Page:On the economy of machinery and manufactures - Babbage - 1846.djvu/268

234 be found, that the increased quantity manufactured by the same capital, when worked with the new improvement, would produce nearly the same rate of profit as other modes of investment.

Perhaps the manufacture of iron would furnish the best illustration of this subject; because, by having the actual price of pig and bar iron at the same place and at the same time, the effect of a change in the value of currency, as well as several other sources of irregularity, would be removed.

(288.) At the present moment, whilst the manufacturers of iron are complaining of the ruinously low price of their produce, a new mode of smelting iron is coming into use, which, if it realizes the statement of the patentees, promises to reduce greatly the cost of production. The improvement consists in heating the air previously to employing it for blowing the furnace. One of the results is, that coal may be used instead of coke; and this, in its turn, diminishes the quantity of limestone which is required for the fusion of the iron stone.

The following statement by the proprietors of the patent is extracted from Brewster's Journal, 1832, p. 349: