430 
LORD RAYLEIGH ON THE LAW OF THE PRESSURE OF GASES, ETC. 
Nitrous Oxide. 
Date. 
July 31-August 5, 1901 . 
August 8-24, 1901 
Mean 
B. 
1-00059 
1-00074 
1-00066 
Argon. 
Date. 
December 28-January 1, 1902. 
January 2-9, 1902 
B. 
1-00024 
1-00019 
Mean . . 1-00021 
The argon was from a stock which had been carefully purified some years ago and 
has since stood over mercury. In this case the two sets of observations recorded 
related to the same sample of gas imprisoned in the aj^paratus. In all other cases 
the gas was renewed for a new set of observations. 
With regard to the accuracy of the results it was considered that systematic 
errors should not exceed xoooo- comparison of one gas with another most 
of the systematic errors are eliminated, and the mean of two or three sets should be 
accurate according to the standard above stated. That nitrous oxide should show 
itself more compressible than according to Boyle’s law is not surprising, but there 
appear to be deviations also in the cases of oxygen and argon. Wliether these 
deviations are to be regarded as real departures from Boyle’s law, or are to be 
attributed to some complication relating to the glass or the mercury cannot be 
decided. At any rate thev are very minute. It will be noted that the oxvyen 
numbers are not so concordant as they ought to be. I am not in a position to 
suggest an explanation, and the discrepancies were hardly large enough to aftbrd a 
handle for further investigation. 
If we are content with a standard of - 5 Woc)» may say that air, hydrogen, oxygen, 
and argon obey Boyle’s law at the pressures concerned and at the ordinary 
temperatures (10° to 15°). 
Throughout the investigation I have been efficiently assisted by Mr, Gordox, to 
whom I desire to record my obligations. 
