1 6 Ramsay, The Newly Discovered Elements. 



specific heats of neon, carried out, it is true, not with the 

 purest specimen of gas, but with a fairly pure specimen, 

 gave the ratio i : v66, as usual. 



This, then, was the long-sought-for element. Its dis- 

 covery fixes the correct place of argon in the Periodic 

 Table, and with it establishes the justness of the current 

 views on the meaning of the ratio between the specific 

 heats of mono-atomic gases. We must conclude that a 

 gas, with the theoretical ratio, may be imagined to consist 

 of spherical molecules, elastic and frictionless ; for, on the 

 kinetic theory, such would be the behaviour of spherical 

 particles with these properties. It may be that some 

 other conformation will equally fit the facts ; but of that 

 I am not able to judge. As for the explanation suggested 

 by Professor Boltzmann for the ratio i "4, found for di-atomic 

 gases, it may be correct ; but it is evident that it stands 

 on quite another footing. It is especially to be remem- 

 bered that it is not fair to place Boltzmann's theory on the 

 same level as that dealing with mono-atomic molecules ; 

 and I venture to think that the discovery of neon has 

 placed the latter on a firmer basis. 



But there is another gas, remaining as a residue after 

 the evaporation of very large quantities of liquid air, and 

 present in the atmosphere in exceedingly minute amount, 

 which will in all probability lend support to the kinetic 

 theory. We have named it " Xenon," or the " stranger." 

 Up to the present moment we have obtained it in only 

 small quantity; but we are collecting it, and, before long, 

 we shall be in a position to give a full account of its 

 properties. It has not been thoroughly separated from 

 "Krypton," the " hidden," which also remains as a residue 

 on the evaporation of liquid air, and which appears to be 

 an element of approximately the same density as argon, 

 namely, 20, and to be also a mono-atomic gas ; nor from 

 argon, which is difficult to separate from krypton. While 



