CLAY MANUFACTURES. 669 
Stone-ware is the product of an unmixed natural clay, burned at 
high enough heat to oblige the impurities to combine with the free 
silica, and thus cause an incipient vitrification or fretting, without loss 
of shape. It should be impermeable to water without any glazing on it, 
but it frequently fails in this point ; its color is bluish-gray, and is due 
to combined iron. 
Earthen-ware is a product of very similar clays burned too lightly 
.to vitrify the body or combine the iron; it is of a yellow or red-color, 
from the free iron, and is porous unless glazed. 
China, that is, the ironstone china made in this country, isa mixture 
of several clays with powdered silica and enough potash feldspar to 
make the body vitreous on burning. Porcelain is made in the same way 
but in very different proportions of material, while ironstone china is 
thick, and opaque porcelain is often thin as an egg-shell and nearly clear 
enough to be called translucent. China is of a dead or bluish-white 
color, while porcelain is of a creamy-white tint. All our china is made 
from imported clay, and in the same way porcelain could be made, but 
it has not seemed profitable to introduce the manufacture up to this date. 
There is only one establishment in Ohio where ornamental } 
aloneis made, but the ornamentation of our best white-ware is very 
artistic and well done. 
STONE-WARE. 
Stone-ware is first in simplicity and in order of establishment as 
well, and will therefore be first treated. 
There are three stone-ware districts in Ohio; the largest at Akron, 
the most widely-spread at Roseville, Perry county, and the least im- 
portant near Rock House, Hocking county. There are also a few 
scattered works in various parts of the State. The Rock House district 
uses the Mercer clay, as will be remembered, and supplies a large 
amount of ware’ to the neighborhood for twenty-five miles around, ac- 
cessible to wagons only ; no ware is shipped by rail. 
The Roseville district is composed of a large number of small 
potteries ; there are not less than eighty-five or ninety in the district, 
and most of them employ only a man and boy or two men, the largest 
employing seven men. The process of manufacture is essentially the 
same in all the districts, the main differences being those which naturally 
arise fromthe very‘ different scales of working. The successive steps 
