



The Ottawa Naturalist. 



Vol. IX. OTTAWA, AUGUST, 1895. No. 5. 



* ARGON: A NEWLY DISCOVERED CONSTITUENT OF 



THE ATMOSPHERE. 



By Frank T. Shutt, M.A., F.I.C., F.C.S. 



Our first knowledge regarding the chemical constitution of the 

 atmosphere may be said to date from Priestley's time. In 1774 this 

 English chemist discovered Oxygen by the experiment, now historical, 

 of heating the red oxide of mercury by means ot the sun's rays, collect- 

 ed and focussed by a burning glass. He worked out somewhat its 

 chemical properties and made known its essential characteristic as the 

 great supporter of animal life and of combustion. He termed it 

 " Dephlogisticated air" because, as he said, " it is so pure, so free from 

 phlogiston," the hypothetical principal of inflammability of an obsolete 

 theory. 



Two years previously, Rutherford, Professor of Botany in Edin- 

 burgh, had experimented with the residual gas produced by respiration 

 of animals in closed vessels containing air. He found it to contain a 

 gas (carbonic acid) that could be absorbed by caustic potash and further 

 a colourless gas, which could not thus be absorbed, that extinguished 

 the flame of a candle and did not support animal life. This was the 

 discovery of phlogisticated air or Nitrogen. 



Scheele, a Sweedish chemist, was, perhaps, the first to recognize 

 clearly that the atmosphere consisted of these two gases. He confirmed 

 the results of Priestley and Rutherford, bringing them together and 

 establishing from them the dual character of the atmosphere. 



So far, however, all the work was of a qualitative character. 

 Cavendish, another English chemist (1731-1810), was the one who 

 established by careful, thorough and skilful quanitative work the com- 



fRead before the Toronto University Club of Ottawa, May 10th, 1895. 



