December 20, 1894] 



NATURE 



173 



on cartesians, and his vector work is apt to de- 

 generate into cartesian shorthand. The object of a 

 calculus is not to save printing, and it is no advantage to 

 have an expression condensed into two or three symbols 

 if you have to think it out at length to understand it. 

 Shorthand is not necessarily short-thought, especially if 

 •it also involves writing operators as quantities. It is 

 possible to know the meaning of 



(up - — I H where — i 



dt 



IS '-' 



d 



it is also possible to knoiv what is meant by " Boyle was 

 the father of chemistry, and brother to the Earl of Cork." 

 It might be suggested that if Mr. Heaviside wants to 

 make either vector analysis or quaternions simple to 

 physicists, he should avoid the confusion between opera- 

 tors and quantities, and between operation generally 

 and multiplication in particular ; or else write an intro- 

 ductory calculus of functions showing where such liber- 

 ties can be taken with impunity. 



Mr. Heaviside has a rooted aversion to 477. This factor 

 came into the system of units from statics, as the mathe- 

 matical treatment of electricity was much the same. 

 Mr. Heaviside employs a medium treatment, and thinks 

 that 47r should, therefore, disappear. He thinks that 

 Maxwell and other mathematicians did not know how 

 4Tr came about, and thought it was a physical necessity. 

 With his treatment it is an advantage to remove 

 the 477 from its usual place ; but it only appears 

 in the denominator elsewhere. It is like the eruption 

 due to a disease : suppress it, and it appears elsewhere. 

 The unsavoury metaphor is not ours. The disease is 

 -the area of a unit sphere being 477. Until Mr. Heavi- 

 side can cure that, he cannot really eliminate 47r. He 

 whitewashes 477 whenever it appears in his book, saying 

 that it is not the B.A. 477 of amazing irrationality. When 

 a man refers to his own ideas as alone rational, nr based 

 on common-sense, or well-known facts, he is generally 

 wrong. 



.Mr. Heaviside is, as is well known, a prolific inventor 

 of new terms. He says he hates grammar ; he has also 

 a murderous hatred of the ()ueen's English when invent- 

 ing terms such as " leakance," " reactance," and " potted." 

 Generally speaking, a writer has no business to insist 

 that his reader shall study a new terminology ; but 

 when any one of Mr. Heavisides reputation invents 

 names which are euphonious and good, they become 

 parts of our language, and we must thank him, especially 

 when his terms are suggestive and systematic. The 

 example is bad though. The English language is 

 capable of improvement ; but if every writer is to 

 alter it to suit his ideas, it will not improve. It is a 

 matter of taste which terms should be adopted ; many 

 object to voltage and gaussage as unsystematic where 

 anipereage, farradage, &c., are not used. Voltage was 

 originally used to denote the pressure for which lamps, 

 dynamos, &c., were designed by the maker, whatever 

 they were run at. Pressure belongs to the same set of 

 ideas as current, capacity, resistance, and quantity ; and 

 if they are used, should also be employed. It is, how- 

 ever, a matter of taste only. 



NO. 1312, VOL. 51] 



The style is that of Whitman, except that Mr. Heaviside 

 is not affected, and has something to say. The similarity 

 is also noted in the Philosophical Magazine. Every line 

 of the book is important, and it is full of interesting 

 digressions on all sorts of subjects. Though the con- 

 verse may not be true, all clever men have a sense of 

 humour, and it is therefore a pity that scientific writers 

 emulate the ponderous dryness of the theologian. Mr. 

 Heaviside's work bristles with humour of a type which 

 he has invented. 



It is generally assumed that a review should be written 



by a man who could have written the book himself. In 



the case of a writer of Mr. Heaviside's calibre there is 



difficulty in getting such reviewers. The real object of a 



book is, however, to teach not those who know the 



contents already, but the student, and it may therefore 



be an advantage to review a book from the student's 



point of view. This review must, therefore, be taken as 



from that point of view ; that is, as written by a reader 



who has not devoted a large enough portion of his time 



to the study of mathematics or mathematical physics to 



be more than a student of them. 



J. Swinburne. 



RECENT PSYCHOLOGY. 



Lectures on Human and Animal Psychology. By Wil- 



helm Wundt. Translated by J. E. Creighton and E. 



B. Titchener. Pp. x. 454. (London : Swan Sonnen- 



schein and Co., 1894.) 

 Grundriss der Psychologic. \'on Oswald KUlpe. Pp. viii. 



478. (Leipzig: W. Engelmann, 1893) 

 Introduction to Comparative Psychology. By C. Lloyd 



Morgan. Pp. xiv. 382. (London : Walter Scott, 



1894) 

 Psychology for Teachers. By C. Lloyd Morgan. Pp. x. 



251. (London: Edward Arnold, 1S94.) 

 Primer of Psychology. By George Trumbull Ladd. 



Pp. XV. 224. (London : Longmans, Green, and Co., 



1S94.) 



THE translation of Prof. Wundt's well-known lectures 

 is taken from the second revised German edition 

 which appeared in 1S92, and is therefore well up to date. 

 It is the first work of the author to appear in English, 

 and the choice made by the translators is a good one : 

 while the book will give to those specially interested in 

 psychology a general sketch of the author's views. Its 

 popular and lucid form will appeal to a wider circle of 

 readers who would hardly care to digest the details and 

 technicalities of the " Grundzuge der physiologischen 

 Psychologic." 



The greater part of the book is devoted to human 

 Psychology, especially in its physidlogical and experi- 

 mental aspects, and there are several interesting chapters 

 on animal psychology, and a short account of the author's 

 views on hypnotic conditions. Prof. Wundt's own 

 opinions are staled rather more dogmatically than is 

 altogether suitable for an elementary book in a science 

 like psychology ; thus, in dealing with intensity of sensa- 

 tion, the validity of the logarithmic formula is very posi- 

 tively enunciated, and it is somewhat surprising to find 



