744 THE POPULAR SCIENCE MONTHLY. 



In this system the solid fuel is converted into crude gas ; this gas is 

 mixed with a regulated quantity of atmospheric air, and then burnt. 

 The arrangements are essentially the gas-producer, or apparatus for 

 converting the fuel bodily into the gaseous state ; then there are th& 

 regenerators. These are sunk chambers filled with fire-bricks, piled in 

 such a manner that a current of air or gas, passing through tbem, is 

 broken into a great number of parts, and is checked at every step by 

 the interposition of an additional surface of fire-brick; four of these 

 chambers are placed below each furnace. The third essential is the 

 heated chamber, or furnace proper. This, the furnace-chamber, com- 

 municates at each extremity with two of the regenerative chambers, 

 and, in directing currents of gas and air upward through them, the 

 two gaseous streams meet on entering the heated chamber, where they 

 are ignited. The current descends through the remaining two regen- 

 erators, and heats the same in such a manner that the uppermost 

 checkerwork is heated to nearly the temperature of the furnace, where- 

 as the lower portions are heated to a less and less degree, the products 

 of combustion escaping into the chimney comparatively cool. In the 

 course of, say, one hour, the currents are reversed, and the cold air and 

 gas, ascending through the two chambers which have been previously 

 heated, take up the heat there deposited, and enter into combustion at 

 their entrance into the heated chamber, at nearly the temperature at 

 which the products of combustion left the chamber. It is not difficult 

 to conceive that by this arrangement, and with its power of accumula- 

 tion, any degree of temperature may be obtained in the furnace-cham- 

 ber, without having recourse to purified gas, or to an intensified 

 draught. Where the temperature of the melting-chamber has cer- 

 tainly exceeded 4,000 degrees of Fahrenheit, the products of combus- 

 tion escape into the chimney at a temperature of only 240 degrees. 

 The practical result of this regenerative system is stated to be, that a 

 ton of steel requires by the ordinary method about three tons of Dur- 

 ham coke which, being estimated as coal, will be about four tons to 

 melt it, whereas, in Siemens's furnace, the melting is effected with 

 twelve hundred-weight of ordinary coal. This economy is produced 

 by reserving the heat, by means of the regenerator, which is ordinarily 

 allowed to escape by the chimney. 



Another plan for consuming coal with economy has been recently 

 introduced by Mr. T. R. Crampton, and is now in use at the Royal 

 Arsenal, Woolwich, and at the Bowling Iron Works, in Yorkshire. 

 Instead of converting coal into gas, as in the Siemens process, the coal 

 is reduced by Mr. Crampton to a very fine powder, and then blown 

 into the heated chamber by means of a fan-blast. By this arrange- 

 ment the perfect combustion of the coal is produced, and a heat of the 

 highest intensity can be obtained. The utilization of this heat, with- 

 out waste, when it is produced, is an important question still requiring 

 careful attention. There are several other experiments being carried 



