Mineralogy and Geology. 419 
The chemical composition is as follows : 
; , Quantity of sulphur required 
* for the metals. Forming: 
Insoluble (silica), 2145 
Sulphur, 27-039 : 
Cobalt, 28-502 16001 ~ CoS 44:503 
Nickel, 1-500 
Copper, 32-988 8-328 CueS 41-316 
fron,  § 811 3-035 -FeS 8-346 
Arsenic, SCTE * : 
99-300 27°364 
Another determination of nickel and cobalt by Mr. J. Hewston, as- 
sistant in Prof. Booth’s laboratory gave very nearly the same numbers. 
The analysis evidently proves that, if the iron replaces cobalt, then 
Cuz is isomorphic with Co and Fe, because there are more than two 
equivs. of (Co, Fe)S combined with Cu2S ; but that if the FeS be re- 
jected as a mere admixture, then precisely 2 eq. of CoS are united to 
1 eq. of Cu2S, and the isomorphism of and Cue is not proved 
compound is AS 2CoS+Cuz2 8. 
e substance subjected to analysis consists therefore of a new min- 
eral, which I shall call Carrodlite,* with foreign admixtures of about 
‘5 pr. ct. of magnetic pyrites, and 3:3 pr. ct. of copper nickel, with 2 
pr. ct. of quartzose gangue ; carrollite consists of— 
: Calculated from the formula 
2CoS+Cuz5, 
By analysis. S+C 
Sniphar 0 os «|, See 28:077 
Cobalt, ‘ s 5 33-256 - 84-050 
Copper, <<. . yrcukak 38-389 37873 
100-000 100-000 
* The name is given in memory of the locality whence it was obtained, as well 
as of a name cherished by every American. : 
