SPECIFIC GRAVITY OF SEA WATER. 429 



3. A certain coincidence with these results, only 

 on a greater scale, is sliown by the experiments of 

 the 15th of Nov. I8I7, in 9° north latitude, and 

 205° west longitude, in which the temperature 

 decreases from the surface to about sixty or 

 seventy fathoms, rapidly and uniformly, from 

 24°, 7 R. to 8°, 8 R. From 69 to 101 flithoms, this 

 rapid decrease, instead of proceeding, is suddenly 

 reduced to the small amount of 0°, 9 R- R^it if 

 we compare these observations with those imme- 

 diately preceding and succeeding them, of the 

 loth, 14th, and 17th of November, we shall hesi- 

 tate to draw from them decisive conclusions. 



The observations of 13th April, I8I6, in 15° 

 south, and 130° west, follow a quite different course 

 from those in September, 181 7, in 36° north. The 

 decrease of warmth from the surface, to as far as 

 a hundred flithoms* depth, is much more incon- 

 siderable, being here only 3°, 6, there nearly treble, 

 namely, 9°, 4 Reaum. It becomes more consider- 

 able between a hundred and two hundred fathoms, 

 namely, 8°, 8 R. Remarkable as this inequality is, 

 it yet seems impossible to ascribe it to an error in 

 the observation, such as too soon drawing up the 

 thermometer ; for, on the one hand, the regular 

 course of the experiments of the 14th Septem- 

 ber, 18 17, and their coincidence with those of 

 the 13th, at the depths of 0, 25, and 100 fa- 

 thoms, does not allow us to suppose any thing of 

 the kind ; on the other side, the observations of 



