i88 Mr. Rennell’s Observations on a Current 
It is quite uncertain at what interval of time, from the 
commencement of strong westerly gales, in the Atlantic and 
Bay of Biscay, the current may operate on the tracks of ships,, 
near Scilly ; for we are not possessed of the data, requisite for 
determining it. If we were to conceive a current, originating 
on the coast of Spain, and afterwards disturbing the courses 
of ships, on the west of Scilly and Ireland ; this would re- 
quire too much time, to agree with one of the instances 
which I mean to adduce : although it is probable, that this 
may be nearly the effect at ordinary times, and when the 
westerly winds blow moderately. But as, in one striking in- 
stance, it appears that the current operated in a very remark- 
able manner, on the ship's course, on the fourth day after the 
commencement of the gale, in the quarter where the ship 
was ; the cause should rather be looked for, in the sudden and 
great accumulation of water, in the Bay of Biscay : otherwise, 
there is no accounting for the sudden appearance of the cur- 
rent. And the very act of accumulation, causing an in- 
draught, there will consequently be a current round the Capes 
of Finisterre, and Ortegal, towards the Bay. Be the exact 
cause, however, what it may, it no doubt originates in the 
Bay, by the action of strong westerly winds : the prevalence 
of such winds, will therefore be the signal for the appearance 
of a current, between Ushant, and the south-west coast of 
Ireland : for though the cause can only be guessed at, the ef- 
fect is too well ascertained, to remain in doubt. 
I shall now adduce the facts, ^on which the idea of the 
existence of a current is founded. 
has been felt, very far within the limits of the south-east trade wind, in the Indian 
Ocean. 
