﻿518 
  

  

  jN'EW 
  yOEK 
  STATE 
  MUSEUM 
  

  

  Action 
  of 
  heat 
  on 
  mixture 
  of 
  silica 
  and 
  bases 
  

  

  Aluminum 
  sili- 
  

   cate 
  

  

  r4:Al203,3Si02 
  

   2Al203.3Si02 
  

   ALO„3SiO, 
  

  

  ^ 
  

  

  '2^3?' 
  

  

  2ALO„9SiO, 
  

  

  2Fe2033^i02 
  

  

  Ferric 
  silicate 
  -J 
  

  

  .Fe^Os^SSiO^ 
  

   4FeO,SiO, 
  

  

  Ferrous 
  

   cates 
  

  

  sili- 
  

  

  2FeO,Si02 
  

  

  FeO,Si02 
  

   2FeO,3SiOs 
  

  

  fFe203,A]203,3Si02 
  

  

  1 
  

  

  Doubleor 
  raul-J 
  Fe203,A]203,6Si02 
  

   tiple 
  silicates 
  ' 
  

  

  I 
  

  

  3FeO,A]203,3SiO, 
  

  

  Agglomerated 
  

   Agglomerated 
  

   Strongly 
  agglomerated, 
  

  

  compact 
  ; 
  fracture 
  stonv, 
  

  

  dull 
  

   Compact, 
  stony 
  fracture, 
  

  

  slightly 
  shining 
  

  

  The 
  mixtures 
  did 
  not 
  de- 
  

   crease 
  in 
  volume 
  ; 
  there 
  

   was 
  no 
  combination, 
  the 
  

   buttons 
  were 
  tenacious 
  of 
  

   a 
  deep 
  gray 
  color 
  and 
  

   magnetic. 
  It 
  is 
  now 
  

   known 
  that 
  silicate 
  of 
  

   protoxid 
  of 
  iron 
  is 
  formed 
  

   with 
  the 
  evolution 
  of 
  

   oxygen. 
  

  

  Bubbly, 
  finely 
  granular 
  in 
  

   one 
  part, 
  crystalline 
  in 
  

   another 
  

  

  Yery 
  easily 
  melted. 
  Deep 
  

   olive 
  green 
  

  

  Melted 
  into 
  compact 
  mass 
  

  

  Melted 
  into 
  compact, 
  homo- 
  

   geneous 
  mass 
  

  

  Apparently 
  was 
  only 
  in 
  

  

  pasty 
  state 
  

   Completely 
  melted 
  into 
  

  

  brilliant 
  black 
  glass 
  

   Melted 
  into 
  compact 
  mass 
  

  

  free 
  from 
  bubbles 
  

  

  From 
  these 
  results 
  Berthier 
  drew 
  the 
  following 
  conclusions: 
  

  

  "No 
  silicate 
  of 
  alumina 
  is 
  completely 
  fusible 
  at 
  the 
  highest 
  tem- 
  

   peratures 
  attainable 
  in 
  the 
  furnace 
  (that 
  is 
  such 
  as 
  were 
  in 
  use 
  when 
  

   Berthier 
  wrote). 
  

  

  Protoxid 
  of 
  iron 
  produces 
  a 
  remarkably 
  fusible 
  silicate. 
  

  

  The 
  fusibility 
  of 
  multiple 
  silicates 
  is 
  greater 
  than 
  that 
  of 
  the 
  

   mean 
  of 
  the 
  component 
  silicates. 
  

  

  