interest--nay, room enough for the free use of the imagination, in a
science which tells of the growth and decay of whole mountain-ranges,
continents, oceans, whole tribes and worlds of plants and animals.

And yet it is not so much for the vastness and grandeur of those
scenes of the distant past, to which the science of geology
introduces us, that I value it as a study, and wish earnestly to
awaken you to its beauty and importance. It is because it is the
science from which you will learn most easily a sound scientific
habit of thought. I say most easily; and for these reasons. The
most important facts of geology do not require, to discover them, any
knowledge of mathematics or of chemical analysis; they may be studied
in every bank, every grot, every quarry, every railway-cutting, by
anyone who has eyes and common sense, and who chooses to copy the
late illustrious Hugh Miller, who made himself a great geologist out
of a poor stonemason. Next, its most important theories are not, or
need not be, wrapped up in obscure Latin and Greek terms. They may
be expressed in the simplest English, because they are discovered by
simple common sense. And thus geology is (or ought to be), in
popular parlance, the people's science--the science by studying
which, the man ignorant of Latin, Greek, mathematics, scientific
chemistry, can yet become--as far as his brain enables him--a truly
scientific man.

But how shall we learn science by mere common sense?

First. Always try to explain the unknown by the known. If you meet
something which you have not seen before, then think of the thing
most like it which you have seen before; and try if that which you
know explains the one will not explain the other also. Sometimes it