INIH4X. 
Page. 
Alkalies, contamination of, by traces of 
calcium 09 
determination of 96-101 
Aluminum, direct method for determin- 
ing 59-00 
ignition of precipitate of 50 
indirect method for determining 54-57 
methods of determining 54-60 
modes of precipitation of 55-56 
Ammonia in rocks, occurrence of 108 
Analyses, ingredients sought in 20 
limit of allowable error in 24 
mode of crushing or grinding rock for. 31-32 
mode of statement of 21-22 
number of portions of powder needed 
for. . .'. 27 
quantity of rock needed for 31,32 
tables showing errors arising from in- 
complete 10, 1 7 
time needed for making 22-23 
unadvisability of qualitative 26 
weight of ground sample needed for.. 32 
weights of portions of powder needed 
for 27. 28 
Austin and Gooch, cited 65, 78 
Bailey, G. H., cited 75, 76 
Barium, contamination of magnesium 
phosphate by 07 
estimation of 73-75 
ignited silica free from 53 
percentage of rock content of 17-18 
preliminary procedure when material 
is scanty 79 
recovery from alumina precipitate of 
possible amounts of 56-57 
separation of strontium from 63-64 
Basic acetate method of precipitating alu- 
minum, iron, etc 55-56 
Baskerville, C, method of separating tita- 
nium from iron and aluminum de- 
vised by 73 
method of separating zirconium devised 
by 77 
Baubigny, II., cited 80 
"Beuteln" in preparing rock sample, objec- 
tions to 32 
Blair, A. A., platinum-tipped crucible tongs 
devised by 23 
Bonn, C., cited 98 (footn i 
Boric-oxide method for decomposing sili- 
cates, description of 49-50 
possible objections to 50 
Boron, estimation of 1 07 
rare occurrence of 21 
Page. 
Broockmann, K., cited 66 
Browning, P. E. , ci led 63 
Briihland Friedheim, cited 61,80 
Brush, < i. J., method of water determination 
devised by 38 
Bunsen, B,., cited 99 (footnote) 
Calcium, contamination of, in weighed al- 
kali chlorides 99 
contamination of magnesium phos- 
phate by 67 
determination of 62-64 
separation of strontium from 63 
Campbell and Hess, cited 60 
Carbon, determination of 101-103 
Carbon dioxide, determination of 101-103 
figure showing apparatus for estima- 
tion of 102 
Carbonaceous matter, determination of fer- 
rous iron as affected by 94,96 
< !arn< >t , A. , cited 58 
Cathrein, A., cited 59, 71 (footnote) 
( 'erium, determination of 77 
rare occurrence of 21 
Chatard,T.M., cited 79 
description and figure of drying oven 
devised by 36-37 
Gooch gravimetric method of estimat- 
ing titanium as modified by 71-72 
method of water determination devised 
by 15 
Chlorine, determination of 103 
Chromium, determination of 79-82, 83 
preliminary procedure when material 
is scanty 79 
tables showing results of tests for 86, 87 
Claassen, E., cited 83 
Clarke, F. W., acknowledgments to 110 
cited 17 
Cloedt and Jannasch, cited 01, 80 
Cobalt, determination of 61-62 
Colorimetric apparatus for estimating tita- 
nium, descriptions and figures of... 70-71 
Colorimetic method for determining chro- 
mium 80-81 
comparison of gravimetric method 
with 81-82 
Columbium, rare occurrence of 21 
Cooke, .1. P., cited 92 
figure of apparatus for determining 
ferrous iron devised by 93 
Copper, determination of 61-62 
Crucible tongs, description and figure of... 23 
Crushing rock, mode of 31 
Curtis, J. S., cited 1 10 
111 
