What is read twice is usually remembered more than what is once written.

Curiosity is one of the permanent and certain characteristics of a vigorous intellect. Every advance into knowledge opens new prospects, and produces new incitements to farther progress.

Forgetfulness is necessary to remembrance. Ideas are retained by renovation of that impression which time is always wearing away,and which new images are striving to obliterate. If useless thoughts could be expelled from the mind, all the valuable parts of our knowledge would more frequently recur, and every recurrence would reinstate them in their former place.

Language is only the instrument of science, and words are but the signs of ideas.

When a man knows he is to be hanged in a fortnight, it concentrates his mind wonderfully.

There is certainly no greater happiness than to be able to look back on a life usefully and virtuously employed, to trace our own progress in existence, by such tokens as excite neither shame nor sorrow.

To tell of disappointment and misery, to thicken the darkness of futurity, and perplex the labyrinth of uncertainty, has been always a delicious employment of the poets