1'r.if. W. Ranisay and Dr. M. W. Travers. 



which confirms that made by Professor Kayser, of Bonn, and by Dr. 

 Friedliinder, of Berlin. 



At the same time we imagined that we had obtained a gas with a 

 spectrum differing from that of argon and yet of approximately the 

 >.imc density ; to this gas we gave the name metargon. It has now 

 been found that the presence of the so-called metargon is to be 

 accounted for by the fact that in removing oxygen from the mixture 

 of these gases, which was then in our hands, phosphorus containing 

 carbon was employed ; this mixture when burned in oxygen yields a 

 spectrum to some extent identical with that furnished by carbon 

 monoxide, but ditt'ering from it in as much as lines of cyanogen are 

 also present. We have no doubt that the so-called metargon, the 

 spectrum of which is visible only at high pressure, and only when 

 impure phosphorus has been employed to remove oxygen, must be 

 attributed to some carbon compound. In spite of numerous experi- 

 ments we have not yet succeeded in producing any gas in quantity 

 which yields this composite spectrum. It is only to be obtained by a 

 mixture of carbon monoxide with cyanogen. 



To obtain the heavier gases krypton and xenon, a large amount of 

 air was allowed to evaporate quietly; the residue was freed from 

 oxygen and nitrogen, and then consisted of a mixture of krypton, 

 xenon, and argon, the last forming by far the largest portion of the 

 gas; this mixture was liquefied by causing it to flow into a bulb 

 immersed in liquid air, and the bulk of the argon was removed as 

 soon as the temperature rose, the krypton and the xenon being left 

 behind. By many repetitions of this process we were finally successful 

 in separating these three gases from each other. While krypton has 

 a considerable vapour-pressure at the temperature of boiling air, the 

 vapour-pressure of xenon is hardly appreciable, and this afforded a 

 means of finally separating these two gases from one another ; in the 

 complete paper the operations necessary to separate them are fully 

 described. 



For neon the process of preparation was different. The air liquefier 

 furnished a supply of liquid air ; the gas escaping from the liquefier 

 consisted largely of nitrogen; this mixture was liquefied in a bulb 

 immersed in the liquid air which the machine was making. When the 

 bulb had been filled with liquid nitrogen a current of air was blown 

 through the liquid until some of the gas had evaporated. That gas 

 was collected separately, and deprived of oxygen by passage over red- 

 hot copper ; it contained the main portion of the neon and the helium 

 present in the air. The remainder of the nitrogen was added to the 

 liquid air used for cooling the bulb in which the nitrogen was con- 

 densed. Having obtained a considerable quantity of this light nitrogen 

 it was purified from that gas in the usual manner, and the argon 

 containing helium and neon was liquefied. By fractional distillation 





