66 REPORT—1840. 
which, during its long existence, marked attention has been 
given to the science of meteorology*. It does not appear, 
from the writings of Sir John Leslie himself, that he had ever 
obtained any very definite results by the use of the ethrio- 
scopet. ‘The action of the reflecting mirror seems not to be 
fully understood, at least so M. Pouillet assertst{. I am 
unable, from experience, to verify his statement, which 
leaves, however, some ambiguity. M. Pouillet employs 
a vessel stuffed with swanskin (peau de cygne), capable of 
having its orifice directed at pleasure, and having a radiating 
thermometer in its centre. By ascertaining the effect upon 
this apparatus of a surface artificially maintained at a given 
temperature, he deduces the mean radiating temperature of the 
atmosphere considered as an indefinite concave. But this 
brings us to general questions of great interest and importance. 
F. Proper Temperature of the Globe and of Space§. 
81. I forbear to repeat what I have formerly said respecting 
the proofs of the proper temperature of the interior of the earth. 
I confine myself to a statement of the very important advances 
since made, both in experimental researches and in the induc- 
tion of laws. 
82. A few fundamental experiments are sufficient to maintain 
Fourier’s position, that the interior heat of the earth exercises 
no perceptible influence on its present climate; we are there- 
fore left to consider the effects of heating and cooling influences 
wholly external. 
83. The imperfect transparency of the atmosphere stops a not 
-inconsiderable share of the solar rays, which are therefore ex- 
pended in heating it directly. But the major part reach the 
surface, and their effect being there concentrated (whilst in 
their transit through the atmosphere it is spread over a vast 
mass of air), the effect is incomparably more intense than else- 
where. The bounding surface of the earth (or ocean) and air is 
therefore to be considered as a true source of heat. From 
thence it is distributed progressively downwards by CoNDUC- 
TION||, upwards by RADIATION and CONVECTION. The warmth 
* Bib. Univ., N.S., iii. 209, and subsequent volumes. Since the publication 
of the former report, we have to regret the loss of the late amiable Mr. George 
Maurice, principal editor of that journal. 
+ Articles Curmate and Metecoroxoey, Encyclopedia Britannica, New Edit. 
t Mém. Chal. Sol., p. 32. 
§ First Report, p. 221; Mahlmann, p. 67, &c. 
|| Even in water. See the interesting and conclusive experiments by M. 
Despretz, Comptes Rendus, vii. 933. 
