118 
EXPOSITION AT VIENNA. 
able for tlieir superior density, compactness, freedom from 
flaws, and tlieir ckeapness,—the machine effecting a great 
saving over hand-labor. The appearance of the crucibles 
justifies these claims for excellence. The details of the ma- 
chinery, as shown by working-drawings, were highly interest- 
ing, and are suggestive of much that may be accomplished 
in the art of forming clay wäre by the use of hydraulic 
power. 
Fire-Bkicks and Clay—England. 
An interesting report on the fire-clay goods of the Lon 
don International Exhibition of 1871, was made by Lieut. 
Grover, R. E. He states that the trade in English pro- 
ducts of this dass has marvellously increased in the past 
thirty years. Over 30,000,000 of fire-bricks are aunually 
made at Stourbridge, instead of 14,000,000 as formerly. 
Newcastle produces 80,000,000 instead of 7,000,000. The 
export trade increased sixfold since 1862. 
The celebrated Stourbridge clay, obtained about twenty 
miles south-west of Birmingham, is dug from shafts in the 
coal measures, generally below three workable seams of 
coal, and between marl, or rock, and an inferior clay. 
The seam averages three feet in thickness. The middle 
portion is selected. After hoisting to the surface, the clay 
is sorted by women, the best lumps, or kerneis, being laid 
aside for glass-house pots. This selected clay costs fifty- 
five Shillings a ton. Ordinary fire-clay costs, at the samo 
place, only ten Shillings a ton. About four tons are 
required to make a thousand nine-inch fire-bricks. The 
clay is mined over an area of about nine square miles, and 
there are about a dozen establishments. 
The percentages of the important ingredients of the 
Stourbridge clays are shown in the following analyses 
made by Mr. F. A. Abel, F. R. S., chemist to the War 
Department, England:—