NATURE 



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THURSDAY, JULY 27, 1S83 



THE MODERN APPLICATIONS OF 

 ELECTRICITY 

 The Modern Applications of Electricity. By E. Hos- 

 pitaller. Translated and Enlarged by Julius Maier, 

 Ph.D. (London : Kegan Paul, Trench, and Co., 1SS2.) 



THIS book professes to be a popular account of all the 

 more important practical applications of electricity 

 that have during the last five years drawn so much public 

 attention to that science. No better popular book than 

 that of M. Hospitalier has appeared, and were it not for 

 certain defects, chiefly of style, the present translation 

 by Dr. Julius Maier would have been admirable. It 

 deals in a fairly easy and at the same time fairly accurate 

 manner with many technical matters, and will no doubt 

 prove a very popular work. Part I. treats of the sources 

 of electricity — batteries and dynamo-electric machines. 

 Part II., which is naturally the largest section of the 

 work, is devoted to Electric Lighting. Part III., the 

 least satisfactory perhaps of the whole, and the one that 

 has suffered most by the fact of being a translation of a 

 foreign work, comprises Telephones and Microphones. 

 In the fourth and last section a number of miscellaneous 

 applications are described, including Electric Motors. 



We have referred above to certain defects of style 

 apparent in the work before us. It is unusual, to say the 

 least, to speak of the " blades " of a battery in referring 

 to the plates of metal or electrodes. Still less usual is it 

 to call the electrode-poles "rheophores" ; a term which 

 probably a great many electricians in this country have 

 never used and do not know of. Neither is it usual to 

 speak of a steam-engine as a " vapor-motor." There are 

 objections against the novel use made by the author or 

 his translator of the term " electrodynamic " as a general 

 adjective to comprise both " magneto-electric " and " dy- 

 namo-electric " machines. The word " electrodynamic " 

 has already its own accepted use in the science ; and if 

 any extension of that use is necessary, all analogy requires 

 that that extension should be in a direction different from 

 that attempted. It is a dangerous experiment in a 

 " popular " book to meddle with accepted technical terms ; 

 for besides being misleading to the public when they sub- 

 sequently attempt to read other and more strictly scien- 

 tific books, it makes the author of the popular work look 

 as if he did not understand what he was writing a':out, 

 when he uses accepted terms in a meaning other than 

 their accepted one. There are other points that strike 

 one as defects. What will the ordinary reader make out 

 of such a sentence as that with which Chapter I. opens ? 

 " We can form a fairly exact idea of a battery by com- 

 paring it to a focus (sic) of heat ; for instance, the furnace 

 of a boiler." Or this (p. 14): "To continue our com- 

 parison between a battery, the focus of electricity and a 

 focus of heat, we say that polarisation in a battery is 

 analogous to the want of draught in a chimney." This 

 precious piece of nonsense is nearly equalled by the fol- 

 lowing : "The battery is only used now in law courts, in 

 national assemblies, and by some experimenters who for 

 some reason or other cannot set up a steam or gas 

 motor." (These italics are ours.) 



But worse than these mild absurdities there are a few 

 Vol. xxvi.— No. 665 



positive errors which no reviewer can conscientiously 

 pass over. There is so much that is excellent in M. 

 Hospitalier's work, that it might seem ungracious to point 

 them out. But the only way to keep up the standard of 

 popular scientific works is to point out where their scien- 

 tific sms lie. In ,i section devoted to electrical units, we 

 are first told that the "unit of intensity" is the ampire. 

 As the author habitually uses " intensity " for electro- 

 motive force (" it corresponds to what the French call 

 ' tension,' " he sa\s), we must beg to remark that the de- 

 finition is wrong. But the book goes on to say (p. S) : — 

 "The ampere is really a perfectly distinct quantity of 

 electricity, as a litre is a definite voiume, and a kilo- 

 gramme is definite weight." Wrong again ; for the 

 ampere is the standard unit of strength of current, and 

 not of either " intensity" or "quantity." To make mat- 

 ters worse, the author adds the following explanation : — 

 " If we say that the intensity of the current traversing a 

 wire is one ampere, we mean by that that the quantity of 

 the current traversing this wire during one second, if the 

 current preserves the same intensity, is one ampere." 

 This statement is happily contradicted by one standing 

 on the opposite page of the book, namely, that "a cur- 

 rent with an intensity of one ampere yields per second a 

 quantity of electricity equal to one coulomb." But how 

 is the unfortunate reader to know which of these to 

 believe ? 



The author and translator are more at home in the 

 applications of electricity. Here, however, we must pro- 

 test against several misstatements and errors. On page 

 81 comes the preposterous dictum that "Edison's coil is 

 exactly like Gramme's," a statement so absurd that we 

 have only to remind the reader that the Edison armature, 

 so far from being like that of Gramme, coiled on an iron 

 ring, is so precisely like that of Siemens, wound shuttle- 

 wise along a cylinder, that, as everybody knows, Edison 

 pays Siemens a royalty for the use of this principle. At 

 another part of the book the armature of the Brush ma- 

 chine is said to be "in principle a Pacinotti's ring," but 

 of that famous machine which anticipated that of Gramme, 

 not only in the employment of a ring-armature but in the 

 application of the segmental collector or commutator, and 

 which differs from Brush far more than it differs from 

 Gramme, the authors maintain a complete silence. They 

 speak of the Gramme " collector " as though Pacinotti 

 had never existed. 



Turning to incandescent lamps, we find those of Swan, 

 Lane-Fox, and Maxim, fairly described ; and due credit 

 is given to these pioneers of the principle of the incan- 

 descent lamp. But of Edison's lamp a very poor account 

 indeed is vouchsafed ; the filament-lamp of charred bam- 

 boo being just casually mentioned, whilst his older lamp, 

 with its horse-shoe of stamped paper, is figured and de- 

 described in detail. 



In describing Faure's accumulator, a modification (due, 

 we believe, to Dr. Fleming) consisting of a number of 

 lead trays, coated with red lead and piled up vertically, is 

 mentioned as if this were the original form. Moreover, 

 we doubt whether "the happy idea of filing up the space 

 between the lead plates used by Plante with red lead," 

 would by any means produce the result of "vastly in- 

 creasing the usefulness " of that excellent apparatus : it 

 would rather destroy it by short-circuiting it. 



