﻿CLAYS 
  OF 
  ^;EW 
  YORK 
  

  

  667 
  

  

  Semi-dry 
  process 
  

   This 
  differs 
  but 
  little 
  from 
  the 
  dry 
  process. 
  The 
  clay 
  usually 
  

   has 
  a 
  slight 
  amount 
  of 
  moisture 
  added 
  to 
  it. 
  

  

  Clays 
  adaptable 
  to 
  the 
  different 
  molding 
  methods 
  

  

  Few 
  clays 
  give 
  good 
  results 
  with 
  all 
  the 
  methods 
  of 
  molding 
  just 
  

   described, 
  and 
  the 
  same 
  clay 
  will 
  not 
  necessarily 
  make 
  a 
  good 
  brick 
  

   with 
  any 
  machine 
  of 
  the 
  same 
  general 
  type. 
  This 
  is 
  specially 
  true 
  

   of 
  stiff 
  mud 
  machines. 
  For 
  the 
  dry 
  press 
  process 
  a 
  wide 
  range 
  of 
  

   clays 
  can 
  be 
  used, 
  for 
  it 
  works 
  with 
  sandy 
  ones, 
  or 
  mth 
  plastic 
  

   materials. 
  Coarse 
  sandy 
  clays 
  however 
  do 
  not 
  lend 
  themselves 
  

   readily 
  to 
  dry 
  pressing, 
  on 
  account 
  of 
  their 
  very 
  slight 
  cohesive 
  

   strength. 
  

  

  As 
  an 
  illustration 
  of 
  the 
  wide 
  range 
  of 
  clays 
  used, 
  we 
  may 
  com- 
  

   pare 
  the 
  two 
  following 
  clays, 
  no. 
  1 
  being 
  a 
  clay 
  used 
  to 
  a 
  large 
  

   extent 
  for 
  making 
  brick 
  in 
  western 
  Illinois, 
  no. 
  2 
  a 
  black 
  clay 
  from 
  

   Wyandance, 
  L. 
  I. 
  

  

  Both 
  feel 
  gritty, 
  but 
  neither 
  contains 
  particles 
  large 
  enough 
  to 
  

   be 
  retained 
  by 
  a 
  100 
  mesh 
  sieve. 
  

  

  When 
  subjected 
  to 
  a 
  mechanical 
  separation 
  they 
  yielded. 
  

  

  1^0. 
  1 
  No. 
  2 
  

  

  Fine 
  sand 
  5^ 
  84^ 
  

  

  Clay 
  substance 
  and 
  silt 
  95^ 
  16^ 
  

  

  100^ 
  100^ 
  

  

  The 
  other 
  physical 
  tests 
  of 
  no. 
  2 
  are 
  given 
  on 
  page 
  740. 
  

  

  Those 
  of 
  no. 
  1 
  are: 
  water 
  reuqired 
  for 
  mixing 
  16^; 
  air 
  shrink- 
  

   age 
  6^. 
  Incipient 
  fusion 
  began 
  at 
  .04 
  with 
  8^ 
  shrinkage; 
  vitrifica- 
  

   tion 
  at 
  4, 
  with 
  a 
  total 
  shrinkage 
  of 
  12^; 
  at 
  cone 
  6 
  viscosity 
  began. 
  

   The 
  soluble 
  salts 
  amounted 
  to 
  .09;^. 
  The 
  tensile 
  strength 
  ranged 
  

   from 
  150 
  to 
  175 
  pounds 
  a 
  square 
  inch. 
  

  

  If 
  the 
  product 
  from 
  the 
  dry 
  press 
  machine 
  is 
  properly 
  burned, 
  it 
  

   gives 
  a 
  good 
  brick, 
  but 
  if 
  not, 
  it 
  is 
  apt 
  to 
  be 
  easily 
  disintegrated 
  by 
  

  

  