We might say that the earth has the spirit of growth; that its flesh is the soil.

In the days of thy youth seek to obtain that which shall compensate the losses of thy old age.

He who does not understand the supreme certainty of mathematics is wallowing in confusion.

The eye - which sees all objects reversed - retains the images for some time.

Being engulfed in practice without delicate knowledge related to it, is in many ways like entering a ship without knowing where it is headed.

Learning is the only thing the mind never exhausts, never fears, and never regrets.

Shadow is the diminution alike of light and of darkness, and stands between darkness and light.