382 Mr Mines, On the relative velocities of difiusion in 



The apparatus employed for this purpose is depicted in fig. 1. 

 It consists of a resistance cell of special shape. The platinum 

 electrodes are fused into opposite points in the wall of a glass 

 tube fifteen centimeters long and thirteen millimeters in internal 

 diameter, about twenty-two millimeters from the lower end, 

 which is sealed. During an experiment the mouth of the tube is 



Fig. 1. 



closed by a cork pierced b}^ a short tube in which slides the glass 

 plunger P. This is prevented from turning by the piece of 

 cork G, which, gripping the plunger and sliding loosely on the 

 rod R, acts as a guide. The plunger is raised and allowed to drop 

 every two minutes by a wheel moved by clockwork and having 

 two pins projecting from opposite spokes in the same direction as 

 the axis. 



