Gulf-Stream on the Coasts of Europe. 273 



i. e. from the meridian of 35° to the Bay of Biscay, was per- 

 formed with little deviation in the latitude of 45°. In this run, 

 exceeding 1200 miles, in a parallel of which, the usual tem- 

 perature, towards the close of November, is about 55^°, he 

 found 63° in the longitude of 35° W., diminishing to GO in 

 the Bay of Biscay ; and 61° in 10° west longitude, near the 

 same spot where the Iphigenia found 55° 7' on the 6th of 

 January, being about five weeks later in the season. At this 

 spot, then, when the Iphigenia crossed Dr Franklin's tract, 

 the temperature, in November 1776, was 5|°, and in Ja- 

 nuary 1822, 3° 2 above the ordinary temperature of the sea- 

 son. 



There can be little hesitation in attributing the universal 

 extension of the stream, in particular years, to its greater 

 initial velocity, occasioned by a moi'e than ordinary difference 

 in the levels of the gulf of Mexico, and of the Atlantic. It has 

 been computed by Major Rennell, from the known velocity 

 of the stream at various points of its course, that in the sum- 

 mer months, when its rapidity is greatest, the water requires 

 about eleven weeks to run from the outlet of the Gulf of 

 Mexico to the Azores, being about 3000 geographical miles ; 

 and he has farther supposed, in the case of the water of 

 which the temperature was examined by Dr Franklin, that 

 perhaps not less than three months were occupied in addi- 

 tion by its passage to the coasts of Europe, being altogether 

 a course exceeding 4000 geographical miles. On this suppo- 

 sition, the water of the latter end of November 1776, may 

 have quitted the gulf of Mexico, with a temperature of 83° in 

 June; and that of January 1822, towards the end of July, 

 with nearly the same temperature. The summer months, 

 particularly July and August, are those of the greatest initial 

 velocity of the stream, because it is the period when the 

 level of the Caribbean Sea and Gulf of Mexico is most de- 

 ranged. 



It is not difficult to imagine, that the space between the 

 Azores and the coasts of the old continent, being traversed 

 by the stream, slowly as it must be, at a much colder season 

 in the instance observed by the Iphigenia, than in that by 

 Dr Franklin, its temperature may have been cooled thereby 



VOL. £11. NO. II. OCTOBER 1825. S 



