The wet-meter was invented by Clegg in 1807, and improved by Crosley in 1815.
The dry-meter was invented by Malam in 1820, and improved by Defries in 1838.
Many improvements and variations have been added since by various parties.
A (Fig. 2183) is a longitudinal and B a transverse section of the wet-meter, which ors6,039,195 persons.
Value of exhibited articles£2,000,000
Number of exhibitors,—
In 1838, Mr. Robert Lucas Chance, of Birmingham, England, successfully introduced the manufacture of Bohemian sheet-glass into his district.
Mr. James Chance perfected thof gun-cotton was made by Braconnet, in 1833, who detailed the action of nitric acid on starch, sawdust, linen, and cotton.
He called it xyloidine.
Pelouse, in 1838, called attention to this compound.
Dumas, in 1843, again cited a mode of preparing, and made suggestions for the application.
Schonbein, in 1846, brought fo
ture of sides and ends on which the sash of a hot-bed rest.
A blast of air heated previous to its introduction into the smelting-furnace.
The process was invented by Nielson, of Glasgow, Scotland, and patented in 1828.
In 1845, Budd patented in England the utilization of the heated gases from the blastfurnace for heating the blast.
By means of the hot-blast, anthracite coals were used successfully in smelting iron in Wales, in 1837, and at Mauch Chunk, Pennsylvania, in 1838, 1839.
The temperature of the air, previous to its being thrown upon the charge in the furnace, is raised to about 600° in an outer chamber or in a series of pipes.
These are variously arranged.
In that illustrated (A, Fig. 2588), the air is first condensed in an exterior chamber, whence it is forced into the pipe a within the reverberatory furnace b. Branches from this pipe terminate in the tuyeres on each side of the furnace, which has a separate fireplace.