No. 275.] 
209 
high temperature. The kaolins are generally meagre to the touch, fri- 
able, and unlike the ordinary clays, and do not form a paste with water. 
The true kaolins are formed of equal parts of silex and allumine, and 
that they may be employed usefully, and compose this article of luxury 
and of value in the arts, it is necessary they should be free from colour- 
ing matter. Generally, if not always, those clays may be distinguished 
from all the ordinary clays by scales of mica which indicate their origin ^ 
and also by their association in granitic districts. This constant asso- 
ciation may often aid us in our searches for this substance, for it is con- 
stant in France, in Germany, in China and Japan. 
1. The Kaolin of Saint' Yriex. 
At this place, which is near Limoge, there is found two varieties of 
clay. The first is called the hard earth, and the other the soapy, or 
ierre dure-, the other, terre savonneuse. The kaolin is found mixed in 
the quarry with grains of quartz and scales of mica. The grains of the 
former are separated as much as possible, as they render the clay more 
infusible. 
It occurs in those quarries at Saint-Yriex, in masses about an inch to 
an inch and a half in diameter. The surface of each mass is carefully 
scraped from all the coloured portions which may adhere to them. This 
part of the operation is performed by females. The hard porcelain clay^ 
or that which is much mixed with the coloured portions, is washed after 
it is broken and thrown into vats, in which it is suffered to remain a 
short time only, when the quartz and coloured matters subside, the 
water is drawn off into other vats, in which it is suffered to repose, when 
the fine particles are precipitated to the bottom. This portion, after it 
is consolidated somewhat and dried, together with the pure masses 
which have been selected at the quarries and put in order by females, is 
sold at Saint-Yriex at 7 francs and 50 centimes per cwt. 
The petuntze, which is the feldspar but slightly changed, and still 
retaining its potash, is not so valuable. This is used principally for 
the glazing, or for forming the enamel* The porcelain quarries of 
Saint-Yriex were discovered in 1760. They furnish at the present time 
most of the materials for the manufacture of this ware for all France, 
though there are many localities of this substance in this country. It 
is well known that the French porcelain is far superior to the English, 
and in fact to any other; and it has attained such a degree of perfection, 
that it is considered the ne plus ultra of the art* 
[Assem. No. 275.] 27 
