Besides these permanent red dyes there are others produced from woods, called in the Middle Ages by the general name of "Brazil"; whence the name of the American country, because the conquerors found so much dyeing-wood growing there. Some of these wood-dyes are very beautiful in colour; but unluckily they are none of them permanent, as you may see by examining the beautiful stuffs of the thirteenth and fourteenth centuries at the South Kensington Museum, in which you will scarcely find any red, but plenty of fawn-colour, which is in fact the wood-red of 500 years ago thus faded. If you turn from them to the Gothic tapestries, and note the reds in them, you will have the measure of the relative permanence of kermes and "Brazil," the tapestry reds being all dyed with kermes, and still retaining the greater part of their colour. The mediæval dyers must be partly excused, however, because "Brazil" is especially a silk dye, kermes sharing somewhat in the ill qualities of madder for silk; though I have dyed silk in kermes and got very beautiful and powerful colours by means of it.
Yellow dyes are chiefly given us by weld (sometimes called wild mignonette), quercitron bark (above mentioned), and old fustic, an American dye-wood. Of these weld is much the prettiest, and is the yellow silk dye _par excellence_, though it dyes wool well enough. But yellow dyes are the commonest to be met with in nature, and our fields and hedgerows bear plenty of greening-weeds, as our forefathers called them, since they used them chiefly for greening blue woollen cloth; for, as you may well believe, they, being good colourists, had no great taste for yellow woollen stuff. Dyers'-broom, saw-wort, the twigs of the poplar, the osier, and the birch, heather, broom, flowers and twigs, will all of them give yellows of more or less permanence. Of these I have tried poplar and osier twigs, which both gave a strong yellow, but the former not a very permanent one.
Speaking generally, yellow dyes are the least permanent of all, as once more you may see by looking at an old tapestry, in which the greens have always faded more than the reds or blues; the best yellow dyes, however, lose only their brighter shade, the "lemon" colour, and leave a residuum of brownish yellow, which still makes a kind of a green over the blue.