$$2 ON ARTIFICIAL TANNIN, 



needles, altogether resembling that formed with amer at a 

 maximum. 



The liquor from which the yellow detonating powder was 

 separated contained some resin, with the addition of a 

 small quantity of amer at a minimum. 



e. No. 2 was treated with concentrated nitric acid. 

 A few small globules of an oily appearance were formed. It 

 was boiled, evaporated to dryness, dissolved in water, and 

 saturated with potash. The compound of amer at a maxi- 

 mum with potash was obtained crystallized. The mother 

 water yielded on evaporation fresh detonating acicular 

 crystals, of a deeper yellow than the first from their retain* 

 ing a little resin. 

 Inferences from From these experiments I concluded, 

 this. 1st, that the substance of an oily appearance is form- 



ed of resin, amer at a minimum for the greater part, 

 amer at a maximum, and perhaps nitric acid com* 

 bined with all three, and contributing to their fluidify: 

 2dly, that amer at a minimum is capable of combining with 

 amer at a maximum *, and forming a detonating compound 

 with potash. 

 Rationale of the 5. The analysis of the matter of an oily appearance is 

 na ysis. founded on the difference of solubility of amers and resin, 



and on that of their compounds with the oxide of lead. 

 Thus, when carbonate of lead is boiled with the oily mat. 

 ter, the amers and a small quantity of resin combine with 

 the metallic oxide, and form compounds soluble in water : 

 and as soon as the greater part of the resin is freed from 

 the amers, it is much less soluble, and consequently will 

 separate; and its separation is farther promoted by its com- 

 bining with a little oxide of lead. The resin, from its affinity 

 for the amers, carries down a small quantity with it. When 

 the soluble compound of amers with lead is decomposed by 

 sulphuric acid, the two amers combine together, so that 

 they jointly form a compound of little solubility with pot- 

 ash; and when this compound is treated with muriatic acid, 



* The compound of the two amers has appeared to me capable 

 of assuming the form of globules of an oily appearance at a tempe- 

 rament of + G0 Q [140° F.] Perhaps the nitric acid contributes 

 to give it this state. 



the 



