Reétxamination of American Minerals. 367 
we believe the first example of a natural subsulphuret that had 
been nae the relation being R*8°. 
been furnished through the kindness of Prof. Dana, 
hit an b abewodiiion of the mineral to select from, which he had 
procured from original specimens in the hands of Prof, Booth, it 
associated. A reéxamination of it gives the following for its 
physical and chemical characters. Hardness 5-5; sp. grav. 4:85.* 
Lustre metallic ; color steel gray ; fracture uneven, without suffi- 
tient indication to make out clearly the nature of its cleavage. 
The results of ate analyses are 
E 
Sulphur, 41°93 40°94 40°99 
Cobalt 87°25 ’ 38°21 37°65 
pper, 1748 17-79 19°18 
Nickel,} < 154 < 154 154 
: 1:26 1 140 
Arsenic, ‘ trace trace trace 
99°46 10003 10076 
These correspond to the general formula 
RS + 
as will be seen by comparing the amount of salah required for 
os metals indicated in the three analyses with the quantities 
nd. 
Sulphur. 2. Sulphur. 3, Sulphur. 
Cobelt, . 8125 st00” sea1 oes ares t21 
€opper, ; ee, AAR 1h is 1779. 1088. 1918. 12°78 
Nic Glee pes riieeee oe F = ‘St 118 tA CL 
ov, (ot ea 93° ies ag 10 10s 
41-83 49-14 
oe ae for the copper, iron and nickel, the entire 
cobalt would be openenied | in the three analyses 
iy 56: 37, sr: 92, and 68-50 pr.ct. The formula requires 
Atoms. Pr. et. 
re aa : . "ae Sate : : ree 
Cobalt, 3 
This is the toriniila ro eoneeieatiol St Linneite, and the min- 
eral in question is a copper Linneite similar in composition to the 
one from Riddarhythan, Sweden. 
he composition of this mineral is interesting, as it Seager 
the only example in the mineral kingdom of the isomorphism 
Copper and cobalt, where the Jatter may be replaced to a great 
or less extent by the former. Amon atifcial uae BY eth 
ing this replacement, we have the cupro-sulphate of cobalt with 
10 and with 7 atoms of water, the latter crystallizing in oblique 
prisms, like the sulphate of cobalt with the same number of atoms 
of Beli which is also the form of green vitriol. 
aa It may pike Sips rita there is a typograp| on. the statement 
. i is never 
Miaevotes 
