a mineral Substance from North America. 59 
The salt was placed upon a filter, so that the lixivium might 
be separated. It was then washed with a small quantity of cold 
distilled water ; and, being dried, remained as above described, 
although constantly exposed to the open air. 
This salt had an acrid disagreeable flavour, and contained a 
small excess of alkali. It did not dissolve very readily in cold 
water ; but, when dissolved, the solution was perfect and per- 
manent. 
Some nitric acid was added to part of the solution, and im- 
mediately rendered it white and turbid. In a short time, a white 
precipitate was collected, similar to that which had been em- 
ployed to neutralise the potash ; and the clear supernatant liquor, 
being evaporated, only afforded nitre. 
Prussiate of potash was added to another portion ; but did 
riot produce any effect, until some muriatic acid was dropped 
into the liquor, which then immediately assumed a tinge of 
olive green, and slowly deposited a precipitate of the same colour. 
Tincture of galls did not affect the solution at first; but, 
when a few drops of muriatic acid had been added, it gradually 
lost its transparency, and yielded an orange-coloured precipitate. 
2. As so large a part of the white precipitate had remained 
undissolved in the foregoing experiment, it was digested again 
with another portion of the same lixivium, but without any 
effect. I therefore washed off the alkali, and boiled some nitric 
acid with the powder, until the acid was completely evaporated. 
After this, the powder was exposed to a strong heat in a sand- 
bath. It was then again digested with the lixivium, and a part 
was dissolved as before ; but still the residuum required to be 
treated with nitric acid, before the alkaline liquor could again 
act upon it ; so that it was necessary to repeat these alternate 
I 2 
