252 



slowly ; the temperature being read the instant that the meniscus coin- 

 cides with G. The vapor tension in cm. of mercury is then the difference 

 between the barometric reading and the height of the mercury column in 

 A plus the mercury equivalent of the liquid in A and pressure of air in 

 the vapor space. 



The principal advantage of this arrangement lies in the ease with 

 which one may secure a series of determinations at different temperatures 

 by merely raising D 5 or 10 cm. as soon as one determination is made, 

 and allowing the liquid in D to cool until the meniscus again coincides 

 with (J. In this way a series of ten or twelve determinations may be made 

 in a half hour. 

 Purdue VnivcrsHy, 

 LaFai/rttc, Ind. 



