One cannot demand of a scholar that he show himself a scholar everywhere in society, but the whole tenor of his behavior must none the less betray the thinker, he must always be instructive, his way of judging a thing must even in the smallest matters be such that people can see what it will amount to when, quietly and self-collected, he puts this power to scholarly use.

A good method of discovery is to imagine certain members of a system removed and then see how what is left would behave: for example, where would we be if iron were absent from the world: this is an old example.

Nothing reveals a man's character better than the kind of joke at which he takes offense.

Most men of education are more superstitious than they admit - nay, than they think.

A donkey appears to me like a horse translated into Dutch.

A man of spirit must not think of the word difficulty as so much as existing. Away with it!

It thunders, howls, roars, hisses, whistles, blusters, hums, growls, rumbles, squeaks, groans, sings, crackles, cracks, rattles, flickers, clicks, snarls, tumbles, whimpers, whines, rustles, murmurs, crashes, clucks, to gurgle, tinkles, blows, snores, claps, to lisp, to cough, it boils, to scream, to weep, to sob, to croak, to stutter, to lisp, to coo, to breathe, to clash, to bleat, to neigh, to grumble, to scrape, to bubble. These words, and others like them, which express sounds are more than mere symbols: they are a kind of hieroglyphics for the ear.