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Proceedings of the Royal Society 
30° and 40° F. As an instance of the diurnal range of temperature, 
it may be mentioned that on the 18th, when at 2 p.m. the tempera- 
ture was 105° F., just before sunrise it was only 59° F. On this 
day, therefore, we had an extreme range of temperature of 46° F., 
and a difference of 40° F. between the dry and wet bulbs themselves 
in the afternoon. The island of Teneriffe lies in very nearly the 
same latitude as Sohag ; hut in order to find a similar climate, it 
is necessary to ascend at least 6000 feet, and pass through the 
mass of clouds which always encircle the peak between the heights 
of 3000 and 5000 feet above the sea. The climate on the Nile in 
Upper Egypt is thus very peculiar. Looking to the height of the 
barometer and the day temperature, it is that of a tropical place at 
or near the level of the sea ; looking to the range of temperature and 
the dryness of the air, it is quite Alpine. 
On the morning of the 17th May the sun was totally eclipsed at 
8.34 a.m. ; at 8.51 the apparatus was exposed to the sun, hut no 
boiling took place; at 8.58 the water began to “sing”; at 9.1 it 
boiled; at 9.3 it was boiling briskly, hut it was not till 9.17 that 
the first drop of distillate fell into the receiver; by 9.1 9 J 1 cubic 
centimetre had passed, and between 9.21 and 9. 29 J 5 c.c. passed. 
The water did not begin to sing until 50 per cent, of the surface 
of the sun had been uncovered, a fact which supports the belief that 
there is a very great absorption of heat rays by the sun’s atmosphere 
near the limbs. During totality the stars shone out brightly, and a 
comet appeared about a degree distant from the sun. The darkness 
was not so great but that I could read a rather closely graduated 
thermometer without difficulty. The fall of temperature during 
totality was only 1 ° F. , and there was no wind or other atmospheric 
disturbance. 
5. On the Heats of Combination of the Metals with the 
Halogens. By A. P. Laurie, B.Sc., and C. T. Burton. 
At the last meeting of the Society a paper was communicated by 
us, describing a new method for determining the heats of combina- 
tion of the metals with the halogens. The following paper is an 
account of our preliminary experiments mentioned in the former 
