Sketch of the Mine of Pasco. 43 
Considering this augmentation as oxide of titanium, its composi- 
tion for 100. would be 
Iron, - - - - - - - 60. 
Oxygen, - - - - - - - 21.60 
‘Protoxide of titanium,  - - - - 18.40 
100. 
Analysis.—Five grains of the same mineral, reduced to an impal- 
pable powder, were treated by sulphuric acid, concentrated and boil- 
ing. The solution was evaporated to dryness, taken by water, and 
filtered, the residue, insoluble, weighed 0.1. This residue gave no 
indications of the oxide of titanium before the blowpipe. To the fil- 
tered solution, tartaric acid and ammonia were added by turns, un- 
til the latter produced no precipitate. A small excess of hydro sul- 
phate of ammonia was then added, and the hydro-sulphuret of iron 
separated by filtration, the solution evaporated to dryness, and the 
residue calcined, gave 0.95 of the protoxide of titanium. 
This mineral may be considered as having the following composi- 
tion for 100. 
fron : Se <A—*. piivig wae 60. 
Oxide of BRIO - - rm - ae | 
Silex, - “ é zs - = 2, 
Oxygen, - 
_ This quantity of oxygen is not exact, ae iron containing an salad 
nite quantity of carbon. 
Art. V.—Sketch of the rich mine of Pasco; by M. pe Rivero, 
received from the author in his Journal of Natural Science, and 
National and Foreign Industry, Jan. 1828, Vol. I. No. 2. pub- 
lished at Lima, and translated for this Journal by a Scholar of 
the New Haven Gymnasium. 
Introductory notice of specimens of silver from Peru and Chili.—Ed. 
Mr. Rivero’s account of the mineral riches of Pasco has excited 
the more interest in my mind, because some of those riches, and of 
those of the contiguous country of Chili, have been recently deposit- 
ed in my hands, by the kindness of Mr. Danitex W. Corr. This 
gentleman, for many years a traveller and resident in various coun- 
tries in Europe and both Americas ; and for the last six or seven 
