69. It follows also from this law of construction that any master who can color can always do any pane of his window that he likes, separately from the rest. Thus, you see, here is one of Sir Joshua's first sittings: the head is very nearly done with the first color; a piece of background is put in round it: his sitter has had a pretty silver brooch on, which Reynolds, having done as much as he chose to the face for that time, paints quietly in its place below, leaving the dress between to be fitted in afterwards; and he puts a little patch of the yellow gown that is to be, at the side. And it follows also from this law of construction that there must never be any hesitation or repentance in the direction of your lines of limit. So that not only in the beautiful dexterity of the joiner's work, but in the necessity of cutting out each piece of color at once and forever (for, though you can correct an erroneous junction of black and white because the gray between has the nature of either, you cannot correct an erroneous junction of red and green which make a neutral between them, if they overlap, that is neither red nor green): thus the practice of color educates at once in neatness of hand and distinctness of will; so that, as I wrote long ago in the third volume of "Modern Painters," you are always safe if you hold the hand of a colorist. 70. I have brought you a little sketch to-day from the foreground of a Venetian picture, in which there is a bit that will show you this precision of method. It is the head of a parrot with a little flower in his beak from a picture of Carpaccio's, one of his series of the Life of St. George. I could not get the curves of the leaves, and they are patched and spoiled; but the parrot's head, however badly done, is put down with no more touches than the Venetian gave it, and it will show you exactly his method. First, a thin, warm ground had been laid over the whole canvas, which Carpaccio wanted as an under-current through all the color, just as there is an under-current of gray in the Loire drawings. Then on this he strikes his parrot in vermilion, almost flat color; rounding a little only with a glaze of lake; but attending mainly to get the character of the bird by the pure outline of its form, as if it were cut out of a piece of ruby glass. Then he comes to the beak of it. The brown ground beneath is left, for the most part; one touch of black is put for the hollow; two delicate lines of dark gray define the outer curve; and one little quivering touch of white draws the inner edge of the mandible. There are just four touches--fine as the finest penmanship--to do that beak; and yet you will find that in the peculiar paroquettish mumbling and nibbling action of it, and all the character in which this nibbling beak differs from the tearing beak of the eagle, it is impossible to go farther or be more precise. And this is only an incident, remember, in a large picture.