of Cape Finisterre and the Canary Islands. S43 
greater in proportion, and might possibly amount to 200 miles 
of easthig. 
It would seem advisable, therefore, that every ship going to 
the Canaries, or intending to sail between those islands and the 
mainland of Africa, and being without time-keepers, as that 
class of merchant ships commonly are, should, to every day’s 
reckoning, add ten miles of easting. This would, in the first 
instance, prevent them from deceiving themselves as they went 
> forward ; in like manner, as it is better to set a clock forward at 
once, than to charge one’s memory constantly with its being too 
slow. Ten miles does not seem too much as a cautionary mea- 
sure, as a ship has very lately been carried ninety-nine miles to 
the east in eight days in that track. What would nqj have 
been the error had she had even a moderately long passage ? 
It is this current which has furnished the roving Arabs of 
the desert with their victims from every nation, and the good 
Mr Willshire with objects of benevolence. 
J. Renneli,. 
London, ) 
^Ith February 1819. j 
Art. IV.— Ow the Submarine Current at the Strait of Gib-^ 
raltar^ and at the Sound near Elsinore 
In our account of Dr Marcet’s experiments on Sea- Water, 
we have noticed the ideas which are at present entertained re- 
specting the existence of a submarine current salter than the 
ocean, which runs out at the Strait of Gibraltar, and unloads its 
waters of their excess of salt. Dr Hudson, in the Philosophi- 
cal Transactions for 1724 seems to have first suggested the 
probability of this submarine current; and there is reason to 
think that Lieutenant, afterwards Admiral Patton, had the me- 
rit of establishing its existence. When this able officer was 
Lieutenant of the Emerald, he was overtaken with a very heavy 
* We have been indebted for the leading facts in this paper to Captain Patton, 
R. N., the brother of the late Admiral Patton.— D. B. 
•I- See this Journal, vol. II, p, 359. Note. * 
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