THERMOMETRICAL JOURNAL. 193 
coaft was at 47°. and in the gulph ftream at, 70°, viz 
By Capt. Billings, | By my experiments | ‘if. between 
1791, June, coaft, 61 | 1789 Nov. coaft, 47 Hieaes. 
do. Stream, 77 do. ftream, 70 7 
ee 
—— 
do. fiream warmer, 16 | do. ftream warmer23 | 
— eee 
Hence it may be concluded that although this difference 
of heat is more remarkable in winter than in fummer, 
yet itis fafficient at all times to guide navigators, fo as to 
take the benefit of its current in going from, and to avoid 
its oppofition in coming to Ametica.—In the latter cafe, 
it has this additional convenience in correcting a reckon- 
ing; for if a navigator can, by this means, know the 
moment he is within the ftream, he knows at the fame 
moment his relative fituation as to the coaft; and if by 
repeated experiment this mode of correétion fhould be 
found folid, it amounts, in effect, to a certainty of the lon= 
gitude, at the precife time when it is important to be ac- 
curate. , 
Captain Billings’ courfe being nearly along the flream, 
he found only fuch alteration in the heat of the water as 
may be accounted for by the cooling of the ftream itfelf, 
in its courfe to the northward, "till he came to lat. 39. 00. 
N. long. 56. 00. W. (a breaft of the Banks of Newfound= 
land) when the mercury fell 10°. Dodtor Franklin, in 
November, 1776, on board of the Reprifal, in lat. 41. 
N. long. 46. W. found about the fame difference; but 
the Reprifal had kept a courfe farther fouth and came in- 
to this cool water in a N. N. E. dire€tion ; while Captain 
Billings being farther North, came in an eafterly directi- 
on, and of courfe might be as much within the influence 
iD Db +e , of 
