ed on again by them. The diminution of
rainfall by the destruction of forests, its increase by replanting
them, and the effect of both on the healthiness or unhealthiness of
a place--as in the case of the Mauritius, where a once healthy
island has become pestilential, seemingly from the clearing away of
the vegetation on the banks of streams--all this, though to study it
deeply requires a fair knowledge of meteorology, and even of a
science or two more, is surely well worth the attention of any
educated man who is put in charge of the health and lives of human
beings.

You will surely agree with me that the habit of mind required for
such a study as this, is the very same as is required for successful
military study. In fact, I should say that the same intellect which
would develop into a great military man, would develop also into a
great naturalist. I say, intellect. The military man would
require--what the naturalist would not--over and above his
intellect, a special force of will, in order to translate his
theories into fact, and make his campaigns in the field and not
merely on paper. But I am speaking only of the habit of mind
required for study; of that inductive habit of mind which works,
steadily and by rule, from the known to the unknown; that habit of
mind of which it has been said: "The habit of seeing; the habit of
knowing what we see; the habit of discerning differences and
likenesses; the habit of classifying accordingly; the habit of
searching for hypotheses which shall connect and explain those
classified facts; the habit of verifying these hypotheses by
applying them to fresh facts; the habit of throwing them away
bravely if they will not fit; the habit of general patience,
diligence, accuracy, reverence for facts for their own sake, and
love of truth for its own sake; in one word, the habit of reverent
and implicit obedience to the laws of Nature, whatever they may be--
these are not merely intellectual, but also moral habits, which will
stand men in practical good stead in every affair of life, and in
every question, even the most awful, which may come before them as
rational and social beings." And specially valuable are they,
surely, to the military man, the very essence of whose study, to be
successful, lies first in continuous and accurate observation, and
then in calm and judicious arrangement.

Therefore it is that I hold, and hold strongly, that the study of
physical science, far fr