[2] 
m 
owing to the easterly or westerly winds. These latter currents have, 
bowcvei', sometimes considerable rapidity; and a curious fact appears 
in relation to the effect of these lake currents upon the waters of the 
basin, viz. that a strong current sets into the basin, in direct oppo. 
sition to the westerly winds when they blow hard; and, conversely, 
a strong current sets out of the basin, in direct opposition to violent 
easterly winds; or, in ('ther words, the current out of, or into, th« 
basin, runs in a direction opposite both to the set of the lake current 
and the direction of the winds, whether easterly or westerly. 
it ii> important to account for this, before proceeding further; and, 
in doing so, we refer to the sketch i-erewiih, to make the matter more 
inieiligibie. 
We ti; St must suppose the surface of the lake, and of the basin, to 
be of the same level, as will always be tlie case, after a few days of 
calm weatijer, and rej>resentthis level by 0° 0' •" and 0'". An east- 
erly wind then setting in, drives a part of the water of the eastern 
half of thelake, into the western, raisitig the surface at 0" and 0'",- 
and lowering ir at 0'; as the surface descends at G' the water in the 
basin uMist also descend, by running out against the wind, there be- 
ing no issue at the west end of the hasin. 
In like manner, when a westerly wind heaps the water at 0' above 
the suiface in the basin, it must rise in the basin by running in against 
the wind, theje being no entrance at the west end. 
As the winds abate, the w aters gradually take a level common to 
both lake and hasin; but not the same as before, for, (the supply be- 
ing nearly equable at all times,) wich westerly winds, more is fojced 
out of the lake over the falls, and with easterly winds less pass that 
way than when the surface is at a mean elevation. The basin has, 
therefore, higher to rise, immediately after an easterly wind, than it 
was depressed by it : and lower to fall, after a westerly wind, than 
it was elevated by that wind. But the return of thelake to its level 
is slow and gradual ; the elevation and depression of the waters at its 
ends, is sudden and violent, and amounts often to several feet. It 
is to this latter operation, therefore, that we are to look for produc- 
ing any considerable effect. 
Having now become acquainted with the causes of the currents of 
the basin, and their operation, we will endeavor to ascertain if they 
can be turned to account in deepening the water on the bar, at the 
mouth of the basin. 
Whether that bank is coeval with the Presque Isle in the form in 
which it now appears, or not, matters little, so long as we may safely 
infer, that its. present state, being that in which it has always been 
known with little deviation, is owing to causes which are evident, 
and some of which can be in a measure controlled — these causes ate 
the inertia of the matter composing it; the force of easterly winds 
and the strength of the basin currents. 
Easterly winds, if preponderatiiigover the resistance of the matter 
and the opposition of the current, would wear aw ay this bank, and 
spread the sand over the interior of the basin. I'he basin ciirrentSi, 
