OF A METHOD OF KEEPING IN MIND THE FORM OF A FACE.

If you want to acquire facility for bearing in mind the expression
of a face, first make yourself familiar with a variety of [forms of]
several heads, eyes, noses, mouths, chins and cheeks and necks and
shoulders: And to put a case: Noses are of 10 types: straight,
bulbous, hollow, prominent above or below the middle, aquiline,
regular, flat, round or pointed. These hold good as to profile. In
full face they are of 11 types; these are equal thick in the middle,
thin in the middle, with the tip thick and the root narrow, or
narrow at the tip and wide at the root; with the nostrils wide or
narrow, high or low, and the openings wide or hidden by the point;
and you will find an equal variety in the other details; which
things you must draw from nature and fix them in your mind. Or else,
when you have to draw a face by heart, carry with you a little book
in which you have noted such features; and when you have cast a
glance at the face of the person you wish to draw, you can look, in
private, which nose or mouth is most like, or there make a little
mark to recognise it again at home. Of grotesque faces I need say
nothing, because they are kept in mind without difficulty.

The position of the head.