Page 235 - Chinese Art, Vol II By Stephen W. Bushell

GLASS. 65

" The vitreous nature of the body imparts a tone and brilliancy to the
colours which are greatly admired, and the best specimens of this ware will
well repay minute study. The choice of groundwork is effective, the grouping
of the colours soft and harmonious, the introduction of European figures is
interesting, and the arrangement of flowers evidence of the highest artistic
skill."
Occasionally the ground comes out crackled after the firing
necessary to fix the enamel colours. The snuff- bottle illustrated in
Fig. 74, made of porcelain roughly decorated with crabs, is coated
over with a thick yellow glaze of mottled tone and cracklsd texture
to simulate glass, and is marked underneath Kn Yueh Hsiian^
pencilled under the glaze.
The alkali, which is an essential ingredient of glass, is generally
furnished by nitre, which forms as an efflorescence on the soil of
the plains of Northern China. Ferns are also burnt for the purpose,
and potash is obtained by lixiviating the ashes : hence their
common name of Uu li tsao, or glass plants. On the sea-coast
soda is used instead, extracted from the ashes of seaweeds. The
other ingredient, silica, is supplied by sand, or, in a purer state,
by pounding quartz rocks mined in the neighbouring hills. The
body is coloured by the addition of small percentages of mineral
oxides to the mass. The three most common colours are those
referred to in the chapter on Architecture (Vol. I. p. 62) : the
deep purplish blue derived from a combination of cobalt and
manganese silicates, the rich green afforded by copper silicate,
and the imperial yellow approaching the full tint of the yolk of an egg
obtained from antimony. A good specimen of this last colour is
illustrated in Fig. 76, a vase which was exhibited in the Paris Exhibi-
tion of 1867, described as " of pure porcelain enamel such as is
used in the imperial manufactory " and afterwards bought, 48/..
for the museum. A brilliant sang de bauf red is obtained from
copper mixed with a deoxidising flux, and a charming turquoise blue
of softest tone from the same element in the presence of an excess
of nitre. Opaque white owes its tint to arsenic, iron gives a gray-