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718 . GEOLOGY OF OHIO. 
the first to be established, and their products have attained as high a 
grade of perfection as any. ‘The name of the Zanesville firm is the 
American Encaustic Tiling Company, Geo. Stanberry, superintendent. 
The stock is chiefly owned in New York, and nearly all the products of 
the works are sold there, in the face of foreign competition. Our best 
tiles are as good as the best of the English and French, but the average 
of foreign tiles exceeds the average of the home manufacture. The 
clays used are of many kinds; those varieties used in largest proportion 
which constitute the “body” clays, and are found in the immediate 
vicinity of the works, but the clays which are used for the more delicate 
processes, come from widely scattered and distant localities. In making 
colored clays, the effort is to obtain a clay as nearly right naturally as 
possible, and then to correct it with the necessary reagents, rather than 
to undertake to establish a new color inaclay. The process in outline is 
as follows: The clays are washed or beaten up to a slip in a “ blunger,” 
and while in this state the necessary metallic oxides are added to color 
them. The slip is strained and evaporated to a paste in iron-lined 
tanks. This paste is stacked up in open cribs in a tight steam-heated 
room, and the clay is then retained until perfectly dry. It is then re- 
duced to powder and uniformly moistened, but so slightly that it is not 
perceptible to the hand, and in this state it is molded. Hach kind of 
powder, though probably indistinguishable in appearance from others, 
has the elements in it which will develop its own color. The presses are 
ingeniously devised machinery, the invention of Mr. Stanberry ; the 
plant of the works in this regard is as efficient as any in operation any- 
where. The simplest tiles are made from clay of one color, and the 
process consists of stamping so much clay powder into a confined space, 
and consolidating it by enormous pressure. Next come those tiles made 
of two colored clays; the first stamping makes the body but leaves 
indentations in its surface, into which the second clay is put, and this is 
pressed into place; the tile is then scraped to get a cleanly-drawn line 
of both colors and again stamped with a flat die. The most complex 
tiles show six colors on their face, and have a band of a seventh kind 
of clay running through the centre to keep the complex mixture from 
warping. These tiles are subjected to frequent tests, to see if the force 
of compression and degree of moistening is correct. They are dried in 
steam-heated closets for as much as six weeks after pressing, in order to 
insure their perfect dryness before burning. ‘The burning is done in 
