36 ANNUAL OF SCIENTIFIC DISCOVERY. 



or total failure. It is the object of this paper to describe a mode of combus- 

 tion, in which, by a modification in the form of furnace, the combustion of 

 wet fuel is not only rendered consistent with the best economical results, but 

 which involves chemical reactions never before, it is believed, successfully 

 applied for such purposes, and which is deserving of particular notice from 

 a scientific as well as from a practical point of view. 



It is a well-established fact in chemistry, that the affinity of carbon for 

 oxygen at high temperatures is so strong, that if oxygen is not present in a 

 free state, any compound containing oxygen, which happens to be present, 

 is decomposed, in order to satisfy this affinity. This fact is well illustrated 

 in the familiar case of the blast-furnace, where this affinit}^ is employed to 

 deprive the ores of iron of their oxygen in the process of reduction to metallic 

 iron. 



In the first stages of combustion, in wet fuels, the chief products given off 

 are steam from the drying of the wet mass, smoke, or volatilized carbon, and 

 oxide of carbon, with, of course, a variable proportion of carbonic acid and 

 carburetted hydrogen. These products, in all ordinary furnaces, pass on 

 together into the stack, carrying with them the heat which they have ab- 

 sorbed and rendered latent. The problem presented is then to recover the 

 heat thus locked up and lost; and by the furnace now under consideration 

 this is accomplished by shutting off almost entirely the access of the outer 

 air, and causing the wet fuel to supply its own supporter of combustion, 

 drawn from the decomposition of the vapor of water at a high temperature, 

 by its reaction with free carbon and the oxide of carbon. 



The practical solution of this problem was first, successfully accomplished, 

 as appears from a decision of Patent Commissioner Holt, by the late Moses 

 Thompson, in 1854. The controversial questions growing out of this inven- 

 tion are entirely foreign to our present purpose, and in no way affect its prac- 

 tical or scientific value. Suffice it to say, in passing, that we find in this 

 invention another instance of a truth already so often signalized in the 

 history of inventions, that important results are often obtained, of the high- 

 est value in promoting material prosperity and the welfare of society, by 

 those who are guided in their search only by the result in view, and not by 

 any exact knowledge of the scientific principles involved. 



Mr. Thompson seems to have been inspired with the conviction that if he 

 could bring the products from the combustion of wet fuel together in a place 

 hot enough for the purpose, and from which the atmospheric air was ex- 

 cluded, they would, as he expresses it in his patent, mutually " consume 

 each other." This notion was realized, and the reaction secured between the 

 elements of water and the carbon of smoke, or the oxide of carbon, in a part 

 of the furnace called by the inventor the mixing-chamber. 



Wherever that place may be situated, or however constructed, the one 

 essential thing about it is, that it should be a very hot place, and one to 

 which the atmospheric air can have no direct access until it has passed by 

 and through the burning fuel. It is, in fact, a retort, or place for combina- 

 tion and reaction, and may be a distinct chamber or flue, or only a recess or 

 enlargement, greater or less, of the main furnace. Wherever it may be 

 placed, or however built, it must meet the essential conditions of a high 

 temperature, and of atmospheric isolation. In this mixing chamber, then, 

 the important chemical reaction before insisted on must be set up. The 

 vapor of water is decomposed, furnishing its oxygen to the highly heated 

 carbon to form carbonic acid, while the oxide of carbon is in like manner 



