The cobaltiferous ore of manganese is the same material which is used to give a blue colour, but in this case the manganese is removed, and the cobalt rendered as pure as possible. For the manganese if in excess produces a purplish brown, and its presence in however small a quantity gives the blue a purple or violet strain. By the simple method of graduating the amount of manganese which was allowed to remain with the cobalt the potters were able to obtain many intermediate shades between dark blue and purple for their monochrome glazes. The green monochromes are scarcely less numerous than the blue. There are the transparent greens of apple or leaf green shades whether even or mottled, which have been described among the glazes applied to the biscuit and among the enamels of the _famille verte_. These were used as monochromes and ground colours; and closely akin to them are (1) the cucumber green (_kua p’i lü_), in which a yellowish leaf green is heavily mottled with darker tints, and (2) the snake skin green (_shê p’i lü_), a deep transparent green with iridescent surface, one of the colours for which the directorate of Ts’ang Ying-hsüan was celebrated. There are good examples of both in the Salting Collection, but it would be useless to reproduce them except in colour. There are the apple and emerald green crackles (in both cases a green glaze overlying a grey or stone-coloured crackle), but these have already been discussed.[338] A somewhat similar technique characterises the series of semi-opaque and crackled green glazes of camelia leaf, myrtle, spinach, light and dark sage, dull emerald and several intermediate tints. These are soft-looking glazes with small but very regular crackle,[339] and their surface often has a “satiny” sheen which recalls the Yi-hsing glazes. They are evidently glazes of the _demi-grand feu_, and the colouring agent is doubtless copper, though apparently modified with other ingredients. How far this particular group was used in the K’ang Hsi period is hard to say. Most of the specimens which I have seen give me the impression of a later make, but as there are a few which might come within the K’ang Hsi limits I have taken this opportunity to discuss them. There is one specimen of a rare green in the British Museum to which I cannot recall a parallel. It is a bowl with the ordinary white glaze, but covered on the exterior with a very bright yellowish green, like the young grass with the sun shining on it. It is, perhaps, rather in the nature of an enamel than a glaze, but the ware has the appearance of age and should belong to the early part of the K’ang Hsi period.