ao8 PETER GUTHRIE TAIT 



Thermodynamics. The Natural Philosophy and Tail's Quaternions are 

 discussed in appropriate chapters. Here we shall consider more carefully 

 his contributions to the history of the doctrine of Heat and Energy. 

 For work of this kind Tail was admirably fitted. Having no claim to 

 be regarded as one of the founders of the modern theory of energy, he 

 was early in closest touch with four of the great pioneers, Joule, Helmholtz, 

 Thomson, and Rankine. He witnessed the striking development of the 

 fruitful ideas of last century, helped in no small way to forge and fix 

 appropriate nomenclature, and probably did more than any other single 

 man to spread a knowledge of the true meaning of the first and second 

 laws of Thermodynamics. Year after year he led his two hundred students 

 round the Carnot cycle, and impressed upon them his weighty reflections 

 on energy and matter ; but to a still larger audience he appealed through 

 his writings, and one of the most characteristic of his elementary books 

 is his Sketch of Thermodynamics. This book was the direct outcome of 

 a controversy with Tyndall as to the historic development of the theory 

 of heat. 



To write complete history when it is in the making is probably a 

 human impossibility. No man, however talented and well informed, can 

 see at one and the same time all the influences at work. Nor can he 

 trace accurately the manner of the working. The personal equation 

 necessarily enters in. The contemporary historian is apt to be biassed, 

 though it may be unconsciously. The mental picture will depend upon 

 the observer, just as witnesses of the same scene do not always tell the 

 same story. Such general considerations must be borne in mind when 

 we consider Tail's contributions to the history of modern science. 



At the same time it must be remembered that Tait diligently read 

 the literature of any subject in which he was specially interested ; and that 

 his knowledge and appreciation of the real significance of the far-reaching 

 work of the early half of last century were probably unsurpassed. His 

 great intimacy with Thomson and Maxwell, two of the geniuses of our 

 time, brought him into immediate contact with the springs of physical 

 thought. 



Bearing this in mind, no later historian can pass by Tait's attitude on 

 the history of the development of the doctrine of energy without a careful 

 consideration of the reasons for this attitude. These reasons Tait himself 

 gave frankly and fully. 



