Chemistry and Physics. 455 



ing and novel phenomena in regard to liquids, which under cer- 

 tain conditions exhibit the phenomena of double-refraction. The 

 present volume is a further contribution to the same remarkable 

 subject in which the observations of the author and his asso- 

 ciates, particularly as the physico-chemical properties of the 

 liquids, are given in detail. These phenomena, in general, are 

 exhibited through a definite interval of temperature included 

 between the point of fusion and the " Klarungs-punkt," or that 

 at which the transition to the transparent isotropic fluid takes 

 place. The chapter discussing in detail the properties of these 

 two points, their relation to the density, their dependence upon 

 the pressure, upon the presence of foreign constituents and other 

 related points is of great interest. Another chapter not less 

 important, treats of the viscosity and other properties of the 

 " crystalline " and isotropic fluids. The author wisely makes free 

 use of the work of Lehmann and by this means is enabled, in a 

 limited space, to present an excellent summary of the entire 

 subject. 



13. " X" Bays: A Collection of Papers communicated to 

 the French Academy of Sciences with additional JVotes and In- 

 structions for the Construction of Phosphorescent Screens; by 

 R. Blondlot ; translated by J. Garcin. Pp. xii, 83 ; with phos- 

 phorescent screen (frontispiece) and other illustrations. London 

 and New York, 1905 (Longmans, Green & Co.). — The subject of 

 the "N"-rays* is one that has excited much attention, although 

 there have been some to raise the question as to the objective 

 reality of the phenomena described. In any case, however, it is 

 a matter of great interest to have the original papers of Professor 

 Blondlot translated and brought together in a single volume ; this 

 work has been well done by M. Garcin. Fifteen papers are in- 

 cluded, all reprinted as they were originally published in the 

 Comptes Rendus of the French Academy. A number of plates 

 are introduced which show the phenomena described, and the 

 frontispiece consists of a phosphorescent screen of calcium sul- 

 phide for use in the observation of the "N"-rays, and prepared 

 in accordance with the methods described in the closing pages of 

 the volume. 



14. Pas elektrische Poyenlicht, seine Entwickelung and seine 

 physikalischen Grundlagen y von W. B. voisr Czudnochow^ski, 

 Zweite Lieferung, pp. 99-194 ; dritte Lieferung, pp. 195-290. 

 Leipzig, 1905 (S. Hirzel). — The second and third parts of this 

 exhaustive work on the electric arc-light, announced in an earlier 

 number of this Journal, have recently been issued. These are 

 largely devoted to a historical discussion of the development of 

 the arc-light from the time of Volta and Dayy down to 1900. The 

 subject has now reached so definite and relatively simple a stage 

 that it is interesting to recall the many and varied attempts to 

 solve the problems which had to be made before success was 



* Named in allusion to the city (Nancy) at the university in which the 

 author is professor. 



