The leading distinction in magnets is the sex, male and female, and the next great difference in them is the colour. Those of Magnesia, bordering on Macedonia, are of a reddish black; those of Breotia are more red than black; and the kind that is found in Troas is black, of the female sex, and consequently destitute of attractive power.

The brain is the highest of the organs in position, and it is protected by the vault of the head; it has no flesh or blood or refuse. It is the citadel of sense-perception.

In comparing various authors with one another, I have discovered that some of the gravest and latest writers have transcribed, word for word, from former works, without making acknowledgment.

Accustom yourself to master and overcome things of difficulty; for if you observe, the left hand for want of practice is insignificant, and not adapted to general business; yet it holds the bridle better than the right, from constant use.

Nulla dies sine linea - Not a day without a line.

Made up of the glories of the most precious gems, to describe them is a matter of inexpressible difficulty. For there is amongst them the gentler fire of the ruby, there is the rich purple of the amethyst, there is the sea-green of the emerald, and all shining together in an indescribable union. Others, by an excessive heightening of their hues equal all the colours of the painter, others the flame of burning brimstone, or of a fire quickened by oil.

Most men are afraid of a bad name, but few fear their consciences.