By R. WALLACE STEWART, D.Sc. IN THE PRESS.-Vol. I. Matter. Vol IV. Heat. Both ready shortly. Full Descriptive Prospectus Post Free on Application. NEARLY READY. Eighth Edition. Revised. 35. 6d. A PRACTICAL ELEMENTARY MANUAL OF MAGNETISM AND ELECTRICITY. By Prof. ANDREW JAMIESON, M.Inst.C.E., M.I.E.E. "A thoroughly trustworthy text-book."- Nature. Eighth Edition, revised and greatly enlarged. 35. 6d. By Prof. ANDREW JAMIESON, M.Inst. C.E., M.I.E.E. "An invaluable companion."-Practical Engineer. Fifth Edition. In Two Parts. Sold separately. ENGINEERING DRAWING AND DESIGN. By SIDNEY H. WELLS, Wh.Sc., A.M. Inst.C.E. Vol. I. Practical Geometry, Plain and Solid. 4s. 6d. Vol. II. Machine and Engine Drawing and Design. 4s. 6d. LONDON HOUSE: 29 Margaret St., Regent St., W. THE "PEANDAR" (P. and R.) SET OF STANDARD METEOROLOGICAL INSTRUMENTS "Student's" Fortin's Standard Barometer. Eminently suited for use in small Observatories, Schools, and for Private Observers. Wet and dry Bulb Thermometer, As illustrated, best quality, £6 6 0 complete, including Register for PASTORELLI & RAPKIN, LD. (STAR) 46 HATTON GARDEN LONDON, E.C. THURSDAY, SEPTEMBER 9, 1909. THE A MONOGRAPH ON THE TRANSIT CIRCLE. Les Observations méridiennes: Théorie et Pratique. By F. Boquet. Tome Premier, Instruments et Méthodes d'Observation. Pp. xi+314. Tome Second, Corrections instrumentales et Équations Personelles. Pp. iv+342+ xii. (Paris: Octave Doin et Fils, 1909.) Price, 2 vols., 10 francs. HESE two volumes comprise one of two completed sections out of a total of twenty-nine devoted to astronomy and celestial physics in a new form of scientific encyclopædia in which astronomy is only one of forty divisions. The whole work, if and when completed, should run to at least a thousand handy little volumes at a uniform price of 5 francs per volume. An index to the complete series is also promised, but it is hardly contemplated that the demand for the whole set will be very great, the idea being that each subject is to be totally distinct, so that a minimum of irrelevant matter need be purchased by any interested specialist, and that such sections as are rapidly rendered out-of-date may be quickly replaced by revised editions without necessitating alteration of the whole work. Our purpose now, however, is to deal only with the two volumes before us, premising that the "Bibliothèque d'Astronomie et de Physique céleste," to which they belong, is under the directorship of M. Jean Mascart. It may be fairly remarked, inasmuch as the titles of the other twenty-eight sections of this "Library" are given, that it is quite possible the number will have to be augmented, as there is at present no obvious place for more than one modern investigation without straining the meaning of some of the published titles. With some 600 pages entirely devoted to meridian observations, we are at first inclined to wonder why so much space was thought necessary. But the wonder does not last long, for the pages are quite small, and the amount of detail is very great, as is only fitting in an encyclopædia. Moreover, we soon perceive that the transit-circle, though the two parts are inevitably studied separately, is the only instrument considered. This strikes us as an error of omission, for there is no other place for discussion of the zenith telescope in any form. There is no mention of the various forms suggested in substitution for the ordinary one, such as the fixed telescope with meridian mirror or the transit with axis view, simply rotating in bearings east and west. A very possible explanation is that these various forms are not of much account in France, but their omission seems to be a mistake. on, are treated with great fulness. The printing chronograph in various forms is naturally conspicuous, this subject being one on which M. Boquet has written more than once before. Another subject with which he has similarly shown familiarity is given an importance we do not remember to have seen before, and that is personal equation, the adequate treatment of which is especially welcome. The various physiological or psychophysiological causes of error are very carefully differentiated, and at the same time no space is wasted on the numerous devices for determining absolute personal equation in transit observations, though a long list of references is given for the use of those who care to pursue the subject. Perhaps those whose "eye-and-ear" observations are consciously or unconsciously taken by what may be called the chronometer comparison method, as distinct from Bradley's (M. Boquet calls it "méthode de l'oeil et de l'oreille par estime du temps "), will question whether their observations are so inferior as M. Boquet assumes. The use of screens also for magnitude equation is liable to meet with similar objections to those urged against the pierced cube of the Greenwich transit-circle, but in this the author is only summarising what has been done and projected. There are, in fact, very few places where he has expressed a decided personal opinion, so that we are inclined to regret that the plan of the work allowed so little scope for personality. With the reservation as to omissions to which we have alluded, we can only hope that the rest of the thousand-odd volumes will maintain the high standard of thoroughness set by M. Boquet. W. W. B. THE HISTORY OF MECHANICS. Lectures de Mécanique. By E. Jouguet. Première Partie La Naissance de la Mécanique. Deuxième Partie L'Organisation de la Mécanique. Pp. x+ 210 and 284. (Paris: Gauthier-Villars, 1908-9.) Price 7.50 and 10 francs. SINCE INCE the eventful appearance of Mach's works on mechanics and heat, much greater interest has been shown in the historical development of applied mathematics, both for its own sake and from a growing conviction that the teacher of a subject ought to know something of its actual growth and expansion, as well as the current methods of expounding it. Recent works by M. Duhem show that even in France, the birthplace and home of clear-cut analytical systems, there is an appreciation of the value of historical research and of tracing the slow formation of the leading ideas and principles of mechanics. For several reasons M. Jouguet's book will be found There does not seem to be much, if anything, of a useful supplement to its predecessors. In the first consequence omitted in reference to the transit circle place he is an engineer, so that he is in full sympathy itself, all kinds of instrumental errors being fully and with such men as Stevinus and Huygens and Galileo, carefully dealt with, several methods of determina- and gives considerable attention to those who, like tion or correction being given in many cases. For Reich and Andrade, propose to deduce the laws of instance, a very clear account is given of Cowell's mechanics from actual experiment. At the same time refraction tables as used at Greenwich, while division he is by no means the case-hardened empiric who error and eccentricity, screw value and error, pivot ignores the claims of logic, and despises speculation. error, wire intervals and inclination, flexure, and so In fact, it is noteworthy, and gratifying, that he prac tically admits Kirchhoff's thoroughly abstract, and so to say a priori, presentation of dynamics to be the best extant from a critical point of view; and he is conscious of the value of a self-consistent theory which can be applied as at least a first approximation to the actual facts of experience. Another advantage of the work is that it does not pretend to be exhaustive. By choosing definite problems (such as impact, for example) and restricting himself to the consideration of really eminent writers, the author is able to give extracts of some length from works of great interest which are not generally accessible. In some ways this is more instructive than any amount of comment can be. M. Jouguet stops short of hydrodynamics, and only gives very brief accounts of the principles of least action and least constraint. Otherwise most of the main principles of dynamics and statics are illustrated. The chapters on internal forces are particularly interesting; so is a passage from Euler, which shows that he was vaguely conscious of the difficulties connected with the relativity of motion, and the impossibility of defining absolutely fixed axes of reference. One reflection is almost certain to occur to the reader of these volumes, namely, that one great advance in the study of natural science has been the rejection of sham proposition about cause and effect, and adequate causes, and so on. It is distressing to find an able man like Wallis giving definitions of the most question-begging description, and stringing together such propositions as "other things being equal, a heavy body has a preference for the path by which it can sink the furthest." However, these early pioneers had a remarkable power of solving problems by elementary principles which they used without being able to express them in a proper, or even intelligible way; and the modern theories of light and electricity once more illustrate the curious paradox that theories based on the undefined and undefinable have the power, not only of simplifying our accounts of phenomena, but also of suggesting paths of discovery, and leading to larger control of the energy surrounding us. If M. Jouguet's work reaches a second edition, he will doubtless correct "Bernouilli " "to 66 Bernoulli." In a work of this kind it is rather irritating to find this time-honoured blunder repeated once more. G. B. M. ORGANIC MEMORY. Die mnemischen Empfindungen in ihren Beziehungen zu den Originalempfindungen. By Prof. Richard Semon. Pp. xv+392. (Leipzig: W. Engelmann; London: Williams and Norgate, 1909.) Price 9 marks. THE HE theory of the Mneme, propounded by Prof. Semon, has attracted the attention both of psychologists and of those naturalists who are interested in the profound problems of hereditary transmission. It is founded on the statement, which everyone is ready to admit, that a stimulus must affect the quality of living matter in such a way that the matter is not the same as it was before the stimulus Re acted. A permanent change, which, in a sense, may be called a memory, has been effected, or, to use the terminology invented by Semon, the action has been engraphic and the change itself is an engram. peated stimulation will make the engram more lasting. All stimuli then produce engrams, and the sum of the engrams of a living being is its mneme. Complex stimuli cause complex engrams, and if there is, under the action of some stimulus or other, a revivification of the complex engrams, then a condition termed ecphoria is produced, and the assemblage of engrams is ecphorized. If the new stimulus is in concord with the awakening of the complex engrams, this concord is termed by Semon homophonia, but if there is a discord, the homophonia may be restored in the case of psychical processes, by an introspective activity of the power of attention, or, in the case of a living organism, by regenerative processes acting ontogenetically, or by adaptation to the new conditions acting phylogenetically. In this volume Prof. Semon discusses the theory with great clearness and commendable brevity, and he gives many illustrations. The theory may help to explain certain peculiar nervous conditions, as has been suggested by Dr. August Forel in his book on "Hypnotism." On the other hand, it may be of service to the naturalist in his ceaseless efforts to explain heredity, as was so forcibly put by Prof. Francis Darwin in his Dublin address to the British Association last year. Thus a stimulus may produce effects which radiate from the organised matter first affected to organised matter throughout the whole organism, either by nerve paths or by proplasmic intercellular filaments, and in this way faint engrams may be made on the matter of the reproductive elements, ova or spermatozoids. In some such way we may account for the transmission of acquired characters, a mode of thought, however, only to be ridiculed by those who hold that acquired characters are never transmitted. It may be said with much cogency that such a theory is only another method of arranging items of knowledge in one's mind; it is only an aid to memory and thought, without being a step towards an explanation. Although founded on well-known physiological facts, it rides off on the wings of the imagination, and it may be questioned if it really advances knowledge. Still, an ingenious theory is a stimulus and possibly a guide, and science is indebted to Prof. Semon for stating it in a succinct form in this interesting book. JOHN G. McKendrick. THE PHYSICS OF THE ION. Les Découvertes modernes en Physique. By Dr. O. Manville. Deuxième édition. Pp. iii +463. (Paris: A. Hermann et Fils, 1909.) Price 8 francs. THE title of this work, "Les Découvertes modernes en Physique," since it is a single volume by a single author, is obviously incomplete. In effect the book is almost entirely, and might have been with great advantage entirely, confined to the relations between electricity and matter consequent upon the conception of the atomic charge and the isolation of the free negative charge as an electron. It is true that two chapters are devoted to the subject of radio-activity, concerning which we read in the preface : "Sur la radioactivité de la matière. . . nous avons dit que des généralités. Le domaine des faits dans cet ordre d'idées est si vaste et surtout si mobile, qu'il est encore très difficile de s'y orienter." Ideas at the present time in radio-activity are more definite and well-grounded than in any other branch of physical chemistry, but it is clear the author's lack of knowledge in the recent and even the older work of the subject is responsible for his views. In subsequent editions this part of the work might be omitted. It follows, no doubt, the precedent set by Sir J. J. Thomson's well-known book on the conduction of electricity through gases; but what was natural enough when that book was written does not apply to a book published in 1909. In the ground covered, the work does not differ materially from the one just quoted and many similar which have since appeared, but the treatment is interesting and lucid, and the critical examination and selection of the material chosen for presentation has been done impartially and well. The lack of any conspicuous originality is compensated for by clearness of exposition. In one respect, in that this is a French work dealing with a scientific movement which, if we exclude radio-activity, has proceeded mainly from this country and from Germany, the author is at an advantage, for the whole territory is surveyed in better perspective in consequence. Both in the first part, which is of a general elementary character, and in the second, which deals for the most part with the mathematical theory of ions in physical phenomena, the author introduces his subject with an excellent account of the older work on the passage of electricity through ionised liquids before passing on to the newer ideas which followed the study of the discharge of electricity, first in high vacua and later, after the discovery of X-rays and other ionising agencies, in gases at various pressures. We are thankful for this juxtaposition of subjects which are usually regarded as independent owing to the fact that the one has been largely developed by chemists and the other by physicists; but at the same time it brings out the difficulties that arise when we seek to apply the newer views to the case of liquid electrolytes. The two subjects have surprisingly little connection with one another at the present time, and anyone who has to teach both must be painfully aware of the difficulties of harmonising them. In this book the newer work on gaseous ions and their properties, the various means of producing ionisation by kathoderays, X-rays, flames, &c., the re-combination and diffusion of ions are discussed very thoroughly from the physical point of view along regular lines. In the second part an account of the electronic theories of metallic conduction and of magneto-optical phenomena is given, while the more metaphysical developments connected with the electronic constitution of matter, and the entanglement of ether by moving masses are properly left to the end of the two parts respectively. The book has no index, and is marred by an extraordinary an extraordinary number of misprints, the rectification of which occupies many pages of errata at the end. OUR BOOK SHELF. Problemi grafici di Trazione Ferroviaria. By P. Oppizzi. Pp. viii+ 204. (Milan: Ulrico Hoepli, 1909.) Price 3.50 lire. In the preface the author tells us that although graphic methods are often used by the general mechanical engineer, they have up to now been neglected by the railway engineer. This book is intended to show how such methods may be applied to the solution of nearly all problems in connection with the working of trains on railways. In this object the author has well succeeded, and it may safely be predicted that any reader who has once used graphics in the very easy and simple manner represented in this book will never again have recourse to analytical methods. Indeed, there are cases where analysis becomes so complicated that its use by a busy engineer, even if he has the required mathematical ability, is out of the question; as an example may be cited the acceleration diagram Tractive of a train drawn by a steam locomotive. effort and resistance vary in a very complicated manner with the speed, and this, again, being the time integral of acceleration, which in turn depends on the difference between tractive effort and resistance, it is easy to see that a purely analytical treatment leads to almost hopelessly involved formulæ. Yet the author is able to solve this and many other problems by his graphics in a comparatively easy way, and with a degree of accuracy quite sufficient for practical purposes. The book contains eight chapters, in which the following subjects are treated:-train resistance as a function of speed, weight, and type of coach and locomotive; tractive effort of locomotives of various types at various speeds, gradients, and curvature of line; speed-time-distance diagrams during acceleration; possibility of making up for lost time; running down tong gradients and action of brakes; total time required for a given run; consumption of fuel or electrical energy and conditions of greatest economy; efficiency of service. In all cases the author gives numerous examples to show the application of his methods to cases which are taken from practical work, and thus even a reader whose mathematical knowledge is only elementary is able to profit by this book. This work should prove most useful to railway engineers, and an English translation would be welcome to many. There is only one fault to find with the book, and that is the very untidy appearance of the diagrams. They have all been drawn on squared paper, the divisions being in millimetres. A page covered closely with such lines is very tiring to the eyes, and if, in addition to the multiplicity of lines, there is some writing added to the curves and the whole is reduced in rather a coarse way by photography, the effect is by no means pleasing. It would have been better if the author had omitted the millimetre divisions and retained only the lines placed a centimetre apart. GISBERT KAPP. General Treatise of Meteorology. Part i., Statical Meteorology. By Prof. A. Klossovsky. (In Russian.) Pp. xii+642. (Odessa, 1908.) THE Complete work will comprise four parts. The two first-statical meteorology and dynamical meteorology-will not necessitate a knowledge of higher mathematics; they will form the course of meteor ology properly so-called, while parts iii. and iv. will be devoted to the exposition of special questions and to the principles and use of instruments. A glance at the first volume of Klossovsky's "Meteorology shows at once that it is the outcome of a long and useful career. In fact, the first meteorological labours of the author date from the year 1882, and from that time Klossovsky has not ceased to devote all his efforts to teaching at the Odessa University, and to the organisation and direction of the network of meteorological stations in the south of Russia. Klossovsky's manual, far from being simply a work of compilationthe most complete of any now extant -is distinguished by its originality and by the wealth of the author's critical views. In many parts of the work we meet with pages where certain connections between meteorological data and those of other sciences are admirably described; e.g. at p. 179 and following pages the calorific economy of the human body is discussed. Further, original observations are met with for the first time; thus, at p. 273, the results of the actinometric observations made by Savelieff at Kiev. Again, the whole chapters devoted to solar radiation and to the study of earth temperature are interesting to read. In no other treatise are the questions relating to underground temperature expounded in so complete a manner. The discussion of the results of the author's observations on the temperature at different depths in soil covered with grass and otherwise is especially noteworthy. On p. 334 there is a table giving for each month of the year the temperature at depths of o'60 m. and 1'20 m. in forest and field adjoining. The forest diminishes the annual amplitude; the differences (field-forest) are +30° C. and +270 for the means of July, -0'4° at a depth of 60 cm. and -0'2° at 1'20 m. in January. Prof. increasing power of modern function-theory. Bôcher's exposition is very good; he begins by a heuristic discussion, which in a way resembles the ordinary method of successive approximations. Having thus been led to a certain expression as a presumptive solution, he proceeds to verify the fact that it is one. Other workers in the same field who receive due attention are Abel, Liouville, Hilbert, Schmidt, and Volterra; and there are various subsidiary or supplementary articles of great interest. As No. 10 of the " Cambridge Tracts in Mathematics and Mathematical Physics," Prof. Bôcher's work thoroughly helps to fulfil the object of the series; it is brief, self-contained, and stimulating, while giving sufficient reference to original sources. The Scaly-winged. A Book on Butterflies and Moths for Beginners. By R. B. Henderson. Pp. xii+ 115. (London: Christophers, n.d.) Price is. net. THE study of entomology is always extending its range, as shown by the numerous books which continue to be published especially relating to the order Lepidoptera, or butterflies and moths, which always seems to be the most popular of all, probably because many insects included in it are attractive in appearance, and easy to collect. The study is pursued systematically in several of our great public schools, and Mr. Henderson informs us in his preface that "the entomological, like most of the other sections of the Natural History Society of Rugby School, is entered by examination," and that as he did not find a suitable book for beginners to use in preparation for such an examination, he has compiled one for the purpose. The various chapters deal with insects in general, and the Scaly-Winged in particular; metamorphosis; Psyche (imago); the Sister States (difference between butterflies and moths); bionomics: the place of Lepidoptera in the scheme of nature; the museum; appendix: note on the vision of insects; and list of some useful books for consultation, Furneaux's One of the characteristics of Klossovsky's work is the care with which the most recent advances have been taken into consideration; e.g. at p. 512 observations made in January, 1907, are noted, and at p. 606 the results of unmanned balloon ascents at Uccle up" Butterflies and Moths" being specially recomto April 11, 1907, are included. The titles of the chapters in this first volume are :-Composition of the atmosphere; physical properties; water in the atmosphere; the oceans; solar radiation; terrestrial radiation; earth temperature; increase of heat with depth; ocean temperatures; temperature of the lower strata of the atmosphere; atmospheric pressure; formation of hydrometeors; temperature and pressure in the upper atmosphere; abnormal departures. H. A. mended. There are twenty-two useful text-illustrations of structure and apparatus, and the instructions for collecting and preservation in the chapter on the museum are particularly good. Fossil Plants. Sixty Photographs illustrating the |