Stanley Matthews

“ The tap-crucibles furnaces are those in which the metal, matte, and slag are all tapped off from time to time. Sump furnaces are those shaft furnaces in which the crucible is partly in the furnace and partly in front of the furnace. The slag runs off continuously over the forehearth. The metal and matte are tapped off into receiving vessels or tap-basins. Sometimes the sump furnaces are not provided with tap-basins, and the metal in them is dipped with ladles direct from the forehearth. Spur or channel furnaces are shaft furnaces without a crucible. ”

“ As the molten metal fills the lower part of the furnace it rises to the same level in the tube until it reaches the basin, from whence it may be removed as clean metal. To enable others skilled in the art to make and use our invention, we will proceed more particularly to describe the same: The figure represents a sectional elevation of a portion of a smelting furnace with our improvements. A represents the furnace, which may be of ordinary or common construction. ”

“ The defendants also introduced experts as witnesses, whose testimony tended to prove that, as stated by one of them, 'the furnaces thus figured by Karsten are planned for withdrawing the reduced metal continuously, and as fast as possible, from the oxidizing action of the blast and the intensely heated part of the slag. So, the metal is made to flow constantly outward and upward through the open eye into the forehearth, which is made as high as the inner crucible; and, generally, the clean molten metal alone is passing through this bootom eye. ”