poiNCARE's "THERMODYNAMIQUE" 273 



those who recognised, as their own, some of the best " nuggets " that shine here and 

 there in his pages. His Kinematic was, throughout, specially open to this objection : 

 and it applies, though by no means to the same extent, to the present work. On the 

 other hand, the specially important and distinctive features of this work, viz. the homely, 

 yet apt and often complete, illustrations of matters intrinsically difficult, are entirely 

 due to the author himself.... 



The chief good of this book, and in many respects it is very good, lies in the fact 

 that the versatility of its gifted author has enabled him to present to his readers many 

 trite things, simple as well as complex, from so novel a point of view that they acquire 

 a perfectly fresh and unexpected interest in the eyes of those to whom they had 

 become commonplace. Surely this was an object worthy of attainment ! But it is 

 altogether thrown away on the non-mathematical, to whom neither new nor old points of 

 view are accessible. 



Tail's review of Poincare^s Thermodynamique appeared in Nature, 

 Jan. 14, 1892 (Vol. XLV). It is a good example of honesty in criticism; for 

 in spite of the great and deserved fame of the author, Tait could only 

 condemn the book as a physical treatise. 



The great expectations with which, on account of the well-won fame of its author, 

 we took up this book have unfortunately not been realised. The main reason is not far 

 to seek, and requires no lengthened exposition. Its nature will be obvious from the 

 following examples.. . . 



Some forty years ago, in a certain mathematical circle at Cambridge, men were 

 wont to deplore the necessity of introducing words at all in a physico-mathematical 

 text-book : the unattainable, though closely approachable, Ideal being regarded as 

 a work devoid of aught but formulae ! 



But one learns something in forty years, and accordingly the surviving members 

 of that circle now take a very different view of the matter. They have been taught, 

 alike by experience and by example, to regard mathematics, so far at least as physical 

 enquiries are concerned, as a mere auxiliary to thought.... This is one of the great truths 

 which were enforced by Faraday's splendid career. 



And the consequence, in this country at least, has been that we find in the 

 majority of the higher class of physical text-books few except the absolutely 

 indispensable formulae. Take, for instance, that profound yet homely and unpreten- 

 tious work, Clerk Maxwell's Theory of Heat. Even his great work, Electricity, though 

 it seems to bristle with formulae, contains but few which are altogether unnecessary. 

 Compare it, in this respect, with the best of more recent works on the same advanced 

 portions of the subject. 



In M. Poincard's work, however, all this is changed. Over and over again, in the 

 frankest manner (see, for instance, pp. xvi, 176), he confesses that he lays himself open 

 to the charge of introducing unnecessary mathematics: and there are many other 

 places where, probably thinking such a confession would be too palpably superfluous, 

 he does not feel constrained to make it. 



T. 35 



