simku.I  DEVELOPMENTS    AT    TONOPAH,    NEV.  143 
Analysis  of  sulphide  ore  from  Montana  vein,  Montana  Tonopah  mine. 
Siliceous  matter 15.  18 
Gold    .72 
Silver    25.02 
Lead    . 6.21 
Copper    1 1.  32 
Iron     _ 9.87 
Manganese 1.  36 
Zinc 5.84 
Selenium    2. 56 
Tellurium    None. 
Arsenic .  19 
.      Antimony .92 
Magnesia    1. 49 
Lime    3.  70 
Carbon   dioxide 0.  34 
Sulphur Not  determined. 
Typical  rich  ore  from  the  oxidized  zone  of  the  Valley  View  vein 
yielded  the  following  results : 
Analysis  of  oxidized  ore  from  the  Valley  View  rein. 
Siliceous  matter 16.53 
Gold .__       .62 
Silver   (38.10  as  sulphides;    24.44  as  chloride,  selenide,  and 
alloy) 62.54 
Lead    _<a _ .32 
Copper    (mostly   oxidized) .09 
Iron     1.39 
Manganese    .  07 
Zinc T .10 
Selenium    .  78 
Tellurium    _ None. 
Arsenic a-       .  <>3 
Antimony .  15 
Sulphur   Not  determined. 
Doctor  Hillebrand's  analyses  show  that  the  carbonate,  which  forms 
small  part  of  the  gangue  in  the  primary  ores,  is  complex,  consisting 
f  carbonates  of  lime,  magnesia,  iron,  and  manganese.  Aside  from 
his,  the  analysis  of  the  primary  sulphide  ore  indicates  the  presence 
f  a  large  amount  of  the  silver  sulphide,  argentite,  which  occurs  also 
s  a  secondary  sulphide,  as  previously  reported.  Oilier  sulphides  of 
ilver  are  also  indicated,  certainly  polybasite,  and  very  probably 
tephanite.  Smaller  amounts  of  galena,  blende,  pyrite,  and  chal- 
opyrite  are  evidently  present.  Of  very  great  interest  is  the  presence 
f  a  considerable  amount  of  selenium,  with  no  trace  of  its  usually 
losely  associated  element  tellurium.  This  occurs,  in  part  at  least, 
s  a  silver  selenide.     The  chemical  form  of  the  gold  is  as  yet  uncer- 
