Determining the Vapour Pressures of Solutions. 379 



(Plate 1.) 



The essential part of the apparatus is as follows : b b' (Plate 1, 

 figs. 1, 2) are two horizontal circular plates of tinned brass. K is a 

 vertical glass cylinder which is gripped between them. The two 

 junctions are made fast with india-rubber bands. 



Five vertical brass rods (of which two, fa fa, appear in the figure) 

 hold the plates b V and cylinder K in position. The combination 

 will in future be referred to as the " drum." GK Gr 2 are two cylindrical 

 tubes ; the lower part of each is made of tinned brass, the upper 

 of glass. They are destined to hold pure water and solution respec- 

 tively. Outside and below the drum they terminate in a pair of 

 three-way taps t y U. 



Pi P 2 are two pipettes, each passing through both lid and base of 

 the drum. Each pipette can be connected to the corresponding Gr-tube 

 in the manner shown in the plate (fig. 2). The upper extremities of 

 the pipettes are placed in connection by a horizontal tube A. 



B is a boiler, and the steam generated in it passes along A, 



VOL, LXII. 2 B 



