212 A. B. Tyler and C. U, Shepard on 
If now we consider the iron and lime as not essential, the 
formula will be CuS+Cu0+HO. 
I have considered one of the atoms of copper here as combined | 
with oxygen; and have taken the difference necessary to make 
100 as water, (or, what amounts to the same thing, have taken - 
the water at one equivalent). The direct determination of the 
latter is in this case a difficult matter, and I have not the oppor- 
tunity now of making it. That the above is the true composi- 
tion of the mineral I think the following considerations show. 
Ist. The fact that sulphur is given off when the mineral is 
heated in a matrass proves the presence of CuS, not of Cu*S. 
This leaves an atom of Cu which can be combined only with 
oxygen. 
2nd. The presence of CuO is indicated by the following 
reactions. The mineral tinges the blowpipe flame green: gives 
off sulphurous acid in the closed tube: ammonia dissolves part 
of it when pulverized, to a deep blue liquid, and as CuS is insol- 
uble in ammonia this must be CuO. 
. All pure sulphurets of the metals hitherto described are 
anhydrous; the presence of water, therefore, in combination, 
and to such an extent as here, is a strong argument for consid- 
ering the mineral partially an oxyd. 
4th. There are exactly two equivalents of Cu present, and just 
enough excess of S above one equivalent to combine with the 
Fe and CaO. If now we consider the extra atom of Cu as com- 
bined with oxygen, there remain about nine per cent (8°61), 
which we are justified in regarding as the correct amount 0 
water contained in the mineral. 
3. Moronolite—A description of this species will be found in 
Jaroso, ee 
oe Tyler gives the following as the result of his examinations. 
! Analyzed by J. Richter with the following result: 
. . o 8! — 
Sulphuric acid, 28-8 Yeas: 151 
Peroxyd of iron, 25) - 
: 7 j 1684 145 
67 1-14 1 
Water, $18 72 
9-2 : 
(KS + es $s) 49 aq. 
