363


Nickel  product  of,  in  the  United  States,
126
properties  of,  114
pure,  method  of  obtaining,  118
separation  of  cobalt  from,  232,  233
silicate  minerals,  comparison  of,  120
specific  gravity  of,  114

heat  of,  234
•steel,  116,  117  i

tests  of,  117
sulphides  of,  115,  116
sulpho-arsenides,    in     the     United ,
States,  120
Nitrate  of  barium,  44  I

potassium,  39  '

silver,  45,  46  '

Nitric  acid,  34

fuming,  preparation  of,  60,  61     j
precaution  in  using,  92  :

test  of,  for  chlorine,  91
Nitro-prusside  of  sodium,  42,  43
North  Carolina,  associations  of  the  dia-
monds found  in,  257,  258
diamonds  found  in,  256,  257
gold,  fineness  of,  76
occurrence  of  gold  in,  73-75
pecnliarity  in  the  gravel  beds

of,  75
production  of  gold  in,  68
Nova  Scotia  gold,  fineness  of,  76

OCTAHEDRITE,  258
Oil  and  gas  wells,  351,  352
well,  sinking  a,  351,  352
Ore,  assorting  the,  in  the  mine,  .{04

correct  relation  between  the  pre-
paratory work  and  the  extracting
of,  283

deposits,  large,  timbering  in  taking
ore  from,  332

distinction   between   the,   and    the  [
gangue,  279

exposed,  283

inclination  of  the,  279,  280

iron,  containing  gold,  examination
of,  89

kidnejs  of,  opening  of,  and  prepar-
ing for  mining,  281

nests  of,  opening  of,  and  preparing  '
for  mining,  281  <

pjritic,  containing  gold,  examina-
tion of,  89

rise  of  the,  279,  280

stoping  out  the,  283

valuable,  in  the  wreck  of  a  mine, '
method  of  gaining,  298

weighing  a  lump  of,  without  scales,
10,11
Ores,  magnetic,  126-128


Oreways,  or  drifts,  271
Osmiridium,  206

melting  of  gold  containing,
81,  82
Oxalate  of  ammonium,  43
Oxalic  acid,  36
Oxide  of  copper,  38,  39

manganese,   separation   of,    192,

193
zinc,  properties  of,  177
Oxides,  metallic,  decomposition  of,  and
separation  of  sulphur  from,
110-113
groups  of,  26-28
of  nickel,  115
Oxygen,  32,  33

PAINT,  production  of,   from  manga-
nese, 201
Palladium,  extraction  of.  from  gold,  83
Parkes's   process  of  desilverizing  lead,

187,  188
Parry's   method   of   determining    phos.
