to unlock most geological problems
which he may meet, in any quarter of the globe. But young men must
remember always, that neither this book, nor all the books in the
world, will make them geologists. No amount of book learning will
make a man a scientific man; nothing but patient observation, and
quiet and fair thought over what he has observed. He must go out for
himself, see for himself, compare and judge for himself, in the
field, the quarry, the cutting. He must study rocks, ores, fossils,
in the nearest museum; and thus store his head, not with words, but
with facts. He must verify--as far as he can--what he reads in
books, by his own observation; and be slow to believe anything, even
on the highest scientific authority, till he has either seen it, or
something like enough to it to make it seem to him probable, or at
least possible. So, and so only, will he become a scientific man,
and a good geologist; and acquire that habit of mind by which alone
he can judge fairly and wisely of facts of any kind whatsoever.

I say--facts of any kind whatsoever. If any of my readers should be
inclined to say to themselves: Geology may be a very pleasant study,
but I have no special fancy for it. I had rather learn something of
botany, astronomy, chemistry, or what not--I shall answer: By all
means. Learn any branch of Natural Science you will. It matters
little to me which you learn, provided you learn one at least. But
bear in mind, and settle it in your hearts, that you will learn no
branch of science soundly, so as to master it, and be able to make
use of it, unless you acquire that habit and method of mind which I
am trying to teach you in this book. I have tried to teach it you by
geology, because geology is, perhaps, the simplest and the easiest of
all physical sciences. It appeals more than any to mere common
sense. It requires fewer difficult experiments, and expensive
apparatus. It requires less previous knowledge of other sciences,
whether pure or mixed; at least in its rudimentary stages. It is
more free from long and puzzling Greek and Latin words. It is
specially, the poor man's science. But if you do not like it, study
something else. Only study that as you must study geology;
proceeding from the known to the unknown by observation and
experiment.

But here some of my readers may ask, as they have a perfect right to
ask, why I wish young men to learn Natu