ON THE SOURCES OF HEAT WHICH INFLUENCE CLIMATE. 465 
“ If the terrestrial globe and all the bodies which compose the solar system, were 
placed in an inclosure devoid of all heat, phenomena would be observed entirely 
contrary to those which we now know to exist. The polar regions would endure 
an immeasurable cold, and the decrease in the temperature, from the equator to 
the poles, would be incomparaby more rapid and extensive. 
“ Upon the hypothesis of the absolute cold of space, if it is possible to conceive 
it, all the effects of heat, such as we observe them on the surface of the globe, 
would be owing to the presence of the sun; the least variations of distance from 
that orb would occasion very considerable changes of temperature in the earth.— 
At the commencement of night the surfaces of bodies w r ould be instantaneously 
exposed to an infinitely intense cold, and organic bodies would not be able to 
withstand the equally sudden action of a contrary description, which would take 
place on the rising of the sun.” 
Thus we perceive that this low temperature assigned to the celestial regions 
through which our planet moves, has a most vigorous effect on the climate at the 
earth’s surface ; its power will be invariable for every point of the globe, whether 
placed under the torid zone or within the polar circle, whether on a level with 
the sea or in elevated mountain ranges. 
That the rays from the moon are totally devoid of any calorific effects, seems 
to have been recently finally set at rest, from experiments made by the beautiful 
thermo-multiplier of Melloni ; this leads to the conclusion that the surface of that 
luminary possesses only the temperature of the planetary spaces, and there, in 
the absence of the solar rays, cold will be experienced of minus 58, Fahrenheit. 
From this it may be inferred that organic bodies, such as we are acquainted with, 
cannot exist on the moon’s surface. 
Only one other source of heat known to us remains to be spoken of. It is 
the caloric, either given out or absorbed in every process, whether natural or 
artificial, which involves change from one state to another. This cause will act 
on climates generally chiefly through the spontaneous variations in the hygro- 
metric state of our atmosphere ; and it will be through this indirect channel that 
the artificial processes of cultivation are capable of improving climate. Other 
artificial means, derived from the works always carried on in densely-peopled 
districts, or in cities, modify the temperature to an extent of one or two degrees 
of Fahrenheit. 
The climate of London is considerably changed through this, the mean annual 
temperature exceeding that of the surrounding country by half a degree; the 
difference would be greater were it not that London, always veiled by smoke 
from the full power of the sun, has a colder mid-day temperature than its 
environs, while the nights of mid-winter are nearly four degrees higher than the 
heat of the surrounding country. 
