stuffs,
several manufacturers have already been induced to engage largely in
its preparation ; and there is now a very extensive establishment in
full operation by M. Guimet, three leagues from Lyons, who likewise
claims the priority of its discovery; the royal porcelain manufactory
at Meissen, in Saxony, also prepares it. The process' for making the
artificial ultramarine, as it was first described by Gmelin, is here
given, as it was published in the Annales de Chimie. The whole process is divided into three parts-:
1.
The pure hydrate of silica is prepared by fusing fine pulverized quartz
or pure sand with four times its own weight of salt of tartar,
dissolving the fused mass in water and precipitating by muriatic acid;
also the hydrate of alumina is prepared from alum in solution,
precipitated by ammonia.
2.
Dissolve the silex so obtained in a hot solution of caustic soda, and
add to seventy parts of the pure silex seventy-two parts of alumina;
then evaporate these substances until a moist powder remains.
3.
In a covered Hessian crucible, a mixture of dried sal soda, one part to
two parts of sulphur, is heated gradually, until it is fully fused, and
to the fused mass add small quantities of the earthy precipitate,
taking care not to throw in fresh quantities until all the vapors have
ceased ; after standing for an hour in the fire, remove the crucible,
and allow it to cool. It now contains the ultramarine, mixed with an
excess of sulphuret, which is to be removed by levigation; and if the
sulphuret is still in excess, it is to be expelled by moderate heat.
Should the color not be uniform, levigation is the only remedy
KYANITE, SAPPARE, DISTHENE.
The name of this mineral is derived from the Greek, signifying blue, and was given to it on account of its blue
