﻿570 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Tlie 
  relation 
  of 
  FeaOg 
  to 
  CaO 
  it 
  will 
  be 
  seen 
  is 
  as 
  1:2, 
  or 
  

   1 
  : 
  3, 
  but 
  the 
  lime 
  could 
  probably 
  be 
  lower 
  still, 
  and 
  yet 
  be 
  

   effective. 
  To 
  prove 
  tbis 
  Seger 
  took 
  the 
  red 
  burning 
  clay 
  from 
  

   Rathenow, 
  whose 
  composition 
  is 
  

  

  Silica 
  , 
  61.30 
  

  

  Alumina 
  18.87 
  

  

  Ferric 
  oxid 
  6.66 
  

  

  Lime 
  .85 
  

  

  Magnesia 
  1.20 
  

  

  Alkalis 
  3.20 
  

  

  Water 
  8.28 
  

  

  To 
  this 
  clay 
  he 
  added 
  increased 
  amounts 
  of 
  lime, 
  which 
  gave 
  

   the 
  proportions 
  of 
  ferric 
  oxid 
  to 
  lime 
  carbonate 
  in 
  the 
  diiferent 
  

   mixtures, 
  as 
  follows 
  : 
  

  

  1:.13, 
  1:.48, 
  1:.83, 
  1:1.18, 
  1:1.53, 
  1:1.88, 
  1:2.23, 
  1:2.58, 
  

   1:2.93. 
  

  

  These 
  nine 
  samples 
  were 
  first 
  burned 
  at 
  a 
  red 
  heat 
  in 
  a 
  small 
  

   gas 
  furnace, 
  and 
  on 
  cooling 
  the 
  color 
  of 
  all 
  of 
  them 
  was 
  found 
  to 
  

   be 
  red. 
  

  

  They 
  were 
  next 
  heated 
  to 
  bright 
  redness 
  and 
  after 
  this 
  it 
  was 
  

   found 
  that 
  the 
  color 
  of 
  the 
  first 
  four 
  was 
  bright 
  red, 
  but 
  still 
  

   slightly 
  off 
  color, 
  the 
  more 
  so 
  the 
  greater 
  the 
  proportion 
  of 
  lime 
  

   which 
  they 
  contained. 
  The 
  fourth 
  had 
  a 
  yellowish 
  brown 
  shell, 
  

   one 
  millimeter 
  thick 
  with 
  a 
  red 
  interior. 
  The 
  fifth 
  and 
  sixth 
  

   showed 
  the 
  yellow 
  color 
  to 
  a 
  greater 
  depth, 
  while 
  the 
  seventh 
  and 
  

   eighth 
  were 
  yellow 
  throughout 
  with 
  a 
  slight 
  tinge 
  of 
  gray. 
  

  

  From 
  this 
  Soger 
  infers 
  that 
  the 
  yellow 
  color 
  first 
  appears 
  when 
  

   the 
  proportion 
  of 
  ferric 
  oxid 
  to 
  lime 
  is 
  as 
  1 
  to 
  1 
  ^^o"* 
  

  

  As 
  regards 
  the 
  action 
  of 
  ferrous 
  oxid. 
  Soger 
  came 
  to 
  the 
  con- 
  

   clusion 
  that 
  in 
  porous 
  bricks 
  the 
  percentage 
  of 
  this 
  can 
  run 
  quite 
  

   high 
  without 
  producing 
  much 
  effect, 
  but 
  in 
  dense 
  bricks 
  the 
  re- 
  

   verse 
  is 
  true. 
  

  

  