No. 129.] 141 



At this period it was a matter of great curiosity with the public 

 to see a hard coal fire kindled with so small a quantity of wood. 

 " From this stove this deponent discovered the importance of 

 burning coal in thin layers which led to the theory, that to ob- 

 tain the maximum amount of heat from anthracite coal, the depth 

 of the stratum should he governed by the size of the lumps and the 

 amount of air used in its combustion; that to secure the most per- 

 fect combustion in a stove or furnace constructed with an ordi- 

 nary draft, if the pea sized coal, the depth of the stratum should 

 be from two or three inches ; for nut sized coal from four to five 

 inches ; for egg sized, seven to eight inches; increasing the depth 

 of stratum as larger coal is used ; with these depths the gaseous 

 products will be carbonic acid, the result of a perfect combus- 

 tion, with a much increased depth the gaseous products will be 

 carbonic oxyde, a combustible gas, which flames with renewed 

 oxygen, as witnessed by the blue flame at tlie top of the smoke 

 pipe of nearly all the steamers that use anthracite coal, 'wast- 

 ing a large amount of heat.' This deponent found that in burn- 

 iag small coal in thin horizontal layers it would soon cool out, 

 leaving the grate covered with unignited coal, the outside burnt 

 to a cinder, the inside but little affected by combustion. This 

 being at the expense of a great W' aste of fuel, time and labor, he 

 tried an inclined grate with better success, but not what he 

 thought was requisite to induce the public to relinquish their 

 long cherished wood fire for a fuel of which they could know 

 but little." 



"During the winter of 1831 and 32, he experimented witl 

 various modifications upon the stove for which he (subsequently) 

 applied for and obtained letters patent of the United States." 

 " This may be classed among the compound stoves ; it having a 

 double furnace, a deep, and a thin fire, an upper or close stove, 

 a lower or open stove. By this arrangement all the advantages 

 of burning coal in thin layers are preserved without the con- 

 stant fear of the coal burning or cooling out. The crude- coal 

 being placed in the front chamber, out of the line of draft be- 

 comes heated and gradually slides into the line of draft as com- 

 bustion progresses. The most perfect combustion being at the 

 thin part of the fire at the forward part of the grate ; more air 



