﻿CLAYS 
  OF 
  KEW 
  YORK 
  857 
  

  

  operation 
  are 
  weighed, 
  thus 
  the 
  percentage 
  of 
  loss 
  is 
  determined. 
  

   The 
  bricks 
  themselves 
  are 
  also 
  to 
  be 
  examined 
  for 
  cracks 
  after 
  

   this 
  treatment. 
  

  

  Resistance 
  to 
  acids 
  

  

  Certain 
  structural 
  clay 
  products, 
  such 
  as 
  bricks 
  for 
  sewer 
  works, 
  

   pavements 
  and 
  w^alls, 
  as 
  well 
  as 
  those 
  used 
  in 
  acid 
  works, 
  which 
  

   are 
  more 
  or 
  less 
  subjected 
  to 
  the 
  action 
  of 
  acids, 
  are 
  to 
  be 
  tested 
  

   for 
  their 
  resistance 
  to 
  the 
  lattor. 
  The 
  best 
  way 
  to 
  do 
  this 
  is 
  to 
  

   pulverize 
  the 
  product 
  to 
  be 
  tested, 
  separating 
  the 
  fine 
  powder, 
  

   then 
  subjecting 
  the 
  coarser 
  material 
  to 
  the 
  action 
  of 
  acids 
  of 
  dif- 
  

   ferent 
  degrees 
  of 
  concentration 
  for 
  24 
  hours. 
  The 
  acid 
  is 
  then 
  

   filtered 
  ofi, 
  and 
  the 
  powder 
  is 
  washed, 
  dried 
  and 
  weighed 
  to 
  

   determine 
  the 
  loss. 
  

  

  Abrasion 
  test 
  

  

  This 
  is 
  described 
  under 
  " 
  Paving 
  brick 
  '', 
  p. 
  745. 
  

  

  