May 



1905] 



NA TURE 



77 



creatures develop from eggs." Further comment is 

 needless. 



Although published in 190 1 and mentioned in the 

 Zoological Record for that year, this book has not 

 previously been brought under our notice. 



Second Stage Magnetism and. Electricity. By Dr. R. 



Wallace Stewart. Second edition. Re-written and 



enlarged. Pp. viii + 416. (London : VV. B. Clive.) 



Price y. 6rf. 

 This book is primarily intended to serve the purposes 

 of a candidate preparing for the second stage examina- 

 tion under the Board of Education (secondary 

 branch). In reading it, we have by no means made 

 our first acquaintance with Dr. Stewart, and the 

 perusal has left us of our old opinion that, whether re- 

 garded as te.xt-books intended to prepare a student for 

 a particular examination or as a source of culture, the 

 books prepared by the author can be very earnestly 

 recommended. He is a lucid and accurate writer. He 

 knows where to draw the line so that an elementarv 

 student shall not be repelled by the complication of a 

 subject. 



The present volume is brought up to date. The im- 

 portance of the field — that is, the medium surrounding 

 an electrified conductor or magnet — is insisted on ; 

 perhaps even their importance is emphasised too much. 

 The tendency of modern thought amongst physicists 

 is to restore to a conductor part, at any rate, of the 

 position that it held in pre-Maxwellian days. The di- 

 electric plays a most important part — that is a position, 

 won for it by Maxwell, which it can never lose. At 

 the same time, one should not lose sight of the fact that 

 there must be some mechanism at the ends of a line of 

 induction, and to-day that mechanism is being studied 

 under the name of electron. The electron is an essen- 

 tial part of a conductor, and the complete phenomena 

 of electricity are not fully accounted for without includ- 

 ing it. 



The volume is almost entirely re-written. It is not 

 surprising, therefore, that there are some unfortunate 

 slips which have escaped the vigilance of the reader. 

 As these are misleading, we will state that on the 

 bottom of p. 33 " positive " and " negative " should be 

 interchanged. The following phrase (p. 42) is very 

 misleading : — " The portions of those walls, which are, 

 as it were, in the shadow of these objects, possess no 

 induced charge." \\'e think that the first thirty pages 

 might be improved in any later edition. Consider- 

 able care has evidentlv been taken ; yet in many cases 

 confusion is introduced by the neglect of some tiny 

 detail. Thus, in describing the attraction and repul- 

 sion of a pithball with subsequent re-attraction, if in 

 the interval it comes i\i contact with an earth-con- 

 nected body, the phrase that we have put in italics is 

 omitted ; and in several cases where a body is touched 

 to earth it is not explicitly said whether the contact is 

 to be broken before a succeeding operation is per- 

 formed or not. Why is it " evident " (p. 16) that 

 doubling- a charge will double the force it exerts on 

 another charge? 



Memoria sohre cl Eclipse Total de Sol del dia 30 de 

 .Agosto de 1905. Bv D. .\ntonio Tarazona. Pp. 

 125. (Madrid : Bailly-Bailliere E. Hijos, 1904.) 

 Those who are familiar with the Spanish language 

 and have made up their minds to go abroad and see 

 the approaching total eclipse of the sun will find in this 

 book a great amount of useful information relating to 

 this interesting event. The work is issued from the 

 Madrid .Astronomical Observatory, the director, Fran- 

 cisco Iniguez, having- contributed a brief preface, and 

 contains full particulars concerning the elements of 

 this eclipse ; in fact, it n-iight be considered a treatise 

 on the subject, so complete is the information. In 



NO. 1856, VOL. 72] 



addition to a great many data which will be of 

 special use to astronomers, there will be found a 

 very full list of towns, in alphabetical order, at 

 which totality occurs, with the times of the different 

 phases of the eclipse. More generally useful 

 perhaps wi'l be found the maps at the end of the 

 volume. These include a map of the world showing 

 the position of the track from the commencement to 

 the end of totality over the earth's surface. A second 

 illustrates on a larger scale the Spanish portion of tlie 

 track, with special lines showing the times of occur- 

 rence and duration of totality. The third, on a much 

 larger scale (i : 1,000,000), indicates that part of Spain 

 alone over which the shadow sweeps, and is very com- 

 plete as regards names of places, railways, &c. Lastly, 

 two star charts are added, one showing the position of 

 the eclipsed sun among the stars, and the second a key 

 map to this chart giving the designations of the stars 

 and planets in this region. 



Visitors to Spain will do well to supplement their 

 literature by securing this volume, and thanks are 

 due to the Madrid Observatory for producing so useful 

 a book so far in advance of the event. 



N aturalistische iind religiose Weltansicht. By Rudolf 

 Otto. Pp. 296. [Tubingen : J. C. B. Mohr (Paul 

 Siebeck), 1904. J Price 3 marks. 



No better book than this could be recommended to the 

 young philosophical or theological student who wishes 

 to obtam a clear and comprehensive view of the de- 

 batable ground where science, philosophy, and 

 theology meet. The author is well read, a skilful 

 debater, a vigorous writer ; and as handbooks ought 

 not to be unnecessarily multiplied, it is to be hoped 

 that this one will be translated. 



Like many other works in defence of religion in 

 general, the book is not so strong on the constructive 

 as on the critical side. The author refers with 

 approval to the attitude of Kant when he solved cer- 

 tain contradictions or antimonies by a reference to the 

 world of things in themselves. As this is precisely 

 the point where Kant's philosophy is most seriously 

 questioned, the argument probably suffers to that 

 extent. But, on the other hand, the author fully 

 realises the unity of the various phases of the one 

 problem religion i<ersus naturalism, and the harm 

 which has been done by concentrating the attention 

 on one phase {e.g. the question of miracles) as if it 

 were the v^-hole. 



The work is valuable mainly for its survey of the 

 most interesting biological theories of the last cen- 

 tury, from Darwin, Hackel, Weismann, down to 

 Wo'lff, Korschinsky, Driesch. The philosophical de- 

 velopment of this last writer is sketched in an 

 enlightening fashion. With regard to the general 

 theory of "development and "descent," the author 

 comes to the conclusion that with the confirmation 

 of any such theory only something relatively external 

 is given, a clue to creation, which does not so much 

 solve its problems as group them afresh. The index 

 at the end of the work gives an explanation of the 

 more difficult terms employed by modern theorists. 



.An Introduction to Projective Geometry and its Ap- 

 plications. Bv Dr. Arnold Emch. Pp. vii + 267. 

 (New York :- 'Wiley and Sons; London: Chapman 

 and Hall, Ltd., 1905.) Price los. 6d. 

 This text-book of modern projective geometry forms an 

 admirable introduction to the subject, and should be 

 known to all who are interested in this branch of 

 mathematics. The first chapter deals with the general 

 properties of projective ranges and pencils and their 

 products, including harmonic and perspective projec- 

 tion, and the projective properties of the circle. Then 



