222 LORD RAYLEIGH AND PROFESSOR W. RAMSAY ON ARGON, 
become slow, 162°843 cub. centims., measured at 757°7 millims. (corr.) pressure, and 
16°81° C., weighed 0°2683 grm. Hence, 
Weight of 1 litre at 0° and 760 millms. . . .  1°7543 grms. 
Density compared with hydrogen(O=16) . . 19°63 f 
This gas was again circulated over red-hot magnesium for two days. Before 
circulation it contained nitrogen as was evident from its spectrum ; after circulating, 
nitrogen appeared to be absent, and absorption had completely stopped. The density 
was again determined. 
(b.) 162,843 cub. centims., measured at 745°4 millims. (corr.) pressure, and 
17°25° C., weighed 0:2755 grm. Hence, 
Weight of 1 litre at 0° and 760 millims. . . . 1°8206 grms. 
Density compared with hydrogen (O = 16) . . 20°38 # 
Several portions of this gas, having been withdrawn for various purposes, were 
somewhat contaminated with air, owing to leakage, passage through the pump, &c. 
All these portions were united in the gas-holder with the main stock, and circulated 
for eight hours, 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-holder, but kept separate. 
(c.) 162°843 cub. centims., measured at 758°1 millims. (corr.) pressure, and 
17:09° C., weighed 0°27705 grm. Hence, 
Weight of 1 litre at 0° and 760 millims. . . .  1°8124 grms. 
Density compared with hydrogen (O= 16) . . 20°28 3 
The contents of the gas-holder were subsequently increased by a mixture of 
nitrogen and argon from 87 litres of atmospheric nitrogen, and after circulating, 
density was determined. The absorption was however not complete. 
(d.) 162°843 cub. centims., measured at 767°6 millims. (corr.) pressure, and 
16°31° C., weighed 0°2703 grm. Hence, 
Weight of 1 litre at 0° and 760 millims. . . . . 1°742 grms. 
Density compared with hydrogen(O=16). . . 19°49 _,, 
The gas was further circulated, until all absorption had ceased. This took about 
six hours. Density was again determined. 
(e.) 162°843 cub. centims. measured at 767°7 millims. (corr.) pressure, and 15:00°C., 
weighed 0°2773 grm. Hence, 
Weight of 1 litre at 0° and 760 millims. . . . 17784 grms. 
Density compared with hydrogen (O=16) . . 19°90 2B 
