=, ~ —— een 
temperature of the interior of the earth, _—*113 
at the temperatu: cavities ieee oA in- 
as the depth Fein the pons sr increases; in i 
somewhat varying, indeed, but calculated on an av. be 
one degree of the centigrade thermometer for 
“ated metres, (ninety-one, to one hundred and thirty-one Soclieh 
2 « Homes the conclusion has gradually prevailed that the earth 
of i 
the 
ence of our globe: that the crust of the earth has gradually pees 
hardened by Saopem and mole calar communication of calor 
from stratum to stratu 
How long it has taken to produce this ne iin 35 
and oe of the present crust of the earth, we hav 
not the means of conjecturing in the present state of im 
canta. 
“La Grange and Dolomieu were the first who returned to 
the old theory of central heat. Hutton, and his.commentator, 
Playfair, followed. Lately, Fourier, in his Researches res- 
pecting the a theory of heat, was led the same way. The 
subject was also taken up by the much : iameinte M. de la Place.” 
The publication of M. Faujas de la Fond on the Evins 
‘lation of Viverais and Velay, the account o 
ogy by 
Sheoty.’ In England, Mr. Kirwan and Professor Jameso: 
adopted Werner’ s theory ; but Hatton and Playfair, Grego- 
Mr. 
Scrope, have greatly contributed to change the’ pesldzival 
opinions 
ea aa os the cena mass of our earth, and the ig- 
ner seems to have packed the untenable character of his 
own opinion as to the aqueous origin of the floetz trap for- 
mation, when, being at Pais: he refused the pressing invita- 
tions to visit Auvergne. 
“ If the proofs hitherto adduced in favor of central fusion be 
sufficient, we ought to consider this theory as fully established: 
if not, further experiments ought to be instituted that shall set 
the question beyond reasonable doubt. 
