Some young folks have wind-fall minds, prematurely detached from the tree of knowledge for a life-long sourness and pettiness.

Doubt is the beginning, not the end, of wisdom.

When a learner, in the fullness of his powers, comes to great truths unstaled by premature familiarity, he rejoices in the lateness of his lessons.

Boundaries which mark off one field of science from another are purely artificial, are set up only for temporary convenience. Let chemists and physicists dig deep enough, and they reach common ground.

Nature is full of by-ends. A moth feeds on a petal, in a moment the pollen caught on its breast will be wedding this blossom to another in the next county.

Ten builders rear an arch, each in turn lifting it higher; but it is the tenth man, who drops in the keystone, who hears our huzzas.

Let truth be a banner big enough to hide the man who holds it up.