﻿CLAYS 
  OF 
  Is'EW 
  YORK 
  789 
  

  

  age 
  tensile 
  strength 
  of 
  only 
  11 
  pounds 
  to 
  the 
  square 
  inch, 
  with 
  a 
  

   maximum 
  of 
  14 
  pounds. 
  In 
  burning 
  the 
  total 
  shrinkage 
  up 
  to 
  cone 
  

   12 
  amounted 
  to 
  18.7^; 
  the 
  color 
  was 
  whitish. 
  At 
  cone 
  34 
  in 
  the 
  

   Deville 
  furnace 
  the 
  clay 
  showed 
  no 
  sign 
  of 
  fusion 
  whatever, 
  and 
  

   is 
  therefore 
  highly 
  refractory. 
  

   A 
  mechanical 
  analysis 
  yielded: 
  

  

  Clay 
  substance 
  97.66 
  

  

  Silt, 
  very 
  fine 
  sand, 
  fine 
  sand 
  2.00 
  

  

  99.66 
  

  

  The 
  composition 
  is: 
  

  

  Silica 
  47.40 
  

  

  Alumina 
  39 
  . 
  01 
  

  

  Ferric 
  oxid 
  .15 
  

  

  Lime 
  tr 
  

  

  Magnesia 
  tr 
  

  

  Alkalis 
  tr 
  

  

  Water 
  14. 
  10 
  

  

  Total 
  100 
  . 
  66 
  

  

  The 
  rational 
  composition 
  is: 
  

  

  Clay 
  substance 
  97.50 
  

  

  Feldspar 
  

  

  Quartz 
  

  

  The 
  sandy 
  clay 
  was 
  more 
  plastic, 
  and 
  required 
  only 
  31^ 
  of 
  water 
  

   to 
  mix 
  it 
  up. 
  The 
  air 
  shrinkage 
  was 
  less, 
  being 
  only 
  6.5^, 
  and 
  the 
  

   tensile 
  strength 
  was 
  20 
  pounds 
  a 
  square 
  inch. 
  At 
  cone 
  9 
  the 
  total 
  

   shrinkage 
  was 
  15^ 
  and 
  the 
  color 
  whitish. 
  In 
  the 
  Deville 
  furnace 
  at 
  

   cone 
  34 
  the 
  clav 
  remained 
  unaffected. 
  

  

  