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that the dean has not allowed the making of a distinguished career in chemistry t o interfere in the least with the making of a very human individual. And it is this that brings us to what is perhaps the most delightful sidelight of his personality, and a t the same time explains one of the principal causes of his successful career. Throughout all the years that he has labored as a teacher and a scholar he has never allowed his broad sympathies to become dulled, nor has he become pessimistic regarding the continued progress of society. He has watched its changing ideals and has been confronted with the disquieting restlessness of modem youth, but his kindly sympathy and his innate conviction regarding the permanence of right principles and ideals have made him an optimist in his own home and out of it.
Vol. 23, No. 3
Doctor Coates has published a large number of valuable papers, but these publications represent but a fragment of his contributions in the form of collaborations with committees and individuals in various chemical fields. I n the Audubon Sugar School he formulated what was possibly the first course in chemical engineering offered in this country. He was probably the first to publish work on the “air activation of chars.” For many years Doctor Coates has been Councilor for the SOCIETY. He is Louisiana Section of the AMERICANCHEMICAL an honorary member of Alpha Chi Sigma, a fellow of the American Institute of Chemical Engineers and of the A. A. A. S., and a member of most of the chemical societies. u’.I,. OWEN
NOTES AND CORRESPONDENCE History and Development of the Modern Yeast Industry
Cs = 0.300
+ 0.00120t” C.
This formula is probably better than Mr. Schaphorst’s for extrapolation purposes, since it is known that the specific heat of the liquid rises rapidly as the critical temperature is approached. H. 0. FORREST E. W. BRUGMANN L. W. CCMMINGS
Editor of Industrial and Engineering Chemistry: I n his interesting paper under the above title ~ I x DENG. . CHEM.,22,1154 (1930)], C. N. Frey discusses the use of molasses as a source of carbohydrates, which, in his opinion, had not been successful until 1915, when Hayduck and also Wohl investiRESEARCH LABORATORY OF APPLIEDCHEMISTRY gated the production of yeast from molasses and ammonia. MASSACHUSETTS ‘INSTITUTE OF TECHNOLOGY I wish t o draw the attention to the fact that, more than twenty CAMBRIDGE, MASS. years before, H. Elion, of The Hague, succeeded in devising a January 24, 1931 process for producing a baker’s yeast of high quality from molasses. This process, Which was patented in several countries in 1895, is employed industrially on a large scale and was of especial use during the war [compare 2. angev. Chem., 39, 1584 Editor o j Industrial and Engineering Chemistry: (1926); J. Inst. Brewing, 36, 334 (1930)l. L. ELION The article under this title by M. J. Dorcas in the Novem’ber, 8 YPERSCAESTRAAT 1930, issue has a paragraph on the “Importance of Selecting SCHEVENINGEN, HOLLAND January 10, 1931 Proper Light Source,” which seems to give an incorrect impression of probable industrial conditions. Dorcas states that “most reactions have a uniform quantum efficiency,” and calculates that under this condition the energy requirement will be a minimum a t the lowest effective frequency (longest wave length). He concludes that “if cost of energy is an important Editor of Industrial and Engineering Chemistry: factor in the process, efficiency demands that the energy be I n reading the article by H. 0. Forrest, E. W. Brugmann, and ENG.CHEM.,23,37 (1931)], it seemed supplied with radiation of the longest wave length capable of L. W. T. Cummings [IND. causing the reaction.” to me that a good approximate formula on the specific heat of This statement is justified only when there is a constant quandiphenyl would be welcome. Consequently, I propose the tum efficiency and a constant absorption of radiation energy, following based on the curve of test results, Figure 5, shown on both independent of wave length, since the energy required by page 39: the reaction must be calculated on the basis of quanta absorbed, 0.001t 0.32 = specific heat while the cost is determined by the energy incident on the syswhere t = temperature of diphenyl in degrees Centigrade. tem. For example, the formation of vitamin D from ergosterol Of course this formula applies only to the temperature range has been shown by Marshall and Knudson [ J . Am. Chem. Soc., between SO” and 360” C., as shown on the curve. 52, 2303 (1930)] to have a constant efficiency of about 0.3 mol W. F. SCHAPHORSTpa- quantum absorbed over the range 3022 to 2300 A,; but 4 5 ACADEMY ST. because of variation in absorption, Fosbinder, Daniels, and N E W A R KN. , J. January 9, 1931 Steenbock [ J . Am. Chem. Soc., 50, 923 (1928)l found that the incident energy necessary forothe same effect was eleven times as great a t 3020 as a t 2650 A. Editor of Industrial and Engineering Chemistry: Constant quantum efficiency, independent of wave length, The formula which Mr. Schaphorst proposed lies below the can hardly be said to be characteristic of most reactions. The data through practically the whole temperature range, and in following extracts from Kistiakowsky’s “Photochemical Procthe worst case, a t 260’ C., gives a value of the specific heat of ess” summarize the evidence: diphenyl which is 7.2 per cent too low. We suggest the following linear formula for the specific heat According to the Einstein-Stark equivalence law, the rate in the range 80’ to 300” C., which agrees with the data within of a photochemical reaction in light of different wave lengths the experimental error: must vary as the number of absorbed light energy quanta. Ex-
Ultra-VioletRadiation in Industry
A Formula for the Specific Heat of Diphenyl
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March. 1931
I-VD r S T R I A L AA’D ENGINEERING CHE-WISTRY
perimentally, this prediction of the law has only been confirmed with a small number of photochemical reactions. All these reactions possess other simple kinetic relations, approaching closely the requirements of the equivalence law, as, for instance, the independence of the rate from the concentration of the reactant, more or less complete absence of catalytic influences, small temperature coefficient, and a quantum yield not far from unity. A higher effectiveness of larger light energy quanta has been frequently observed. Numerous illustrations in Chapter VI of this monograph show how rapidly the quantum efficiency may decrease with increasing wave length; such a decrease is especially probable in the case of chain reactions, which have the greatest photochemical sensitivity. The wave length for maximum energy efficiency must be determined for each individual case; but for the rather complex reactions such as are listed by Dorcas as of present industrial importance, the above considerations make it obvious that this wave length is usually well below the threshold value. BURTH. CARROLL BUREAU OF STANDARDS WASHINGTON, D. C. December 29, 1930
Editor of Industrial and Engineering Chemistry: Mr. Carroll objects to a statement that “most reactions have a uniform quantum efficiency” and the deduction from this that
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it is most efficient to use energy of as long a wave length as is capable of performing the desired reaction. He cites a number of instances where carefully studied reactions show that this does not hold exactly. In any case where the reaction has been thoroughly investigated the data so obtained must be used to determine the most efficient method of supplying radiation to cause this reaction. Other details must also be considered, such as concentration of materials, duration of exposure, and presence or absence of air or other reacting materials. I n the absence of this specific information, however, we can accomplish most by assuming that any given reaction obeys the laws that are supposed to apply to photochemical reactions, which leads us to the statements made in my paper. In many of the industrial reactions that have been carefully studied, it has been found that by using very short wave radiation antagonistic reactions or undesirable side reactions occur that put a practical limit to the range of frequencies that can be used to best advantage. Occasionally a slower rate or less efficient utilization of radiation corresponding to longer wave lengths is more desirable to use, even though the particular case be one where it is known that slight increased quantum efficiency is obtained by radiation of high frequencies.
M. J. DORCAS NATIONAL CARBON COMPANY, INC. CLEVELAND, ORIO January 20, 1931
BOOK REVIEWS Elements of Chemical Engineering. BY WALTER L. BADGER AND WARRENL. MCCABE. Chemical Engineering Series. 625 xvii pages. McGraw-Hill Book Company, Inc., New York, 1930. Price, $5.00.
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The first thing that impresses one when he opens this volume is the number and the excellence of the illustrations. In an introductory textbook illustrations of the type found here are of importance second only to the subject matter. With 314 original line drawings of exceptionally good workmanship scattered through its pages, the book stands almost in a class by itself in this respect. But good illustrations are by no means the only merit. The various unit operations of chemical engineering are well presented. The authors have not hesitated to use the language of mathematics where such was desirable, but they have kept always in mind that this is a book presenting the elements of chemical engineering, wherein it is neither necessary nor desirable to demonstrate the full power of mathematics in dealing with engineering data. In reviewing such a book as this, there naturally comes t o mind the great pioneer work, “F’rinciples of Chemical Engineering,” which attempted, for the first time, a fairly broad treatment of a considerable group of the unit operations of chemical engineering. Since this older book is so well known, the new book now under review, covering about the same field, will probably be examined by most readers with the older book as a sort of measuring stick. The unit operations chosen for treatment in “Elements of Chemical Engineering” are necessarily about the same as those selected by Walker, Lewis, and hlcAdams, but there are some notable differences. For instance, the Badger and McCabe book includes a chapter on pumps and pumping and one on crystallization. The intluence of the older book is, however, clearly discernible in the newer one, and such resemblance as exists is a tribute to the older work; but there is a vigorous independence of thought and presentation running through the new book which gives it a character of its own. With no wish to review the faults of the Walker, Lewis, and McAdams book, which are several, nor its merits, which are many, the reviewer ventures the statement that Badger and McCabe have produced a book distinctly superior in several respects to the older work, and that the ground covered in the two books is much more nearly the same than admitted by Badger and McCabe in their preface. In the re-
viewer’s opinion Badger and McCabe’s book is incomparably the best introduction to chemical engineering yet published. No doubt “Principles of Chemical Engineering” will continue to find a wide use, particularly those parts of it which give a more extended theoretical treatment of unit operations than was permissible in the present volume. A particularly happy development now would be such a revision of “Principles of Chemical Engineering” as would make it frankly a more advanced treatise in which a knowledge of the “Elements of Chemical Engineering” would be assumed as a prerequisite.-HARRY A. CURTIS AND E. C. BAIN. 173 High Speed Steel. BY hl. A. GROSSMAN pages. 111 figures. John Wiley and Sons, Inc., New York, 1931. Price, $3.50. High-speed steel is a complex alloy, containing carbon, tungsten, chromium, vanadium, and often cobalt, besides the usual impurities of iron. Its metallurgy has been correspondingly complex, and the general conception of what goes on in its heat treatment has been a patchwork quilt put together from many isolated articles and observations. Grossman and Bain have vastly clarified the situation by drawing an ingenious analogy to straight carbon steel and putting the metallurgy of high-speed on a comparable basis to that of a less complex steel. Hence, anyone who has a grasp of the principles of the heat treatment of ordinary steel can read this book with ease and understanding. Many professors of metallurgy who have struggled to get some idea of this complex system into the heads of their students will rise up and bless the authors. The man who is practically concerned with the production, treatment, and use of high-speed steel will be equally appreciative. Much “high-brow” stuff on x-ray spectra, expansion curves, and equilibrium diagrams is utilized in setting forth the story, but i t all comes in so naturally and patly that the practical man can assimilate it readily. The description of melting and working shows very detailed acquaintanceship with the processes, and clearly brings out why each precaution is necessary. It is a highly authoritative treatise from cover to cover. It will be the backbone of the high-speed library of every metallurgist a t all interested in the subject. The codification of scattered facts and the clarification of ideas on a subject so important in science and practice is a great service. If ever a book was worth $3.50 to a metallurgist, this is.H. W. GILLETT
