﻿96 
  Thietieth 
  Reeoet 
  oist 
  the 
  State 
  Museum. 
  

  

  were 
  further 
  expanded 
  in 
  an 
  essay 
  entitled 
  Illustrations 
  of 
  

   Chemical 
  Homology, 
  which 
  was 
  published 
  in 
  the 
  Proceedings 
  

   of 
  the 
  American 
  Association 
  for 
  the 
  Advancement 
  of 
  Science, 
  

   for 
  1854, 
  and 
  explicitly 
  set 
  forth 
  in 
  an 
  abstract 
  of 
  the 
  same, 
  

   published 
  in 
  the 
  American 
  Journal 
  of 
  Science 
  for 
  September, 
  

   1854. 
  A 
  summary 
  of 
  these 
  views, 
  in 
  the 
  language 
  of 
  the 
  

   original 
  memoirs, 
  together 
  with 
  some 
  further 
  illustrations 
  

   taken 
  from 
  a 
  later 
  paper 
  by 
  the 
  author 
  in 
  the 
  Compte 
  Rendu 
  

   of 
  the 
  French 
  Academy 
  of 
  Sciences 
  for 
  June 
  29, 
  1863, 
  is 
  given 
  

   in 
  the 
  Seventeenth 
  of 
  the 
  Chemical 
  and 
  Geological 
  Essays, 
  

   collected 
  by 
  Prof. 
  Hunt 
  into 
  book-form 
  and 
  re-published 
  in 
  

   1875. 
  "It 
  was 
  asserted 
  that 
  the 
  simple 
  relations 
  of 
  volumes 
  

   which 
  Gay 
  Lussac 
  pointed 
  out 
  in 
  the 
  chemical 
  changes 
  of 
  gases 
  

   apply 
  to 
  all 
  liquid 
  and 
  solid 
  species, 
  thus 
  leading 
  the 
  way 
  to 
  a 
  

   correct 
  understanding 
  of 
  the 
  equivalent 
  volumes 
  of 
  the 
  latter. 
  

   While 
  chemists 
  have 
  not 
  hesitated 
  to 
  assign 
  high 
  equivalents 
  

   to 
  bodies 
  of 
  the 
  carbon 
  series, 
  they 
  have 
  been 
  inclined 
  to 
  make 
  

   the 
  equivalent 
  weights 
  of 
  denser 
  mineral 
  species 
  correspond 
  to 
  

   formulas 
  representing 
  the 
  simplest 
  possible 
  ratios. 
  We 
  endeav- 
  

   ored, 
  from 
  a 
  consideration 
  of 
  the 
  theory 
  of 
  equivalent 
  volumes, 
  

   to 
  point 
  out 
  the 
  errors 
  to 
  which 
  this 
  method 
  has 
  led, 
  and 
  to 
  

   show 
  that 
  we 
  must 
  assign 
  to 
  most 
  mineral 
  species 
  much 
  higher 
  

   equivalent 
  weights 
  than 
  have 
  hitherto 
  been 
  admitted." 
  

  

  "It 
  was 
  further 
  asserted 
  that 
  a 
  relation 
  similar 
  to 
  that 
  

   observed 
  in 
  the 
  formulas 
  of 
  allied 
  hydrocarbonaceous 
  bodies, 
  

   and 
  designated 
  as 
  chemical 
  homology, 
  exists 
  in 
  the 
  formulas 
  

   of 
  mineral 
  species. 
  It 
  was 
  shown, 
  from 
  the 
  relations 
  of 
  carbon, 
  

   sulphur, 
  and 
  oxygen 
  on 
  the 
  one 
  hand, 
  and 
  of 
  hydrogen 
  and 
  

   the 
  metals 
  on 
  the 
  other, 
  that 
  M 
  2 
  S 
  2 
  , 
  M 
  2 
  2 
  , 
  and 
  H 
  2 
  2 
  (M 
  repre- 
  

   senting 
  any 
  metal) 
  may 
  be 
  compared 
  with 
  H 
  2 
  C 
  2 
  . 
  This 
  view 
  

   will 
  be 
  applied 
  in 
  extending 
  the 
  application 
  of 
  the 
  principle 
  of 
  

   homology." 
  

  

  " 
  We 
  have 
  further 
  asserted 
  that, 
  for 
  species 
  crystallizing 
  in 
  

   the 
  same 
  form, 
  the 
  density 
  varies 
  directly 
  as 
  the 
  equivalent 
  

   weight, 
  so 
  that 
  the 
  quantities 
  obtained 
  in 
  dividing 
  the 
  one 
  by 
  

   the 
  other, 
  and 
  known 
  as 
  the 
  atomic 
  or 
  equivalent 
  volumes 
  will 
  

   be 
  equal. 
  Such 
  a 
  relation 
  is 
  already 
  recognized 
  between 
  species 
  

   of 
  the 
  same 
  genus, 
  and 
  we 
  now 
  propose, 
  having 
  fixed 
  an 
  equiva- 
  

   lent 
  weight 
  for 
  one 
  species, 
  to 
  calculate, 
  from 
  their 
  densities, 
  

   those 
  of 
  the 
  species 
  isomorphous 
  with 
  it, 
  and 
  to 
  show 
  from 
  their 
  

  

  