ARGON, A NEW (CONSTITUENT OF THE ATMOSPHERE. 39 



to liberation of silicon, Imt it distillt'd ovei- in di-ojis into tlie cold |i;irL of tlie 

 tube. Again no change of volume occuned, nor was tlie surface of the distilled 

 sodium tarnished ; it was brilliant, as it is when sodium is distilled in vuciio. 

 It may probably also be concluded from this expcuimenL that silicon, even while 

 being liberated, is without action on argon. 



The action of compounds was then tried ; those chosen were such as lead to 

 oxides or sulphides. Inasmuch as the [)latinum-metals, which are among the most 

 inert of elements, are attacked by fused caustic soda, its action was investigated. 



(h) Fuml (Mid red-liot caustic soda. — The soda was pi-e[iared from sodium, in 

 an iron boat, by ad<ling drops of water cautiously to a lump of the metal. When 

 action had ceased, the soda was melted, and the l>oat introduced into a piece of 

 combustion-tube placed in the cii'cuit. After three hours' circulation no contrac- 

 tion had occurred. Hence caustic soda has no action on argon. 



(i) Soda-lime at a red, heat. — Thinking that the want of porosity of fused 

 caustic soda might have hindered absorption, a precisely similar experiment was 

 carried out with soda-lime, a mixtui-e which can be heated to bright redness 

 without fusion. Again no result took place after three hours' heating. 



(j) Fiised potasHinm lutrate was tried under the impression that oxygen plus 

 a base might act where oxygen alone failed. The niti'ate was fused and kept at a 

 bright-red heat for two hours, but again without any diminution in volume of 

 the argon. 



(k) Sodium, peroxide. — Yet another attempt was made to induce combination 

 with oxygen and a base, by heating sodium peroxide to I'edness in a current of 

 argon for over an hour, but also without effect. It is to be noticed that metals of 

 the platinum group would have entered into combination under such treatment. 



(1) Persidphides of sodium and calcium. — Soda-lime was heated to redness in 

 an open crucible, and some sulphur was added to the red-hot mass, tiie lid of the 

 crucible being then put on. Combination ensued, with tV)rmation of polysulphides 

 of sodium and calcium. This product was heate<l to redness for three hours in a 

 brisk current of ai-gon, again \vith negative I'esult. Again, metals of the platinum 

 group would have combined under such treatment. 



(m) Some argon was shaken in a tul)e with niti'o-hydrochloric acid. On addi- 

 tion of potash, so as to neutralize the acid, and to absorb the free chlorine and 

 uitrosyl chloi'ide, the volume of the gas was barely altered. The slight alteration 

 was evidently due to solubility in the aqueous liquid, and it may be concluded 

 that no chemical action took place. 



(n) Bromine water was also without effect. The bromine vapor was removed 

 with potash. 



