The eye which turns from a white object in the light of the sun and goes into a less fully lighted place will see everything as dark.

A single and distinct luminous body causes stronger relief in the objects than a diffused light; as may be seen by comparing one side of a landscape illuminated by the sun, and one overshadowed by clouds, and illuminated only by the diffused light of the atmosphere.

Whatever you think matters - doesn't. Follow this rule, and you will add decades to your life. Rodger Rosenblatt As a well spent day brings happy sleep, so life well used brings happy death.

The supreme misfortune is when theory outstrips performance

The Bactrian have two humps; the Arabian one only. They are swift in battle and most useful to carry burdens. This animal is extremely observant of rule and measure, for it will not move if it has a greater weight than it is used to, and if it is taken too far it does the same, and suddenly stops and so the merchants are obliged to lodge there.

When you are painting you should take a flat mirror and often look at your work within it, and it will then be seen in reverse, and will appear to be by the hand of some other master, and you will be better able to judge of its faults than in any other way.

People reveal themselves completely only when they are thrown out of the customary conditions of their life.