[222] Cobalt, the source of the ceramic blues, is obtained from cobaltiferous ore of manganese, and its quality varies according to the purity of the ore and the care with which it is refined.

[223] 0. C. A., p. 263. This very dark blue recalls one of the Chia Ching types noted on page 36.

[224] See p. [10].

[225] But see p. [177].

[226] Biscuit is the usual term for a fired porcelain which has not been glazed.

[227] See p. [17].

[228] It has been suggested by Mr. Joseph Burton that the opacity of the colours described in the preceding paragraphs may have been due to the addition of porcelain earth to the glazing material.

[229] See p. [82].

[230] See, however, p. [85].

[231] See p. [2].