at the total solar Eclipse in 1882. 57 
bulb thermometer are much less, namely from 49*5° to 66'2° Fahr. 
The temperature of the water of the Nile is very nearly the mean 
of the maximum and minimum temperatures of the air above it. 
These means were on the 
14th, 15th, 16th, 17th, 18th, mean 
77-5°, 74-5°, 79-0°, 79-5°, 82*75°, 78*65°. 
The temperature of the Nile is a little below this mean. The 
large range of temperature in the air is partly due to the cooling 
effect of the evaporation from the surface of the water. 
The evaporation experiments were made on water contained in 
a deep plate. It contained 400 cubic centimetres and exposed a 
free surface of 248 sq. centimetres when full, and 280 sq. centi- 
metres when nearly empty. It was set upon a tin cone which 
raised it about 6 inches above the ground. The difference of the 
effect of the sun upon the water and upon the sand close to it was 
well shown on the 16th at 2 p.m. when the water in the plate had 
a temperature of 82*5° F. while the temperature of the sand was 
134° F., making a difference of more than 50° F. 
The following notes of the weather were made at the time and 
are of use when taken in connection with the observations of the 
calorimeter. 
16th May. — The sun rose in a cloudless sky and there was a 
very light wind from the west. As the morning wore on, it came 
round more and more to the north and freshened slightly. At 
10 a.m. the wind seemed freshening and came in gusts, retarding 
distillation. In the afternoon it was calm. 
17th May. — The day of the eclipse, the sun rose in a cloudless 
sky and the inhabitants of Sohag had already begun to collect on 
the banks of the Nile where they remained until the eclipse was 
over. The temperature recorded as at 8.30 a.m. was really 
observed 50 seconds after totality began, and I had no difficulty in 
reading the thermometer although all the principal stars were 
shining brightly, along with an unsuspected comet which appeared 
with totality, between two and three sun’s diameters from the 
darkened disc and with a slightly curved tail quite as long 
as the sun’s diameter. This comet had not been detected before 
and I understand that it was never seen afterwards. It was 
a very striking feature of the eclipse to those whose occupa- 
tions enabled them to look at it. I made a sketch immediately 
totality was over. Perhaps the most impressive period of the 
eclipse is during the two or three minutes that precede the total 
phase. Until a very large proportion of the sun’s disc has been 
obscured the decrease of light causes no remark, especially from 
people who are accustomed to climates where clouds are more 
common than sunshine. But when the time comes that every 
minute and indeed ever} 7 second alters by many per cent, the 
