ent the list of several hundred errors, absurdities,
contradictions, and mutual refutations of scientists, in the physical
sciences, now before me; errors not sought after, but incidentally
observed and noted in the spare hours' reading of a busy professional
life.

It is worthy of notice, that the uncertainties of science increase just
in proportion to our interest in it. It is very uncertain about all my
dearest concerns, and very positive about what does not concern me. The
greatest certainty is attainable in pure mathematics, which regards only
ideal quantities and figures; but biology--the science of life--is
utterly obscure. The astronomer can calculate with considerable accuracy
the movements of distant planets, with which we have no intercourse; but
where is the meteorologist bold enough to predict the wind and weather
of next week, on which my crops, my ships, my life may depend? Heat,
light, and electricity may be pretty accurately measured and registered,
but what physician can measure the strength of the malignant virus which
is sapping the life of his patient? The chemist can thoroughly analyze
any foreign substance, but the disease of his own body which is bringing
him to the grave, he can neither weigh, measure nor remove. Science is
very positive about distant stars and remote ages, but stammers and
hesitates about the very life of its professors.

4. Such, then, are a few of the uncertainties, imperfections, and
positive and egregious errors of science at its fountain head. To the
actual investigator infallible certainty of any scientific fact is
hardly possible, error exceedingly probable, and gross blunders in fact
and theory by no means uncommon. But how greatly diluted must the
modified and hesitating conviction possible to an actual observer
become, when, as is generally the case, a man is not an actual observer
himself, but _learns his science at school_. Such a person leaves the
ground of demonstrative science, and stands upon faith. The first
question then to be proposed to one whose demonstrative certainty of the
truths of physical science has disgusted him with a religion received on
testimony and faith, is, How have you reached this demonstrative
certainty in matters of science? Are you quite sure that your certainty
rests not upon the testimony of fallible and erring philosophers, but
solely upon your own personal observations and experiments?

To take only the initial standard of astronom