copper gives rise to acute attacks of illness, and also states “that animals exposed to oxide of zinc in the form of dust or who receive it in their food over a length of time” show no signs of poisoning. In his visits to the large smelting works a t Bleiberg, Belgium, he could not find any evidence of ill-health among the workmen traceable to the zinc itself. 1
THISJ O U R N A L . 6, (1914). 871-2.
2
“Diseases of Occupation,” 1907.
Rambousek, Professor of Factory Hygiene and Chief State Health Officer a t Prague,’ states that “Industrial poisoning, from zinc is unknown. The chronic zinc poisoning among spelter workers described by Schlockow, with nervous symptoms, is undoubtedly to be attributed to lead.” Armit2 claims having seen a similar syndrome in the case of the inhalation of nickel-carbonyl, iron-carbonyl and cobalt fumes. It is generally conceded that copper has a toxicity, though according to Lehman (quoted by Rambousek) “opinions are divided on this point.” The experience of C. A. Hansen, of the General Electric Company, is worth giving in extenso: “We have just had an experience here that seems to warrant the publication of this warning to any one who contemplates working with copper, in the electric arc furnace. “We melted 5000 lbs. of electrolytic copper scrap-uncontaminated except for a small amount of admixed iron-in a threephase arc furnace of the ordinary steel furnace type, the experiment lasting some five hours. A few hours after pouring off, all of the ten men in the furnace building suffered inconvenience in breathing. For the 24 ensuing hours severe nausea was experienced in each case and a soreness throughout the entire system similar to that of acute grippe. “Since in all other respects the run resembled an ordinary steel run, I attribute the trouble we experienced to copper which was shown t o be present in the furnace fumes. The temperature of the copper bath as a whole a t no time exceeded 1300’ C., so that probably the copper was volatilized only a t points directly beneath the electrodes. Rambousek. “Industrial Poisoning,” 19 13, translated by Sir Thomas Legge, p. 151. “Toxicology of Nickel Carbonyl,” Journol of H y g i e n e . 7 (1911), 525-551; I b i d . , pp. 565-600.
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