67 
TEMPERATURE OF THE SEA. 
seasons of the year when the air is most rarefied and contains 
the greatest quantity of moisture. They are more general also 
at those periods when a change of wind is expected, as when the 
moon enters her different quarters, and at the change of the 
monsoons. 
During our voyage up the Yellow Sea, I "made many experiments 
on the temperature of the water at different depths. The statement 
of the greater part of them I lost in the shipwreck of the Alceste, 
with many of my other papers. I have exhibited the results of those 
which I preserved an account of in the annexed table. 
Date. 
1816. 
North 
Latitude. 
East 
Longitude. 
Current. 
Deptli in Fathoms. 
Temperature 
of 
Difference of 
Temperature 
between 
Air. 
Surface. 
Bottom. 
Air and 
Surface. 
Surface 
and 
Bottom. 
July 23. 8 A.M. 
35. 1. 
123. 46. 
11 Miles. 
40. 
76° 
74° 
65° 
2° 
9° 
24. 12 M. 
36. 24. 
122. 59. 
15. 
75° 
71° 
67° 
4° 
4° 
25. 8 A.M. 
37. 30. 
122. 40. 
20. 
72° 
67° 
62° 
5° 
5° 
• 8 P. M. 
— 
15. 
74° 
69° 
66° 
5° 
3° 
26. 6 A.M. 
37. 58. 
121. 34. 
— 
15. 
74° 
67° 
66° 
7° 
1° 
27. 11 P.M, 
38. 12. 
120. 20. 
7 Miles. 
15. 
75° 
74° 
72° 
1° 
2° 
They were made with a hollow brass cylinder capable of containing 
about ten ounces of water. Valves at the top and bottom permitted 
the ingress of the water as the instrument descended, but prevented 
its egress when drawn up. A thermometer with Fahrenheit’s scale 
graduated to degrees was attached to it. Each experiment was re- 
peated several times, and the instrument allowed to remain at the 
given depths for unequal periods, with the view to ascertain if any 
difference of temperature would be the consequence. These periods 
varied from five to ten minutes, but in no instance did any alteration 
of temperature occur. The water was drawn each time from the 
bottom ; soundings always having been taken before the experiment 
was made. 
The four first experiments were made in open sea, the fifth in 
k 2 
