50 
INDEX. 
Pago. 
Morgan and Smith, cited on divalent con- 
dition of iron in chalcopyrite 45 
Missouri, determination of marcasite 
from --- 26 
Mixtures of pyrite and marcasite, curve 
showing oxidation coefficients of. 30 
data obtained f or - - 27-31 
New Jersey, composition of specimen 
from -- 39 
Nickel, influence of presence of 32 
Oregon, composition of specimens from . 36 
Ostwald, W. , cited on increased solubility 
due to pulverizing 17 
Oxidation of pyrite and marcasite, con- 
ditions of 13-14 
by ferric sulphate, method of 15-16 
Oxidation coefficients, marcasite 27 
pyrite 25 
pyrite and marcasite, statement of . - 17 
mixtures of pyrite and marcasite, 
curve showing 30 
determinations of 28-29 
Paramorphism, observations on 40-41 
Penfield, S.L., acknowledgments to 48 
cited on method of distinguishing 
pyrite and marcasite 14 
cited on type of pyrite-marcasite 
from Folkestone, England 38 
Potassium permanganate, oxidation of 
pyrite and marcasite by .- 46-47 
Pyrite, action of copper sulphate on 14 
action of ferric solutions on 14-20 
color of 11-12 
crystalline form of 1.1 
data obtained for 25 
density of 12 L3 
determination of small amounts of . . . 30 
oxidation of 13-14,46 
oxidation coefficient of 25 
impurities in, influence of 31-34 
Pyrite and marcasite, data obtained for 
mixtures of 27-31 
oxidation coefficient of 17 
preparation of, for tests 20-22 
reasons for different behavior of, 
toward ferric solutions 19 
Page. 
Pyrite and marcasite, uncertainty of 
methods of distinguishing 11-14 
Rammelsberg, (J. F., cited on density of 
pyrite and marcasite 12 
Ransome, F. L., acknowledgments to 48 
Rio Tinto, Spain, composition of speci- 
men from 36,38 
Roxbury, Conn., determination of pyrite 
from 25 
Sadebeck, A., cited on marcasite from 
Littmitz, Bohemia 37 
Somerville, Mass., composition of speci- 
men from 39 
South Dakota, composition of specimen 
from 36,37 
Spain, composition of specimen from 36,38 
Starke, Shock, and Smith cited on divalent 
condition of iron in arsenopyrite. 45 
Stokes, H. N. , cited on density of pyrite 
and marcasite 12 
Sulphides, apparatus for oxidizing, figure 
showing 22 
apparatus for washing, figure show- 
ing 21 
Sulphur oxidized in ferric solutions act- 
ing upon pyrite, amount of 15 
deduction of expression for 16-17 
Tassin, Wirt, acknowledgments to 48 
j Temperature, influence of 18-19 
Temperature and strength of standard 
solution 17 
Texas, composition of specimen from 39 
Utah, determination of pyrite from 25 
Van Hise, C. R., acknowledgments to 48 
Vogt, J. H. L., cited on action of ferric 
chloride on pyrite 15 
! Weardale, England, determination of 
marcasite from 26,27 
| Webb City, Mo., determination of mar- 
casite from 26,27 
Weed, W. H., acknowledgments to 48 
Wisconsin, composition of specimen from 36, 38 
Wisconsin, determinations of marcasite 
from =. 26 
Wohler. F., cited on attempted conver- 
sion of marcasite into pyrite 41 
o 
