[ -53 ] 



I THEN gradually projeded on it 55 grains of malfha, which 

 was all I had ; this burned juft as the pitch, but was attended 

 with a blacker fmoak, yet the nitre was fo far from being 

 alkalized that to produce this efFedl I was obliged to throw on il 

 29 grains of Cannel coal. Now 33,5 grains of Cannel coal, if it 

 alone had been ufed, would fufEce to alkalize 240 grains of nitre, 

 as will prefently be feen, therefore the 5 5 grains of maltha and 

 the one grain of pitch contained no more carbon than 33,5 — 

 29=4,5 grains ; therefore 1 00 grains of maltha contain no more 

 than 8 grains of carbon. And as thefe 8 grains of carbon pro- 

 voked no turbulent eruption of air from the nitre, it is plain they 

 did not contribute to its decompofition, but were taken up by 

 the air it fpontaneoufly emitted, and partly by the ambient at- 

 mofpheric air. 



Of AfphalU 

 Its colour is greyifh black. 

 Its luftre 2.3. greafy. Tranfparency o. 

 Its fradure perfedly conchoidal. 



Its hardnefs from 7 to 8, very brittle. Specific gravity from 

 1,07 to 1,165 '^y ™y trials. It feels fmooth, but not greafy; 

 has no fmell, except while pounding ; does not ftain the fingers ; 

 when heated it melts, fwells and at laft inflames, but it requires 



Vol. VI. U for 



