401 
November 29, 1875. 
Tar PresipeNt (PROFESSOR CLERK MAXWELL) in the Chair. 
The following communication was made to the Society : 
On the temperatures observed in a deep boring at 
Speremberg near Berlin, as given im a report of 
a paper by Professor Mohr, of Bonn, an ‘ Nature’ 
of October 21, 1875. By Mx O. Fisner. 
The greatest depth recorded is 3390 feet. The temperatures 
are given in Reaumur’s scale. The author shewed that the 
equation ' 
PASM 
V=— F550 + 0:012982 « +.7:1817, 
in which v is the temperature, and x the depth, exactly repre- 
sents the temperature curve. This curve would give a maxi- 
mum temperature of 
40°7532 R., or 123°6947 Fah., 
at a depth of 5171 feet. If there was no cause to disturb the 
temperature, it ought to conform to a straight line, given by 
the above equation altered by omitting the term in 2”. Conse- 
quently a cause was sought which would change such a straight 
line to the parabolic form. The first cause examined was a 
change in the conductivity of the strata depending on the 
depth, and it was found that a law, which would make the 
conductivity vary inversely as the distance of any point above 
the level of greatest temperature, would account for the observed 
facts. But it was argued that such a law was entirely improb- 
able. 
The next cause examined was the effect of the descent of 
water through the strata, and the author believes that this cir- 
cumstance will account for the observed temperatures. 
