82 REPORT—1840. 
123. A very deep experimental bore has been sunk at La 
Grenelle, near Paris. The latest report* (Aug. 1839) gives a 
temperature of 27°°5 cent. at a depth of 281 metres, which 
would infer an increase of about 1° cent. for 164 metres (the su- 
perficial temperature being under 11°), a result Hardly probablet ; 
and as the depth of the bore then was between 400 and 500 
metres, either the depth of observation has been misstated, or 
the temperature was raised by water flowing from the bottom. 
124. The following are the depths of the most remarkable 
Artesian wells at present known {:— stentie wisi 
rencnh feet. 
La Grenelle, Paris (June 1839) . . . . . . 143671 
Neu Salzwerk, near Minden (Sept. 1839) . . . 1434°8 
Temperature of brine, 18°°5 R. 
Nowe Brzesko, Poland (1838) . . . . . ~- 1403°8 
Cessingen, Luxembourg (April 1839) . . . . 1646°5§ 
125. Perhaps the most interesting, and certainly the most 
singular observations, on subterranean temperature, are those 
on the frozen soil of Siberia. At Jakouzk, in lat. 62°, where the 
mean temperature is —6° Reaum. =18°5 Fahr. (accompanied 
with such a rigour of climate, that mercury has been known 
to remain frozen for three consecutive months ||), the heat of 
summer thaws the soil to an extreme depth of only three feet]. 
To search for a permanent spring is a matter of great difficulty. 
A well has been dug to the depth of nearly 400 English feet, 
with the following most remarkable results as to the tempera- 
ture of the ground** :— 
Surface . 9. 2 . . — 6% Reaumur. 
77 English feet . . .—5°5 
119 cr) . . . oo 4 ‘0 
382 ne oh og eee ON5 
* Comptes Rendus (Paris), ix. 218. 
+ This result is altogether at variance with that formerly published (Comptes 
Rendus, vi. 505), where it appears that at a depth of 400 metres the tem- 
perature was 23°-5 c., giving an increase of 1°. for 31°5 metres, in which also 
some other springs near Paris very nearly coincide. A still later observation 
confirms this remark. On the 18th August, 1840, MM. Arago and Walferdin 
obtained a temperature of 26° 43 c. at 505 metres, giving 32°3 metres for 1° c. 
(Comptes Rendus, 2 Nov., 1840.) 
{ Poggendorff, xlviii. 382. Notices of some other Artesian wells, Pogg., 
xxix. 8362. For an a¢count of two Artesian brine springs at Kissengen, see 
my paper in Jameson’s Journal, April 1839. 
§ It has lately been stated, that the observations of temperature in this Ar- 
tesian well, at the depths of 180, 230, 280, and 337 metres, give a coincident 
result of 1°c. for 13 metres of descent, or more than twice as rapid an increase 
as that usually observed. (L’Jnstitut, 1840, No. 340.) 
|| Erman, Comptes Rendus (Paris), vi. 502. 
q Bischoff, Warmelehre, p. 137. 
** Erman, wé sup. See also Von Baer, in Brit. Assoc., Eighth Rep., Sect. p.96. 
