Notices respecting New Books. 759 



with those already described in connexion with the electro- 

 scope with the metallic coating on the outside of the glass 

 envelope. 



The experiments described above are to be considered as 

 preliminary. The phenomena are still under observation, 

 and we hope in a future communication to be able to give 

 further details with regard to the magnitude of the forces 

 concerned and the laws which govern their action. 



Since the paper was communicated to the Royal Society, 

 our attention has been called to a short paper by Sir William 

 Crookes, of 1879, published in the 'Proceedings of the Royal 

 Society,' in which certain movements of gold leaves in vacuum, 

 similar to those which we have observed, are described. 



LXIX. Notices respecting New Books. 



Electrons, or the Nature and Properties of Negative Electricity. By 

 Sir Oliver Lodge, P.R.S.,D.Sc, LL.D. London : GreorgeBell 

 &Sons. 1906. Pp. xvi + 230. 



n^HE discoveries of the past decade in physics will probably rank 

 -*- among the most important ever chronicled in the history of 

 science. To the mind of the average cultured person as well as to 

 the philosophic mind these discoveries appeal with an intensity 

 which cannot be rivalled by that of other scientific discoveries, 

 however important these may appear to the specialist. Por the 

 theories which have resulted from a detailed study of the phe- 

 nomena of cathode and Rontgen rays, and of radio-activity, have 

 enabled us to catch glimpses of the solution of that mysterious yet 

 intensely fascinating problem, which for so long a time has entirely 

 baffled human enquiry — the ultimate nature and constitution of 

 matter. Quite apart from the comparatively small class who have 

 made a special study of the subject, there are hundreds of educated 

 persons who take a keen interest in the results of scientific in- 

 vestigations directed towards it, even though they may be unable 

 to follow in detail the researches and arguments by which specialists 

 have been led to form their opinions. To all such we can cordiall} 1 " 

 recommend a perusal of Sir Oliver Lodge's latest contribution to 

 the literature of pure electrical theory. It will prove a most 

 useful guide to the serious student ; and will be found to be full 

 of interest to the general reader who has an elementary knowledge 

 of physics. Pew writers on scientific subjects can arouse the 

 interest and enthusiasm of their readers in the way which is 

 characteristic of Sir Oliver Lodge : and the work under notice 

 will enable any intelligent reader to form a clear idea of the present 

 state of a problem which has courted yet defied human enquiry 

 ever since the days of the Greek philosophers. 



