riiiiM WOOD AND < i) \i.. J 



to which the charring process had been conducted, hut as 

 these coals are sold by measure, and n<>t by weight, and as tin 

 bulk is not materially diminished in perfecting the process, the 

 loss sustained from this circumstance heing in part compensated 

 by the heat disengaged in expelling the remaining innammabli 

 matter, we may consider this defect, inordinary cases, as un- 

 important: the result, however, is given for perfect charcoal. 



The coak used to experiment upon was produced in the larg< 

 way, and that which was most free from earthy, or other fo- 

 reign matter, as well as most perfecl in Other respects, was 

 selected. The result is less than was anticipated, and shows 

 that the commonly received opinion thai it contains as much 

 carbonaceous matter as charcoal, in equal weights, is erroneous, 

 and what is still more erroneous is, the opinion that an) llim o 

 quantity of coak, by measure, will in its combustion disengage 

 as much heat as an equal quantity of the coal from which it is 

 produced. One bushel of bituminous coal produces in retorts 

 about one and a half bushels of coak. in consequence of swell- 

 ing during the process, and yet its specific gravity i> stated, in 

 some tahles. as nearly equal to the coal. 



The composition balls of Lehigh coal, charcoal, and fire clai . 

 were made for the purpose of ascertaining whether a rerj eco- 

 nomical fuel mighl not he formed of the culm or line portions 

 of the two former, by combining them with the latter article. 

 as they possess very little value, and tin same practice having 

 been adopted with considerable advantage in various parts ol 

 Europe. 



The tire produced by these balls was found t" beverj cl< m 

 and beautiful in ii> appearance : it^ superior cleanliness is in 

 consequence of the ashes being retained by tin clay, and tin 

 balls wire found to retain their original shape, after tiny wen 

 leprived of the combustible materials. The beauty of the fir 

 is enhanced by the shape and equality in the size of the balls. 

 which, during the combustion, present uniform luminous fai 

 \ i difficult) was found in igniting or perfectly consuming thi 

 combustible materials of the balls, and the loss in beat, when 

 compared with the combustion of the si ■ quantity "i • 



v OL. I". — G 



