2 Temperature of the Terrestrial Globe. 
2. It partakes of the common temperature of the planetary 
spaces ; being exposed to the radiations from the innumerable stars 
which surround the solar system. 
3. The earth preserves in its interior a part of that siaiiee heat 
which it had at the time of the first formation of the planets. 
We shall separately examine each of these three causes, and the 
phenomena which they produce. We will show, as clearly as we 
are able in the present state of the science, the principal features of 
these phenomena. For the purpose of giving a general idea of this 
great question, and showing at a glance the results of our researches, 
we present them in the following summary, which is in some meas- 
ure a synoptic table of the contents of this article, and of several 
which have preceded it 
The solar system is . aidaned in a region of the universe, every 
ale of which has a common and constant temperature, determined 
by the rays of light and heat which proceed from the surrounding 
stars. ‘This low temperature of the planetary space, isa little below 
that of the polar regions of the earth. The earth would have only 
the same temperature with the heavens, were it not for two causes 
which are concurring to heat it, One is the internal heat which it 
possessed at its formation, a part of which only is dissipated through 
the surface; the other is the continued action of the solar rays, 
which penetrate the whole mass, and produce at the surlane; the 
diversities of climate. 
The primitive heat of the globe has no longer any sensible effect 
upon the surface: but it may be very great as we approach the 
center. ‘The temperature of the surface does not exceed by the 
thirtieth of a centesimal degree, (,';° Fahrenheit,) the lowest state 
to which it can ever be reduced. At first it diminished very rap- 
idly: but at present with the greatest slowness. 
The observations heretofore collected seem to show that the tem- 
perature of different points of the same vertical line, is proportional 
tothe depth, aud that this increase of temperature, as we advance 
towards the center, is about one degree for every thirty or forty me- 
ters. Such a result supposes a very high internal temperature. It 
vannot proceed from the action of the sun’s rays; and itis naturally 
by the heat which belonged to the earth at its formation. 
temperature, of about one degree for thirty-two 
meters will Dot aly remain the same. It gradually diminishes ; 
but many ages must ela : before it can be reduced to half its pres- 
ent value. 
