J. Orton on the Andes and Amazons. 203 
In two analyses the following results were obtained : 
4 2. ean. 
S, 31°81 31°51 31°66 
Cu, 45°94 45°95 45°95 
As, 13°65 13°74 13°70 
Sb, 6-03 oes 6-03 
Fe, 0°81 0°64 0°72 
SiO., 1°03 1:13 1:08 
99°27 99°14 
In analysis No. 2, owing to accident, a part of the antimony 
was lost, but still some five per cent remain 
If the iron present is considered as iron pyrites, and this 
peter with the silica deducted, the following mean is ob- 
tained: 
8 Cu As Sb 
31°68 47°21 14°06 619 "= O04 
These numbers give the ratio 1: 3: 8 between the arsenic, cop- 
“e and sulphur, corresponding to the formula 3Cu,S+ 
8 
8, Sb)S,, which is that of enargite as described by Brei- 
thaupt, Field and Burton, 
This California enargite differs however from those hereto- 
baer 
Arr, XVIIL—Physical Observations on the Andes and the 
mazons; by JAMES ORTON. 
Tuer following observations were made during a scientific 
tion across the continent of South America, in the year 
The instruments used were two mercurial barometers 
‘on Was broken in the valley of Quito,) after a tour of ten 
thousand miles had not varied a hair’s breadth. he route 
+ This Journal, I, xxvii, 52. Pogg. Ann., Ixxx, 383. 
+ Proc. Acad. Sei Philad., 1857, 168. { This Journal, II, xlv, 34. 
2s 
7 
= 
