OF A METHOD OF LEARNING WELL BY HEART.

When you want to know a thing you have studied in your memory
proceed in this way: When you have drawn the same thing so many
times that you think you know it by heart, test it by drawing it
without the model; but have the model traced on flat thin glass and
lay this on the drawing you have made without the model, and note
carefully where the tracing does not coincide with your drawing, and
where you find you have gone wrong; and bear in mind not to repeat
the same mistakes. Then return to the model, and draw the part in
which you were wrong again and again till you have it well in your
mind. If you have no flat glass for tracing on, take some very thin
kidts-kin parchment, well oiled and dried. And when you have used it
for one drawing you can wash it clean with a sponge and make a
second.