SPECULATIVE SCIENCE. 153 



Newcomb's animadversions on my chapters on the kinetic theory of 

 gases and transcendental geometry. On the former he expatiates as 

 follows : 



For the benefit of the non-scientific reader we may say that there is no 

 theory of modern physics, the processes supposed by which are invisible to di- 

 rect vision, which is more thoroughly established than this. It explains with 

 the utmost simplicity and without introducing any but the best known prop- 

 erties of molecules, a great number of diverse phenomena, seemingly incapable 

 of explanation in any other way. The only objection of the author which we 

 can completely understand is that the theory in question i. e., the kinetic theory 

 of gases- seems to him incompatible with his own favorite doctrine that mole- 

 cules are inelastic. Should he have any hesitation in pitting his a priori idea 

 against so widely received a theory, it should relieve him to know that the sup- 

 posed antagonism arises only from his own misapprehension. No elasticity is 

 assigned the molecules in the Tcinetic theory, but only an insuperable, repulsive 

 force which causes the molecules to repel each other when they are brought suffi- 

 ciently near together. The reader who has any interest in following the author 

 in his attempt to show that Maxwell and his colaborers were guilty of a long 

 series of fallacies and errors in attempting to prove the theory in question, may 

 read the chapter, as an abstract is impossible. 



So " no elasticity is assigned to the molecules in the kinetic the- 

 ory." Well, that is startling news indeed ! I hope it has been con- 

 veyed to Sir William Thomson, who at latest accounts was still en- 

 gaged in the arduous, but, as we are now informed by Professor 

 Newcomb, utterly useless study of vortex-rings, which he hopes to 

 make available as substitutes for elastic atoms or ultimate molecules. 

 At the last meeting of the British Association Sir William Thomson 

 read a paper " On the Average Pressure due to the Impulse of Vortex- 

 Rings on a Solid," of which an abstract is published in "Nature" 

 for May 12, 1881 (vol. xxiv, pp. 47, 48). In this paper Sir William 

 says : 



The pressure exerted by a gas composed of vortex-atoms is exactly the 

 same as is given by the ordinary kinetic theory, which regards the atoms as hard 

 elastic particles. 



I do not' deem it necessary to multiply quotations from the writings 

 of other scientific men in support of my statement that the kinetic 

 theory of gases can not dispense with the assumption of the elasticity 

 of ultimate- molecules. No intelligent reader who has glanced at page 

 42 of my book can be in any doubt as to what is taught on the subject 

 by the founders and promoters of the theory in question. But I will 

 add one citation, because it is from a book to which I shall have occa- 

 sion to refer for another purpose. The most thorough mathematical 

 treatise on the kinetic theory of gases, indorsed as such by Clerk 

 Maxwell, is the well-known little book of Henry William Watson. It 

 is in the form of propositions ; and the very first words of the first 

 proposition are these : 



