178 
On Underground Temperature. 
[Apri , 
prisoned between the disks of the geo-thermometer would 
in the upper portion gradually become cooler, as heat was 
conducted away from it into the body of the rock ; and it 
would gradually become warmer in the lower portion, as 
heat was conducted into it from the body of the rock. But 
at the particular depth at which the two lines A C and A F 
intersect no alteration would take place. 
That such an effeCt was actually produced is shown by 
the following table, the first two columns of which are taken 
from Dunker’s Table II., in his paper entitled “ Ueber die 
Benutzung tiefer Bohrlocher zur Ermittelung der Temper- 
atur des Erdkorpers, und die desshalb in dem Borloche I zu 
Sperenberg auf Steinsalz angestellten Beobachtungen.” 
The two temperatures marked with asterisks differ from 
those quoted in the British Association Report from Dunker’s 
quarto paper of 1872 in the “ Zeitschrift fur Berg-Hutten und 
Salinen-Wisen.” But they are printed as here given in the 
oCtavo paper from which they have been copied, and are stated 
there to be the mean results of several observations. Dunker 
considered the deepest observation with the geo-thermometer 
unsatisfactory. 
Depth 
Temp. R. 
Temp. R. 
Water 
shut off, 
Surface Temp. 
7*18°. Abso- 
Being at 
the rate 
Absolute 
Being at the 
rate of 
in 
feet. 
Water 
shut off. 
Water not consequent lute Increase 
shut off. alteration at each depth 
of i° R. 
per No. 
Increase 
at depths. 
✓ 
i° R. 
i° F. 
15 
9 ' 4 ° 
10-35 
of Temp. 
-0-95 
in Col. 2. 
of feet. 

per ft. 
per ft. 
30 
9'56 
10*20 
— 0*64 
— 
— 
— 
— 
— 
50 
g*86 
10*40 
- 0*54 
— 
— 
— 
— 
— 
100 
io'i6 
12*30 
— 2*14 
2*g8 
33 
— 
— 
— 
300 
14*60 
I 3-52 
+ 1*08 
4-44 
45 
— 
— 
— 
400 
14*80 
14*30 
+ 0*50 
0*20 
500 
— 
— 
— 
500 
i 5'!6 
14*68 
■f - 0*48 
0*36 
277 
— 
— 
— 
700 
17*06 
16*08 
4-o*g8 
i*go 
105 
— 
— 
— 
goo 
18*50 
17*18 
+ 1*32 
0*44 
455 
— 
— 
— 
1100 
*ig*go 
ig*o8 
+ 0*82 
1*40 
143 
11*72 
94 
42 
1300 
21*10 
20*38 
+ 0*72 
1*20 
166 
— 
— 
— 
1500 
22*80 
22*08 
+0*72 
1*70 
118 
— 
— 
— 
1700 
24*10 
22*go 
+ 1*20 
1 * 3 ° 
154 
— 
— 
— 
igoo 
25*90 
24*80 
4- 1*10 
i*8o 
hi 
— 
— 
— 
2100 
*27*70 
26*80 
4-o*go 
1*80 
hi 
7*80 
128 
57 
2300 
28*50 
28*10 
4-0*40 
o*8o 
250 
— 
— 
2500 
2g*70 
2 g* 5 ° 
4-0*20 
1*20 
166 
— 
— 
— 
2700 
30-50 
30-30 
4-0*20 
o*8o 
250 
2*80 
214 
95 
2goo 
— 
31*60 
— 
— 
— 
— 
— 
— 
3100 
— 
32*70 
— 
— 
— 
— 
— 
— 
33 °o 
36-15 
33*60 
— 
— 
— 
— 
— 
3390 
34*10 
4-2*05 
5*65 
122 
— 
— 
— 
3500 
— 
34*70 
— 
— 
— 
— 
— 
— 
3700 
— 
35 * 8 o 
- — 
— 
— 
— 
— 
— 
3900 
— 
36*60 
— 
— 
— 
— 
— 
— 
4042 
38-25 
38*10 
4-0*15 
2*10 
310 
7*75 
212 
95 
In the above table the first column gives the depth in 
Prussian feet, at which the observations of temperature 
were made. 
