make himself master of the facts which they embody, an acquisition 

 which will be of much greater importance to him than any form of 

 words on which a demonstration may be more or less compactly con- 

 structed." 



There can be no doubt that Clausius was the first to throw a clear 

 light upon the then dark and doubtful foundations of Carnot's 

 theorem. Sir William Thomson writes of this in 1851, "the merit 

 of first establishing the proposition upon correct principles is entirely 

 due to Glausius." 



As Professor Willard Gibbs says, " Rankin was attacking the 

 problem in his own way with one of those marvellous creations of the 

 imagination of which it is so difficult to estimate the precise value." 

 The question of the amount of mechanical effect to be derived from 

 heat, he further says, " was completely answered, on its theoretic side, 

 in the memoir of Clausius, and the science of thermodynamics came 

 into existence." " It might be said, at any time, since the publication 

 of that memoir, that the foundations of the science were secure, its 

 definitions clenr, and its boundaries distinct." To Clausius then be 

 the honour of making a science of Thermodynamics. 



Clausius' subsequent work in this line consists essentially in work- 

 ing out the results of the law he discovered, and in investigating its 

 foundations on general dynamical principles applied to molecular 

 physics. In working out the results of his law he explored in two 

 directions. He applied his discovery to work out the theory of 

 the steam engine, and of many known phenomena, and also to dis- 

 cover properties of matter revealed by his analysis. This latter line 

 is contiguous with his exploration of the dynamical foundations of 

 the theory of heat. His analysis revealed the existence of eutropy as 

 a property of matter, a property for which mankind has no sense, 

 such as exists for feeling temperature, and which consequently 

 escapes attention, and is most difficult of apprehension ; so difficult, 

 indeed, that although fundamentally as important as temperature in 

 the theory of steam engines, its existence is ignored by all except the 

 very foremost amongst those who study the working of steam engines. 

 Clausius has left little to be done in the theory of heat engines 

 except to work out, in the lines he has laid down, the details that 

 experiments may prove to be most important. Clausius applied his 

 theory to investigate the laws of specific and latent heat, of saturated 

 steam, of the relations of heat and electricity in conductors, in ther- 

 mopiles, and in electrolytes, and to the laws of radiant heat. He 

 showed that radiant heat was no exception to the law that heat flows 

 of itself from hot to cold bodies, and so proved the futility of the 

 ingenious suggestion that the death of the universe by the degrada- 

 tion of energy might be avoided by the reconceutration of heat 

 radiations by reflection from the confines of the ether. He showed 



