"DYNAMICS" 231 



course very useful helps to the students of the general class of Natural Philosophy. 

 In the earlier days " Little T and T'" and Tait's Thermodynamics were the 

 only books which were serviceable in supplementing the lectures. The 

 former was a sealed book to the majority of those studying for the ordinary 

 M.A. degree ; and the latter in its first chapter covered a limited ground, 

 while most of the second chapter was too condensed food for the ordinary 

 mind to assimilate. We had, accordingly, to trust largely to the lectures, for 

 the mode of treatment and the illustrations given were peculiarly Tait's own. 



The article "Mechanics" which Tait contributed to the Encyclopaedia 

 Britannica in 1883 formed the foundation of an advanced text-book on 

 Dynamics, which was published in 1895 (A. and C. Black). Having used 

 paper-bound copies of the article as a text-book in his Honours Class for the 

 twelve intermediate years Tait was able, when its publication in usual book 

 form was determined on, to modify and improve along lines which experience 

 had indicated. As explained by Tait in the letter to Cayley quoted above 

 (p. 155), the Britannica article was originally planned by Maxwell; but the 

 details had to be arranged by Robertson Smith, the editor, so as not to 

 overlap other articles. The book accordingly, although largely a reprint, 

 contains sections on Attraction, Hydrodynamics, and Waves which were not 

 in the original article. 



If from the point of view of the student the book has a fault, it is that 

 of brevity and conciseness. But there can be only one opinion as to its 

 thoroughness and accuracy. The ground covered is greater than in any other 

 book on the subject, for it includes not only what is ordinarily understood by 

 Dynamics of particles and rigid bodies but also the more important parts of 

 elasticity and motion of fluids. The foundations are Newton's Laws of 

 Motion ; for although Tait had himself, in scientific papers and otherwise, 

 tried to devise a system free from the explicit assumption of Force in the 

 Newtonian sense, yet to the end he regarded Newton's Laws of Motion as 

 the most practical way of introducing the student to a study of the subject. 



Naturally there are strong resemblances between Tait's Dynamics and 

 " T and T'," especially in certain modes of proof; but in his own book Tait 

 restrains himself from treating developments which make a great demand 

 upon the mathematical knowledge of the reader. 



Occasionally the extreme brevity of a statement is such that the student 

 on a first reading fails to see immediately all that is implied ; but a critical 

 examination of such statements shows that they are complete without being 



