TA?rNING MATTER, &C. 



Coal. 



Idd grains of Copal ^ ... ^ . .67 grains. 



Mastifch. .....*.... 66 



Balsam of Peru 64 



— Klemi 63 



Tacamahac * * , * 6^ 



Guaiacum * ... 58 



— '■ Gum ammoniac , ^8 



. Amber 66 



Olive oil ^ 55 



Balsam of Tolu 54 



Asa foetida 51 



— Wax 50 



: — ,— Dragon's blood 48 



Benzoin 48 



Olibannm 44 



Myrrh 40 



Asphaltum 40 



Gamboge 31 



Elastic bitumen 31 



Gum arabic 29 



Liquorice 25 



Manna 25 



Tragacanth 22 



Caoutchouc. ............ .12* 



87 



Experiments, 

 &c. on an arti- 

 ficial substance 

 havingthecha-f 

 racters of tan- 

 ning matter^ ' 



I 



The coal obtained froin the resinous bodies by means 

 of sulphuric acid, is in a much greater proportion, than 

 ■when equal quantities of those substances are exposed to 

 simple distillation. 



For, (as I have stated in my first Paper,) 100 grains 

 of common resin by the humid process afforded 43 of coal^ 

 which after a red heat still weighed 30 grains. 

 ' But the same quantity of resin by distillation, only 

 ' yielded | of a grain of coal. 



One hundred grains of mastich, by the first method, 

 afforded 66 grains of coal. 



* Caoutchouc and elastic bitumen were only superficially carbo- 

 nized by the sulphuric acid, so that the proportion of coal as above 

 stated, is considerably less than that, which in reality might hav<» 

 been obtaiatd from therrj . 



3 . One 



I 



