258 Notices respecting New Books. 



the coefficient of m 2 in the general term being - -. 



Apparently the only cases wherein this admits of summation 

 are when m = (the point of contact), or m==2^2 (the 

 other end of the diameter) ; in the latter case we obtain 



i'rrpa 1 11 1 _7r 



~V~ ~3 + 5 7 + V 



so that the end density is 



p ~lbV 

 a result obviously also deducible from (7) by putting \i — \. 



XXIII. Notices respecting New Books. 



The Elements of Electro-Chemistry (treated experimentally). By 

 Dr. R. Lupke. Translated by M. M. Pattison Muir, 31. A. 

 London: H. Grevel and Co., 1897. 



TN this treatise the fundamental and elementary parts of electro- 

 ■*■ chemistry are presented in such a manner that it forms an 

 introductory text-book to the more exhaustive works of Ostvvald 

 and Nernst. The subject is divided into three parts, corresponding 

 with its historical development. The first of these treats of the 

 facts of electrolysis and the general laws of Faraday, Hittorf, and 

 Kohlrausch ; it terminates with an account of the dissociation 

 theory of Arrhenius in which electrolytes are considered as solutions 

 containing ions or dissociated molecules, and questions regarding 

 coefficients of ionization and heat of ionization are discussed. Ln 

 the second part a sketch of the physical theory of solutions is 

 given, leading up to a very short chapter on the apparently ano- 

 malous behaviour of electrolytes and the explanation of it given 

 by Arrhenius. This chapter appears unduly compressed, seeing 

 that the volume deals specially with electrolytic solutions. The 

 third part contains a description of Nernst's application of modern 

 theory to the chemistry and physics of the voltaic cell, which is 

 presented in an elementary manner. 



The volume requires very much revision, particularly in the 

 statements involving electrical units. Thus on p. 35 w T e find the 

 remarkable statement that " This quantity of electricity expresses 

 the electrochemical equivalent, that is to 8&y t the number of coulombs 

 which causes the separation, in one second, of that fraction of the 

 atomic weight of a metal, or of the [formula-] weight of an anion- 

 group, expressed in grams, which corresponds with a single 

 valency.' 1 (The italics are ours.) The translator adds a footnote 

 to elucidate the chemical part of the statement, but confirms the 

 two electrical errors involved in it. The confusion of amperes 

 with coulombs appears again later on the same page, and the 



