88 ANNUAL OF SCIENTIFIC DISCOVERY. 



mosphere, its heating power is not such as to injure sheet- iron, or 

 even to make it red-hot. In fact, so long as there is an escape up- 

 wards, the iron funnel is not injured. The damage arises during and 

 after stoppages of the furnace, when the blast is obstructed in its 

 passage upwards by the settlement of the materials in the furnace, so 

 that the atmosphere rushes down to meet the ascending gases, and of 

 course causes a very high local temperature. His practice is to ex- 

 clude the atmospheric air as much as possible. The affinity of the 

 gases for oxygen is so great that the air-leakage raised the tempera- 

 ture quite sufficient for safety, whilst the full combustion of the gase- 

 ous escape would melt down the bricks in the flues and destroy the 

 texture of the iron tube. It was not possible for him to say what 

 combinations took place at high temperatures, where carbonic oxide, 

 carbonic acid, hydrogen, and nitrogen are mixed in such proportions. 

 At any rate, he found a smothered combustion to be the most suitable 

 and economical for the purposes in view. He was quite aw T are that, 

 by the plan he had pursued, the utmost heat is not extracted from the 

 gases ; and that, by different means, a temperature may be obtained 

 capable of performing all the operations of the forge ; and if it be true 

 that the solid carbon of the furnace, in its escape as carbonic oxide, 

 will unite with another dose of oxygen for saturation, there can be 

 little doubt that, with properly constituted gas furnaces, there is 

 enough at present passing oif to convert the pig-iron into bar-iron. 

 Civil Engineer and Architect's Journal, Sept. 



The London Mining Journal, for March 30, contains an account of 

 the mode adopted by the Ebbw Vale Company, in South Wales, for 

 collecting and using the gases from blast-furnaces. At these works 

 there are 11 furnaces in blast, making from 1,400 to 1,500 tons of pig- 

 iron per week ; the five blast-engines have 25 boilers attached to them. 

 At present, 19 of these boilers, with the gases applied to them, get 

 sufficient steam to work the engines to their maximum duty, ivithout 

 using coal. The gases have also been applied to the pumping-engine, 

 to several hot-air stoves, and are about to be applied to the calcination 

 of iron stoves, moulders' stoves, and other purposes. The company 

 thus save 1,000 tons of coal per week. The description is illustrated 

 by diagrams, but can perhaps be rendered intelligible without them. 

 Into the top of a blast-furnace of the usual description, a cylinder or 

 tube is fixed, by which an annular chamber is formed round the inside 

 of the furnace to receive the gases. This tube is made of common 

 boiler-plate, three eighths or one half inch thick, with three-inch angle- 

 iron riveted round the top, forming an outside flange, which rests 

 upon the cast-iron ring usually placed on the top of the furnace imme- 

 diately under the charging-plate. The diameter of this tube should 

 be about twelve inches less than the inside of the furnace at the top, 

 and the depth of the same six to seven feet. A little fine dust thrown 

 round the angle-iron after the tube is lowered to its place makes a 

 perfect joint. An orifice is made through the brick-work of the fur- 

 nace, in which is inserted the pipe for conveying the gas from the 

 annular chamber to the place of combustion. This pipe leads into a 

 box resting on the brick-work, into which the gases are thus brought, 



