162 



BISTORf OF PITCOAL. 



Products of dif- 

 ferent coals. 



General con- 

 clusions. 



« Coak» OiL 



tbs. oz. dr. lbs. oz. 



Viilanueva ''Gs 8 4'» 7 9 



Belmez 70 2- -10 4 



Langreo •..•75 0"1] 11 



English ....64 1 0-. 7 



Wafer, 



dr. 

 0. 



0- 

 4- 

 4. 



Ib^. 

 4 



7 7 



4 7 



12 14 



Gasses lost* 



lbs. oz, dr. 

 5 () 



7 4 

 3 2 

 t) 2 



19 



12 



8 



16 



Tliose which 

 yield most tar 

 not easiest to 

 distil. 



From these observations it follows, that the oily product 

 is more abundant than the aqueous froni three of these 

 coals. 



2. Tliat the weight of the gasses is as variable as that of 

 the liquid. 



a. That the veal quantity of coal furnished by these bi- 

 tuminous substances is in general above '60, and less thain 

 •80. 



4. That it is three tiilies as riluch &s wood affords : atid we 

 know nothing but indigo, that can be compared with pitcoal 

 ID this respect. 



5. That the matter of pitcoal varies as much in its car- 

 bonaceous, oily, gaseous, and other products, as the organ-*' 

 ized bodies, that are formed at present before our eyes. 



6. That its oily produce is in general much greater, than 

 our resinous woods, as the oak, elm, ash, &c., can furnish. 



7. That pitcoal is thrice as serviceable, in furnaces that 

 admit its use, as any wood known, since it leaves thrice as 

 much coally matter. 



8. That its coak, in consequence of its azotization, de- 

 rives from our atmosphere much more tire thaa charred wood, 

 since it cannot burn but by decomposing a much larger 

 quantity of oxigen, 



9. That as tlie oily and gaseous products are formed as 

 well in the open air as in close vessels, some coals produce 

 more flame than others, and are consequently better adapt- 

 ed to furnaces where a considerable current of flame is re- 

 quired; as those of bronze, porcelain, earthenware, &c. 



10. That those which leave most coak after distillation 

 ^ill consequently last longer in iron works, reverberatorj 

 furnaces, &c. 



Of these four coals perhaps the richest in oil would not 

 be the most easy to distil, at least by lord Dundonald s me- 

 thod, since they run, swell up, and agglutinate, so as to- 

 ward 



