1895.] Argon, a new Constituent of the Atmosphere. 281 



XII. Solubility of Argon in Water. 



Determinations of the solubility in water of argon, prepared by 

 sparking, gave 3 - 94 volumes per 100 of water at 12. The solubility 

 of gas prepared by means of magnesium was found to be 4'05 volumes 

 per 100 at 13'9. The gas is therefore about 2 times as soluble as 

 nitrogen, and possesses approximately the same solubility as oxygen. 



The fact that argon is more soluble than nitrogen would lead us to 

 expect it in increased proportion in the dissolved gases of rain water. 

 Experiment has confirmed this anticipation. " Nitrogen " prepared 

 from the dissolved gases of water supplied from a rain-water cistern 

 was weighed upon two occasions. The weights, corresponding to 

 those recorded in I, were 2'3221 and 2'3227, showing an excess of 

 24 milligrams above the weight of true nitrogen. Since the corre- 

 sponding excess for " atmospheric nitrogen " is 11 milligrams, we 

 conclude that the water " nitrogen " is relatively more than twice as 

 rich in argon. 



On the other hand, gas evolved from the hot spring at Bath, and 

 collected for us by Dr. A. Richardson, gave a residue after removal 

 of oxygen and carbonic acid, whose weight was only about midway 

 between that of true and atmospheric nitrogen. 



XIII. Behaviour at Low Temperatures* 



Preliminary experiments, carried out to liquefy argon at a pressure 

 of about 100 atmospheres, and at a temperature of 90, failed. No 

 appearance of liquefaction could be observed. 



Professor Charles Olszewski, of Cracow, the well-known authority 

 on the constants of liquefied gases at low temperatures, kindly offered 

 to make experiments on the liquefaction of argon. His results are 

 embodied in a separate communication, but it is allowable to state 

 htre that the gas has a lower critical temperature ( 121) and a 

 lower boiling point ( 187) than oxygen, and that he has succeeded 

 in solidifying argon to white crystals, melting at 189'6. The den- 

 sity of the liquid is approximately 1'5, that of oxygen being 1-124, 

 and of nitrogen 0'885. The sample of gas he experimented with was 

 exceptionally pure, and had been prepared by help of magnesium. It 

 showed no trace of nitrogen when examined in a vacuum tube. 



XIV. 'Ratio of Specific Heats. 



In order to decide regarding the elementary or compound nature 

 of argon, experiments were made on the velocity of sound in it. It 

 will be remembered that, from the velocity of sound in a gas r the 



* The arrangements for the experiments upon this branch of the subject were 

 left entirely in Professor Ramsay's hands. 



VOL. LV1I. * 



