48 
PROFESSOR RAMSAY AND DR. AY. TRAA^ERS 
“ Metargon.” It will be remembered that Professor Schuster, in a letter to ‘Nature’ 
(vol. 58, p, 199, June 30, 1898) pointed out that the spectrum of metargon presents a 
close analogy with that of carbon in the “ Swan ” spectrum. This we verified, and 
subjected the gas to prolonged sparking with oxygen in presence of caustic soda, 
attempting thus to oxidise and remove the carbon compound. The carbon spectrum 
was, however, still visilJe in a “ Pllicker” tube at a pressure of several millimetres 
of mercury. We were inclined to ascribe this spectrum to the presence of a 
compound of carbon with one of the usually inert gases. But we have since failed 
to detect this spectrum ; and we think it probable that in removing oxygen from the 
sparked gas some carbon was introduced with the phosphorus we then used. Bemsex 
(‘ American Chemical Journal,’ V, No. 6) has drawn attention to the fact that some 
specimens of yellow phosphorus contain carbon, probably in combination, and that on 
burning the })hos})horus, carbon monoxide and dioxide are formed. After the sup¬ 
posed purification from carboii compounds, we must have introduced carbon monoxide 
into the argon of which the bulk of the sample of gas consisted, and still recognising 
a spectrum similar to that of carbon, we ascribed it to the presence of “ metargon.” 
J’he phosphorus we at present em})loy does not produce such a spectrum, and 
we must therefore withdraw our statements regarding this supposed gas. 
On making a mixture of pure yellow phosphorus with powdered charcoal, and 
using it to remove oxygen from argon, the spectrum of the remaining gas was 
identical with that which we described as “ metargon,” even to the Imight bands in 
the violet, wliicli are not present in the spectrum of pure carbon monoxide, but 
winch are visible in tlfat of cyanogen. Some crude phosphorus, kindl}^ given us by 
Mr. George Albright, gave the same spectrum, when used to remove oxygen from 
argon. 
We can only express our regret that such a simple cause has led us into an 
erroneous statement, which we here retract. 
It will be seen from what follows that tlie inert gases of. the atmosphere form a 
well-defined series parallel to that of the halogens, and of the metals of the alkalies. 
Thus we liave :— 
? Fluorine. Chlorine. Bromine. Iodine. 
Helium. Neon. Argon. Krypton. Xenon. 
Lithium. Sodium. Potassium. Ilubidimn. Cmsiurn. 
It is unlikely tliat any gas possessing an atomic weight higher than that of 
xenon is to be found in atmo,spheric air. Tlie (piestion as to the precursor of helium 
will be discussed later. Tbe atomic weights of these gases are taken as twice their 
densities, on the apparently well-founded assumption that the ratio 1'66 between the 
specific heat at constant volume and tliat at constant pressure implies that the 
molecule and tlie atom are identical. If this assumption, which is full}" justified on 
physical grounds, is denied, then these elements can find no place in the jieriodic 
