﻿Penfield 
  and 
  Warren 
  — 
  Minerals 
  from 
  Franklin^ 
  N. 
  J. 
  SttT 
  

  

  The 
  ratio 
  of 
  SiO, 
  : 
  (Pb+Zn+Mn+Fe+Ca) 
  O 
  : 
  (Cl+OH) 
  = 
  

   3'00 
  : 
  6*03: 
  1*05 
  wliich 
  approximates 
  closelj 
  to 
  3 
  : 
  5: 
  1, 
  and, 
  

   since 
  two 
  chlorine 
  atoms 
  are 
  equivalent 
  to 
  one 
  oxygen, 
  this 
  

   leads 
  to 
  the 
  general 
  formula 
  RjoCl^SigO^j, 
  R 
  = 
  Pb 
  and 
  Ca, 
  and 
  

   only 
  traces 
  of 
  Zn, 
  Mn 
  aod 
  Fe. 
  Before 
  discussing 
  the 
  general 
  

   formula 
  further, 
  it 
  may 
  be 
  stated 
  that 
  there 
  were 
  observed, 
  

   intimately 
  associated 
  with 
  the 
  nasonite, 
  a 
  few 
  particles 
  of 
  

   clinohedrite, 
  H^CaZnSiO^, 
  and 
  it 
  is 
  probable 
  therefore 
  that 
  the 
  

   small 
  percentage 
  of 
  zinc 
  (0*82 
  per 
  cent 
  ZnO) 
  was 
  derived 
  from 
  

   a 
  slight 
  admixture 
  of 
  this 
  latter 
  mineral. 
  It 
  seems 
  therefore 
  

   best 
  to 
  deduct 
  from 
  the 
  foregoing 
  analysis 
  the 
  ZnO, 
  and 
  

   sufficient 
  amounts 
  of 
  SiO.^jCaO 
  and 
  H^O 
  to 
  form 
  the 
  clinohe- 
  

   drite 
  molecule. 
  The 
  ratio 
  then 
  becomes 
  SiO^ 
  : 
  (Pb+Mn 
  + 
  Fe 
  

   + 
  Ca) 
  O: 
  (Cl 
  + 
  OH) 
  =-298: 
  -4.-96: 
  -098 
  = 
  3-00: 
  5-01: 
  0-99 
  or 
  

   almost 
  exactly 
  3 
  : 
  5 
  : 
  1. 
  Furthermore 
  the 
  ratio 
  of 
  SiO^ 
  : 
  PbO 
  : 
  

   (Ca+Mn+Fe) 
  O: 
  (Cl 
  + 
  OH) 
  = 
  -298: 
  -294: 
  -202: 
  •098 
  = 
  3-00: 
  

   2-97 
  : 
  2-04 
  : 
  0-99 
  or, 
  very 
  closely, 
  3:3:2:1. 
  Since 
  Fe, 
  Mn, 
  

   and 
  water 
  (hydroxyl) 
  are 
  present 
  only 
  in 
  very 
  small 
  amounts, 
  

   they 
  may 
  practically 
  be 
  disregarded, 
  and 
  the 
  empirical 
  formula 
  

   expressed 
  as 
  Pb.Ca.Cl, 
  (Si^O^ 
  or 
  Pb, 
  (PbCl)', 
  Ca, 
  (Si,0,)3. 
  

  

  Below 
  we 
  have 
  given 
  the 
  analysis, 
  after 
  deducting 
  2*16 
  per 
  

   cent 
  of 
  clinohedrite, 
  substituting 
  for 
  MnO 
  and 
  FeO 
  equivalent 
  

   amounts 
  of 
  CaO, 
  for 
  the 
  remaining 
  0*09 
  per 
  cent 
  of 
  water 
  

   (hydroxyl) 
  an 
  equivalent 
  of 
  chlorine, 
  and 
  calculating 
  to 
  100 
  per 
  

   cent, 
  while, 
  for 
  comparison, 
  the 
  theoretical 
  composition 
  cor- 
  

   responding 
  to 
  the 
  formula 
  PbgCa,C]2 
  (81^0^)3 
  is 
  also 
  given. 
  

  

  SiO 
  .... 
  

  

  Analysis 
  corrected. 
  

   18^32 
  

  

  Theory. 
  

   18-21 
  

  

  PbO 
  .... 
  

  

  CaO 
  

  

  CI 
  

  

  . 
  ..... 
  67-32 
  

  

  - 
  11-59 
  

  

  3-57 
  

  

  67-68 
  

  

  11-33 
  

  

  3-59 
  

  

  = 
  201, 
  

  

  100-80 
  

  

  -80 
  

  

  100-81 
  

   •81 
  

  

  100-00 
  100-00 
  

  

  Before 
  the 
  blowpipe, 
  nasonite 
  is 
  very 
  apt 
  to 
  decrepitate, 
  but 
  

   if 
  a 
  fragment 
  can 
  be 
  held 
  in 
  the 
  forceps 
  it 
  fuses 
  at 
  about 
  2 
  to 
  

   a 
  semi-transparent 
  globule, 
  and 
  the 
  characteristic 
  flame 
  colora- 
  

   tion 
  of 
  lead 
  is 
  obtained. 
  In 
  the 
  closed 
  tube 
  the 
  mineral 
  gives 
  

   a 
  trace 
  of 
  water 
  and 
  an 
  abundant 
  sublimate 
  of 
  lead 
  chloride, 
  

   the 
  residual 
  mineral 
  fusing 
  to 
  an 
  amethystine 
  glass 
  in 
  the 
  bottom 
  

   of 
  the 
  tube. 
  The 
  powdered 
  mineral, 
  when 
  heated 
  alone 
  on 
  

   charcoal 
  in 
  the 
  reducing 
  flame, 
  gives 
  a 
  white 
  sublimate 
  of 
  lead 
  

   chloride 
  distant 
  from 
  the 
  assay, 
  a 
  yellow 
  coating 
  of 
  oxide 
  nearer, 
  

  

  