252 



sldwly; the temperature beiiif? read the instant that the meniscus coin- 

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

 between tlie l)arometric readinj; and the heiglit of tlie mercui'y column in 

 A plus the mercury etiuivah-nt of the liquid in A and pressure of air in 

 the vapor space. 



The principal advantai,'e of this arrangement lies in the ease with 

 which one may secure a series of determinations at different temperatures 

 by merely raising D n (ir 10 cm. as soon as one determination is made, 

 and allowing the licpiid in I) to cool until the meniscus again coincides 

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

 in a half hour. 

 Purdue Vnivcrslty, 

 LaFayettc, Ind. 



