MR. J. PRESTWICH ON SUBMARINE TEMPERATURES. 
599 
found to leak slightly ; but it was considered that the expansion of the water in coming 
to the surface would compensate for this loss. 
This instrument was placed in water at 67° F. (19 0, 4 C.) until it acquired its tempe- 
rature. It was then replaced with other water at 32°. Left in it for two hours, the 
temperature of the water in the bathometer fell to 52 0, 7, showing a difference, in that 
time, of 14°*3, which difference Lenz further estimated would have amounted only to 
7° had the apparatus passed through water ranging from 32° to 67°, instead of being 
exposed to a constant temperature of 32°. Taking this as the rate of refrigeration at 
given temperatures and in given time, Lenz then employed Biot’s formula for ascer- 
taining the gain or loss of heat of a body placed in a medium possessing a higher 
or lower temperature than itself, as the basis for calculating the correction required in 
each particular observation. Corrections were also made for the depths, by allowing 
on the one hand for the angle of the rope from the vertical, and on the other for the 
gain in length by tension under water*. 
Lenz gives a Table of his observations as originally taken, and again repeats the Table 
with the corrected temperatures and depths. These two are combined in the following 
Table, in which it is shown that, even with uncorrected readings, Lenz obtained on three 
occasions a temperature below 4° C., while six corrected readings indicate a tempera- 
ture below 3° Cent., or of from 36° to 37° Fahr. 
Date. 
Lat. 
Long. 
Depth 
toises. 
Angle 
of 
rope. 
Temperature. 
Time 
employed 
in 
hauling 
up the 
instru- 
ment. 
Time 
of its 
remain- 
ing 
at the 
bottom. 
Corrected 
observations. 
At 
surface. 
At 
depth. 
Depth. 
Temp. 
min. 
min. 
toises. 
1823. Oct. 10 ... 
7 20 n. 
21 59 
w. 
500 
6 
6 
2o-8 C. 
5 C. 
30 
15 
539 
2-20 C.t 
1824. May 18 ... 
21 14 „ 
196 1 
„ 
139 
10 
0 
26-4 
16-7 
6 
15 
140 
16-36 
„ >. 
„ 
399 
0 
0 
5-1 
17 
10 
413 
3-18 
„ ». 
,, j. 
„ 
649 
10 
0 
„ 
4-9 
32 
10 
665'1 
2-92 
„ » 
.. i. 
„ 
„ 
979 
25 
0 
„ 
4-6 
56 
15 
914-9 
2-44 
1825. Feb. 8 
25 6 „ 
156 58 
„ 
179 
25 
0 
21 '5 
14 
3 
2 
167 
14-00 
1825. Aug.31 ... 
32 6 „ 
136 48 
„ 
89 
10 
0 
21-45 
1354 
4 
15 
89-8 
13-35 
„ .. 
„ .i 
,, 
„ 
229 
25 
0 
„ 
7-06 
8 
15 
214 
6-51 
„ „ 
„ 
„ 
479 
25 
0 
„ 
4-75 
15 
15 
450-2 
3-75 
„ „ 
„ » 
„ 
579 
10 
0 
„ 
3-56 
19 
15 
592-6 
2-21 
1826. Mar. 6 
32 20 „ 
42 30 
„ 
969 
5 
10 
20-86 
3-92 
50 
15 
1014-8 
2-24 
1825. Aug. 24 ... 
41 12 „ 
141 58 
„ 
199 
10 
0 
19-2 
5-9 
10 
15 
205 
5T6 
„ „ 
„ 
„ 
525 
20 
0 
„ 
3-4 
25 
15 
512-1 
2-14 
1826. Mar. 24 ... 
45 53 „ 
15 17 
192 
0 
0 
14-64 
10-56 
9 
15 
197-7 
10-36 
” 
” ” 
383 
0 
0 
” 
10-26 
13 
8 
396-4 
9-95 
t This should probably be 3° "20. 
* Poggfindoeff’s Annalen der Physik und Chemie, vol. xx. 1830, pp. 78, 90, 106 ; and ‘ Bulletin Universel ’ 
for 1831, yoI. i. p. 275. 
