Remarks on the Geology of Maine. 69 
more elevated ; it would arise from the contact of the air, and 
from the radiant heat of the stars, sun, earth and atmosphere ; but 
the first of these could have little influence, from the extreme 
tenuity of the fluid; so that the mean temperature indicated by 
the thermometer would differ very little from that which it would 
indicate if it were removed from the atmosphere and placed a 
short distance above it. 
¥* * * * * * ~ 
Nore.—In the proceedings of the Academy, on the 17th of 
April last, the following passage occurs: 
“*M. Poisson presented a supplement to his work, entitled Thé- 
orie Mathématique de la Chaleur. 'This supplement is consti- 
tuted of the Memoir upon the Temperature of the solid eee A of 
the Giobe, of the Atmosphere, and of these regions of space 
versed by the Earth, which was inserted in the Compte Renda 
de la séance de Académie of the 30th of January last; and to 
which the author has added several notes, relating, guthcipally; to 
the temperature of the earth and of space, at different epochs. 
One of these notes contains the complete determination of the 
laws of refrigeration of a sphere of very great diameter, as the 
earth, for example, which has not before been deduced from the- 
ory. Another contains an example of the calculation of the tem- 
peratures and densities of the atmospherick layers, regard being 
had to the propagation of heat from layer to layer, and to the con- 
ditions which terminate the atmosphere ; that is, to the condition 
of an elastic force which is nothing in the upper layer of the at- 
mosphere ; which can only result from a temperature of this layer 
proper to its liquefaction.” 
pe Iil.— Miscellaneous Remarks on certain portions of the Ge- 
ology of Maine, in a letter from Dr. Cuartes T. Jackson, to 
the Editor, dated Boston, Nov. 13th, 1837. 
TO PROF. B. SILLIMAN. 
Sir—I nave lately returned home after spending five months 
in the continuation of the geological survey of Maine. two months 
of which time has been spent in the forests of the public lands of 
that state. 
