i8(5 Mr. Renn ell's Observations on a Current 
that the Caspian Sea is higher by several feet, at either end, 
as a strong northerly, or southerly, wind prevails. There- 
fore, as water pent up, in a situation from which it cannot 
escape, acquires a higher level, so, in a place where it can 
escape, the same operation produces a current : and this cur- 
rent will extend to a greater or less distance, according to the 
force with which it is set in motion ; or, in other words, ac- 
cording to the height at which it is kept up, by the wind. 
It may possibly be asked, why a similar current does not 
prevail in the British Channel, from the same westerly winds? 
To this I answer, that the increased height and velocity of 
the tides, during the prevalence of such winds, prove that a 
part, at least, of the same effect which happens in the Bay of 
Biscay, is produced in the Channel ; and I have little doubt, 
that there is, in fact, a current also ; but that, as it is blended 
with the common tide, the effect on the senses is lost : for it 
may appear only in the form of a stronger flood tide, or a 
weaker ebb, than at other times. Whereas the Bay, a wider 
space, and of a different form, allows a freer scope to the 
tides, than the British Channel does : it being high water 
nearly at the same time, all over the Bay ; but varying in 
the Channel, at least five hours. And it may be concluded, 
from analogy, that the form of the Channel does not allow of 
the same effect being produced by ‘the wind, on its included 
waters, as may be produced on those of the Bay : these meet- 
ing with an opposition, in the coast of France, the others 
having a partial exit, at the Btrait of Dover : we may also 
conclude, that if no such phenomenon as a tide existed, a 
current, though less strong than in the Bay, would be per- 
ceived in the British Channel. 
