104 Experiments on a Sulstance which possesses 



Coal. 



100 grains of Copal - - 67 grains. 



Mastich - - 6Q 



• Balsam of Peru - 64 



Elemi - - 63 



Tacamahac - 62 



. Guaiacum - 58 



— — Gum ammoniac - 58 



. Amber - - bQ 



— — Olive oil - - bb. 



— ■ ■ Balsam of Tolu - 54 



Asafoetida - - 51 



Wax . - 50 



Dragon's blood - 48 



Benzoin - - 48 



Olibanum - - 44 



Myrrh - - 40 



Asphaltum - 40 



Gamboge - - 31 ' 



— ^ Elastic bitumen - 31 



Gum arable - 29 



Liquorice - - 23 



Manna - - 25 



Tragacanth - 22 



Caoutchouc - 1 2 * 



The coal obtained from 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 

 3-4ths of a grain of coal. 



100 grains of mastichj by the first method, afforded CQ 

 grains of coal. 



* Caoutchouc and elastic bitumen were only superficially carbonized by 

 the sulphuric acid, so that the proportion of coal above stated is considerably 

 less than that which iu reality might have been obtained from them. 



100 grains 



