13 Tendency of Elastic Fluids io Diffjision. 



pensate the diminution. Remaining air in the upper phiat 

 was a very liltle worse than common airj it being of the 

 standard 1-47, when the former was 1-44. The gas in the 

 under phial was still nitrous, and nearly of the same purity 

 as at first ; for throe parts of it required four of atmospheric 

 air to saturate them. 



3. Nitrous gas and one two-tliirds oxygenous were tried 

 in the same way. After four hours the apparatus was taken 

 down under water. The upper phial was two-thirds filled 

 with water, and the gas in it was partly driven down the 

 tube into the other phial, by which, and the previous pro- 

 cess, the nitrous gas was compiclely saturated, and nothing 

 but azotic, with a small portion of oxygenous, were found 

 in the under phial. The remaining gas in the upper phial 



xcas still one-half oxygenous. 



4. Nitrous gas and hydrogenous. In three hours the 

 upper phial was onc-fourlh nitrous, and of course the under 

 must have a like part 6f hydrogen. 



5. Nitrous gas and azotic. After three hours the upper 

 phial was one-fifth nitrous. 



In the two last experiments the quantity of nitrous gas 

 in the upper phial was less than might be expected ; but 

 the tube was at first filled with common air, and some must 

 enter on connecting the apparatus, which is suflicient to 

 account for the results. 



Fourth Class. 

 Azotic GaSf with Mixtures containing Oxygenous Gas. 



1. Azotic gas and one two-thirds oxvgcnous. After 

 standing three hours the upper phial was of the standard 

 1'7S, or about one- fourteenth oxygenous. 



2. Azotic gas with atmospheric air. After standing 

 three hours the upper phial Vv'as not sensibly diminished by 

 nitrous gas ; the under phial, however, had lost two per 

 cent., or onc-tcnth of its oxygen. The reason of this was, 

 that the azotic gas in this ocperiment, having been just 

 made for it from nitrous gas, this last had not been com- 

 pletely saturated with atmospheric air, and hence had seized 

 upon all the oxygon ascending into the upper phial. 



Havinjr 



