from AIRTHREY. 267 
weighed 1 grain, and was arfenic. The diflolved portion I 
confidered as fulphur. 
10. THE potafh folution, being mixed with nitric acid, 4 
grains of fulphur fell. The remaining 7.6 grains muft have 
been converted into fulphuric acid, by the adtion of the nitric 
acid. Accordingly, muriate of barytes occafioned a copious 
precipitate. 
11. THE 84 grains of roafted ore being reduced to a fine 
powder, mixed with half their weight of pounded charcoal, and 
roafted a fecond time in a glafs-tube, one grain of fulphur fu- 
blimed. But the tube breaking before the roafting had been 
continued long enough, the procefs was completed in a cru- 
cible. The roafted ore weighed 70 grains. 
12. From the preceding analyfis, we learn that the confti- 
tuents of the Airthrey ore, are as follows : 
Iron, :" 45:5 
Copper, - 17.2 
Arfenic, - 14.0 
Sulphur, - 12.6 
Water, - 3-4. 
Foreign bodies, 6. 
99.6 
Lofs, - 4. 
100.0 
If we fuppofe the water and the earthy refidue to be only acci- 
dentally prefent, then the only effential conftituents are the firft 
four, and the ore would be a compound of 
Iron, 51.0 
Copper, 19.2 
Arfenic, 15.9 
Sulphur, = 14.1 : 
100.6 
VoL. VI.—P. II. L 1 If 
