366 



NA TURE 



[August i8, 1898 



moment, and cannot be said to affect adversely in any 

 degree the purpose that the volumes were intended to 

 fulfil. If to what has already been said in their favour, 

 it is added that they are illustrated with fifteen litho- 

 graphic plates containing over one thousand figures, it 

 will be evident that Dr. Chyzer and Prof Kulczyiiski 

 have produced a work which will take rank as one of the 

 most important contributions to our knowledge of 

 European spiders that has appeared this century. 



R. I. POCOCK. 



OUR BOOK SHELF. 



Electrodyna7nics : The Direct Current Motor. By C. A. 

 Carus-Wilson, M.A., late Professor of Electrical 

 Engineering, McGill University, Montreal. Pp. 298. 

 (London : Longmans, Green and Co., 1898.) 



In no department of applied science has advance in the 

 last few years been more striking than in the application 

 of the continuous current motor to traction purposes. 

 This rapid advance has, however, until quite recently 

 been rather in the United States, in Canada, and on the 

 Continent, than in our own country. The appearance of 

 this book by Prof Carus-Wilson, of the McGill Uni- 

 versity, dealing with those problems which face the 

 electrical engineer when deciding upon the choice of 

 motors, is therefore singularly opportune. 



The growth of our great towns has brought about an 

 ever-increasing demand for rapid transit combined with 

 frequent stoppages. In all the new schemes for under- 

 ground electric railways in London an attempt is being 

 made to combine these two opposing requirements. The 

 starting torque or accelerating power of a motor is its 

 most important merit from the traction engineer's point 

 of view. Prof Carus-Wilson lays considerable stress 

 on the properties of series and shunt wound motors at 

 rest before proceeding to treat of his subject in a more 

 general way. His graphical methods of attacking the 

 various mechanical problems are very carefully worked 

 out, and the book is illustrated throughout by a remark- 

 able series of very neat and clear diagrams — some 

 theoretically obtained, and others the result of experi- 

 ments on the tractive force and acceleration of actual 

 electric locomotives. 



The author makes use of many new terms, the meaning 

 of which one does not fully appreciate on a first reading. 

 Many expressions are used in quite an unusual sense, as, 

 for example, " magnetisation curve," meaning a curve of 

 distribution of magnetic flux. The term "acceleration 

 curve " is also applied where one would be inclined to 

 say "curve of velocity." These differences of language 

 are, however, no doubt inseparable from the originality 

 of the author's methods. 



The book, though not a large one, is yet undoubtedly 

 an important contribution to technical literature. 



D. K. M. 



A Trip to Venus. By John Munro. Pp. 254. (London : 

 Jarrold and Sons, 1897.) 



The apparent similarity between the physical conditions 

 of the planet Mars and those which exist upon the earth 

 have furnished several writers with material upon which 

 to exercise their imaginations. Many considerations 

 point, however, to the earth's twin sister, Venus, as 

 possessing conditions of habitability more closely re- 

 sembling those enjoyed by us than would be found on 

 Mars, which fact has given Mr. Munro a text for this 

 novel. 



The prescription for a story on extra-terrestrial affairs 

 appears to contain as essential constituents a description 

 of a flying machine in which " a new force " is utilised, 



NO. 1503, VOL. 58] 



a modicum of astronomical information, a few senti- 

 mental episodes, and some representations of wonderful 

 forms of organic life observed in the "other world" 

 with which the narrative is concerned. Mr. Munro 

 departs but very slightly from this formula. The actors 

 in his little drama are a gentleman who represents the 

 mind of the average man and tells the story, an 

 astronomer who speaks like a text-book, an inventor 

 who constructs a flying machine of marvellous efficiency, 

 and a young lady whose presence naturally introduces 

 into the narrative the vein of sentiment without which 

 no novel is complete. This is the company which 

 makes the trip to Venus and Mercury, and brings back 

 information as to the inhabitants of those planets and 

 on various other objects and phenomena which, un- 

 fortunately, astronomers have to actually observe from 

 the bottom of a restless atmospheric sea. 



It is perhaps a doubtful compliment to say that a 

 work of fiction is instructive, but we cannot resist 

 paying it in the present case. As a story Mr. Munro's 

 novel is but of indifferent quality, but as a series of 

 short disquisitions upon astronomical matters, more or 

 less worked into a narrative, the book is worth reading, 

 especially as it possesses the merit of correctness so far 

 as it goes. 



The idea of the supposed inhabitants of Mars signalling 

 to the earth by burning different elements, which are 

 subjected to spectroscopic analysis by the astronomer of 

 the party, is noteworthy, and it is a pity that the author did 

 not make more of it. The description of the meeting of 

 the Royal Astronomical Society, given in the last chapter, 

 is a disappointing and unnecessary epilogue of the story.. 



A Dictionary of Bird Notes, Qt'c. By C. L. Hett. 

 Pp. 138. (Brigg: Jackson, 1898.) 



This little volume is obviously intended for the field- 

 observer, being bound with the corners rounded off and 

 blank pages for notes opposite the pages of letter-press. 

 The author has secured the cooperation of a number 

 of fellow bird-lovers ; and their joint labours have 

 resulted in the production of a syllabic reproduction 

 of the notes of every British bird, which it may be 

 hoped will prove satisfactory not only to themselves but 

 to ornithologists in general. Judging from his preface,, 

 the author himself appears to be confident that he has 

 achieved complete success, but we fear that many 

 persons would require a supplemental education before 

 they are capable of appreciating the merits of his 

 scheme.. The correctness of many of the notes are 

 self-apparent, but some are decidedly difficult of pro- 

 nunciation by the uninitiated, and it is to be hoped that 

 many of his readers are unfamiliar with the precise tone 

 of "the snore of a drunken man," which is given as one 

 of the notes of the chaffinch. 



The glossary of popular, local, and old-fashioned 

 names of British birds, which forms one of the appendices, 

 will certainly prove useful to young ornithologists dwell- 

 ing in the provinces, and may sometimes even be a help 

 to their more experienced brethren. R. L. 



Chemical Analysis, Qualitative and Quantitative.. 

 By W. Briggs, M.A., and R. W. Stewart, D.Sc. 

 Pp. x -I- 128. (London : W. B. Clive.) 



The pupil who uses this book ought to obtain an intelli- 

 gent grasp of the principles of chemical analysis. A 

 chapter on simple experiments in manipulation leads to 

 chapters on the reactions of the various groups of metals 

 and the acids, and these are followed by instructions for 

 systematic analysis, analysis of mixtures, and volumetric 

 work. The instructions are clear and concise, but, as 

 might be expected from the nature of the subject, the 

 book departs but little from the style of others of the- 

 same kind. 



