October 3, 1907] 



NA TURE 



563 



continuous in action, the wet material passing in at 

 th<; lop and leaving- it at the bottom in a partially 

 drii-d condition. It is then passed on to the electrifying 

 machine, where an alternating electric current is 

 passed through it, and is then again passed on to 

 a kneading and moulding machine. The cost of 

 manufacturing fuel by this process is such that it 

 can be sold at a large profit. The fuel produced is 

 ' id, dense, and comparatively smokeless. Electro 



I (oa! averages 30 cubic feet to the ton, ordinary 



i .iveraging 45 cubic feet. 



BOOKS ON WIRELESS TELEGRAPHY. 

 1 Handbook of Wireless Telegraphy ; its Theory and 

 I'ractice. By Dr. J. Erskine-.Murray. Pp. .\vi + 

 ;j2. (Lx)ndon : Crosby Lockwood and Son, 

 H,<<7-} Price 10s. 6d. net. 

 .\iiliotis generates sur la TeUgraphie sans Fil. By 

 K. de \'albreuze. Pp. vi + 169. (Paris: L'Eclairage 

 lAtctriiiiie, 1907.) 



THERE is a stor)-, probably apocryphal, of a 

 learned professor who undertook to edit the 

 writings of a colleague At the end of the first 

 paragraph he started to write a footnote, with which 

 he proceeded until he had completed a treatise in 

 several volumes of far superior value to the work he 

 was supposed to be editing. Dr. Erskine-Murray has 

 adopted e.xactly the opposite system in writing his 

 "Handbook of Wireless Telegraphy," as the follow- 

 ing rough summary of its contents will show. He 

 apparently started out with the good intention of 

 writing the book himself, and in the first few pages 

 has succeeded in presenting from a somewhat 

 original point of view the similarities and differences 

 between the various known systems of telegraphy. 

 But on the ninth page appears the first sign of weak- 

 ness in a half-page verbatim quotation from Sir 

 Oliver Lodge; there is little harm in this, it is true, 

 or in the quotation of equal length from \'on Bezold 

 three pages farther on. But it represents apparently 

 the incubation stage of a disease which subsequently 

 develops alarming severitj'. At p. 17 we find it 

 establishing a firm hold in a five-page quotation from 

 Hertz. Then for a time all goes smoothly, and we 

 read a description of the earlier wireless telegraphy 

 experiments from the author's own pen with feelings 

 of relief. But on the sixtj'-second page there is a 

 serious relapse in the form of a quotation twenty- 

 eight and a half pages long from a paper on co- 

 herers published by Dr. Eccles in the Electrician. .At 

 the end of this quotation we are told that the results 

 may be summarised in a few words — the summary- 

 occupies sixteen lines. We would suggest that in the 

 next edition of the handbook Dr. Erskine-Murray 

 retains only the summary and gives the necessary 

 reference to the original paper. 



.After such an experience we are not surprised at 

 meeting on p. too the first of three successive quota- 

 tions occupying, with a dozen or so lines of inter- 

 polated reference, more than twenty pages ; on p. 124 a 

 three-page quotation from a paper b\' Lieut. Tissot ; 

 on p. 129 five pages from a paf>er by Mr. Duddell. 

 Then, after a brief rest, comes a twenty-page descrip- 

 NO. 1979. VOL. 76 J 



tion of the Lodge-Muirhead system from an article 

 by .Mr. .Marillier in the Electrician, and immediately 

 after this twelve pages descriptive of tests on the 

 Fessenden system, including some very uninterest- 

 ing official correspondence; and so the handbook 

 proceeds to a finish with two more quotations 

 fourteen and fifteen pages long respectively, and nine 

 others var>ing from one and a half to six pages in 

 length. The only thing that causes surprise in the 

 latter part of the book is that, when Dr. Erskine- 

 Murray refers to Euclid's " well-known work on 

 geometry " in support of his contention that the 

 surfaces to be kept clean in relay contacts are " thin, 

 very thin," he resists the temptation to quote at 

 length from that authority (with kind permission of 

 the author). 



It is hardly necessary to say that when in a book 

 of 31S pages, 140 are verbatim quotations from other 

 writers, the whole is not particularly coherent. 

 With all due respect to Dr. Erskine-Murray, we 

 submit that this handbtxjk is a striking example 

 of how not to write on wireless telegraphy or 

 anv other subject. Books on scientific or technical 

 subjects have a quite definite function to fulfil, distinct 

 from that fulfilled by publications in scientific journals 

 or papers. One does not look to them for new dis- 

 coveries, or rarely even new theories, but one expects, 

 in a handbook at least, to find a clear risume of 

 existing facts and theories welded together into a 

 consistent whole possessing some sort of literary as 

 well as scientific homogeneity. He who takes up 

 this handbook with such expectations is destined, we 

 fear, to grievous disappointment, though he may find 

 much of intrinsic value and interest, particularly, for 

 e.xample, the seventeenth chapter, on theories of trans- 

 mission. 



.M. de Valbreuze's book is of a different stamp; 

 there is nothing in it very novel, either in subject- 

 matter or treatment, but it gives from start to finish 

 a clear and carefully-thought-out account of electric- 

 wave telegraphy. The author starts in a manner 

 rather characteristic of French writers by a fairly 

 full account of the most elementary electrical and 

 magnetic principles. In fact, it is not until half-way 

 through the book that we are introduced to wireless 

 telegraphy proper. Nevertheless, room is left for a 

 summary of the more important researches and de- 

 scriptions of the leading systems. Though in no 

 sense an advanced treatise, the book is likely to prove 

 of interest to the expert as well as to the beginner; 

 at least, it can be read through without tedium, and 

 can be recommended to all who, possessing little or 

 even no electrical knowledge, are anxious to become 

 acquainted with the leading principles and practice 

 of wireless telegraphy. 



We have already, on more than one occasion, com- 

 mented in Nature on the number of books which 

 have been written on wireless telegraphy. Each year 

 sees fresh ones added to the list, and still an in- 

 satiable public, its imagination fired by the mys- 

 terious mechanism of this newest art. Is, Oliver Twist 

 like, asking for more. The two volumes before us 

 show how, in different manners, this craving may 

 be allaved. Maurice Solomo.n. 



