706 GEOLOGY OF OHIO. 
GLAZED BRICK. 
The manufacture of glazed brick, though of recent origin, is already 
attracting a great deal of interest and attention among architects and 
builders. The bricks are of various colors, and are employed to make 
symmetrical and ornamental designs in building fronts. Very striking 
effects are obtainable through their use. The coloring, of course, ‘must 
be put upon an ordinary red or light-colored brick, and the proper 
mixture of re-agents to make a good enamel on a red clay is a question 
for pottery decorators to settle; and it seems as if to them it had been 
intrusted, for nearly all those firms visited, which decorate their own 
wares, had work of this sort on hand. 
Some colors are very easily obtained; the yellows are made by using 
a simple lead glaze on a cheap, buff fire-brick ; blacks are made by a 
manganese and iron glaze; white and blue are the most difficult to make, 
as the strong red color, native to the clay, has first to be concealed by 
an opaque layer of white, which then is finished with a white or blue 
glaze; green is made in the same way. In the most skillful use of these 
bricks only a few colors are employed, such as red, black, blue, white, 
yellow, and possibly green, though all colors can be produced as well as 
those mentioned. ‘There is no steady source of manufacture of these 
brick in the State at present, unless, as is possible, the Dover Fire 
Brick Co. has already started ; its preparations were nearly complete in 
the midsummer (1883.) 
RooFInG- TILE. 
In only a few places in Ohio is roofing-tile manufactured to any 
extent; the largest and most complete works seen was that of Mr. J. C. 
Ewart, of Akron. 
He uses the Akron sewer-pipe shale as a material for tile, and it | 
answers that purpose very well. The grinding and tempering is done 
in tracers such as used for sewer-pipe; when tempered it is put into a 
horizontal cylinder, in which a piston is working ; whatever is put into 
the cylinder is forced out, at the end of the stroke, in a series of parallel 
plates, about 6 inches wide, by § inches thick, and extending along 
until cut up into lengths. Considerable oil is used to keep the clay smooth 
and to keep the freshly-pressed plates from sticking. These plates are 
adjusted, one after another, on a series of dises arranged on the circum- 
ference of a revolving circular disc. This disc moves through % of. its 
