﻿1000 Notices respecting New Books. 



with the ring and tripod, which show that the difference 

 between the axial and radial coefficients increases, while the 

 axial coefficient diminishes more rapidly at low temperatures. 

 I have also investigated the expansion of a drawn silica 

 rod, 30 cm. long, by a Newton's ring method, giving one 

 whole ring for 10 ~ 6 expansion. The results will be published 

 by the Physical Society, and are of interest as confirming 

 the importance of the effects of strain. 



OIII. Notices respecting New Books. 



Physical and Chemical Constants and some Mathematical Functions. 

 By Dr. G. W. C. Kate and Professor T. H. Lajsv. Pp. vi + 

 153. Longmans, Green & Co. Price 4s. 6d. net. 



TT is not often that we would turn to a collection of data for 

 A stimulus : but there is something decidedly invigorating about 

 this new collection of physical and chemical constants. The 

 authors have evidently set before themselves the aim of making 

 use of the large amount of work of precision which has been done 

 in recent times and of discarding much that was becoming out of 

 date. Prom the point of view of general interest they have had 

 the advantage of the rapidly increasing amount of perfectly new 

 matter in connexion with radioactivity and ionization, and 

 especially of those data which apply particularly to the atom or 

 molecule. The presence of these, collected for the first time in 

 one volume, enhances the interest of the book. It gives one 

 in summary form an idea of the great achievements effected by 

 modern workers in science. 



The book must, however, be considered chiefly in regard to its 

 utility. The present writer, since the volume appeared, has 

 used it at every possible opportunity with the object of estimating 

 its utilitarian value. In making this estimate it must be 

 remembered that it does not attempt, as Landolt and Bornstein's 

 tables do, to give practically every datura of value. This would, 

 of course, be impossible in a work of its modest size and insig- 

 nificant price. The worker who wishes some guide as to what 

 has been ascertained on a particular subject ma}^ therefore go 

 away disappointed. The object clearly has been to include as 

 many as possible of those data which are constantly required 

 in connexion with research or teaching work ; and the success 

 is very great. There is no question that the authors will soou 

 find their book in every physical and chemical laboratory ; there 

 is no other that comes anywhere near it in utility. 



This being the case, it behoves us to point out a few particulars 

 in which improvement may perhaps be effected. 



On p. 5, the value of the gas constant P should be specified 

 as ergs per gram molecule, not per gram. The electrical and 

 magnetic definitions (pp. 5 & 6) require in some cases the speci- 

 fication of the medium (air or vacuum). The definition of specific 



