20 FUEL AND FURNACES. [l. 



price of coal. It is to be hoped that a process will yet be 

 devised, by -n-hich the fine dust and waste may be rendered 

 equal in value to the pure anthracite, or even superior to it 

 for some purposes where more flame is required. 



The use of plaster and other like cements, to unite fine coal 

 into block or masses for fuel, as proposed by Hollands and 

 Whittaker, (Lend. Journ. p. 39, 1849,) is objectionable, since 

 it does not " add fuel to the fire," but 10 per cent, a&lies, in 

 addition to the larger amount of ash usually in fine culm. 



Reverleratory Furnace. — The air is often admitted to the 

 sides, &c. of a reverberatory, by leaving interstices for it to 

 enter. Portions of melted matter dropping down, often choke 

 these interstices ; to prevent which, A. Dalton proposes making 

 the upper part project over the openings. (Lond. Journ. 

 xxxvii. Aug.) 



Portable Blast Furnace. — Barron Brothers' blast furnaces 

 require special notice, on account of the economy of time and 

 fuel which their use exhibits, although the peculiar method of 

 using the blast claimed for them has hitherto been applied 

 only to small portable furnaces, used by jewellers, brass- 

 founders, &c. This peculiarity consists in having the twyers 

 of much larger dimensions than usual, and fitted with a straight 

 pipe projecting some inches from the outside of the furnace, 

 the size and projection proportioned to the size of the furnace. 

 The blast, of moderate tension, issues from a nozzle a little 

 less than the diameter of the pipe, into which it does not enter, 

 but terminates just outside of it. The blast being urged, en- 

 ters the pipe, and drawing in with it a body of surrounding 

 air, Avith which it becomes mingled by the length of the pipe, 

 enters the furnace as a broad current of air. The peculiar 

 efi"ect of the arrangement is shown by taking out the pipe, 

 passing the nozzle into the twyer as in ordinary furnaces, and 

 closing the twyer around it with clay. When thus circum- 

 stanced, there will not be melted more than from one-half to 

 one-fourth of metal in a crucible put in the furnace, as will 

 be melted when arranged as above described. The small 

 portable blast furnaces are of four different sizes, adapted to 



