250 Mr GRAHAM on the Law of 



closely to the preceding ; but the return air was in slight excess 

 above the theoretical quantity. Thus, 



1 oxygen was replaced by 1.056 air, by experiment. 



1 1.054 air, by theory. 



Oxygen, therefore, affords a most striking confirmation of the 

 law. 



11. Nitrogen. Prepared by burning an excess of phosphorus 

 in a confined portion of air, and allowing the residuary gas to 

 stand over water for several days. 



Specific gravity, 0.9722. Root, 0.9860. Reciprocal of root, 

 1.0140. 100 nitrogen should be replaced by 98.60; and 100 air 

 should replace 101.40 nitrogen. 



Thermometer, 66. Barometer, 29.23. Diffusion into moist 

 air as in the preceding experiments. 



836 measures contracted 3 measures in two hours and forty 

 minutes, as corrected by standard ; and 13 measures in eighteen 

 hours, which was the maximum contraction ; for in twenty-three 

 hours and a half from the beginning of experiment, a contraction 

 of 12 measures was indicated. Taking the last as the true re- 

 sult, 



y^zr: 1.0143 = diffusion-volume of nitrogen by experiment. 

 1.0140 diffusion-volume of nitrogen by theory. 



12. Olefiant Gas. Specific gravity likewise 0.972, &c. as in 

 nitrogen. The gas was carefully made, collected in a low re- 

 ceiver, allowed to stand over water for twenty-four hours, and fi- 

 nally washed with caustic ley. 



Thermometer, 59. Barometer, 29.83. 800 measures of this 

 gas were replaced by 785 measures of air, in twenty-five hours, 

 correcting from standard. 



|^ 1.0191 =: diffusion-volume of olefiant gas, by experiment. 



1 80 



The contraction in this experiment is a little above the theo- 



