ARGON, A NEW CONSTITUENT OK THE ATMOSPHERE. 



33 



Two of the most characteristic lines, which are easily seen in an ordinary 

 pocket spectroscope, and which sei'ved at once to identify the gas, are in the least 

 refrangible part of the red end of the spectrum. Their wave-lengths are 696.56, 

 705.64 M. They cannot be mistaken for lines of any other substance, because 

 they are so much less refi-angible than any otlier conspicuous red lines. We 

 ap})end a slip on which Mr. Crookes has registered the lines of both spectra. 



Mr. Crookes has compared the spectra of the two samples of gas, one prepared 

 by means of magnesium, the other by sparking with oxygen ; the gases were both 

 in vacuum tubes. He says : 



" There can be no doubt as to theii' identity in all the chief lines." Professor 

 Schuster has also kindly made a comparison of the spectra of the two samples of 

 gas, using a Leyden jar, and sparking at atmospheric pressure. He states that the 

 ten chief lines of both specti-a ai'e identical. These obsei-vations place it beyond 

 question that the gas produced by both processes is the same in the main ; but 

 until the absolute identity of both specti'a is proved, it is possible that one sample 

 may contain some gas not present in the other. 



12. Solubility of Argon in Water. 



The tendency of the gas to disappear when manipulated over water in small 

 quantities having suggested that it might be more than usually soluble in that 

 liquid, special experiments were ti'ied to determine the degree of solubility. 



The most satisfactory measures relating to the gas isolated by means of oxygen 

 were those of September 28th. The sample contained a trace of oxygen, and (as 



