TERRA-COTTA, BRICK, ETC.
341
bridge clay. The following analyses show the composition of the celebrated Stourbridge and other foreign clays :—
l.*
a-t
34
44
Silica,.
65.10
73.
50.20
51.90
Alumina,.
22.22
19.93
34.13
30.03
Potash, .
.18
.89
.39
.89
Lime,.
.14
.39
.30
1.60
Magnesia,.
.18
-
-
.18
Protoxide of iron, ....
( 1.92
.87
.87
1.50
Phosphoric acid, ....
.06
-
-
-
Water and organic matter,
9.86
6.40
13.70
13.90
* English Stourbridge, Percy. t Coblentz, for glass-pots,
t German clay for glass-pots, from Bremen, Germany.
Note. —Numbers 2, 3 and 4, made in the New Jersey State Laboratory.
Ceramic Enamels.
Chemisch-technische Fabrik bei Elbogen in Böhmen. Director , Max Rosier. C. F. Merker , Agent , 1 Getreidemarkt , Vienna. There was from this source a very interesting exhibition of coloring materials for the use of potters and decorators, which was honored with the Progress Medal. The highest skill of the chemist is called for by this art, and the demand is such that the manufacture of standard colors, or enamels, ready for use, has become an important industry. A large gktss case was filled with a collection of the manufactures of their establishment, consisting of fluxes, glazes, colored glazes and enamels, and metallic oxides for glass, porcelain, stoneware and majolica. These are accompanied by proof-tiles, upon which the colors have been tested by burning, showing all the colors and shades of color—the greens, blues, red, rose, yellow, etc., etc. All the preparations of chromium, copper, mercury, gold and cobalt were beautifully displayed. By the courtesy of the director I have been favored with a price-list, from which I make the following extracts for the benefit of amateur decorators and others, who have found difficulty in getting such materials in the United States.