November, 1930
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AMERICAN CONTEMPORARIES Louis Munroe Dennis
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H E long and distinguished career of Professor Louis Mun- planning of new laboratories of chemistry. He is recognized as roe Dennis as teacher, investigator, and administrator the world leader in this field. An important contribution made by Professor Dennis in the a t Cornell University started in 1887, when he accepted a n instructorship in chemistry, after having received two de- field of industrial chemistry that resulted in a substantial degrees a t the University of Michigan. Two years later he left crease in the cost of manufacturing synthetic phenol was his for Europe, where he pursued advanced studies until 1891 in invention and development of a novel process for the sulfonaMunich, Dresden, Aachen, and Wiesbaden. tion of benzene. This process was adopted by the War Department of the United States in 1917. I n the early days a t Cornell he gave In recognition of his world-wide reputainstruction in the fields of m e t a l l u r g y , tion as a scientist and an educator Colgate qualitative and quantitative analysis, gas University in 1923 bestowed upon Proa n a l y s i s , and chemical spectroscopy, in fessor Dennis the honorary degree of docthe last two of which he was the pioneer tor of science. A similar honor was conin America. For fourteen y e a r s he lecf e r r e d upon him by the University of tured before large classes in introductory Michigan in 1926. chemistry, and for a much longer period During the twenty-seven y e a r s of h i s he has given lectures in a d v a n c e d inservice thus far as head of the department organic chemistry, with especial emphasis upon the rarer elements. An ardent adof chemistry, Professor Dennis has given continual evidence of marked ability as an vocate of v i s u a l instruction, P r o f e s s o r organizer and executive. Under his able Dennis will always be remembered by his guidance the department has shown steady s t u d e n t s and colleagues, not only as a progress, not only in material things, but most interesting and inspiring lecturer and also in academic work and in productive user of the purest English but also as an scholarship and research. Important mileexpert manipulator of apparatus upon the lecture table. stones in academic progress have been the organization, in 1910, of a four-year course He has always strongly and rightly insisted that the university teacher of chemleading to the degree of bachelor of chemistry and, during the year just passed, of a istry should carry on independent research five-year course in chemical e n g i n e e r i n g as well as his work of teaching. His own under the joint administration of the Deresearches have been confined to no narrow L. M . Dennis line, although the greater part of his work partment of Chemistry and the College of has been in the field of the rarer elements He was the first Engineering. The establishment of the George Fisher Baker in America to work with hydronitric acid and its compounds h’on-Resident Lectureship in Chemistry a t Cornell University and has made notable contributions to the chemistry of the rare is the direct outgrowth of the plan, conceived and executed by earths, and of gallium, indium, selenium, and tellurium. More Professor Dennis, to bring to America each semester one of recently his interest has centered chiefly upon germanium, Europe’s leading scientists. and an extended series of articles from his pen clearly entitles Among the students, in whose welfare and development he him to the rank of leading authority in the world in this field takes a genuine and constant interest, Professor Dennis comtoday. He is also beyond question the foremost inorganic mands the highest respect, not unmixed, perhaps, with a little chemist in America. awe, which has earned for him the sobriquet of “King.” AnyThe methods of instruction in research practiced by Professor one who has seen him in action knows that he is a “live wire” Dennis, and his criteria of “publishability” are familiar to all and a “go-getter” in the best sense of these terms. So high who have enjoyed the privilege of working under his efficient a valuation is set by him upon the achievement of results, that direction. A piece of work must be “thoroughly rounded out” he has but little patience with the delinquent, the excuse maker, to meet his approval. The successful careers of scores of young or the “alibi hunter.” His oft-repeated “Do it now!” has acmen in the teaching profession and in the industries pay elo- celerated many a laggard pace and aroused many a dreaming quent tribute to his skill as a director of scientific research and mind. as a teacher of the methods of investigation. Professor Dennis is most emphatically not a seeker after Professor Dennis is the author of several books, including publicity or notoriety. This, however, does not explain his “Chemical Problems in Inorganic Chemistry” (1890), “Ele- rather frequent absences from national meetings of the AMERICAN mentary Chemistry,” and “Laboratory Manual of Elementary CHEMICAL SOCIETY.He is very fond of associating with his Chemistry” (with Frank 1%’. Clarke, 1902), “Manual of Quali- fellow chemists and other fellow men. rln unfortunate accident tative Analysis” (with Theodore Whittlesey, 1902), “Gas Analy- in his research laboratory years ago resulted in an impairment sis” (1913, with M. L. Nichols, 1929), “The Baker Laboratory of his hearing so serious as to render difficult, if not quite imof Chemistry a t Cornell University” (1923), and is the translator possible, active participation in public discussion. The exof “Methods of Gas Analysis” (Walther Hempel, 1902). tent to which he has overcome this handicap in his daily life Since 1895 he has been profoundly interested in all matters attests the strength of his character and the power of his will. pertaining to laboratory design and construction, and his counsel Although a thoroughly loyal and public-spirited Ithacan and has been eagerly sought by representatives of many colleges, American, who has on various occasions given freely of his time universities, and other organizations in connection with the and expert knowledge for the benefit of his community and his
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country, Professor Dennis may be regarded as a true “citizen of the world,” who “knows his Europe” as do few Americans. He has crossed the Atlantic many times, and has in the aggregate spent many months in touring various parts of England and the continent. In his numerous avocational interests Professor Dennis has displayed energy and skill of an order comparable with that shown in his professional work. As a young man he excelled in baseball, tennis, and boxing, and sang second bass in his college glee club. His remote Scotch ancestry may be in part responsible for his later proficiency in golf, his keen business insight, and his canniness as a purchaser of laboratory equipment and supplies, and perhaps even for his dignified disapproval of Volsteadism. He is one of the most skilful local players of pool, billards, and bridge.
Vol. 22, No. 11
A fitting climax to the long series of constructive achievements that marks the career of Professor Dennis is afforded by his conspicuously successful work in planning the magnificent Baker Laboratory of Chemistry a t Cornell. His was the master mind chiefly responsible for the intricate design of this edifice, in which have been incorporated the ideas and ideals accumulated by him over a period of more than half a lifetime of observation and study in America and Europe of the principles of laboratory design and administration. The Baker Laboratory stands as a monument t o the constructive genius and executive ability of Louis Munroe Dennis. To but few men has been vouchsafed a memorial so lasting and so truly characterizing their life work as this! A . W. BROWNE
NOTES AND CORRESPONDENCE Vapor Pressure and Heat of Vaporization
Carbon Black in Rubber Insulating Compounds
Editor of Industrial and Engineering Chemistry: I n a paper by Nutting which appears on page 771 of the July AND ENGINEERING CHEMISTRY, the equation issue of INDUSTRIAL L = A ( T , - T)” is put forward as new. I t has, however, previously been suggested by Thiesen, Verhandl. deut. Physik. Ges., 16, 80 (1897) ; Kendall, Medd. Vetenskapsakad. Nobelinst., 2, No. 29 (1912), No. 36 (1913); Hemptinne, Bull. sci. mad. TOY. Belg., [5] 12, 296 (1926); and Winter, J . Phys. Chem., 32, 576 (1928). The use of a factor which vanishes for T = T , is common to many empirical latent-heat formulas; L , of course, vanishes a t the critical point. The fact that L varies slowly with T can be reproduced by taking a fractional power of the factor. With regard to similar surface-tension formulas to which Nutting refers, it has been shown by Sugden, J . Chem. Soc., 125, 32 (1924), that for a number of non-associated liquids the classical van der Waals expression for the variation of surface tension with temperature may be written y = K ( l - T/T,)’.* = KI(T, - T)’.2 T. S. WHEELER ( K ,K1 are constants).
Editor of Industrial and Engineering Chemistry: In an article under the above title by W. B. Wiegand and C. R. Boggs, which appeared in the August issue of INDUSTRIAL AND ENGINEERING CHEMISTRY, the statement is made: “carbon black may be incorporated in a dielectric such as rubber without detracting from its insulating or dielectric properties. Published results to the contrary were in error, probably because the material was added in excessive amounts.” The “published results” were those of the authors of this note [Bur. Standards, Tech. Paper 299, 713, 720, 721, 7221. I4 I3
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6 WALNUTAVE.
HARTFORD, CHESHIRE,ENGLAND August 28, 1930
Editor of Industrial and Engineering Chemistry: It appears t h a t a relation between heat of vaporization and temperature, given as new near the close of my paper on vapor pressure, has already reached a respectable middle age and the dignity of repeated discovery. I am indebted to Professor James Kendall and to Mr. Wheeler for calling my attention to the fact. It is indeed surprising that a relation so simple, so logical, and so useful should not have found a place in our standard reference texts of thermodynamics and of physical chemistry. Both surface tension and heat of vaporization are obviously simple functions of energy of association and therefore of the temperature measured downward from the critical temperature. Numerical data fit this formula very closely over a wide range of temperatures. Still it finds no place in texts devoting pages t o outworn and empirical relationships. P. G. NUTTING U. S. GEOLOGICAL SURVEY D. C. WASHINGTON, September 27, 1930
c
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3 7 a g6 u
g 5 I-
24 A W
E 3 2
Figure 1-Effect
of Carbon C o n t e n t on t h e Dielectric Constant of Rubber
We wish to point out that our results are not contrary to those of Wiegand and Boggs. When both sets of results are plotted on the same scale, as is done in Figures 1 , 2 , and 3, they show substantially the same effect of carbon black on the electrical properties. The only discrepancy is that their results show a small lowering of the power factor with certain proportions of carbon, which our published results do not show. This agreement is
