284 Dr. Davy’s observations on the 
March 27th. 
S. lat. io° 30". W. long. 24 0 
25". 
Hour. 
Weather. 
Temp, of air. 
5 A. M. 
Fair 
79 
6 
Rain approaching 
78 
6 30 
- Raining heavily 
75,5 
7 
Rain just ceased 
76,5 
8 
Sunshine 
- 79^5 
9 
Raining 
76 
10 
Cloudy 
79,5 
12 
Fair 
80,5 
The showers in each instance were accompanied by hard 
gusts of wind, and thunder and lightning. The rain-water, 
the temperature of which was ascertained, was collected 
in a glass as it ran from the awning. 
The equatorial regions appear to be particularly subject to 
storms, violent rain, and electrical phenomena, the effect of 
which, in diminishing the temperature, seems to afford a 
natural explanation of the comparative coolness, both of the 
atmosphere and the ocean, that we experienced each time we 
passed the line. 
The temperature of the sea, it has been asserted by some 
writers, is subject to little or no diurnal variation. That this 
remark is far from correct, is evident from the slightest in- 
spection of the Meteorological Journal ; it is an opinion that 
could be formed only from hypothetical views, ill founded. 
The fact, as the Journal exhibits, is, that the diurnal change 
of the temperature of the sea is very nearly as great as that 
of the incumbent atmosphere. From all the observations I 
could make, when the circumstances were most favourable 
to accurate results, when the weather was fine, the sea 
smooth, and the land at a great distance, it appeared to me. 
