If nature has arrayed herself in all the colours of the rainbow, she has not been niggardly in offering man the materials wherewith to copy them. The mineral, animal, vegetable kingdom--each helps him to realize, however faintly, her many manifold beauties: to give some idea, however slight, of that glorious flood of colour, which light lets loose upon the world. Metal, ore, earth, stone; root, plant, flower, fruit; beast, fish, insect--in turn aid the arduous task. The painter's box is a very museum of curiosities, from every part of the universe. For it, the mines yield their treasures, as well as the depths of the sea: to it come Arab camel, and English ox, cuttle-fish and crawling coccus: in it the Indian indigo lies next the madder of France, and the gaudy vermilion of China brightens the mummy of Egypt. Varied, indeed, are the sources whence we derive our pigments; and if they still leave much to desire, improvement is clearly manifest. Slowly but surely, year by year, we are advancing. With the growth of science, the exhaustless stores of creation, will there at last be attained--step by step, though it be--that summit of the artist's hopes, a perfect palette? CHAPTER VII. ON THE NEUTRAL, WHITE. The term "colour" is equivocal when applied to the neutrals, yet the artist is bound to consider them as colours; for a thing cannot but be that of which it is composed, and neutrals are composed of, or comprehend, all colours. With regard to colour, then, _white_ in a perfect state should be neutral in hue, and absolutely opaque; that white being the best which reflects light most brilliantly. This property in white is called _body_; by which in other pigments, especially those that are transparent, is meant _tingeing power_. White, besides its uses as a colour, is the instrument of light in painting, and compounds when pure with all colours, without changing their class. Yet it dilutes and cools all colours except blue, which is specifically cold; and, though it does not change nor defile any colour, it is changed and defiled by all colours. This pureness of white, if it be not in some degree broken or tinged, will cast down or degrade every other colour in a picture, and itself become harsh and crude. Hence the lowness of tone which has been thought a necessity in painting, but is such only because our other colours do not approach to the purity of white. Had we all necessary colours thus relatively pure as white, colouring in painting might be carried up to the full brilliancy of nature; and, in fact, more progress has already been made in that respect, than the prejudice for dulness is disposed to tolerate.