( 110 ) 



TABLE IL 



Control measurement at mark m^ {PI. 1. Comm. xY". 117). 



of the water from the jacket (Table III, cols. H and 111) gives an 

 immediate opportunity of judging the degree of accuracy of the 

 pressure measurements. When everything mentioned in the foregoing 

 has been taken into consideration it appears that the pressure is 

 certain to within 0.02 mm. and, in favourable circumstances, to 



