198 LORD KELVIN, DR. M. MACLEAN, AND MR. A. GALT, ON THE 



On drawing the air from the funnel by the side aperture near its lower end, and 

 testing it by the brass tubular filter, 0'18 centim. diameter (4 of 32), a mean of 

 four experiments showed 2'5 volts positive. 







Fig. 4. 



34. Arrangements were now made to test the effect of falling water upon air 

 only, uninfluenced by impact of drops on any hard solid. The metallic plate at the 

 bottom" of the funnel was removed, and the funnel, 24 6~ centlms. long, was placed 

 vertically in a position giving a clear fall of 640 centims. from the lower end of the 

 funnel to a water-trough below (see fig. 4). A new aperture was made in the funnel 

 near the centre. The filter used had 1 2 wire gauzes and 1 1 plugs of cotton wool. 



