SCIENCE
A TREATISE ON GYROSCOPIC AND ROTATIONAL MOTION. By Andrew Gray, F.R.S. Macmillan. 42s. net.
It was quite time that we had in English a standard treatise on gyroscopic motion. Space is, of course, devoted to the subject in various well-known text-books on rigid dynamics, and there are one or two good little books of an elementary nature, such as Perry's Spinning Tops and Crabtree's Spinning Tops and Gyroscopic Motion, but hitherto the man in search of detailed information on problems concerning tops in the widest sense has had to go to Klein and Sommerfeld's Theorie des Kreisels, if he could not find what he wanted in Sir George Greenhill's Report. That Professor Gray should be the man to supply our want is only fitting. At the University of Glasgow, where he succeeded to the chair of Natural Philosophy left vacant by Lord Kelvin's death, an interest in gyroscopic motion is traditional, and Professor Gray inherited a collection of apparatus for experiment in this field which he has extended by many ingenious and convenient forms of gyroscope described in the book before us. His own researches on the general dynamics of gyroscopic systems have added clearness to that branch of applied mathematics, and his son is an expert in the design and application of practical gyrostats. A judicious combination of experimental and theoretical treatment forms the great attraction of Professor Gray's book.
The problems of gyroscopic motion range from the behaviour of the schoolboy's top to that of this great top, the earth, and include a great number of engineering applications. The torpedo is kept in its course by a gyroscope; the gyroscopic compass, which makes no use of magnetic properties, has rendered possible the navigation of a submerged submarine; Schlich invented a gyroscopic apparatus, which has been tried successfully in small ships, for keeping a vessel from rolling in a rough sea; with Brennan's monorail the car is kept upright by means of a gyroscopic device; and many other ingenious uses have been made of the seemingly paradoxical properties of spinning tops. The gyroscopic compass is, unfortunately, not treated in Professor Gray's book, nor is there any account of other naval and military applications of the gyroscope, since the author, finding that the official secrecy, necessarily imposed at the time of writing, would prevent him giving anything but a fragmentary account, has preferred to reserve his discussion of these appliances to a promised second volume. Very little is said of the monorail (in fact, Brennan's name is not mentioned), which is less explicable. Many practical applications of gyroscopic theory to such problems as the drift of projectiles, golf balls, and boomerangs (the last-named treated necessarily in a very general manner) come up for consideration, and the forgotten diabolo, child of a passing craze, is resurrected to provide an example of the effect of equality of the principal moments of inertia on the stability of rotation of a body under no forces. Most attention is, however, given to the first two subjects mentioned above—the top spinning on a flat surface, and the earth spinning through space—which are, of course, the classical problems in rotational dynamics. It need scarcely be said that Sir George Greenhill's work is abundantly cited.
"In the present work my aim has been to refer, as far as possible, each gyrostatic problem directly to first principles, and to derive the solutions by steps which could be interpreted at every stage of the progress," says the author in his preface, and he has followed this aim with considerable success. It is, of course, impossible to treat many of the problems of rotational dynamics without mathematical analysis of some complexity, and a knowledge of elliptic functions and such-like weapons of the applied mathematician lies, perhaps, outside the scope of the average engineer and inventor. Professor Gray, who deplores the present ignorance of inventors in the matter of gyroscopic motion, has kept the needs of this class before him, and has taken care to arrange his matter so that those who cannot always follow the mathematical exposition given can, at least, gain a clear knowledge of the results. The first chapter, which contains no mathematical symbols, forms an excellent introduction to the subject and is quite elementary, and elsewhere in the book, when practical problems, such as the drift of a projectile, are being discussed, the nature of the investigation is stated as simply as may be. Throughout the inquiry is illustrated, as far as possible, by experiment and diagram.
"Les Anglais enseignent la méchanique comme une science expérimentale; sur le continent, on l'expose toujours plus ou moins comme une science déductive et a priori. Ce sont les Anglais qui ont raison, cela va sans dire." In these words, the late Henri Poincaré, the greatest mathematician of his generation, praised the British tradition of teaching dynamics as an experimental subject, which is so well maintained in this book. Some specialists, no doubt, will find minor omissions in their subject, but, on the whole, with the exceptions already noted, the book is very complete. It is printed with the well-known elegance in all that pertains to mathematical symbols of the firm of Robert Maclehose, and the general production is very good. We do not understand, however, why the illustrations in the first chapter are nearly all reproduced a second time further on in the book, especially as they are mostly photographs of apparatus, which do not necessitate frequent reference. And—the question that has to be asked so often with English books—why is the index so defective?
EVERYDAY EFFICIENCY: A PRACTICAL GUIDE TO EFFICIENT LIVING. By Forbes Lindsay. W. Rider & Son. 4s. 6d. net.
It is stated in the preface that the material of this Practical Guide to Efficient Living has been used extensively as a correspondence course, so that anyone who is thinking of paying pounds to be taught by post how to be efficient can save most of his money. All the most notable authorities on Efficiency—Ike Marvel, Buddha, Arnold Bennett, Walter Dill Scott, Prentice Mulford, Yoritomo-Tashi, and Baudelaire (to what the last-named said is added what he might have said)—are quoted, and many varieties of type and a liberal use of capital letters add to the strenuousness of the book. There is much about Ideals ("Ultimate and Other Ideals") and much about Money, much about Character Formation and much about Vocational Efficiency. We attribute our own inefficiency largely to the fact that we cannot whistle, for this seemingly trivial accomplishment is of far-reaching use—"Whistle and wear a smile for fifteen minutes, and you will most assuredly begin to feel cheerful"; "Sing and whistle as you dress." But, again, we have not done the essential thing, which is, we are told, to read the lessons of the Course again and again, and to devote close thought to them. Alas, we fell a victim to Waning Will, a fault early handled in the book, and although somewhat comforted to learn that it is a "common form of weakness," we could not bring ourselves to adopt the cure, which is "When a resolution is formed, record it definitely in your file under the head of Ideals, Aspirations, Tasks, Duties, or other appropriate designation." The appropriate designation for the reading of this book is undoubtedly Task. The author, who has also written books entitled Efficiency and The Psychology of a Sale, is a man who has evidently obeyed his own great precept, "Don't admit any limit to your attainment and capacity." His intense self-respect will prevent him feeling hurt on learning that a smile is the only aid to efficiency which we have derived from his book.
ANAPHYLAXIS AND ANTI-ANAPHYLAXIS. By Dr. A. Besredka. English Edition by S. Roodhouse Gloyne. Heinemann. 6s. net.
Medical research bears so directly on the well-being of every one of us that it is astonishing that more people do not take an interest in it. The existing indifference may be attributed partly to the lack of good popular books describing recent advances in an easily comprehensible way, partly to the nomenclature adopted by the medical profession, which is apt to frighten the layman into imagining that the exotic polysyllables in question can be used only for phenomena of unimaginable complexity and obscurity. Complex they always are, of course, with the complexity of all natural manifestations, but very often the main lines of the problems which have arisen, and the methods of attack, can be stated in plain language. The book before us, which deals with the profoundly interesting subject of anaphylaxis, is not avowedly written for the enlightenment of the public, yet it is in most parts accessible to anybody with a slight knowledge of medicine, and, not being a "popular" book, it has the advantage of being free from the erroneous generalisations so often introduced in presenting a branch of science to the lay reader. The subject is described as one still in the course of development, and is not given that false air of completion so dear to the populariser.
The phenomena of anaphylaxis are among the most striking in medical science, and have only recently been investigated, for although isolated cases of what we should now call anaphylaxis had been previously noted, Richet was the first to show the significance and extent of the subject in his memoir of 1902, in which he established many of the most important points. The essence of anaphylaxis is that the injection into an animal of a small quantity of one of certain substances—which in some cases are, and in others are not, poisons (with a poison the dose must, of course, be less than the fatal one)—puts the animal in a particular sensitive state, so that a very small second injection produces fatal results of a very violent and well-marked character. Some time must elapse after the first injection for the sensitive state to establish itself, and the second injection must be of exactly the same nature as the first, this latter fact constituting the so-called specificity of the anaphylactic effect. This specificity has been applied for identifying blood of a doubtful source, since an animal which has been sensitised with an injection of blood from a given species is sensitive only to blood of the same species. Further, the blood of an animal in the sensitive state can be used to render another animal sensitive, a result known as passive anaphylaxis.
The important bearing of anaphylaxis on clinical practice is obvious. With therapeutic sera accidents have been fairly common in the past, grave effects following a second injection; this is a pure anaphylactic phenomenon. Much research has been done to find out methods of preventing the anaphylactic shock, and the most important advances in the field of anti-anaphylaxis are due to Dr. Besredka. His book naturally devotes much space to this aspect of the study, and gives details of the successful technique which he has developed. He worked mainly on guinea-pigs, having obtained extreme regularity of reaction with these animals. His most important result, both from the theoretical and the practical standpoint, is that vaccination against anaphylaxis can be produced by a system of gradually increasing doses, starting with the injection of a very small amount of the substance in question. This has led to a routine for serum injection by graduated doses, which has been successful in averting serum sickness. Besredka's interpretation of his results is against Richet's theory that the second injection combines with a substance, the toxogenin, present in the serum as a consequence of the first injection, and so produces a poison, the apotoxin. He considers rather that the reaction of the injected substance, the antigen, with the substance already formed (which he calls sensibilisin) itself produces the fatal result by disturbing the equilibrium of certain nerve cells where the combination takes place. By graduating the doses the reaction is watered down into a series of slight shocks, so that the great shock produced by a single injection is spread over a comparatively large time, and becomes innocuous. He finds an analogy between the effect and the mixing of water and sulphuric acid. If the water is poured in quickly there is an explosive action, but if it is added gradually the combination takes place without violence. "In our opinion the anaphylactic poison does not exist."
There are a great number of interesting experiments cited in the book which we cannot mention here. The translator has done his work well, although we do not like some of his importations from the French. It should not be impossible to find expression more English than "titre of toxicity" and "fulminating cases." He has added an excellent chapter on "Recent Work on Anaphylaxis." We are glad to see at last a short work in English on the subject, which is one of the most fascinating fields in modern medicine. Somebody should translate and bring up to date Richet's excellent little book. It is a pity that the nomenclature of the subject cannot be made uniform.
THE NEW TEACHING SERIES OF PRACTICAL TEXT-BOOKS:
APPLIED BOTANY. By G. S. M. Ellis.
FOUNDATIONS OF ENGINEERING. By W. H. Spikes.
CHEMISTRY FROM THE INDUSTRIAL STANDPOINT. By P. C. L. Thorne.
Hodder & Stoughton. 4s. 6d. net each.
This new series is rather pompously announced as striving to build "up the New Humanism on the basis of the student's immediate economic interest and environment" (which implies a considerable modification of the accepted meaning of Humanism). We translate this as meaning that it is intended to give the reader some idea of the various sciences and arts as they find application in industry and commerce. This is a worthy object, and, on the whole, the books are simple and interesting expositions of the utilitarian aspect of the sciences in question. There is, perhaps inevitably, a tendency to hurry over fundamental difficulties which will not, we think, leave an intelligent student satisfied. For instance, to say that a force is whatever changes motion, without further explanation, may well puzzle the reader, who knows that he can push against a heavy stone without producing any apparent motion. However, there is a distinct place for books of this general character, which do good work by showing to a wide audience the peaceful achievements of science and its practical aspects; they act as a counterblast to the deadening tradition of rule of thumb. The industrial chemistry is particularly comprehensive, and has an excellent set of original diagrams of industrial plant. The series is well printed and well illustrated, and, for present times, moderately priced. It deserves wide recognition.
PROJECTIVE VECTOR ALGEBRA. By L. Silberstein. G. Bell & Sons. 7s. 6d. net.
It is not often that a book appears describing an essential advance in pure mathematics which is intelligible to the man of moderate attainments in that science—by moderate attainments we mean such knowledge of mathematics as is picked up in one or two years at a university. Dr. Silberstein, who is well known in this country for his original work, especially in connection with the theory of relativity, has, in his Protective Vector Algebra, developed his latest researches in geometry in a form which is attractive and free from pedantic formalities, and has throughout aimed at simplicity of expression, in contrast to certain modern mathematicians who endeavour to lend importance to minor conventional problems by a bewildering display of definitions and theorems. The essential novelty of the book, from which the whole theme is developed, is the generalised definition of the addition of vectors, which does not need any construction of parallel lines, but depends solely on a straight line construction making use of the points where the vectors cut an arbitrary fixed straight line. Dr. Silberstein's definition is a generalisation of the Euclidean one, to which it reduces if the arbitrary line just mentioned is moved away to infinity, and if the space is Euclidean. The knowledge of geometry which is demanded is little more than the usual postulates of projective geometry and Desargues' theorem. From his definition the author proceeds to prove the associative law, and then, after dealing with the equality of non-coinitial vectors, gives many interesting uses of the generalised vector algebra. The proof of Pascal's theorem gives a striking example of the power and simplicity of the new method, and the whole treatment of conics will delight the student of projective geometry. Altogether the book is a very original and striking contribution to a fascinating branch of mathematics.