The climate of our own country is exceedingly variable. The
transitions from heat to cold are very sudden, the range of the
mercury is very great. In the North, we have almost the Arctic
winters; in the South, almost the peculiarities of the tropics. Of the
State of Pennsylvania it has been said, that in this respect it is a
compound of all the countries in the world. Mr. Jefferson and Dr.
Rush, as before observed, insisted that our climate has changed; and
Williams, the historian of Vermont, contends that New England has
deteriorated in its seasons, temperature, harvests, and health, since
its early settlement. Our winds blow from every point of the compass,
but a due north wind is very rare. Our great western lakes have a
large influence on our climate. Some learned men have asserted, that,
if they were land, their area being about ninety-four thousand square
miles, the region would be so cold as to be scarcely inhabitable.

Such is an outline of our subject. The science itself is by no means
systematized. Many things are taken for granted which may yet be
disproved. If, says Humboldt, we perceive a want of connection in the
phenomena of certain sciences, we may anticipate the revelation of new
facts, whose importance will probably be commensurate with the
attention directed to other branches of study. What we want is a
larger class of observers, and not only those who are professional
persons, but those who would commune with Nature, and seek to
invigorate their minds by the acquisition of new ideas, and a recourse
to rich and pure sources of enjoyment.

But more than this. It is a requirement of the present age, says the
same authority, that there should be an equal appreciation of all
branches of mathematical and physical science; for the material wealth
and the growing prosperity of nations are principally based upon a