“I have discovered the secret of happiness – it is work, either with the hands or the head.”

If one gains an interest in the history of the earth, he is quite sure to gain an interest in the history of the life on the earth. If the former illustrates the theory of development, so must the latter.

Women are about the best lovers of nature, after all; at least of nature in her milder and more familiar forms.

As with other phases of nature, I have probably loved the rocks more than I have studied them.

The beautiful vagabonds, endowed with every grace, masters of all climes, and knowing no bounds.

More than any other poet, Whitman is what we make him; more than any other poet, his greatest value is in what he suggests and implies rather than in what he portrays, and more than any other poet must he wait to be understood by the growth of the taste of himself.

It is the life of the crystal, the architect of the flake, the fire of the frost, the soul of the sunbeam. This crisp winter air is full of it.

If I were to name the three most precious resources of life, I should say books, friends, and nature. And the greatest of these, at least the most constant and always at hand, is nature.

To strong, susceptible characters, the music of nature is not confined to sweet sounds.

To still others, who again have their human prototypes, it means a struggle, more or less fierce, to keep soul and body together; while to many insect forms, it means death.

The birth of a baby and the blooming of a flower are natural events, but the laboratory methods forever fail to give us the key to the secret of either.

Nature teaches more than she preaches.

One of the most graceful of warriors is the robin. I know few prettier sights than two males challenging and curveting about each other upon the grass in early spring. Their attentions to each other are so courteous and restrained.

Without the name, any flower is still more or less a stranger to you. The name betrays its family, its relationship to other flowers, and gives the mind something tangible to grasp. It is very difficult for persons who have had no special training to learn the names of the flowers from the botany.

The geologist is pretty sure to be an evolutionist.

A man can fail many times, but he isn’t a failure until he begins to blame somebody else.

Man has climbed up from some lower animal form, but he has, as it were, pulled the ladder up after him.