166 Dr Horner on the Specific Gravity of Sea-Water^ ^c. 
Tile temperatures in the usual soundings from 70 to 80 fa-> 
thorns, appear, on account of their considerable number, from 
which mean numbers may be deduced, the best calculated to 
supply fundamental data. Yet some singular results appear in 
them. Among these is the statement in the South Sea, that 
in 18° N. Lat. and 76 fathoms*' depth, in December, the wa- 
ter was 2J° R. warmer than in 11° N. Lat. and 70 fathoms depth, 
in November. Perhaps the local places of observation have had 
here some Influence. The observation in 11° Lat. lies in the 
west of the Mariana islands, and in the north of the Philippines, 
consequently sheltered against the warmer currents from the 
south, by a kind of wall, and open only to the north, while, on 
the other hand, the place in 18° Lat. lies more in the open sea. 
The temperature, found at a depth of 90 fathoms, in the Chi- 
nese Sea, to the west of Lucon, is remarkably cold ; perhaps 
in consequence of the nortli-cast currents prevailing in Decem- 
ber. 
Almost daily observations on the temperature were made in 
the Atlantic Ocean, from tlie 20th of April to the 18th of June, 
1818, mostly at a depth of 70 fathoms. In order to balance 
the possible errors of the observations which may arise from the 
difference in the time that the thermometer was under water, I 
have added several together, and noted the mean number. They 
are in the following Table. The figures in parentheses show 
the number of observations, the mean of which is given. 
Obseuvatioi^; 
Temper 
the \ 
on the 
Surface. 
ature of 
Vater 
below the 
Surface. 
Depth in 
Fathoms. 
Latitude. 
Longitude. 
April 20.— 26. 
(5) 
18.6 
13.0 
57 
17'’l5's. 
3°20V. 
— 27.— 30. 
(4) 
20.8 
13.5 
66 
10 24 
12 2 
30. — May 4. 
(5) 
22.1 
11.8 
67 
5 12 
17 5 
May 3.— 10. 
(8) 
22.7 
11.4 
74 
0 43 N. 
20 28 
10.— 16. 
C7) 
22.6 
11.4 
75 
4 51 
24 38 
15.— 19. 
(5) 
21.2 
11.5 
67 
9 34 
29 38 
20.— 24. 
(5) 
20.3 
16.1 
71 
19 30 
35 7 
25.— 30. 
(6) 
18.3 
14.8 
71 
31 0 
36 30 
31. — June 6. 
(5) 
15.1 
12.3 
68 
40. 30 
29 40 
June 7. — 13. 
(T) 
13.2 
9.6 
77 
48 9 
17 14 
This table shows a similar anomaly to that which we noticed 
Ml the South Sea. That is, the proportionately low temperature 
