112 Analysis, §-c. of Cordier’s Essay upon the 
“One of the elements of this problem, that which seems to 
needs further investigation most, is the permanent increase of 
temperature in descending fro — surface towards the centre 
of the earth. It may be aske 4, e the e pane ei already 
made, sufficiently exact? Have eae been sufficiently examined 
and criticised as to the manner of conducting them? Are the con- 
sequences deduced from them, legitimate and conclusive of the 
ques Let us therefore, in the first place, examine the ex- 
periments which have already been made with this v song 3 S@- 
condly, let us give an account of the experiments which w 
instituted ourselves for the same purpose ; thirdly, let us amet 
_— the results and conclusions they a 
‘*On the experiments hitherto made as to some da tempera- 
— —These relate, to the _ temperature ture of sens I spr ings. 
“The 
these 
have been pushed as pages four or five baiiged metres, (one 
thoudnad six hundred and forty English feet.) 
“In France, we possess observations on the temperature of 
the cave under the Observatory of Paris, during one hundred 
tant lately brought to perfection by M. Arago, 
‘Those m: M. Gensanne, in the mines of Girmagny, about 
the middle of the last century ; the experiments of M. D’Aubuis- 
son, in the mines of Brittany, in 1806. 
“In Switzerland, we have the experiments made by De Saus- 
sure, about forty years ago, in ~ salt mines of Bex 
“In Saxony, we have those Pe3 Friesleben and Hum- 
boldt, collected in 1791; those of M. D’ Aubuisson, in 1802, and 
especially those of M. Trebra, i in 1805, 6, 7 an 
n Great Britain, = have a great number, from 1815 to the 
ani time; by Messrs. M’Lean, Reed, and W. Fox, in Corn- 
wall and Devonshire ; Be by Messrs. Bald, hae and Fenwick, 
in the coal nhs of the north of 
or ought we to omit those made b Humboldt, in the mines 
‘eru and Mexico, at a former perio aise 
* These ercrinens may 5 a Bi bya to be further considered, before the 
= concales ern lished: therefore the authorities cited by Cor- 
a er 
Ce stone ‘See Disse 
Secon} 179, in in » 1210, hea, Journal ie es ag ech ‘S ‘OI, p- Waa’ : 
In Swi Ips, 1 
Chimes tom. 25, p. 210. des 
mip sy: ton. 3, 8, pp Sh, 10, 3 200. . learn des iiews. tom. 11, p- 
wh Gr -Iyp. as 
nn Chin de Py. a. 18, p- 200; has 16, p- 
Smee ay 21, p. 308. Geographical distribution of plants, By 
