The beauty and genius of a work of art may be reconceived, though its first material expression be destroyed; a vanished harmony may yet again inspire the composer; but when the last individual of a race of living things breathes no more, another heaven and another earth must pass before such a one can be again.

When ... we realize the possibilities of deep sea life still unknown to us, every haul of the dredge should be welcomed by an expectant enthusiasm equaled in other fields only by the possible hope of communication with our sister planets.

I can only think of one experience which might exceed in interest a few hours spent under water, and that would be a journey to Mars.

To be a Naturalist is better than to be a King.

... the only other place comparable to these marvelous nether regions, must surely be naked space itself, out far beyond atmosphere, between the stars, where sunlight has no grip upon the dust and rubbish of planetary air, where the blackness of space, the shining planets, comets, suns, and stars must really be closely akin to the world of life as it appears to the eyes of an awed human being, in the open ocean, one half mile down.

Earth has few secrets from the birds.

To write honestly and with conviction anything about the migration of birds, one should oneself have migrated. Somehow or other we should dehumanize ourselves, feel the feel of feathers on our body and wind in our wings, and finally know what it is to leave abundance and safety and daylight and yield to a compelling instinct, age-old, seeming at the time quite devoid of reason and object.