38 ANNUAL OF SCIENTIFIC DISCOVERY. 



consume each other on their way to the boiler and stack. This chamber 

 should be about one-half the capacity of all the fire-chambers, and it should 

 extend down about as low as the back end of the grate. The flue through 

 which the products of combustion pass out of this chamber and under 

 the boiler should be in section about one square foot to forty cubic feet of 

 mixing-chamber. 



" The operation of my furnace is as follows: A hot fire of dry fuel is kin- 

 dled in the lower or fire-chambers of the furnaces, and after it has been con- 

 tinued till the masonry is well heated, the chamber above the grate is fed with 

 the begasse or other wet fuel. This hot fire in the tire-chamber, especially 

 towards the front of it, under the principal mass of the wet fuel, must be 

 preserved throughout the operation. The heat from the masonry and the 

 fire-chamber will be communicated to the wet fuel, which will cause steam 

 and other gases to issue from it and mix with the intensely hot gases of 

 combustion from the fire-chamber, and in a short time the mixing-chamber 

 will present intense combustion and heat, the dampers of the fire-chambers 

 being partially closed. The lower part of the wet charge will by degrees 

 become dry and charred, and will fall through the grate prepared as above 

 into the fire-chamber, and supply, or nearly supply, the place of other dry 

 fuel in preserving the fire in this chamber; and the wet fuel, being from 

 time to time supplied, will furnish, in a highly heated state, aqueous vapors, 

 which, descending through the corrugations and otherwise into the fire- 

 chamber and mixing-chamber, will be decomposed, furnishing much oxygen 

 to the fire, and supply the oxygen necessary to combustion of all the com- 

 bustible gases issuing from the fire-chamber. If by accident the fire in the 

 lower part of the furnace should predominate, the draught should be dimin- 

 ished and more wet fuel added; and if by accident the fire in the fire-cham- 

 ber should become too much cooled down, the draught should be let on, 

 and any deficiency of dry fuel should be supplied to the fire-chamber. 

 Under proper management, little or no dry fuel need be fed to the fire- 

 chamber after the operation is fairly commenced the charred matter 

 falling through the open grate will supply its place; and the caloric thus 

 produced by the combustion of wet fuel will be vastly greater than from 

 the same quantity by measure of the same fuel when dry. In the fire- 

 chamber and in the mixing-chamber, under intense heat, the carbonaceous 

 gases will decompose the steam from the wet fuel, and effect complete com- 

 bustion. 



" When the operation is fairly commenced, if the water in the wet charge 

 amounts to say fifty per cent, by weight of the fuel, the dampers of the fire- 

 chamber should be nearly or quite closed to exclude the air; vapor from the 

 wet charge will then descend through the corrugations and otherwise into 

 the fire-chambers, and support the combustion therein, while other portions 

 of the vapor will enter the mixing-chamber, and complete the combustion 

 there. If the fuel, however, contains much smaller quantities of water, 

 more air in proportion should be admitted at the damper, the object being 

 to admit no more air than will supply the deficiency of the vapor." 



It will be observed that in this mode of combustion the wet fuel is subject 

 to a constant process of distillation by the fire in the ash-pit. The products 

 of this distillation react on each other in the mixing-chamber in the manner 

 already described, while, at the same time, a portion of watery vapor is 

 decomposed in the ash-pit. 



Theoretically, no more heat can be generated in this mode of combustion 



