If only the emotional side of the matter has been remembered, when you come to draw it you will be hopelessly at sea, as it is remarkable how little the memory retains of the appearance of things constantly seen, if no attempt has been made to memorise their visual appearance.

The true artist, even when working from nature, works from memory very largely.  That is to say, he works to a scheme in tune to some emotional enthusiasm with which the subject has inspired him in the first instance.  Nature is always changing, but he does not change the intention of his picture.  He always keeps before him the initial impression he sets out to paint, and only selects from nature those things that play up to it.  He is a feeble artist, who copies individually the parts of a scene with whatever effect they may have at the moment he is doing them, and then expects the sum total to make a picture.  If circumstances permit, it is always as well to make in the first instance a rapid sketch that shall, whatever it may lack, at least contain the main disposition of the masses and lines of your composition seen under the influence of the enthusiasm that has inspired the work.  This will be of great value afterwards in freshening your memory when in the labour of the work the original impulse gets dulled.  It is seldom that the vitality of this first sketch is surpassed by the completed work, and often, alas! it is far from equalled.

In portrait painting and drawing the memory must be used also.  A sitter varies very much in the impression he gives on different days, and the artist must in the early sittings, when his mind is fresh, select the aspect he means to paint and afterwards work largely to the memory of this.

Always work to a scheme on which you have decided, and do not flounder on in the hope of something turning up as you go along.  Your faculties are never so active and prone to see something interesting and fine as when the subject is first presented to them.  This is the time to decide your scheme; this is the time to take your fill of the impression you mean to convey.  This is the time to learn your subject thoroughly and decide on what you wish the picture to be.  And having decided this, work straight on, using nature to support your original impression, but don’t be led off by a fresh scheme because others strike you as you go along.  New schemes will do so, of course, and every new one has a knack of looking better than your original one.  But it is not often that this is so; the fact that they are new makes them appear to greater advantage than the original scheme to which you have got accustomed.  So that it is not only in working away from nature that the memory is of use, but actually when working directly in front of nature.