﻿Notes 
  upon 
  the 
  Lithology 
  of 
  the 
  Adirokdacks. 
  97 
  

  

  densities, 
  those 
  of 
  the 
  species 
  isomorphous 
  with 
  it, 
  and 
  to 
  show 
  

   from 
  the 
  formulas 
  corresponding 
  to 
  these 
  equivalent 
  weights 
  

   that 
  the 
  different 
  genera 
  thus 
  related 
  are 
  homologous, 
  or 
  exhibit 
  

   other 
  intimate 
  relations. 
  

  

  " 
  An 
  attempt 
  was 
  then 
  made 
  to 
  fix 
  the 
  volume 
  of 
  the 
  pris- 
  

   matic 
  and 
  rhombohedral 
  carbon 
  -spars, 
  which 
  were 
  compared 
  

   respectively 
  with 
  the 
  isomorphous 
  species 
  bournonite 
  and 
  the 
  

   red 
  silver 
  ores, 
  proustite 
  and 
  pyrargyrite. 
  The 
  received 
  formula 
  

   of 
  bournonite 
  being 
  doubled, 
  and 
  that 
  of 
  the 
  rhombohedral 
  

   sulphides 
  made 
  to 
  correspond 
  with 
  it, 
  we 
  find 
  for 
  the 
  prismatic 
  

   species 
  an 
  equivalent 
  volume 
  of 
  508, 
  and 
  for 
  the 
  rhombohedral 
  

   ones 
  546-564. 
  In 
  accordance 
  with 
  this 
  the 
  equivalent 
  of 
  calcite 
  

   corresponds 
  to 
  C 
  8 
  oCa 
  8 
  o0 
  9 
  o(C=6 
  and 
  0=8), 
  while 
  dolomite, 
  chaly- 
  

   bite, 
  and 
  diallogite 
  become 
  C 
  36 
  M 
  36 
  O 
  108 
  , 
  and 
  calamine 
  and 
  mag- 
  

   nesite 
  C^M^O^. 
  For 
  the 
  prismatic 
  carbonates, 
  aragonite, 
  like 
  

   calcite, 
  is 
  C 
  3 
  oM 
  30 
  9 
  o, 
  while 
  strontianite, 
  cerusite 
  and 
  bromlite 
  

   are 
  C 
  25 
  M 
  25 
  75 
  , 
  and 
  wither! 
  te 
  is 
  C 
  22 
  M 
  22 
  66 
  ." 
  

  

  " 
  From 
  Gflauber-salt 
  and 
  borax 
  were 
  deduced, 
  in 
  like 
  manner, 
  

   an 
  equivalent 
  volume 
  of 
  about 
  440, 
  corresponding 
  nearly 
  with 
  

   that 
  of 
  saccharose 
  with 
  C 
  48 
  =430, 
  and 
  with 
  these 
  were 
  compared 
  

   the 
  silicates 
  of 
  the 
  amphibole 
  group, 
  from 
  which 
  it 
  was 
  con- 
  

   cluded 
  that 
  these 
  silicates 
  present 
  among 
  themselves 
  relations 
  

   similar 
  to 
  those 
  of 
  the 
  homoeomorphous 
  carbon-spars. 
  The 
  

   attempts 
  to 
  deduce 
  correct 
  formulas 
  for 
  these 
  and 
  other 
  silicates 
  

   at 
  that 
  time, 
  were, 
  however, 
  vitiated 
  by 
  many 
  incorrect 
  analyses, 
  

   and 
  rendered 
  uncertain 
  by 
  doubts 
  as 
  to 
  the 
  equivalent 
  weight 
  

   of 
  silicon." 
  

  

  "An 
  important 
  point 
  in 
  the 
  question 
  of 
  homology 
  and 
  

   homceomorphism 
  was 
  then 
  referred 
  to 
  in 
  the 
  following 
  lan- 
  

   guage 
  : 
  — 
  The 
  similarity 
  in 
  crystallization 
  between 
  species 
  whose 
  

   formulas 
  differ 
  only 
  in 
  the 
  elements 
  of 
  water 
  has 
  been 
  pointed 
  

   out 
  by 
  Laurent 
  in 
  certain 
  salts 
  of 
  organic 
  acids, 
  and 
  is 
  seen 
  in 
  

   several 
  mineral 
  species. 
  The 
  chabazites, 
  for 
  example, 
  give 
  the 
  

   formula 
  3 
  Ro. 
  Si0 
  3 
  , 
  3 
  A1 
  2 
  3 
  , 
  2 
  Si 
  3 
  , 
  with 
  15 
  HO 
  and 
  18 
  HO, 
  

   while 
  the 
  variety 
  ledererite 
  affords, 
  according 
  to 
  Hayes 
  and 
  to 
  

   Rammelsberg, 
  but 
  6 
  HO. 
  The 
  hydrous 
  iolites 
  are 
  also 
  cases 
  in 
  

   point, 
  as 
  well 
  as 
  aspasiolite, 
  the 
  serpentines, 
  and 
  the 
  talcs, 
  with 
  

   their 
  varying 
  proportions 
  of 
  water. 
  In 
  the 
  formulas 
  of 
  these 
  

   species, 
  water 
  appears 
  to 
  replace 
  magnesia, 
  and 
  Scheerer 
  has 
  

   shown 
  that 
  many 
  different 
  species 
  may 
  be 
  referred 
  to 
  a 
  common 
  

  

  7 
  

  

  