Page:On the economy of machinery and manufactures - Babbage - 1846.djvu/269

Rh {| class="_ruled_cols" ! Fuel in tons of 20 cwt. each cwt. 112 lbs. ! Ironstone. ! Limestone. ! Weekly produce in pig-iron. ! Tons. ! ! Cwt. ! Tons.
 * + | "Comparative view of the quantity of materials required at the Clyde Iron Works to smelt a ton of foundry pig-iron, and of the quantity of foundry pig-iron smelted from each furnace weekly.
 * - class="_units_row"
 * 1. With air not heated and coke
 * 7&numsp;
 * 3
 * 15&numsp;
 * 45
 * 2. With air heated and coke
 * 4 || 3 || 10&numsp; || 60
 * 3. With air heated and coals not coked
 * 2 || 3 || 7 || 65
 * }
 * 3. With air heated and coals not coked
 * 2 || 3 || 7 || 65
 * }

(289.) The increased effect produced by thus heating the air is by no means an obvious result: and an analysis of its action will lead to some curious views respecting the future application of machinery for blowing furnaces.

Every cubic foot of atmospheric air, driven into a