1896.] On some Physical Properties of Argon and Helium. 203 



Fig. 1. 



D 



with a cap, D, perforated by two parallel slits. Eacli slit is \ in. 

 (6 mm.) wide, and the distance between the middle lines of the slits 

 is \\ in. (38 mm.). 



The arrangements for charging the tubes and varying the pres- 

 sures of the gases are sketched in fig. 2. A gas pipette, DE, com- 

 municates with the tube C, so that by motion of the reservoir E and 

 consequent flow of mercury through the connecting hose, part of the 

 gas may be transferred. The pressure was measured by a (J -shaped 

 manometer F, containing mercury. This was fitted below with a 



Fig. 2. 



p 2 



