THE KINETIC THEORY OF GASES. 287 



ing therefore into the predicted place in the Periodic Table. The 

 specific beat ratio of this new gas, to which the name "neon" or "the 

 new one" bas been given, is, as in the case of helium and argon, If; 

 like tbem, too, it resists combination with other elements and possesses 

 a brilliant and characteristic spectrum. 



This account of the fulfillment of a prediction has, I am afraid, been 

 somewhat elaborate for the general reader; but it is interesting as a 

 case of discovery, where many lines of evidence, founded on the work 

 of many different observers, have led to the foreseen conclusion. It 

 possesses, to my mind at least, some of the qualities of a scientific 

 poem : An orderly arrangement of ideas, drawn from man} 7 different 

 sources, each throwing light on the other, and all tending toward a 

 final event. It is true tbat the subject is not one to which poetical 

 diction can be applied with advantage; the details are too complicated, 

 too unfamiliar, and to be expressed only' in language which bas not 

 received the impress of poetical tradition ; but to enlarge on this would 

 opeu a wide field of discussion, in which aesthetics, a subject not as yet 

 reduced to accurate formulation, and perhaps hardly susceptible of 

 treatment by scientific methods, would form the chief theme. 



In epic poems the "argument" usually precedes the matter. Here 

 it may be convenient to reverse the order, and to sum up the preceding 

 pages by the argument. We have seen, then, that the discovery by 

 Lord Rayleigh of a discrepancy in the density of atmospheric nitrogen 

 has resulted in the discovery of a new constituent of air, argon; its 

 discovery has led to that of a constituent of the solar atmosphere, 

 helixim; speculations on the ultimate nature and motion of the parti- 

 cles of which it is believed that gases consist has provoked the con- 

 sideration of the conditions necessary in order that planets and 

 satellites may retain an atmosphere, and of the nature of that atmos- 

 phere; the necessary existence of an undiscovered element was fore- 

 seen, owing to the usual regularity in the distribution of the atomic 

 weights of elements not being attained in the case of helium and argon ; 

 and the source of neon was therefore indicated. This source, atmos- 

 pheric air, was investigated, and the missing element was discovered. 

 A new fact has been added to science, and one not disconnected from 

 others, but one resulting from the convergence of many speculations, 

 observations, and theories, brought to bear on one another. 



