Page 405 - Oriental Series Japan and China, Brinkly

POLYCHROMATIC GLAZES

seen conditions of temperature. But that they were

also manufactured intentionally scarcely admits of

question. M. Jacquemart, writing on the subject
" As for the
of Tao-pieny or flambe, ware, says :

cause of the transmutation, modern science knows

it so well that each of its effects can be obtained

with certainty in the laboratory. Metals change their

condition and appearance according to their combi-

nation with oxygen. Thus, to confine ourselves to

the question under consideration, oxydised copper

gives a beautiful red verifiable enamel, which, thrown

en masse on the surface of a vase, forms the tint called

haricot. With another equivalent of oxygen, it be-

comes protoxide, and produces a beautiful green,

capable of being changed into celestial blue when
Nowthe oxygenation is pushed a little farther.
these

various combinations can be accomplished suddenly
Whenin the kiln by bold tours de main.
a clear fire,

placed in a quick draught, draws in a large volume

of air, all the oxygen is not consumed, and a portion

can enter into combination with the fusing metals.

If, on the other hand, there be passed into the oven

thick smoke whose carbonaceous mass, thirsting for

oxygen, absorbs everywhere this gas essential to com-

bustion, the oxides may be destroyed and the metal

completely restored. Subjected at a given moment

to these different conditions by the rapid and simul-

taneous introduction of currents of air and sooty

vapours, the haricot glaze assumes at last a most pic-

turesque aspect. Veined colours, changing, capricious

as the flames of alcohol, diaper the surface the oxy-
;

dised red, passing by violet to pale blue and green

protoxide, even disappears completely on salient

points which have become white, and thus fur-

33 1