58 Mr Buchanan , On a solar Calorimeter used in Egypt 
visible radiating area of the sun and when at last this area is 
halved in one second and becomes nothing in the next, the effect 
which this sudden extinction of the sun produces, is a very 
profound one. And this not on man only, but also on the beasts. 
There were some turkeys in the camp, and they went about 
as usual until the final phase above indicated began, when they 
showed every symptom of alarm. When the sun reappears his 
light increases as rapidly as it disappeared, and five minutes after 
totality all interest in the eclipse has gone. What struck me 
most besides the comet, were two so-called protuberances. I say 
so-called because to the naked eye they look much more like in- 
dentations or notches in the moon’s disc and coloured red. This 
is a subjective effect and due to the same cause as the “ black 
drop ” in the case of the transit of Venus. 
Of all the natural phenomena which I have had the oppor- 
tunity of witnessing there is none which produces so powerful an 
impression as a total eclipse of the sun. In connection with this 
it may be recalled that the eclipse of 17th May, 1882, repeats 
itself after 19 years on the 17th May, 1901, with this important 
advantage, that in place of seventy seconds the maximum duration 
of totality will be six minutes and a half, and it will occur very 
nearly at noon at stations in Sumatra and Borneo. 
The 18th May was the hottest day experienced. Perfect 
calm reigned until 2 p.m. when a breeze began to blow up the 
Nile and continued throughout the afternoon although it was 
never very strong. During this forenoon the maximum results 
were obtained with the calorimeter and the temperature of the air 
reached its maximum 105° F. at 2 p.m. It will be noticed that 
the temperature of the wet bulb thermometer was only 65°, or 
40° F. below the dry bulb ; the air was of extraordinary dryness. 
One effect of a climate such as this where great dryness is 
associated with very high temperature, is that, although perspira- 
tion is abundant, the skin is never moist, indeed it is so dry that 
it has a tendency to crack. Another remarkable subjective effect 
of high air temperatures such as those of the afternoon of the 
18th is the notice given when the temperature of the air passes 
from below that of the human body to above it. It is a matter 
of common experience that in preparing a warm bath, very slight 
differences of temperature can be appreciated by the hand when 
the water is at, or about the temperature of the human body. 
With air the conditions are different ; the capacity for heat of all 
the air that can at any moment touch exposed portions of the 
body is very small and produces no noticeable effect. But al- 
though it cannot do so directly it can do so vicariously for instance 
through the metal rim of a pair of spectacles. The calorimetric 
work described in this paper necessitated continuous exposure to 
