﻿CLAYS 
  OF 
  NEW 
  YORK 
  729 
  

  

  occur 
  in 
  the 
  clay, 
  and 
  a 
  special 
  apparatus 
  is 
  used 
  to 
  extract 
  them. 
  

   The 
  clay 
  and 
  a 
  certain 
  percentage 
  of 
  shale 
  are 
  ground 
  in 
  a 
  dry 
  pan, 
  

   then 
  carried 
  up 
  to 
  an 
  inclined 
  screen. 
  Those 
  particles 
  which 
  

   pass 
  through 
  are 
  mixed 
  by 
  means 
  of 
  wheels 
  and 
  scrapers 
  at- 
  

   tached 
  to 
  a 
  revolving 
  arm. 
  The 
  bricks 
  are 
  molded 
  on 
  stiff 
  mud 
  

   machines 
  and 
  repressed 
  on 
  a 
  hand-power 
  machine. 
  Chamber 
  driers 
  

   are 
  used 
  and 
  burning 
  done 
  in 
  down-draft 
  kilns, 
  scove-kilns 
  or 
  a 
  

   continuous 
  kiln. 
  The 
  clay 
  burns 
  to 
  a 
  buff 
  brick; 
  farther 
  burning 
  

   at 
  a 
  higher 
  heat 
  gives 
  a 
  hard, 
  greenish 
  yellow 
  brick, 
  which 
  is 
  

   smaller, 
  but 
  sold 
  for 
  paving 
  purposes. 
  The 
  pavers 
  made 
  at 
  this 
  

   yard 
  are 
  a 
  mixture 
  of 
  clay 
  and 
  shale, 
  while 
  the 
  building 
  brick 
  are 
  

   clay 
  alone. 
  The 
  following 
  is 
  a 
  report 
  of 
  tests 
  made 
  on 
  these 
  brick 
  

   in 
  the 
  laboratory 
  at 
  Cornell 
  university. 
  All 
  the 
  bricks 
  were 
  tested 
  

   on 
  edge, 
  as 
  used 
  for 
  the 
  purpose 
  of 
  paving. 
  The 
  sides 
  were 
  dressed 
  

   to 
  parallel 
  planes 
  on 
  an 
  emery 
  wheel, 
  so 
  as 
  to 
  get 
  a 
  uniform 
  bearing 
  

   over 
  every 
  part. 
  Single 
  layers 
  of 
  thick 
  paper 
  were 
  placed 
  between 
  

   the 
  brick 
  and 
  the 
  machine. 
  

  

  