﻿Clarice 
  and 
  8teiger 
  — 
  Experiments 
  with 
  Pectolite, 
  etc, 
  257 
  

  

  That 
  is, 
  analcite 
  and 
  leucite 
  become 
  members 
  of 
  the 
  garnet- 
  

   sodalite 
  group 
  of 
  minerals, 
  and 
  their 
  relations 
  to 
  nephelite, 
  

   albite, 
  prehnite, 
  natrolite, 
  etc., 
  natural 
  and 
  artificial, 
  are 
  per- 
  

   fectly 
  clear. 
  In 
  analcite 
  there 
  may 
  be 
  admixtures 
  of 
  strictly 
  

   analogous 
  ortho- 
  or 
  trisilicate 
  molecules 
  ; 
  but 
  these 
  remain 
  to 
  

   be 
  separately 
  discovered. 
  

  

  [N^ow 
  these 
  formulse 
  are 
  not 
  ultimate 
  verities 
  to 
  be 
  blindly 
  

   accepted. 
  They 
  are 
  simply 
  expressions 
  which 
  represent 
  com- 
  

   position 
  and 
  a 
  wide 
  range 
  of 
  established 
  relationships, 
  and 
  

   which 
  serve 
  a 
  distinct 
  purpose 
  in 
  the 
  correlation 
  of 
  our 
  knowl- 
  

   edge. 
  Properly 
  used, 
  with 
  due 
  recognition 
  of 
  their 
  limita- 
  

   tions, 
  they 
  are 
  helpful, 
  and 
  suggest 
  possibilities 
  of 
  research 
  ; 
  

   misused, 
  they 
  may 
  become 
  mischievous. 
  They 
  now 
  satisfy 
  

   all 
  known 
  conditions 
  ; 
  and 
  that 
  is 
  a 
  sufficient 
  warrant 
  for 
  their 
  

   existence. 
  

  

  U. 
  S. 
  Geological 
  Survey, 
  July 
  1, 
  1899. 
  

  

  