30 ARGOK, A NEW CONSTITUENT OF THE ATMOSPHERE. 



magnesium was 19.086, and allow inir for (.•ontraciion on sparking uitli oxygen the 

 density is calculable as 20.01. The following determinations of density were also 

 made : 



(a) After absorption in glass tubes, the water circulator having been used, and 

 subsequent circulation by means of meicuiy ciixnilator until the rate of contraction 

 had grown slow : 



162.843 cubic centimeties, measured at 737.7 mm. (coir.) pressure and 

 16°.81 C, weighed 0.2683 gramme. Hence, 



Weight of I litre at o° and 760 mm i-754i grammes. 



Density compared with hydrogen (O = i6) 19-64 



This "iifi was acrain circidated over red-hot magnesium foi' two days. Befoi-e 

 circulation it contained nitrogen, as was evident from its spectrum ; after circu- 

 lating, nitrogen appeared to be absent, and absorption had completely stopped, and 

 thf density was again determined. 



(b) 162.843 cubic centimetres, measured at 745.4 mm. (corr.) pressure and 

 17°.25 C, weighed 0.2735 gramme. Hence, 



Weight of I litre at 0° and 760 mm 1.8206 grammes. 



Density compared with hydrogen (O = 16) 20.38 



Several portions of this gas having been withdiaw 11 t'oi- various pui'poses were 

 somewhat contaminated with air, ow ing to leakage, passage thiough the pump, etc. 

 All these portions were united in the gas-holder with the main stock, and circulated 

 for eight houns, during the last three of which no contraction occurred. The gas 

 removed from the system of tubes by the mercury-pump was not restored to the 

 gas-holdei', but kept separate. 



(c) 162.843 cubic centimetres, measured at 758.1 mm. (corr.) j)ressure and 

 17°.09 C, weighed 0.27705 gramme. Hence, 



Weight of r litre at 0° and 760 mm 1 .8124 grammes. 



Density compared with hydrogen (O = 16) 20.28 



The contents of the gasholder were subsequently increased by a mixture of 

 nitrogen and ai'gon from 37 litres of atmospheric niti'ogen, and after circulating, 

 density was determined. The absorption was, however, not complete. 



(d) 162.843 cubic centimetres, measured at 767.6 mm. (corr.) pressure and 

 16°.31 C, weighed 0.2703 gramme. Hence, 



Weight of r litre at o" and 760 mm i . 743 grammes. 



Density compared with hydrogen (() = 16) i9-S4 



