174 MISCELLANY. 
D. The acid solution (1) struck a deep blue colour with the ferrocyanide 
of potassium, and yielded a white but scanty precipitate after some time 
with a solution of sulphate of magnesia ; this precipitate, when collected 
on a filter and washed, was blackened by hydro-sulphuret of ammonia. 
Ammonia when added in excess to the acid fluid caused a brown coloured 
precipitate: this, when washed and digested in a solution of caustic 
potash, yielded a fluid by filtration, which was not altered by the 
addition of an excess of muriate of ammonia, although much ammonia 
"was evolved. 
E. The ammoniacal fluid, when separated from the brown coloured 
precipitate, was mixed with hydro-sulphuret of ammonia; a slight opa- 
lescence was tardily produced. Another portion of the same ammoniacal 
fluid was treated with oxalate of ammonia ; an abundant precipitate 
ensued. 
From these experiments it would appear that the hydro-chloric acid 
solution contained iron, as shown by experiment D; the absence of 
alumina was also shown by the same experiment, and the presence of 
lead. 
The existence of iron, and the probable presence of traces of zinc, were 
shown by experiment E. 
Manganese did not appear to be present; for when a portion of the 
original powder was subjected to the blow-pipe flame with carbonate of 
soda, the fused mass did not possess any green tinge, so characteristic of 
manganese even in the smallest quantity. 
The powder when acted upon in the first instance by hydro-chloric acid 
evolved sulphuretted hydrogen. I next ascertained the quantity of sul- 
phate of barytes in six different specimens in the powder called calamine 
with the following results: — 
Specimens. 
1. Sulphate of barytes 83 in 100 parts. 
2. " '* 78 
3. *' " 87.5 
4. " *' 85 — — 
5. " * 81 
6. " " 85 — - 
The other ingredients did not appear to differ materially in quantity 
in the diflferent specimens, as far as could be judged of by a qualitative 
analysis. 
The following may be looked upon as the constituents of the powder of 
the shops, called calamine. 
Sulphate of barytes. 
Oxide of iron. 
Carbonate of lime. 
Lead (probably sulphate.} 
Zincl (mere traces.) 
