Argon. 101 



than that of atmospheric nitrogen not so treated. This served to 

 corroborate their previous results and conjectures. 



The preparation of argon on a large scale is a tedious process. It 

 involves first the separation of the oxygen by red hot copper and the 

 drying by chemicals of the remaining gas. It is then passed several times 

 over magnesium turnings heated to bright redness. For this 



purpose mercury gas holders and a Sprengel vacuum pump are used. It 

 takes at least two days to effect perfect elimination of the last traces of 

 nitrogen. 



The density of this gas argon as calculated from a mixture with 

 oxygen, is 19.7, and on the assumption of its proportional amount in 

 atmospheric nitrogen -20.6. As prepared from Nitride of magnesium, 

 the average density from a number of determinations in 19.90. This 

 gas gave no spectrum of nitrogen in the vacuum tube. 



It would avail little for me to give here a minute account of the 

 characteristic lines of the spectrum of argon. Mr. Crookes, whose 

 assistance as an authority on spectrum analysis was asked, has made a 

 careful record of the wave-lengths. Part of the evidence from this work 

 would seem to indicate that argon is a mixture and not an element, 

 since two distinct spectra at different temperatures were noticed. We 

 however, know that the spectrum of certain elements is apt to vary with 

 the temperature and pressure under which the experiment is made. 

 Mr. Crookes concludes "that Lord Rayleigh and Prof. Ramsay have 

 added one, if not two, to the family of elementary bodies " 



Argon is about two and a half times as soluble in water as nitrogen. 

 It has been proved that dissolved gases from rain water furnish 

 " nitrogen" considerably heavier than true pure nitrogen. This greater 

 solubility of argon has already suggested a method for its preparation. 



To Professor Olszewski, of Cracow, was first assigned the task of 

 determining argon's physical constants, His results are that it has a 

 lower critical point and a lower boiling point than oxygen. He has 

 liquefied it and, further, solidified it to white crystals. At ordinary tem- 

 perature it is a colourless, odourless gas. 



The ratio of its specific heat, the result of a number of experiments, 

 calculated from the velocity of sound in it, is 1.66. That for diatomic 

 gases varies from 1.29 to 1.42. From the fact now recorded it appears to be 



