SCIENCE
CATALYSIS IN THEORY AND PRACTICE. By Eric K. Rideal and Hugh S. Taylor. Macmillan & Co. 17s. net.
In spite of the difficulties which war-time placed in the way of publishers, the production of scientific books, both in England and Germany, has been astonishingly large during the past five years. The greater number of them have—naturally enough—been devoted either to technical subjects or to branches of science having an immediate technical application. The field of industrial chemistry, especially, has been well tended by the writers, and not only new books, but new series of books—such as Messrs. Longmans' Monographs on Industrial Chemistry, Messrs. Churchill's Textbooks of Chemical Research, and Messrs. Baillière, Tindall, and Cox's Industrial Chemistry series—have appeared to bear witness to the activity of the English chemists. Certain subjects in particular have been extensively treated; we may instance synthetic colouring matters, colloid chemistry, and catalysis, the last-named subject having books devoted to it in all the series just specified. In these the subject is handled from the industrial point of view, but it is frequently seen that the commercial and the theoretical developments of a science are mutually stimulating, discoveries made in the laboratory without any object but the wresting of knowledge from nature finding commercial application, and the commercial processes suggesting fresh theoretical problems. The great industrial importance of catalysis has led to a revived interest in the scientific theories of the process, and the latest book on the subject, by Drs. Eric Rideal and Hugh Taylor, deserves praise for having devoted considerable attention to the historical and theoretical aspect of the subject, which has been rather neglected of late.
There are many chemical reactions which are promoted or accelerated by the addition of a small quantity of some foreign substance which is not used up in the process and does not appear in the final products. Thus one of the romances of chemistry was the discovery, occasioned by the chance breaking of a thermometer in the vessel, that the presence of a small quantity of mercury greatly hastens the oxidation of naphthalene to phthalic acid, a process of great importance in the manufacture of synthetic indigo. Similarly the presence of finely divided metals accelerates many reactions, such as oxidations and hydrogenations—for example, asbestos impregnated with particles of platinum promotes the oxidation of sulphur dioxide to the trioxide in the manufacture of sulphuric acid. The researches of Baker and others, showing that certain gas reactions, which ordinarily take place rapidly, proceed very slowly indeed if the gases are thoroughly dried, point to a catalytic action of small traces of moisture. The enzymes of the human body which accelerate the chemical processes of digestion and assimilation constitute another class of catalysts, and Drs. Rideal and Taylor class under catalytic action the effect of radiant energy in promoting such combinations as that of hydrogen and chlorine, although it is perhaps rather extending the usual conception of the term to do so. These examples will indicate the wide range of the subject and help to make intelligible Ostwald's famous generalisation that "there is probably no kind of chemical reaction which cannot be influenced catalytically, and there is no substance, element, or compound which cannot act as a catalyser," which is no doubt true if very slight accelerations of reaction be taken into account. Of course a catalyst cannot affect the final state of equilibrium, but only quicken or institute (the discussion as to whether, in some cases, the catalyst initiates or merely accelerates a reaction already taking place imperceptibly slowly seems to us pointless) a reaction theoretically possible. Other, the so-called negative, catalysts hinder reactions; other substances "poison," or stop, the action of ordinarily activating materials; others again, the "promoters," increase the efficacy of the catalyst. The phenomenon is a complex one.
By no means the least interesting and valuable feature of the book before us is the exposition of the historical development of the subject. We who are apt to look on the feminine scientist as a product of the last twenty years are reminded that there was at least one woman chemist of ability in the eighteenth century, Mrs. Fulhame, whose Essay on Combustion, published in 1774, emphasised the importance of the presence of moisture in gaseous reactions. Faraday, "the prince of experimenters," also worked on catalysis, and, in fact, originated the adsorbtion theory of the process, which attributes the action to the extended compressed film formed at the surface of a porous solid. It is not only in the chapter expressly devoted to the early history that we find an account of the original workers; the advances made by them receive recognition throughout the book in connection with the branches in which they experimented. The treatment of the various theories of catalysis—the intermediate compound, the adsorbtion, electrochemical, and radiant energy theory—might have been extended with advantage. The mathematical exposition of the adsorbtion theory is one of the weakest things in the book, and McLewis's work is not very clearly handled. The difficulties of giving an adequate summary of this part of the subject are undoubted, but the need of it is so marked that we regret that the authors have not spent more energy on the task. This is not the place to deal in detail with the account of the practical applications of catalysis, which is excellently done and includes the most recent work, some of it, such as Partington's improvements in oxidising ammonia, only made public last year. The use of catalysts in, to take a few examples at random, surface combustion, the hardening of oils by hydrogenation (used so extensively in margarine making), the fixation of nitrogen, and electrolysis is well described, and there is a good chapter on ferments and enzymes, and another on the Grignard reagent. Omissions may be noted here and there, but the book is not, of course, intended to give detailed instructions to the commercial chemist. Rather, we believe, is it meant to supply to chemists in general, and even to the lay reader, an idea of the nature of the process of catalysis, which is becoming more important every day, and the extent of its applications, with sufficient detail to make the reactions clear, as far as they are at present understood. As a general exposition of the subject the book is really needed, and will undoubtedly find a place on the shelves of all who follow the advances of science.
TEN BRITISH PHYSICISTS. By Alexander Macfarlane. John Wiley & Sons, and Chapman & Hall. 7s. 6d. net.
Writing of the life of Rankine, Professor P. G. Tait gave as his opinion that "the life of a genuine scientific man is, from the common point of view, almost always uneventful," and, if the man in question has no interests but science, this is, in general, true. Engaged in researches on the laws of nature, the most that he demands from life is that he shall have his study, his laboratory, food, shelter and peace, and such an attitude does not lead to high adventure or romances of passion. Consequently, in writing biographies of physicists it is advisable not to dwell too long on their everyday life, marriages and meals, for there is a certain monotony about the material lives of these great men. In the lives before us, which are little more than sketches, the author has rightly laid most stress on the scientific achievements of his ten physicists, but he has a tendency to reduce his account to a catalogue of the discoveries and advances made. An estimate of the place of each man in the thought of the time, and of his scientific character, of the general tendencies of his work and the place it now occupies in the history of the science, deserves to take a rather larger place in these short biographies than it has received.
Happily many of the ten are men of very interesting personality. The selection—James Clerk Maxwell, W. J. M. Rankine, P. G. Tait, Lord Kelvin, Charles Babbage, William Whewell, Sir G. G. Stokes, Sir G. B. Airy, J. C. Adams, and Sir J. F. W. Herschel—if based on no clearly-defined plan, has the merit that it includes one or two men who have been unduly neglected. Rankine, in spite of his important work on thermodynamics, does not receive much attention from the physicists of to-day, possibly owing to his unattractive "molecular vortices," and Babbage is known to most people rather from the sneer in the Ingoldsby Legends:
Master Cabbage, the steward, who'd made a machine
To calculate with, and count noses—I ween
The cleverest thing of its kind ever seen,
than for his really great, though imperfect, achievements. Why Babbage is set down as a physicist, when his whole effort was devoted to the perfecting of calculating machines, we do not know, but the life is one of the most interesting, and makes an attempt to expound the causes—obvious enough, perhaps—of his misfortunes. It is a generous appreciation of an ill-starred genius, now seldom heard of. Whewell, again, is scarcely known as a physicist, but rather as the historian of inductive science; we suppose that his writings on the tides have secured him his place. Joule is mentioned in early life, and was certainly one of the leading physicists of the century, yet he is not among the selected ten—neither, for that matter, is Faraday, so it is evident that scientific prowess has not been the test of admission.
On the whole the ten are versatile men, although no one of them could come near in diversity of performance to the great Thomas Young, who was not only a physicist of the first rank but also a physician, a classical scholar, and one of the first successful decipherers of Egyptian hieroglyphics. Rankine and Whewell were fair poets, and Clark Maxwell deserves higher praise for his verses. His description of Kelvin's reflecting galvanometer, in the form of a parody of Tennyson's "Blow, bugle, blow," illustrates the ease and finish of his light verse:
O love! you fail to read the scale,
Correct to tenths of a division.
To mirror heaven those eyes were given,
And not for methods of precision—
Break, contact, break, set the free light-spot flying,
Break contact, rest thee magnet, swinging, creeping, dying.
The poem is quoted in the life of Kelvin, and two of Rankine's songs are given. We hope that physicists can still show the same accomplishment.
The lives are well written, and, while not a very profound contribution to the history of the science, make very pleasant reading for scientist and layman. There is, however, occasionally a lack of proportion, as when Clark Maxwell's work on electro-magnetic waves receives little attention compared to his other far less important achievements.