228 Notices respecting New Boohs. 



no well-defined freezing-point could be detected. The iron, 

 however, was of very inferior quality, and by no means homo- 

 geneous. The glaze on the porcelain tube was attacked by 

 the iron, but the pyrometer was otherwise uninjured and 

 showed no change of zero. It should certainly be possible 

 with these instruments to observe the effects of various im- 

 purities in altering the melting-point even of steel, and it is 

 probable that the results in this case might be of some value 

 to manufacturers. 



XXII. Notices respecting New Books. 



Elementary Thermodynamics. By J. Paekee, M.A. 

 (Cambridge University Press.) 



n^HIS is an interesting work. It bristles with originalities. They 

 -*- are not always quite sound, but originality seldom is. The book 

 is very refreshing after the flood of text-books with which the 

 world of students is inundated. It is not written to suit any 

 syllabus. It is written to advance science by bringing forward the 

 methods and views of the author. These methods and views, even 

 where they are open to criticism from being ingeniously complex 

 or unreally simple, are those of an ingenious and original mind, 

 and are consequently worthy of serious consideration. 



As the book is full of matter that it would be interesting to criticise, 

 some few points only can be chosen. The division of forces into 

 contact-forces and ether-forces is interesting, though the descrip- 

 tion of contact-forces which implies that particles are absolutely 

 rigid is almost certainly an unreal simplification which is hardly 

 required in order to justify Thermodynamic principles, and which, 

 unless essential, should not have been introduced. This same 

 unnecessary simplification leads to a very curious calculation as 

 to the velocity of a molecule of ice (p. 118). Ether-forces are 

 gravitation, radiation-forces (by which radiation moves particles), 

 the causes of chemical, physical, electric, and magnetic actions. 

 " Radiation-forces are, of course, far too small to be detected by 

 instrumental means." Why " of course " ? What about Tesla 

 motors ? To these radiation-forces he attributes comets' tails, 

 without any the least explanation as to how they came to be due 

 to the forces which move particles when a body is w 7 armed by 

 radiation. Though he divides the Energy of a system into Mecha- 

 nical and non-Mechanical Energy, the latter being generally heat, 

 he does not seem at first clearly to distinguish Matter Kinetic 

 Energy and Ether Kinetic Energy. In these divisions and dis- 

 tinctions it would make it much easier to follow if the author had 



