Mr. Schmeisser's Account of a mineral Substance , &c. 413 
As to hardness, its surface could be scratched with a hard 
knife, but not scraped. 
Its specific gravity I found as 3,586, compared to distilled 
water of 6o° temperature. 
Properties of the Substance. 
N. B. The first experiments, which pointed out a distinction 
between its basis and the ponderous earth of Scheele, were 
made, at Dr. Crawford's desire, by his assistant Mr. Cruik- 
shank, and were afterwards repeated by himself ; the account 
of which is inserted in the second volume of the Medical 
Communications. 
EXPERIMENT I. 
I reduced a certain quantity of the substance to a very fine 
powder, and boiled it in water for some time, but no solution 
took place. 
EXPERIMENT II. 
With acids. It was not affected by sulphuric acid ; but 
was entirely soluble in nitric and muriatic acid, with a strong 
effervescence, during which a great quantity of gaz was dis- 
engaged, which when tried, was entirely absorbed by lime- 
water, extinguished flame, and had no smell. 
EXPERIMENT III. 
Diluted sulphuric acid dropped into a diluted solution of 
this substance in nitric and marine acid, occasioned a white 
powdery precipitate, which was insoluble in water. 
3H2 
