NA TURE 



[November 6, 1902 



qualities of sensation ? then we find ourselves still 

 completely in the dark. Wundt himself seems to have 

 felt this inadequacy and to have introduced in conse- 

 quence towards the close of his exposition a new factor, the 

 "entgegen kommende Triebe desempfindenden Wesen." 

 This introduction of the " feeling being " amounts, it would 

 seem, to nothing more than an admission of our ignor- 

 ance. And indeed we have here reached the very kernel 

 of the problem of life, of that mystery of the relations of 

 soul and body which has vexed the thinkers of all ages, 

 of that " master knot of human fate " of which the Persian 

 poet wrote eight hundred years ago 



" There was the door to which I found no key, 

 There was the veil through which I might not see." 



And these words remain equally true to-day, in spite of the 



splendid labours of Johannes Miiller, of Fechner, of 



Wundt and of many others. 



It is interesting to note that Wundt assumes the 

 principle of the inheritance of acquired characters as 

 absolutely necessary to the explanation of the evolution of 

 the nervous system, and that in this he is in agreement 

 with most of the psychologists who have considered the 

 problem. For the principle of natural selection, which is 

 so satisfactory when we are dealing with the neck of the 

 giraffe or the protective colouring of a butterfly, seems 

 hopelessly inadequate when we have to account for 

 those million-fold coordinated details of nervous disposi- 

 tion which together determine in large part, if not wholly, 

 the tendencies and character of a human being. 



In the last section Wundt deals with Weber's law and 

 maintains his well-known psychological interpretation of 

 it, in opposition to the now very generally accepted 

 physiological interpretation. The attention of English 

 readers may be called to the novel and ingenious ex- 

 planation suggested by Heymans in the Zeitschrift ficr 

 Psychologie, Bd. 26. W. McD. 



THE MODERN DYNAMO. 

 The Generators of Electricity at the Paris Exhibition of 

 1900. By 'C. F. Guilbert. Pp. iv + 766. (Paris : 

 C. Naud, 1902.) Price 30 fr. 



THERE were probably few who went to the Paris 

 Exhibition two years ago who did not pay a visit 

 to the Palais d'Electricite ; and no one who did so can 

 have failed to have been impressed by the enormous 

 size of the electric generators exhibited there. We even 

 know of feminine sightseers, on pleasure bent, sparing a 

 few hours from the fascinating display of M. Worth to 

 look at, and possibly learn a little about, the "purrin' 

 dynamos." The massive grandeur of these magnificent 

 machines, examples of the best design and workmanship 

 of all nations ; the complicated nature of their parts 

 working in perfect harmony and smoothness, and 

 obedient to the control of one or two men ; their spotless 

 cleanliness and the impression of reserved power which 

 they conveyed ; all these must have moved even the 

 most matter-of-fact observer into sympathy with the 

 ideas which inspired Mr. Kipling to write " M'Andrew's 

 Hymn." Such a collection merited the permanent record 

 which it has obtained in the pages of M. Guilbert's book. 

 Something of the spirit of the machines which he de- 

 scribes seems to have entered into the author, for his 

 NO. 1723, VOL. 67] 



book, like the dynamos, is very large. There are nearly 

 800 pages, with, to use the author's own words, "615 en- 

 gravings and plans, of which 118 plates." M. Guilbert 

 has adopted a somewhat novel plan with the laudable 

 desire of making his book attractive to foreign readers. 

 The title pages and preface are in the language of the 

 country in which the copy is to be sold ; the chapter and 

 section headings, the descriptions of the illustrations and 

 the tables, are given in French, German and English. 

 We rather doubt the wisdom of this innovation, since it 

 increases the size of a volume already bulky, and still the 

 most important part, the text, remains only in French. 

 The result of the translation, too, is apt at times to be 

 rather humorous, as, for example, when the author 

 translates rSsume (which the mere Englishman is content 

 to use in the original French) into a non-existent 

 English equivalent. 



Criticism of a book of this kind is almost out of the 

 question. M. Guilbert begins by describing the system 

 of classification which he has adopted, and then, taking 

 each division in turn, gives a more or less detailed 

 description of the principal exhibits which come within 

 it. Photographs of the generators and clearly executed 

 diagrams of the whole machine or of important details 

 greatly help out the letterpress. The book is therefore, 

 in a way, like a descriptive catalogue, but it is one which 

 gives a large amount of very valuable information, and 

 M. Guilbert deserves great credit for the painstaking 

 way in which he has collected and the clear manner in 

 which he has arranged the data supplied by the manu- 

 facturers. It may be objected that the work is two years 

 out of date and that the machines of 1900 are almost 

 ready for the scrap heap in 1902. But rapid as the 

 advance of electrical engineering is, there are few- 

 engineers who will not benefit to-day by the careful 

 study of what was best two years ago, especially 

 as it is the best, not of one country only, but of all 

 countries ; there will be many also interested in the 

 design and improvement of electric generators who 

 will desire to possess this book, even though it should 

 become in the course of a few years of historical interest 

 only. 



As we turn over the pages of M. Guilbert's book, we 

 find difficulty in selecting any particular machine for 

 special notice. As the most noticeable feature in dynamo 

 development in recent years has been the steadily 

 increasing size of the unit, we may perhaps be pardoned 

 if we pick out one of the largest machines exhibited at 

 Paris. The Allgemeine Elektricitats Gesellschaft ex- 

 hibited a three-phase alternator of 4000 h.p. The output 

 of this machine was 3000 kilovolt-amperes with a power 

 factor of o"9, making 2700 kilowatts. This alternator is 

 one of a set of twenty-two, eight of which are already 

 installed at the Berlin Electricity Works, the remaining 

 thirteen being under construction. To bring this machine 

 to Paris and to erect it in the German annexe, where 

 there was no travelling crane, was a work of no small 

 difficulty. The total weight was 160 tons, the armature 

 frame weighing 80 and the field magnet 70 tons, the 

 remaining 10 tons being due to the bedplate. The 

 armature and field magnet were brought to the exhibi- 

 tion in quarters, each quarter being carried mounted 

 between two railway trucks in the position most suited 



