( 227 ) 



excess of piessure lui'1 to be applied it appeared that even iu the 

 remotest tube the mercurv soon stands still. After the adjustment 

 is made we usually wait 10 minutes to make sure that no further 

 change occurs. During that time several readings can be prepared 

 or taken, amongst others those of the 8 thermometers, indicating 

 the temperature. 



As the temperature during the observations is kept as equable as 

 possible, and as the cylindrical vessels have been taken as short as 

 possible (comp. § 2) the movement of the menisci of the mercurv- 

 columns through the alteration of temperature of the gas, after the 

 adjustment has been made, is very slight. 



(December 21ih, 1898.) 



