G. E. Belknap—Under-water Oceanic Temperature. 29 
mak Pass is cleared, the temperature of the water rises, and 
the current is found to be setting to the southwestward. 
The following table will show some of the differences of 
temperature observed on the line sounded from Honolulu to 
the Bonin Islands, and that part of the northern line from the 
emg point of Kamtchatka to Onnimak Pass in Behring’s 
ea: 
Southern Line, Northern Line, 
Central North Pacific. North Pacific and Behring’s Sea. 
Surface, ec te 78. 8: 36°-4 to49° F, 
Under Surface 30 f’ms,70°°8) — 73°°5 31°°5 41°°9 
- BO: * 6875... 727% 31°°9 89°°7 
me 100.2": GE 70° 31°°1 38°°5 
. 200 “* 48°%5 — 58° 34°°3 37°°9 
"3 $00" 64 6075 34°°4 37°°3 
. 500 “ 88°9 40°°6 34°°8 35°°9 
. 1000 “ 35° 5 33°°5 33°°8 
ee 2000: “33° 33°°9 33°°5 33°°8 
ns S000. 38°. 7. 83.8 art 33°'3 
The very low temperatures noted at the depth of 30 
fathoms to 206 fathoms are some of those observed in the cold 
stratum already described in this report. 
he serial temperatures observed on this northern line were 
not so extended as could have been wished, owing to the loss 
and breakage of thermometers and to the fact that two of the 
instruments furnished had to be thrown aside as worthless. In 
the latter case the mercury would crowd up past the needle, 
rendering the indications valueless, and that defect in those 
instruments could not be overcome. 
The thermometers sent down at the 3,664 fathom cast came 
up unharmed, and as some of the “ Challenger’s” instruments 
broke at a depth of 3,875 fathoms the maximum pressure 
which the Miller-Casella thermometers will bear must be some- 
where between those depths, or a pressure of about four and 
three-fourths tons per square inch.* The temperature indicated 
at 3,664 fathoms is 33°°8 F. 
I should take into consideration, however, the fact that 
using hempen line and time intervals for sounding, that the 
depths found by the “Challenger” were not so accurate as those 
obtained by the “Tuscarora” with piano wire and dynamo- 
meter. 
* From later results obtained by the Challenger this deduction is probably 
incorrect, as I believe she received whole thermometers back on one or two occa- 
sions from a depth of over 4,000 fathoms. 
