[206] Of course, all the columns of colour are to be of equal length.
[207] The degree of darkness you can reach with the given colour is always indicated by the colour of the solid cake in the box.
[208] The figure a, Fig. 5., is very dark, but this is to give an example of all kinds of depth of tint, without repeated figures.
[209] Nearly neutral in ordinary circumstances, but yet with quite different tones in its neutrality, according to the colours of the various reflected rays that compose it.
[210] If we had any business with the reasons of this, I might, perhaps, be able to show you some metaphysical ones for the enjoyment, by truly artistical minds, of the changes wrought by light, and shade, and perspective in patterned surfaces; but this is at present not to the point; and all that you need to know is that the drawing of such things is good exercise, and moreover a kind of exercise which Titian, Veronese, Tintoret, Giorgione, and Turner, all enjoyed, and strove to excel in.
[211] The use of acquiring this habit of execution is that you may be able, when you begin to colour, to let one hue be seen in minute portions, gleaming between the touches of another.
[212] William Hunt, of the Old Water-colour Society.
[213] At Marlborough House, among the four principal examples of Turner's later water-colour drawing, perhaps the most neglected is that of fishing-boats and fish at sunset. It is one of his most wonderful works, though unfinished. If you examine the larger white fishing-boat sail, you will find it has a little spark of pure white in its right-hand upper corner, about as large as a minute pin's head, and that all the surface of the sail is gradated to that focus. Try to copy this sail once or twice, and you will begin to understand Turner's work. Similarly, the wing of the Cupid in Correggio's large picture in the National Gallery is focussed to two little grains of white at the top of it. The points of light on the white flower in the wreath round the head of the dancing child-faun, in Titian's Bacchus and Ariadne, exemplify the same thing.
[214] I shall not henceforward number the exercises recommended; as they are distinguished only by increasing difficulty of subject, not by difference of method.
[215] If you understand the principle of the stereoscope you will know why; if not, it does not matter; trust me for the truth of the statement, as I cannot explain the principle without diagrams and much loss of time.