The painter who draws by practise and judgment of the eye without the use of reason is like the mirror which reproduces within itself all the objects which are set opposite to it without knowledge of the same.

It is an acknowledged fact that we perceive errors in the work of others more readily than in our own.

Make an effort to collect the good features from many beautiful faces.

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.

Beyond a doubt truth bears the same relation to falsehood as light to darkness.

Whoever despises the high wisdom of mathematics nourishes himself on delusion and will never still the sophistic sciences whose only product is an eternal uproar.

It is no small benefit on finding oneself in bed in the dark to go over again in the imagination the main lines of the forms previously studied, or other noteworthy things conceived by ingenious speculation.