8 



tlie apparatus, and the amount of tlie pressure was measured 

 by a column of mercury in an open manometer. There was 

 some difficulty in measuring the volume owing to the 

 occasional escape of bubbles of gas, which caused abrupt 

 alterations of the level. The results obtained are given in 

 the following table, which also contains a column of volumes 

 calculated on the supposition that the amalgam is a mere 

 mixture of fluid mercury and gas, allowance being made for 

 the pressure on the gas due to tlie column of mercury in the 

 amalgam itself The extreme case was assumed, namely, 

 that this additional pressure is represented by a column of 

 mercury half the height of the amalgam. 



