﻿296 
  W. 
  F. 
  Hillebrand 
  — 
  Mineralogical 
  Notes. 
  

  

  The 
  analyses 
  below 
  represent 
  the 
  composition 
  of 
  {a) 
  the 
  

   rejected, 
  (Jj) 
  the 
  original, 
  an(l(c) 
  the 
  selected 
  material. 
  Analysis 
  

   (J)) 
  is 
  given 
  chiefly 
  because 
  of 
  the 
  cobalt 
  determination, 
  the 
  

   nickel 
  being 
  probably 
  a 
  little 
  high. 
  Although 
  but 
  0'22 
  and 
  

   0"13 
  grams 
  respectively 
  were 
  available 
  for 
  the 
  analyses 
  {a) 
  and 
  

   (c), 
  the 
  data 
  are 
  believed 
  to 
  be 
  more 
  trustworthy 
  on 
  the 
  

   whole 
  than 
  those 
  of 
  (J), 
  hence 
  the 
  figures 
  under 
  (cl) 
  have 
  been 
  

   obtained 
  by 
  calculation 
  based 
  on 
  {c) 
  and 
  {a) 
  only, 
  after 
  reduc- 
  

   ing 
  them 
  to 
  100. 
  Under 
  {e) 
  is 
  shown 
  the 
  theoretical 
  composi- 
  

   tion 
  of 
  NiTe^. 
  Small 
  amounts 
  of 
  iron, 
  traces 
  of 
  copper, 
  and 
  

   perhaps 
  of 
  one 
  or 
  two 
  other 
  elements 
  are 
  omitted, 
  besides 
  the 
  

   J-2 
  per 
  cent 
  of 
  gold 
  and 
  petzite 
  that 
  remained 
  unattacked 
  by 
  

   cold 
  dilute 
  nitric 
  acid 
  in 
  which 
  the 
  nickel 
  mineral 
  is 
  readily 
  

   soluble. 
  

  

  The 
  specific 
  gravity 
  of 
  (b) 
  at 
  22*5 
  was 
  7*72, 
  which 
  is 
  proba- 
  

   bly 
  higher 
  than 
  the 
  true 
  density 
  of 
  the 
  pure 
  nickel 
  telluride. 
  

  

  a 
  he 
  d 
  e 
  

  

  NiTea 
  

  

  Te 
  -. 
  75-29 
  77-72 
  80-75 
  81-40 
  81-29 
  

  

  Ni 
  ) 
  _., 
  17-16) 
  ,„., 
  18-60 
  18-71 
  

  

  Co 
  1" 
  ^^^^ 
  -10 
  f 
  ^^^^ 
  

  

  • 
  Ag 
  8-44 
  5-09 
  -^Q 
  

  

  99-44 
  100-07 
  99-92 
  100-00 
  100-00 
  

  

  If 
  hessite 
  and 
  native 
  tellurium 
  constitute 
  the 
  foreign 
  admix- 
  

   ture, 
  the 
  mineralogical 
  composition 
  of 
  {a) 
  and 
  (c) 
  is 
  shown 
  to 
  

   be 
  as 
  follows 
  : 
  

  

  a 
  c 
  

  

  NiTe, 
  84-44 
  97-89 
  

  

  Hessite 
  13-51 
  1'38 
  

  

  Tellurium 
  2-05 
  -73 
  

  

  100-00 
  100-00 
  

  

  There 
  is 
  here 
  indicated 
  a 
  considerable 
  selective 
  separation 
  of 
  

   the 
  foreign 
  minerals, 
  since 
  the 
  relative 
  proportions 
  of 
  tellurium 
  

   and 
  hessite 
  are 
  very 
  different 
  in 
  the 
  two 
  mixtures, 
  but 
  the 
  

   amounts 
  operated 
  on 
  were 
  so 
  small 
  that 
  a 
  very 
  slight 
  actual 
  

   error 
  in 
  a 
  determination 
  might 
  give 
  rise 
  to 
  this 
  change 
  in 
  the 
  

   relative 
  proportions 
  of 
  impurities 
  without 
  affecting 
  materially 
  

   the 
  ratios 
  found 
  for 
  the 
  components 
  of 
  the 
  nickel 
  tellnride. 
  

   The 
  three 
  analyses 
  taken 
  together 
  point 
  unmistakably 
  to 
  jS'iTe, 
  

   as 
  the 
  formula 
  for 
  the 
  latter 
  mineral. 
  The 
  question 
  then 
  

   arises, 
  is 
  this 
  Genth's 
  melonite, 
  or 
  is 
  it 
  a 
  new 
  mineral 
  'I 
  Genth 
  

   found 
  

  

  