With the ancients, who do not appear to have known any of the lakes, it was different; they valued it much, and, it is said, used it for their monochrome pictures[246]. If they did so, it confirms Fuseli’s account of the process of painting, or rather of drawing, those pictures. It is a resin of a warm semi-transparent, dullish red colour; and is best used as a varnish which darkens on exposure to the air. If this varnish were laid over the white ground of the monochromes, after the first process of drawing with the point, the outline would be seen through, and the indentation made by the point upon the tender chalk ground being filled up with the varnish, would present a dark outline, the point being then applied, would cut down to the white ground, and so produce the light reliefs[247]. The other reds known to the ancients appear to have been mostly opaque. Cennino mentions Lac or Lake. But it appears that in his days it was principally procured by discharging the colour from shreds of scarlet and purple cloths. His editor imagines that he also knew and recommended gum lac. Be that as it may, neither the ancients nor the school of Giotto seem to have known anything of the fine lakes; whether prepared from the Indian gums, from madder, or from other substances, that enrich the palette of painters, both in oil and water-colours now. Sir Humphrey Davy, however, seems to think that lake made from madder may have been known to the ancients[248]. Of blue colouring substances, the most beautiful known to the ancients, as to us, was ultramarine. Pliny says the best of azures came from Egypt, the second kind from Scythia, and a third from Cyprus. It is not possible to determine accurately whether all these were true ultramarine, for it appears that then, as now, it was often adulterated, and even imitated, by boiling native blue earths with woad, or by grinding smalt with it. That manufactured in Spain, and at Puteoli, was entirely artificial[249]. It is said, on the authority of Theophrastus, that one of the kings of Egypt invented the method of making the beautiful Armenian blue, so precious that kings sent presents of it to each other. And this corresponds with the value of ultramarine at all times. The Lapis Lazuli, from which the colour is made, is found in Siberia, and on the borders of Persia, as well as in China, where the preparation of the colour has long been known. It is probable that the superiority of the colour brought from Egypt was owing to the method of preparing it, for the most genuine kinds were certainly likely to be those of Scythia and Armenia[250]. Of that brought from Scythia there were four preparations of different degrees of beauty and intensity of colour; and shortly before Pliny wrote, one Nestor had invented a new preparation from the lightest part of the Egyptian blue.