491 



APPENDIX III 



ARGON, A NEW CONSTITUENT OF THE ATMOSPHERE 



WBITTEN BY PEOFESSOE MENDELEEFF IN FEBEUAEY 1895. 



THE remarks made in Chapter V., Note 16 bis respecting the newly discovered, 

 constituent of the atmosphere are here supplemented by data (taken from 

 the publications of the Boyal Society of London) given by the discoverers 

 Lord Bayleigh and Professor Kamsay in January 1895, together with obser- 

 vations made by Crookes and Olszewsky upon the same subject, 



This gas, which was discovered by Bayleigh and Bamsay -in atmo- 

 spheric nitrogen, was named argon l by them, and upon the supposition of 

 its being an element, they gave it the symbol A. But its true chemical 

 nature is not yet fully known, for not only has no compound of it been yet 

 obtained, but it has not even been brought into any reaction. From all that 

 is known about it at the present time, we may conclude with the discoverers 

 that argon belongs to those gases which are permanent constituents of the 

 atmosphere, and that it is a new element. The latter statement, however^ 

 requires confirmation. We shall presently see, however, that the negative 

 chemical character of argon (its incapacity to react with any substance), and 

 the small amount of it present in the atmosphere (about 1 per cent, by 

 volume in the nitrogen of air, and consequently about 1 per cent, by volume 

 in air), as well as the recent date of its discovery (1894) and the difficulty 

 pf its preparation, are quite sufficient reasons for the incompleteness of the 

 existing knowledge respecting this element. But since, so far as is yet known, 

 we are dealing with a normal constituent of the atmosphere * W S the 



From the Greet Ap-ybv inert, 



t bia In Note 16 bis, Chapter V., I mentioned that, judging from the specific gravity 

 of argon, it might possibly be polymerised nitrogen, N 5 , bearing the same relationship to 

 nitrogen, N^, that ozone, Oj, bears to ordinary oxygen. If this idea were confirmed, stilt. 

 one would not imagine that argon was formed from the atmospheric nitrogen by those; 

 reactions by which it was obtained by Eayleigh and Ramsay, but rather that it arises 

 from the nitrogen of the atmosphere under natural conditions. Although this proposition 

 is not quite destroyed by the more recent results, still it is contradicted by the fact that 

 the ratio of the specific heats of argon was found to be T66, which, as far as is now known, 

 could not be the case for a gas containing 8 atoms in its molecule, since such gases (sea 

 Chapter XIV., Note 7) give the ratio approximately l'8-(for example, CO,j). La abstain. 

 ing from further conclusions, for they must inevitably be purely conjectural, I consider, 

 it advisable to suggest, that in conducting further researches upon argou it ought be well. 



