Drawing is based upon perspective, which is nothing else than a thorough knowledge of the function of the eye.

The function of muscle is to pull and not to push, except in the case of the genitals and the tongue.

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.

The young man should first learn perspective, then the proportions of objects. Next, copy work after the hand of a good master, to gain the habit of drawing parts of the body well; and then to work from nature, to confirm the lessons learned.

Even the richest soil, if left uncultivated will produce the rankest weeds.

Every now and then go away, have a little relaxation, for when you come back to your work your judgment will be surer. Go some distance away because then the work appears smaller and more of it can be taken in at a glance and a lack of harmony and proportion is more readily seen.

O time! swift devourer of all created things!