CHAP. VIT.] HEP-SEA TEMPERATURES. 297 
Thermometer. Difference. 
Standard . = 1 C. 
54 , 479 
56 . + 0°67 
(hae + (0) °65 
(Bie j + 0°76 
‘Thomson . + 0-03 
During these experiments the water in the cylin- 
der was of course maintained as far as possible at 
the same—or at a known temperature; a certain 
amount of calorific effect must, however, be pro- 
duced by the sudden compression of the water, and 
the next series of experiments was performed in 
order to determine the amount of that effect. Three 
of Phillips’s encased maximum thermometers (Sir 
William Thomson’s design), being entirely protected 
from any effect fron. compression, were employed for 
this purpose, with the following result :— 
Pressure, 6,817 lbs. = 2,500 fathoms. 
Thermometer. | Difference. 
5 Se 7 + 0°05 C 
Orde Se es es +0 92 
9,645 . + 0°11 
so that this source of error is absolutely trifling. 
The true error of the Miller-Casella thermometer, 
as deduced from these observations, is— 
For 250 fathoms 0°:079 C. 
For 2,500 fathoms 0°:79 C. 
