PAUT 3.] Mallet: On M^sorln and Alacamitefrom the Nellore District. 171 
mecliamcally mixed, being left (with silica, &c.) as a red powder when the mineral 
was treated with dilute acid. 
It was not found possible to isolate sufficient chrysocolla in a pure state from 
the ore to make a separate analysis of it. Adopting, however, the normal com¬ 
position of the mineral, the above figures would be equivalent to— 
Cu. 
CuO. 
Pe, 0, 
CaO. 
BaO. 
CO, 
SiOa 
so. 
S. 
H, 0. 
Malacliite 
77*02 
55-65 
14*98 
... 
6*39 
Calcite 
•46 
•26 
•20 
Chrysocolla 
12*83 
... 
6*81 
4*39 
2-63 
Barite 
'84 
•65 
*29 
Chalcocite 
2*78 
2-22 
•66 
Ferric oxide 
674 
6-74 
100-67 
2*22 
61-46 
6-74 
•26 
•65 
15*18 
4-39 
•29 
*66 
9-02 
After deducting the cujmic oxide and water equivalent to the silica, and the 
carbonic acid equivalent to the lime, there remains a residue of, water 6’39, car¬ 
bonic acid 14-98, cupric oxide 56-65 ; quantities which have the oxygen ratio of 
1: 1-92 : 1-97 ; the oxygen ratio in tjqoical malachite being 1:2:2. It is clear, 
therefore, that the ore is an impure malachite owing its dark colour to admixture 
with ferric oxide and chalcocite. Some specimens, indeed, of the Gannypentah 
ore, which are seen to be impure malachite by the eye, have a dark colour owing to 
a smaller admixture of the same kind. 
It is not certain that the lime exists as calcite, but it is probable, calcite 
having, as before remarked, been found in some specimens of the ore. The 
point is, however, of no importance with reference to the main question. Thus, 
if the lime be included with the chrysocolla, the above-mentioned ratio will be 
1: 1-94: T99. 
I have alluded to small portions of the mysorin in which, when viewed with 
a lens, green is almost absent. Fragments of such, when dropped into dilute 
acid, give merely a minute bubble or two of carbonic acid; the liquid is faintly 
tinged with green, and the fragment remains almost unacted on. When heated 
with strong hydrochloric acid, iron is abundantly dissolved. Such portions of 
the ore are in fact merely ochroous ferric oxide. The amount of effervescence 
increases with the amount of green -visible in the specimens experimented on. 
Atacamite .—Amongst the specimens of cojiper ore from the iNellore district 
in the Museum, there is a mass of chalcocite, which ajjpears to have been origin¬ 
ally obtained by Mr. Kerr, a gentleman who endeavoured, but unsuccessfully, to 
work the mines about the year ^1835. The specimen weighs about six pounds, 
and evidently formed a portion of an irregular vein, two or three inches thick. 
It contains a few dissemminated crystals of magnetite, and is intersected by small, 
