wn, no data are afforded to judge from; but what vast
atmospheric agencies must be at work when such wonderful results in the
smaller lakes have been made evident!

People who live at the Niagara Falls, and I agree with them in
observations extending over a period since 1826, believe that these
Falls have receded considerably; and, although I do not enter into the
mathematical analysis of modern geologists respecting them, as to their
constant retrocession, believing that earthquake split open the present
channel, yet I have no doubt that the level of Lake Erie is considerably
affected by the diminution of the yielding shaly rocks of their
foundation. Earthquake, and not retrocession, appears to me, who have
had the singular advantage, as a European, of very long residence, to
have been the cause of that great chasm which now forms the bed of the
Niagara, from the Table Rock to Queenston, in short, a rending or
separating of the rocks rather than a wearing; and this is corroborated
by the many vestiges of great cataracts which now exist near the Short
Hills, the highest summit of the Niagara frontier, between Lakes Erie
and Ontario, as well as by the great natural ravine of St. David's. But
this is a subject too deep for our present purpose, and so we shall
continue to treat of the Great Lakes in another point of view.

Chemically considered, these lakes possess peculiar properties,
according to their boundaries. Superior is too little known to speak of
with certainty--Huron not much better--but Erie, and particularly
Ontario, have been well investigated. The waters of these are pure, and
impregnated chiefly with aluminous and calcareous matter, giving to the
St. Lawrence river a fresh and admirable element and aliment.

The St. Lawrence is of a fine cerulean hue, but, like its parent waters
of Erie and Ontario, rapidly deposits lime and alumine, so that the
boilers of steam-vessels, and even teakettles, soon become furred and
incrusted. The specific gravity of the St. Lawrence water above Montreal
is about 1.00038, at the temperature of 66 deg., the air being then 82 deg. of
Fahrenheit. It contains the chlorides, sulphates, and carbonates, whose
bases are lime and magnesia, particularly and largely those of lime,
which accounts for the rapid depositions when the water is heated.

A very accurate analysis gives, at Montreal, in July, atmospheric air in
solution or admixture 446 per cent; for a quart of this water, 57