368 On a solar Calorimeter used in Egypt 

 TABLE III. continued. 



By far the most important agent in altering the true rate, 

 as due to the sun alone, is the wind. During the three days 

 we were fortunate in having both calm and wind, so that an 

 idea can be formed of the cooling effect of wind. On the 

 1 6th with a calm afternoon the mean rate between 2 and 

 3 p.m. was 1*221, and on the I7th, when it was breezy, the 

 rate was 1*087 or about 10 per cent. less. 



The breezes which occur on the Nile are usually cool and 

 from the north. They did not at any time exceed force 3 of 

 Beaufort's scale. They were never steady, but came in puffs 

 or gusts, so that one 20 c.c. or even 5 c.c. interval would be 

 affected and the subsequent one not. 



On the 1 3th some satisfactory observations were made 

 when the sun though behind a cirrus cloud was still able 

 to keep distillation going. The rate was 0752 at 10 a.m. 



