iSO APEENDIX. 



1.3th April, 1816, find their confirmation in the 

 preceding ones of the 7th of April, m 18° south, 

 which give a diflference of to 125 fathoms of 

 4°, 8 R., that is, from to 100 fathoms ; likewise 

 3°, 8 R. The same observations then give for the 

 second hundred of the depth in fathoms, likewise 

 iibout 8° Reaumur. 



It is not to be discovered, from the observations, 

 whence this difference in the progressive decrease 

 of the warmth arises. It cannot well be ascribed 

 to the influence of the seasons, at least in latitude 

 35° north: the observations of June and September, 

 show an agreement with each other. The reason 

 perhaps is, tliat the perpendicular rays of the sun 

 penetrate the water, between the tropics, to a 

 greater depth than in latitudes where the sun 

 never appears in the zenith. The place of constant 

 temperature, independent of the seasons, must, pro- 

 bably, lie much deeper between the tropics than 

 beyond them. 



5. The observations of the 22d of September, 

 1817, in 28° north latitude, and in 152° west lon- 

 gitude, seem to present a nuich more uniform 

 course, particularly if we set aside the statement 

 in twenty-five fathoms' depth, which does not 

 appear to agree with the higher or lower observ- 

 ations. We have from them a decrease of heat, of 

 3°, 5 R. for the first fifty fathoms ; 3°, R. for the 

 second fifty fathoms, and 4° 3 R., from a hundred 

 to two hundred. 



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