the Ocean at Different Depths. 



11 



eter, and surrounded by a highly non-conducting substance. — ^The 

 results are contained in the following table : — 



From this table the following conclusions may be drawn : 



1. Between the equator and 45° the temperature of the ocean 

 decreases regularly to the depth of a thousand fathoms, — beyond 

 this no experiments have been made. 



2. The decrease of temperature is at first rapid, it gradually de- 

 creases, and becomes at last insensible. 



3. The point where the decrease becomes insensible appears to 

 rise with the latitude. At 41° and 31° it is between two hundred 

 and three hundred fathoms, at 21° it is near four hundred. To this 

 remark there appears to be a slight exception at 45° 53', when the 

 temperature at four hundred fathoms is still at 10° C. but perhaps 

 that observation is modified by the proximity of the land, since it 

 was made in the Atlantic Ocean only 15° W. from Greenwich, and 

 consequently near the coast of Europe, while the others were made 

 in the south sea far from any continent j but even in this case the 

 point where the decrease of temperature becomes insensible is still 

 evidently near two hundred fathoms. 



4. The lowest temperature observed is 2.2° C (36° F.) and it 

 is perhaps that of all the depths at which the decrease is insensible. 

 The locality of that temperature rises with the latitude ; and it would 

 be interesting to know at what latitude it reaches the surface. 



The results of M. Lenz, in regard to the saltness of the sea, have 

 been deduced from its specific gravity. It had previously been 



A toise = 1.066 English fathoms. 



