of temperature of the atmosphere is the same at 
all hours. According to a yearly mean, the 
coldest hour of the day, in Europe, is 5 o’clock 
in the morning, and the warmest hour of the day 
is from 2 to 3 in the afternoon. The rise is most 
considerable some hours after the minimum; the 
fall, some hours after the maximum. ‘The heat 
increases for 9 to 10 hours, decreases for 14 to 
15 hours. The greatest daily range of tempera- 
ture in Europe takes place in July, and the least 
in December. The average temperature of the 
winter months in England is about 40°, and of 
the summer months 65°. Devonshire and Corn- 
wall are about 4° warmer than London. ‘The 
annual average of the thermometer at the north 
and south points of England, Carlisle and Sand- 
wich, is 48° and 50°; the maximum in 1820 was 78° 
and 83°, and the minimum was 12° and 27°. The 
mean temperature of Ireland varies from 47° to 
53°. At Kinfaun’s Castle, in Scotland, latitude 
56° 23’, the mean temperature for 1830 was 
47-626; the rain 30°85 inches; the coldest day 
10°; and hottest 79°; barometer from 30°53 to 
28°73. In leeds, Yorkshire, the thermometer 
was, July 18, 1825, at 92°; June 25, 1826, at 93°; 
and January 2, 1827, at 11°. The thermometer 
in Italy ranges between 75° and 96°; and in win- 
ter seldom descends below 40°, except in the 
mountains in the higher Apennines, where it falls 
to 20°. In New South Wales, the coldest month 
averages 54°, and the hottest 75°; it rains 100 
days in the year; the north-west wind is a 
scorching sirocco; the air is generally dry, but 
the night dews are heavy. At the volcanic islands 
of the Gallipogos, half a degree north of the equa- 
tor, the daily temperature is from 74° to 91°. 
The Red Sea is as hot as any part of the world; 
the thermometer ranges in 14 hours from 94° to 
112°; from Babelmandel to Suez, the coast for 
40 miles inland is a dry sand, without a blade of 
grass or drop of water. The cold at Tabreez in 
Persia, is so intense in February that persons are 
often frozen to death. The average heat of Bos- 
ton is 47'3°; of Philadelphia, 53°7°; of Washing- 
ton, 58'1°; of Detroit, 47°4°; of Cincinnati, 56:8’; 
of Pittsburgh, 542°; of New Harmony, 56:69’; of 
Charlestown, 57° to 60°; of Richmond, 56:1°. 
The temperature is so variable in South Carolina, 
that the thermometer sometimes varies 50° in 24 
hours; it ranges no less than 83° in the year; 
the rain averages 50 inches. Sudden changes of 
temperature prevail in Africa; one is recorded 
of 27° in 24 hours. In Siberia and Hudson’s Bay, 
mercury sometimes becomes solid, proving the 
cold to be 39° below zero; wine and spirits be- 
come a spongy mass of ice. At Bear Lake, Cap- 
tain Franklin, on 7th February, found the ther- 
mometer at 58° below zero; and for two days it 
had been 575°. In the latitude of London, Ame- 
rica is 13° colder than Europe; and in 40° nevsinnls, 
is 86° colder than Europe. The mean tempe- 
rature, according to Parry, for the 6 winter 
months, was at 
IV. 
TEMPERATURE. 
417 
Latitude. Temperature. 
Winter Island 66° 30’ LMG of! 
Igloolik 69° 20’ 18° 3 
Melville Island 30 AO AGN. 24° 
No snow fell at Melville Island, and only 8 inches 
at Winter Island. An iceberg, seen by Parry, 
was above 250 feet out of the water, and there- 
fore 1,800 feet thick. Spring is the most rapid 
in the Arctic regions. The snow disappears, and 
birds of passage re-appear; then, within a few 
days, the trees burst into foliage, the ground is 
covered with flowers, and mosquitoes are thawed 
in millions, while horseflies, sandflies, &c., render 
summer less comfortable than winter. Spiders, 
frogs, fish, &c., frozen and as brittle as ice, re- 
vive with the thaw. 
In the temperate zone, the annual evaporation 
is 37 inches; but in the tropics from 90 to 100; 
and the mean quantity of rain is in the same 
proportion. In latitudes 46°, 47°, and 48°, the 
heat at sunset is the mean of the day. The mean 
quantity of water held in a cubic foot of air, in 
this climate, is 3°789 grains. All the moisture 
in the atmosphere is equal to a depth of 13 
inches; and if all fell as rain it would cover the 
earth to the depth of 13 inches. The average 
fall of rain in the United Kingdom is about 34 
inches; but in the western and hilly counties it 
is 48 or 50 inches. The average rain in London 
for 40 years, between 1777 and 1817, was 20°686 
inches; at Paris in 15 years, was 18°649 ; at Glas- 
gow in 17 years, was 21:033; at Manchester in 
33 years, was 36104; at Kendal in 1830, was 
58:03. At Edmonton in 1831, the highest ther- 
mometer was 82°, and lowest 10°; barometer 
80°5 and 289; rain 26°8; winds 232 days wes- 
terly, 8 non 6 south. At Cheltenham, 1831, 
thermometer highest 77:5, lowest 25; barome- 
ter 30°26 to 28°52; rain 34°6; winds 166 days wes- 
terly, 36 north, and 55 south. Evaporation is 
everywhere as the surface of water, and as the 
temperature. There would be no interval between 
the solid and vaporous states but for the pres- 
sure of the atmosphere. All liquidity is, there- 
fore, the effect of atmospheric reaction ; and this 
is overcome when the force of the atomic mo- 
tion of heat exceeds the compressive of 15 pounds 
to the square inch. It appears, therefore, to be 
the direct tendency of the motion called heat to 
disperse the atoms of a body; and vapour, steam, 
or gas isa conflict between the atoms of the beay 
and those of the atmosphere. Hence it is that 
water fills the receiver of the air-pump with 
steam, and that it boils at such low temperature 
in elevations where the barometer falls consider- 
ably. Atmospheric air, at the freezing tempera- 
ture, contains from a 200th to 160th of its weight 
of water, and double at every 22d or 27th 
degree. At 52°, it contains a 100th; at 74°, a 
50th; and at 98°, a 25th. Hence, as cooled, it 
deposits the excess; and this is the dew of clear 
and calm nights. The earth is more heated by 
the solar rays than the air; and by night the 
2D 
