Old age takes in part savoury wisdom for its food - see to that your old age will not lack in nourishment.

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

Be a mirror, absorb everything around you and still remain the same

Weight is caused by one element being situated in another; and it moves by the shortest line towards its centre, not by its own choice, not because the centre draws it to itself, but because the other intervening element cannot withstand it.

When you look at a wall spotted with stains...you may discover a resemblance to various landscapes, beautiful with mountains, rivers, rocks, trees. Or again, you may see battles and figures in action, or strange faces and costumes, and an endless variety of objects which you could reduce to complete and well-drawn figures.

Putting your hand into a river, you simultaneously touch the last of what is passing and the first of what is coming.

Experiment is the sole interpreter of the artifices of Nature.