18 Metallurgy of Iron. 



Mr. Chenot conceived the idea of a furnace which should consist 

 only of the roasting and reducing regions ; his apparatus is but 

 the upper portion of an ordinary blast furnace,, the carburetting 

 and fusing regions being dispensed > with. In this the ore is re- 

 duced at a low red heat, and the metal obtained in the form of a 

 gray, soft, porous mass, constituting a veritable metallic sponge, 

 and resembling spongy platinum. The furnace of Chenot is a 

 vertical prismatic structure forty feet high, open at the top for the 

 reception of the ore, and having below a moveable grate by which 

 the charge can be removed ; the bottom is susceptible of being 

 closed air-tight. The lower part of the furnace is of iron plate,, 

 and is kept cool, but about mid-way the heat is applied for the re- 

 duction of the ore, and here comes in a most important principle, 

 which will require a particular explanation, It is required to heat 

 to moderate redness the entire surface of the rectangular vertical 

 furnace throughout a length of several feet, a result by no means 

 easy to be effected by the use of a solid combustible,, but readily 

 attained by a gaseous fuel such as i» employed by Mr. Chenot. 



We have already explained the theory of the production of 

 carbonic oxyd. The possibility of employing this gas as a com- 

 bustible was first suggested by Karsten, and in 1841 Mr. Ebelmau 

 of the School of Mines at Paris, made a series of experiments on 

 the su' ject by the direction of the Minister of Public Works. The 

 process employed by this chemist consisted essentially in forcing 

 a current of air through a mass of ignited coal of such thickness 

 that the whole of the oxygen was converted into carbonic oxyd \ 

 this escaping at an elevated temperature was brought into contact 

 with the outer air, and furnished by its combustion a heat sufficient 

 for all the ordinary operations of metallurgy. A consideration 

 of great importance connected with this process is, that it permits 

 the use of poor earthy coals, aud other waste combustibles, .which 

 could hardly be employed directly, while by this method the whole 

 of their carbonaceous matter is converted into inflammable gas. 

 Wood and turf may be made use of in the same way, and the gas 

 thus obtained will be mingled with a portion- of hydrogen, and 

 probably with some hydrocarburet ; a similar mixture may be ob- 

 tained with charcoal or anthracite, if a jet of steam be intro- 

 duced into the generating furnace, a modification of the process 

 which has however the effect of reducing the temperature of the 

 evolved gases. 



This mode of employing combustibles becomes of great impor- 

 tance in the process of Chenot,, who generates the gas in small 



