The floating vapour is just as true an illustration of the law of gravity as the falling avalanche.

One goes to Nature only for hints and half-truths. Her facts are crude until you have absorbed them or translated them ... It is not so much what we see as what the thing seen suggests.

Culture means the perfect and equal development of man on all sides.

Nature teaches more than she preaches. There are no sermons in stones. It is easier to get a spark out of a stone than a moral.

[T]he cold warms me—after a different fashion from that of the kitchen stove.

If the October days were a cordial like the sub-acids of fruit, these are a tonic like the wine of iron. Drink deep or be careful how you taste this December vintage. The first sip may chill, but a full draught warms and invigorates.

[Theodore Roosevelt] was a naturalist on the broadest grounds, uniting much technical knowledge with knowledge of the daily lives and habits of all forms of wild life. He probably knew tenfold more natural history than all the presidents who had preceded him, and, I think one is safe in saying, more human history also.