264 
feud* 
will be the adulteration. This process may be checked 
thus. Take the scoria of the last mentioned fusion ; dis- 
solve it in muriatic acid or nitric acid : filter it : precipi- 
tate it by carbonat of potash (a solution of pearl ash) : 
wash and dry the precipitate, which will be a carbonat of 
lime, or whiting. The weight gives the quantity of 
whiting wherewith the lead was mixed. 
Or, dissolve the lead you suspect in nitric acid ; preci- 
pitate by well made, saturated, prussiat of potash, or prus- 
siat of lime. The prussic acid will throw down the lead 
only. This may be washed, and melted with any re- 
ducing fiux. If prussiat of potash be used, precipitate 
the remaining solution by carbonat of potash, which will 
throw down the carbonat of lime, which being washed, 
dried and weighed, will give the weight of the adultera- 
tion. 
Or, dissolve the lead suspected in nitric acid : preci- 
pitate with a solution of sulphuret of lime. This will 
throw down only the lead. 
Or, dissolve in nitric acid ; and precipitate with chro- 
mat of pot- ash, which will not decompose nitrat of lime. 
Chromat of Lead. This beautiful colour may be made 
thus. 
In the vicinity of Baltimore and Philadelphia, the Gra- 
nite and the Gneiss of the primitive strata, are succeeded 
by Steatite and Amphibole : these two last appear to be 
somewhat intermingled (but not in the same stone) : to 
these as a stratum, succeeds the granular or crystallized 
primitive limestone, which, near Philadelphia, is the mar- 
ble of White Marsh. Between the limestone and the stea- 
tite, but enveloped in steatite, in Chester county about 
twelve miles from Philadelphia, and at the Bare hills about 
nine miles from Baltimore, is found a chromated iron. 
When this pounded fine, and treated for an hour in 
