4IO 



NA TURE 



{March 3, 1887 



pr three of its medical graduates on the Senate, founded 

 an institute for the study of comparative pathology which, 

 under Sanderson, Klein, Greenfield, Roy, and Horsley, 

 has accomplished results of great benefit both to domestic 

 aniinals and to man. 



If, however, physiology and pathology are to some 

 extent provided with means for research, others of the 

 sciences allied to medicine and surgery are absolutely 

 destitute. Physiological chemistry has scarcely existed 

 in England since the days of Prout, and at the present 

 day there is not a single laboratory where this difficult 

 and important branch of knowledge is pursued. When 

 Dr. Gamgee's excellent text-book is completed, the Inde.x 

 Auctorum will scarcely contain an English name. 



Pharmacology — the experimental investigation into the 

 action of drugs — is another foi'eign science. Eraser and 

 Brunton have done much to redeem this country from 

 absolute sterility, but in London there ought to be a 

 laboratory like that of Prof. Schmiedeberg for this most 

 obviously and practically useful of all medical sciences. 



A laboratory for the study of Physiology would be the 

 most closely connected with the memory of Hunter, with 

 the Museum, and with the traditions of the College. A 

 laboratory of physiological, pathological, or therapeutical 

 chemistry would perhaps fill the most absolutely vacant 

 space. A laboratory devoted to the direct study of the 

 nature, origin, and propagation of Diseases, to their pre- 

 vention, and to surgical methods of treatment would be 

 the most directly useful and probably the most imme- 

 diately fruitful. 



So much is needful before England can begin to con- 

 tribute her fair share to the common sum of knowledge, 

 that it is scarcely possible to go far wrong in deciding 

 what branch of medical science should first be taken up. 



The Royal College of Surgeons has a great opportunity, 

 and one that is not likely to return. If the great acces- 

 sion to its resources should be frittered away on a multi- 

 tude of objects, the opportunity will be missed, and 

 probably for ever. But we cannot doubt that the leading 

 scientific surgeons in the kingdom will decide on using 

 the Wilson bequest for the endowment of some new and 

 urgently needed institution for research, which will be 

 an honour to the College, a credit to the nation, and an 

 instrument for increasing knowledge and diminishing 

 suffering for centuries to come. 



THE ELECTRIC MOTOR 

 The Electric Motor and its Applications. By T. C. 

 Martin and Jos. Wetzler. (New York : Johnson, 1887.) 

 /CONSIDERING the very rapid strides that have been 

 ^^ made during the past six years in the industrial 

 application of electric motors, the appearance of this 

 handsome volume, giving the latest information on this 

 topic, is thoroughly timely. It constitutes, though some- 

 what popular in style, a welcome addition to the library 

 of the electrical engineer. Those who are accustomed 

 only to the slow and steady development of industries in 

 the Old World can hardly appreciate the revolution that 

 is setting in in consequence of the employment, especially 

 in small workshops and factories, of electric motors in 

 place of steam-engines or gas-engines. They win their 

 way because, though the actual cost of power is no 

 cheaper, the expense of the electric motor is less than 



that of the steam-engine or gas-engine. It is less trouble- 

 some to keep in order, takes less room, runs at a more 

 uniform speed, and is more cleanly. What wonder, then, 

 that thousands — literally — of electric motors are already 

 in use in New England, where an invention is welcomed, 

 not sneered at, because it is new. 



Much of the volume before us has already seen the 

 light in another form in the pages of our American con- 

 temporary, th.t Electrical JVorld, but the matter has been 

 very carefully edited and arranged. It is by no means a 

 scissors-and-paste affair ; but a well-considered treatise, 

 abundantly illustrated with drawings of motors and of 

 their various applications. It treats the subject both 

 historically and systematically. 



The first chapter is devoted to an exposition of the 

 elementary principles of electric motors. Almost at once 

 we are plunged into the essence of the matter, the deve- 

 lopment in the armature of the motor of the counter- 

 electromotive force, that crux of the untrained electrician. 

 In this connection Jacobi's law, that the electric motor 

 does its greatest possible work when it diminishes the 

 original current to one-half, is given, and correctly giv-en, 

 not as a law of maximum efficiency, for which it has been 

 so often mistaken, but as a law of maximum activity. But 

 the authors have missed the point that Jacobi's law even 

 in this sense is only true when the condition of supply of 

 the electric energy is that of a given constant electro- 

 motive force. Jacobi's law would obviously not apply to 

 motors placed in a circuit in which the given condition of 

 supply was that of a constant current. The chapter con- 

 cludes with some very apposite remarks on the genera! 

 principles of construction of electric motors, quoted from 

 a paper in the Philosophical Magazine by an English 

 electrician, Mr. W. Mordey. 



Chapter II. is devoted to early motors and experi- 

 ments in Europe, from Barlow's wheel and the primi- 

 tive engines of Jacobi and Fromcnt down to the famous 

 Pacinotti machine. The complement to this narrative is 

 found in Chapter III., which deals with the early motors 

 and experiments in America, beginning with Davenport 

 in 1S37. The most celebrated of these was that of Prof. 

 C. G. Page, who succeeded in constructing a motor of 10 

 horse-power. The authors incidentally mention that, in 

 the period of the Civil War, between 1S60 and 1867 not a 

 single patent on electric motors was issued in America, 



Chapter IV. deals with the electric transmission of 

 power, as developed successively by Pacinotti, Fontaine, 

 and Marcel Deprez. In this connection the theory of the 

 efficiency of electric transmission is explained by the use 

 of graphic diagrams in which the areas are proportional 

 to the energy transmitted or to the work performed. The 

 experiments of Marcel Deprez are mildly criticised, and 

 rules for calculating the cost are given. 



The modern electric railway and tramway in Europe 

 occupy Chapter V. Here several of Sie nens's tramways 

 are described, also those at the Giant's Causeway, at 

 Brighton, and at Blackpool. Chapter VI. gives a similar 

 account of the modern electric railway and street-car line 

 in America. From this account it appears that .Mr. 

 Stephen D. Field is in America awarded the sole right to 

 use " the combination of an electric motor operated by 

 means of a current from a stationary source of elec- 

 tricity conducted through the rails," which " combina- 

 tion " he patented in 18S0. Drawings of the electric 



