Reéramination of American Minerals. 375 
were one or two fine specimens of iodid of silver. A reéxamin- 
ation of this mineral is especially interesting, from the fact that 
its composition is still in doubt, owing to the discrepancy between 
the original analysis of Vauquelin on the mineral from Zacatecas 
in Mexico, and that of Domeyko on the mineral from Chanarcillo 
in Chili. 
Jodi Vauquelin. Domeyko. 
odine, : A are 46°89 
Silver, . R ava Ag? I 5425 Ag 
The constitution of the native Chlorids and Bromids of Silver 
would lead to the supposition that Domeyko’s analysis was the 
correct one, and this is strengthened by its resemblance to the 
artificial iodid of silver. : 
he specific gravity was found to be 5-366, being a little lower 
than that given by M. Domeyko. The analysis of an exceed- 
ingly pure specimen gave me— 

& 
Iodine, 52-934 53°109 
Silver, 46521 46°380 
Chlorine, ‘ trace trace 
Copper, trace trace 
99°455 99°489 
clearly showing its constitution to be” 
Ag I= Iodine 58°85, Silver 46°15 = 100, 
leaving no doubt of its perfect analogy to the natural chlorid and 
bromid of silver. The other properties of this mineral are no 
mentioned, as they are all fully stated in all works on mineralogy. 
39. Copiapite. 
Sis it afforded 
f 2 
Sulphuric acid, ; Fi ‘ 80°25 30-42 
P ee ; 31°75 _ 80°98 
a of iron, . rota : 
ss . i: . 54 not estimated. 
Undissolved, ; ‘ 3 fe 05 
100-74 
The analyses correspond to the formula 
#e §2 +118. 
