A man's own addition to what he learns is cement to bind an otherwise loose heap of stones into a structure of unity, strength, and use.

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.

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.

A calculating engine is one of the most intricate forms of mechanism, a telegraph key one of the simplest. But compare their value.

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

Degree is much: the whole Atlantic might be lukewarm and never boil us a potato.

Ignorance may find a truth on its doorstep that erudition vainly seeks in the stars.