274 



RECENTLY DISCOVERED GASES. 



decidedly diminished. The density was somewhat diminished, and 

 helium was stronger in the spectrum. The entire amount of neon had 

 become, by these operations, so divided up that it was not j)ossible to 

 carry out a further purification without preparing a greater quantity 

 of crude neon. On this Dr. Travers and I are at present engaged. 



In the meantime Mr. Baly has made exact measurements of the lines 

 of the neon spectrum, at the same time eliminating all the lines which 

 belong to argon and to helium by superposed x>lates. The values were 

 compared with iron lines photographed upon the same plate, and the 

 measurements were carried out by means of different pairs of these 

 known lines. The most important lines are the following: 



Most important lines of the new spectrum. 



Red. 



Red. Red. 



Yellow 

 (D 6 ). 



Green. 



Blue. 



6402 

 6383 

 6335 



6267 

 6218 

 6164 

 6143 



6096 



6074 

 6030 



5853 



5401 



' 5341 



5331 



*4716 



4722 

 4710 

 4709 

 4704 



* The third figure in this number is probably a misprint (Tr). 



Up to the present we have had little time to study thoroughly the 

 other companion of argon in the atmosphere. Dr. Travers and I have, 

 however, worked upon it. The heavier fraction of the air contains three 

 gases, one of which appears very perplexing. We have named it 

 "metargon." This gas remains, mixed with excess of argon, after the 

 evaporation of liquid air or argon. Up to this time we have not suc- 

 ceeded in obtaining it in a condition free from argon. Its peculiarity 

 is that when it is mixed with oxygen and subjected to the influence of 

 the electric spark in presence of caustic potash it shows constantly the 

 " Swan-spectrum" as of carbon monoxid. We have treated a mixture 

 of carbon monoxid and argon in a similar way, and, after fifteen minutes 

 sparking, all the carbon had disappeared; in a Pliicker tube no trace 

 of the carbon spectrum could be recognized. I will, however, not yet 

 venture to express an opinion as to the nature of this gas. It needs 

 further investigation, and for this at present we have no time. 



As regards krypton, which is distinguished by three brilliant lines, 

 one in red, one in yellow and one in green, we are in much the same 

 position. We have collected a considerable quantity of the impure gas, 

 which shows the spectrum finely, although that of argon is also present. 

 We hope that we shall soon be able to pursue this portion of our work 

 further. We can merely note here that the specific gravity of the gas 

 which shows this spectrum in such a marked way is not far different 

 from that of argon. 



The heaviest of these gases we have weighed, although in impure con- 

 dition. Its density is 32.5. I need not call your attention to the fact 

 that there is space for an element of the helium group between bromin 



