162 Scientific Proceedings, Royal Dublin Society. 
Here we have the following results:—As 38 increases the 
evaporation increases; 7’, on the whole, increases, but shows no 
particular influence over the rate of evaporation; W is again 
apparently almost non-effective. But the important fact is this, 
that the rate of evaporation is greater when the relative humidity 
is less, in spite of the fact that a low percentage of relative 
humidity evidently implies a low water-temperature. It is there- 
fore to be inferred that the relative humidity of the air is a much 
more influential agent than the temperature of the water in pro- 
moting evaporation. At the same time, it must not be forgotten 
that a more rapid evaporation necessarily produces some cooling 
of the water-surface. 
In Tables 18 and 19 will be found corresponding information 
to that of Tables 16 and 17, but for the one-foot pipe. 
