.478 Temperature of the Ocean> tee. [Book VII, 



" The bottle had a coating of wool, three inches 

 thick, which was wrapped up in an oiled fkin, and let 

 into a leather purfe, and the whole inclofed in a well- 

 pitched canvas bag, firmly tied to the mouth of the 

 bottle, fo that not a drop of water could penetrate to 

 its furface. A bit of lead fhaped like a cone, with its 

 bafe downwards, and a cord fixed to its fmall end, 

 was put into the bottle ; and a piece of valve leather, 

 with half a dozen flips of thin bladder, were ftrung on 

 the cord, which, when pulled, effectually corked the 

 bottle on the infide." I have here put down two 

 of the experiments which were made during that 

 voyage. 



< Auguft 4, 1773, north latitude 80. 30'. The 

 heat of the air was 32, of the water at the furface 36, 

 of water fetched up from the depth of 60 fathoms 

 under the ice 39 *. 



c September 4, 1773, north latitude 65. The 

 heat of the air was 66', of the water at the furface 

 , of water from the depth of 683 fathoms 40. 



It appears from all thefe experiments that, when 

 the atmofphere was hotter than the furface of the fea* 

 the fuperficial water was hotter than that at a great 

 depth i and when the atmofphere was colder than the 

 furface of the fea, it is evident that the fuperficial wa- 

 ter 'was fomewhat colder than that at a confiderable 

 diftance below it : and I doubt not that this will ge- 

 nerally be the cafe, though fudden changes in the 

 temperature of the t atmofphere, which cannot be in- 

 itantly communicated to the fea, may occafion parti- 

 cular exceptions. 



c In the year 17795 feverd experiments were made, 

 with great accuracy, in order to inveftigate the tern* 



Voyage towards the North Pole, p a 143. 



perature 



