﻿XXXV1U 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  tions 
  all 
  highly 
  disturbed 
  and 
  associated 
  with 
  bosses 
  of 
  granite. 
  

   They 
  range 
  from 
  certain 
  schistose 
  beds 
  beneath 
  the 
  Carboniferous 
  

   limestone, 
  through 
  Oolitic, 
  up 
  to 
  Eocene 
  and 
  Miocene 
  strata 
  ; 
  and 
  in 
  

   this 
  memoir 
  Mr. 
  Pratt 
  corrected 
  some 
  grave 
  errors 
  inserted 
  in 
  the 
  

   French 
  map 
  of 
  the 
  district. 
  

  

  In 
  1837 
  Mr. 
  Pratt 
  gave 
  "A 
  Description 
  of 
  the 
  Geological 
  Character 
  

   of 
  the 
  coast 
  of 
  Normandy," 
  in 
  which 
  he 
  corrected 
  some 
  of 
  the 
  views 
  

   previously 
  published 
  by 
  De 
  la 
  Beche 
  and 
  Elie 
  de 
  Beaumont, 
  and 
  de- 
  

   scribed 
  with 
  great 
  accuracy 
  the 
  strata 
  ranging 
  between 
  the 
  Lias 
  and 
  

   the 
  Chalk 
  Marl, 
  which 
  he 
  showed 
  are 
  the 
  true 
  equivalents, 
  some- 
  

   what 
  modified, 
  of 
  similar 
  strata 
  in 
  England. 
  

  

  Several 
  other 
  memoirs 
  were 
  contributed 
  to 
  this 
  Society, 
  all 
  of 
  

   considerable 
  value 
  ; 
  and 
  one 
  on 
  the 
  coal- 
  deposits 
  of 
  the 
  Asturias 
  to 
  

   the 
  British 
  Association 
  in 
  1845, 
  in 
  which 
  he 
  shows 
  that 
  the 
  coal 
  of 
  

   the 
  district 
  is 
  of 
  true 
  Carboniferous 
  age, 
  and 
  that 
  beneath 
  it 
  are 
  

   several 
  remarkable 
  beds 
  of 
  haematite, 
  one 
  of 
  pure 
  unmixed 
  ore 
  

   50 
  feet 
  in 
  thickness. 
  

  

  Mr. 
  Pratt 
  was 
  also 
  well 
  known 
  to 
  the 
  Geological 
  Society 
  of 
  France, 
  

   to 
  which 
  body 
  he 
  communicated 
  memoirs. 
  

  

  It 
  must 
  still 
  be 
  fresh 
  in 
  the 
  minds 
  of 
  many 
  Fellows 
  of 
  the 
  Society 
  

   that 
  we 
  were 
  much 
  indebted 
  to 
  Mr. 
  Pratt 
  for 
  various 
  contributions 
  to 
  

   the 
  Museum 
  ; 
  among 
  others, 
  a 
  collection 
  of 
  Catalonian 
  fossils, 
  and 
  a 
  

   quantity 
  of 
  Mammalian 
  bones 
  from 
  the 
  caves 
  of 
  Palermo. 
  Also, 
  in 
  

   conjunction 
  with 
  the 
  late 
  Mr. 
  Daniel 
  Sharpe, 
  he 
  devoted 
  great 
  time 
  

   and 
  labour 
  to 
  the 
  arrangement 
  of 
  a 
  vast 
  accumulation 
  of 
  specimens 
  

   of 
  rocks 
  and 
  fossils, 
  both 
  foreign 
  and 
  British. 
  Mr. 
  Pratt 
  also, 
  un- 
  

   assisted, 
  revised 
  the 
  collection 
  of 
  minerals 
  in 
  the 
  Museum 
  ; 
  and, 
  

   indeed, 
  until 
  a 
  few 
  years 
  ago, 
  when 
  his 
  health 
  gave 
  way, 
  Mr. 
  Pratt, 
  

   known 
  and 
  respected 
  in 
  the 
  Council-room, 
  in 
  the 
  Museum, 
  and 
  at 
  

   the 
  evening-meetings, 
  was 
  esteemed 
  by 
  all 
  as 
  an 
  able 
  and 
  zealous 
  

   Member 
  of 
  the 
  Geological 
  Society. 
  

  

  He 
  died 
  last 
  year, 
  at 
  the 
  age 
  of 
  75. 
  

  

  Eilhard 
  Mitscherlich, 
  the 
  eminent 
  Professor 
  of 
  Chemistry 
  at 
  the 
  

   University 
  of 
  Berlin, 
  was 
  born 
  on 
  the 
  7th 
  of 
  January, 
  1794, 
  at 
  

   Neuende, 
  near 
  Jever, 
  in 
  East 
  Friesland, 
  where 
  his 
  father 
  was 
  pastor. 
  

   Here 
  he 
  studied 
  under 
  the 
  historian 
  Schlosser, 
  with 
  whom 
  he 
  went 
  to 
  

   Frankfort. 
  In 
  1811 
  he 
  went 
  to 
  Heidelberg 
  and 
  afterwards 
  to 
  Paris, 
  

   devoting 
  his 
  attention 
  to 
  the 
  study 
  of 
  history 
  and 
  philology. 
  In 
  

   1818 
  his 
  pursuits 
  took 
  a 
  different 
  direction, 
  and 
  at 
  Berlin 
  he 
  gave 
  

   himself 
  wholly 
  to 
  the 
  study 
  of 
  the 
  natural 
  sciences, 
  and 
  especially 
  

   of 
  chemistry. 
  In 
  the 
  last-named 
  science, 
  in 
  1820 
  and 
  1822, 
  he 
  

   speedily 
  rendered 
  his 
  name 
  famous 
  by 
  his 
  memoirs 
  in 
  the 
  'Annals 
  

   of 
  Chemistry 
  and 
  Physics,' 
  "On 
  the 
  relation 
  existing 
  between 
  crys- 
  

   talline 
  form 
  and 
  chemical 
  proportions." 
  In 
  other 
  words, 
  he 
  dis- 
  

   covered 
  the 
  law 
  of 
  isomorphism. 
  By 
  this 
  law 
  he 
  first 
  showed 
  that 
  

   the 
  crystalline 
  form 
  of 
  compound 
  bodies 
  is 
  in 
  relation 
  to 
  the 
  nature 
  

   of 
  their 
  components 
  and 
  the 
  weight 
  of 
  their 
  equivalents 
  ; 
  so 
  that 
  in 
  

   numerous 
  compound 
  bodies, 
  by 
  virtue 
  of 
  analogies 
  of 
  composition, 
  

   one 
  of 
  the 
  principal 
  components 
  may 
  be 
  replaced 
  by 
  another 
  without 
  

  

  