Intelligence and Miscellaneous Articles. 24 7 



Thus, if there were but one system per atom, the sum of: 

 the moments of the magnets in a cubic centimetre of gas at 

 standard temperature and pressure would, taking the number 

 of molecules in the cubic centimetre as equal to 3 X 10 19 , be 

 *30, which is about half the value of the same quantity for 

 oxygen, the most magnetic gas known. 



XVIII. Notices respecting New Books. 



Les Oscillations electriques : Principes clela Telegvaphiesans Jil. By 

 C. Tissot. Paris : Octave Doin et fils. — Theorie cles Moteurs 

 Thermiques. By E. Jouguet. Paris : Octave Doin et fils. 



T_)OTH of these small books belong to the useful series published 

 -*^ under the name of Encyclopedic Scientijique. The former con- 

 sists of a very clear summary of the principles underlying the modern, 

 theory of electric waves and their applications. Although it is 

 mainly mathematical vet the author is fully abreast of recent 

 experimental work, and his mathematics is selected so as to eluci- 

 date phenomena and not to display merely abstract properties 

 of equations. It can be recommended as giving a thoroughly 

 satisfactory presentation of the subject. 



The same attention to the practical side is paid in M. Jouguet's 

 volume on Heat Engines. Nevertheless it is only to the engineer 

 who wishes to discuss scientifically the principles of his practice 

 that the work will prove attractive. To such, however, the book 

 will be found to contain a very thorough elementary treatment of 

 the energy and heat relations of thermal transformations including 

 a complete discussion of the sources of loss of efficiency. Like 

 many others amongst the French School of Physicists, M. Jouguet 

 is specially good on the subject of ii reversible transformations. 

 Concerning his numerical data, perhaps it maybe pointed out that 

 the retention of the old formula for the connexion of latent heat 

 of steam with temperature, is liable to criticism in the light of 

 more recent determinations. 



XIX. Intelligence and Miscellaneous Articles. 



To the Editors of the Philosophical Magazine. 



ftFXTT ifMifv — The U niver sity, Glasgow. 



UEMXEME^, June 17th, .1910. 



T)EFERRINGr to Mr. W. J, Harrison's further statement in the 



-*-* / Phil. Mag. for June regarding my paper " On the Damping 



of Long Waves in a Rectangular Trough,'' Phil. Mag. [6] vol. xvii. 



pp. 154-164, I do not admit the legitimacy of his criticism but am 



undesirous of pursuing* the matter further. 



E. A. Hou*tou>\ 



