July 7, 1910] 



NATURE 



working. Hence it becomes a matter of the greatest 

 importance that the mechanical properties of the par- 

 ticular model chosen should not merely approximately, 

 but with mathematical precision, represent the corre- 

 sponding electrical properties of the circuit it is in- 

 tended to represent. 



It becomes thus necessary to idealise the mechanical 

 model by attributing to it properties which differ 

 more or less from those it actually has in its natural 

 condition. Take as an example the conceptions of 

 electric current and ohmic resistance. According to 

 the author's "foundations," these are respectively 

 represented by speed (linear or angular) and friction. 

 But what kind of friction ? The coefficient of friction 

 as applicable to solid bodies will not do, for this 

 implies the existence of pressure between the surfaces 

 in contact, and there is nothing analogous to pressure 

 in the electrical case. 



Thus one is driven to assume that ohmic resistance 

 can only be represented by liquid friction of a par- 

 ticular kind, namely, of a kind which will 

 cause the frictional resisting force to in- 

 crease exactly in proportion to the speed with 

 which a body is moved through the liquid. The 

 author takes a boat which is towed through the water, 

 and assumes that the pull in the tow-rope is exactly 

 pioportional to the speed. As an alternative to the 

 tow-rope he assumes that the boat is fitted with a 

 propeller which exerts the same thrust at all speeds, 

 and he uses this model to illustrate the case of an 

 inductive circuit. The mass of the boat corresponds 

 to the inductance ; the frictional coefficient, that is, the 

 resisting force per unit speed, corresponds to the 

 ohmic resistance, and the speed to the electric current. 

 The E.M.F. is represented by the thrust of the pro- 

 peller. Under these conditions the speed of the boat 

 will increase by a logarithmic curve, and approach 

 asymptotically the final value where the thrust of the 

 propeller is exactly balanced by the frictional resist- 

 ance. Thus, having discarded our conception of the 

 real nature of ships' resistance and propeller thrust 

 and substituted an idealised model, the performance 

 of this model is an exact representation of what goes 

 on in an electric circuit, and the equation of the speed 

 of the boat is identical with the equation of the cur- 

 rent in the electric circuit. 



The author has not contented himself by merely 

 imagining mechanical models, but has actually con- 

 structed one so as to be able to demonstrate 

 the properties of an electric circuit. The model con- 

 sists of a square frame, one side being provided 

 with rails for a car to travel along. To represent 

 ohmic resistance, the car can be fitted with a paddle 

 moving in a liquid. The mass of the car represents 

 inductance, the force with which it is pulled along 

 stands for E.M.F. , the speed for current, the displace- 

 ment for quantity of electricity (coulombs), and if a 

 capacity effect is to be shown an elastic string is 

 attached to the car. In addition to this model, the 

 author has others to show various electrical pheno- 

 mena, all of them very ingenious and instructive, 

 especially when he shows side by side curves of har- 

 monic motions obtained by oscillograph attached to 

 the electric circuit, on the one hand, and, on the other, 

 NO. 2123, VOL. 84] 



curves obtained by mechanical means from the corre- 

 sponding models. 



The book is divided into four parts. In the first 

 the fundamental principles are established by mechan- 

 ical analogies ; then comes an exposition of harmonic 

 motions ; whilst in the third part the properties of 

 alternating-current circuits are studied in detail, in- 

 cluding a chapter on the symbolic method. In the 

 fourth part we find practical applications to trans- 

 formers, motors, polyphase circuits, and high- 

 frequency oscillations. At the end we find a number 

 of problems given as exercises for students. These 

 are well selected. Gisbert Kapp. 



OVK BOOK SHELF. 

 Die New School of Japan, Founded for the Purpose 



of Making the Use of the Newly Invented Letters. 



Pp. x+58. (Tokyo: Dokuritsu Bungakki.) 

 This singular production is an attempt, by means 

 of a quaintly conceived dialogue between two 

 Japanese script reformers, to enlist home and foreign 

 support, especially financial support, towards the 

 promulgation of yet another script for the purposes of 

 the Japanese written language, by modifications of 

 and additions to the roman alphabet of the West. 

 But European scholars have already accomplished 

 this, and the existing system of romanisation is 

 sufficiently perfect for all practical purposes. That 

 system uses the roman letters, as we use them, to 

 transcribe the characters of the Japanese syllabary, 

 each of which represents a vowel or an open syllable ; 

 Ihus ka. ki, few, ko, ke represent simply and adequately 

 corresponding simple kana (syllabic) characters. But 

 ihe proposed system would use single alphabetic letters 

 to represent the kana. Thus ka, ki, &c., are written 

 n, V. u, k ; for ke a sort of reversed fe is used. The 

 modifications of sound, voicing, doubling, and 

 lengthening are denoted by ordinary devices and com- 

 binations of these, and a few new letters are invented. 

 Thus Kono hon wa, Okuma Shigeru to Yamada Eizo 

 . . . (this book contains a talk between Okuma Sh. 

 .-md Yamada Ei.) is printed, according to the new 

 system, Pfe ex g Ttuf-Cat m Ofr-Tict (two or three 

 new letters are represented here by their nearest usual 

 ones). Eizo Yamada is the " originator " of the new 

 system ; the preface, dated November, 1909, is signed 

 by him and Muneyasu Oki, who is "business asso- 

 ciate," and photographs of inventor and associate 

 follow the preface. 



For our part we fail to see any advantage whatever 

 in this proposal. Why the Japanese continue to put 

 their thought on paper under a variety of forms that 

 render mere decipherment an impossibility to all 

 foreigners save a verv few who have time and 

 patience, or are under some necessity to undertake a 

 most repulsive study of several years' duration at 

 least, the people of Japan alone can tell. Written 

 Japanese, mainly on this account, is more difficult to 

 acquire, even to read merely, than Chinese, yet with 

 a very few changes the difficulty might be very 

 greatly lessened without change of character, and 

 with romanisation would largely disappear. In no 

 long course of time, probably, the unintelligent use of 

 the Chinese ideograph would diminish, the assimila- 

 tion of written to colloquial speech would develop, 

 and Japanese would present only the ordinary difficul- 

 ties incident to a strange vocabulary, a syntax based 

 upon impersonalitv and lack of inflections, and a mass 

 of idioms necessarily differing widely in allusion and 

 reference from those of Aryan languages. 



F. Victor Dickins. 



