XL SCIENCE PROGRESS. 



The hiduction Coil in Practical Work. By Lewis Wright, pp. 172. 

 London : Macmillan & Co., 1897. 

 The enormous number of induction coils which during the last 

 years have come into general use, the users in many cases having no 

 previous experience in electrical matters, makes the publication of a 

 book giving practical direction as to the use of a coil of some value. 

 Mr. Wright not only describes in popular language the modern induc- 

 tion coil, and the practical details necessary to apply it to the production 

 of Rontgen rays, but also gives descriptions of other experiments which 

 can be performed with such a coil. Thus there are chapters on dis- 

 charges in partial vacua, spectrum work, and discharges in high vacua. 

 No doubt the book will be found of great service, particularly to medical 

 practitioners who are attempting to apply Rontgen rays to diagnosis. 



Elements of Electro-Cheiuistry. By Dr. Liipke. Translated by M. M. 

 Pattison Muir. London : H. Grevel & Co., 1897. 



This work is intended to give those who are not in a position to 

 make an exhaustive study of the subject an insight into the modern 

 theories of electro-chemistry and of the experiments by means of which 

 these theories are supported. The various laws are throughout deduced 

 directly from the result of experiment, and mathematical discussions are 

 only very sparely introduced. The experiments, which are very fully 

 described, are of the nature more of lecture experiments than of exact 

 quantitative determinations. Hence it follows that the book is more 

 suited as a handbook for use in a laboratory where the students perform 

 elementary physico-chemical experiments, or for the use of a teacher 

 who wishes to illustrate his lectures by experiments, than as a text-book 

 for the use of students anxious to know how the results have been 

 actually obtained. 



The first part of the book deals with the modern theories of 

 electrolysis, and in this section we find a consideration of Hittorf's 

 experiments on the velocity of the ions, Kohlrausch's work on the 

 electrical conductivity of dilute solutions, Arrhenius's theory of dis- 

 sociation. The second part deals with Van't Hoff's theory of solu- 

 tions, and contains chapters on osmotic pressure, vapour pressure 

 of solutions, boiling and freezing points of solutions, the connections 

 between osmotic pressure, vapour pressure, increase of boiling point 

 and lowering of the freezing point, and on the applications of Van't 

 Hoff's law to solutions of electrolytes. The third part deals with the 

 osmotic theory of the current in galvanic cells. This section includes 

 a chapter on Nernst's calculation of the E. M. F. of cells from the 

 osmotic pressure theory. In the next three chapters, which are on con- 

 centration cells, Daniell cells, and reduction and oxidation cells, the 

 formulae, etc., obtained m the first chapter of this section are applied. 

 There are also chapters on the solution pressure of the metals, intensity 

 of fixation and polarisation, irreversible cells, accumulators, and the 

 energetics of galvanic elements. The last chapter deals with so 



