s down beyond the reach of the sun's rays, when the water of the
well which it has formed is no longer kept liquid, and the stone is
buried in the ice. In summer, however, the water is kept liquid; and
circular wells, formed in this manner, are of frequent occurrence on the
glaciers, sometimes, in the morning, covered by a thin crust of ice.

Thus, the stones at the bottom of streams must tend to raise, rather
than lower, this temperature. Is it possible that, in the agitation of a
stream at its bottom, if violent, momentary and minute vacua may be
formed, tending to increase the intensity of the cold?

HERNE HILL, _Sept. 2, 1836._

FOOTNOTES:

[Footnote 31: London's _Magazine of Natural History_, vol. ix., pp.
533-536.--ED.]

[Footnote 32: The query was as follows:--

_An Inquiry for the Cause of the Difference in Temperature of River
Water and Spring Water, both in Summer and Winter._--In the summer time
the river water is much warmer than that from a spring; during the
severe frosts of winter it is colder; and when the stream is covered
over with ice, the spring, that is, well or pump water is unaffected by
frost. Does this difference proceed from the exposure of the surface of
the river water, in summer, to the sun's direct influence, and, in
winter, to that of frost; while the well water, being covered, is
protected from their power? Or is there in river water, from the earthy
particles it contains, a greater susceptibility of heat and
cold?--_Indigena_. _April 19, 1836._--ED.]

METEOROLOGY.[33]

280. The comparison and estimation of the relative advantages of
separate departments of science is a task which is always partially
executed, because it is never entered upon with an unbiased mind; for,
since it is only the accurate knowledge of a science which can enable us
to present its beauty, or estimate its utility, the branches of
knowledge with which we are most familiar will always appear the most
important. The endeavor, therefore, to judge of the relative _beauty_ or
_interest_ of the sciences is utterly hopeless. Let the astronomer boast
of the magnificence of his speculations, the mathematician of the
immutability of his facts, the chemist of the infinity of his
combinations, and we will admit that they all have equal ground for
their enthusiasm. But the highest standard of estimation is that of
utility. The far greater proportion of mankind, the uninformed, who are
unable to perceive the