Page:Popular Science Monthly Volume 38.djvu/331

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AMERICAN INDUSTRIES SINCE COLUMBUS.

in the two fire-boxes P R, after traversing the heating-chamber Q, could only reach the chimney by passing out of the door Y. This arrangement was not calculated to produce a very rapid combustion of the fuel, and therefore large fireboxes were necessary. The dimensions of this furnace would not be thought small even at the present time, for the heating-chamber Q was ten and a half feet long and seven feet wide, and the two fire-boxes were each four feet square.

PSM V38 D331 Diagrams of heating furnace in a slitting mill 1764.jpg
Fig. 18.—Longitudinal and Transverse Sections of Heating Furnace in a Slitting-Mill (1764.)

The above construction of slitting-mills was not the initial form; for in that, the axes of the rolls and cutters, instead of being in the same, were in parallel planes, and instead of being driven directly from the water-wheels, there was interposed between the water-wheel shafts and those of the rolls and cutters some clumsy wooden gearing. Fig. 19 (from Swedenborg) shows a