﻿672 
  KEW 
  YORK 
  STATE 
  :MTJSEUM 
  

  

  specially 
  if 
  a 
  continuous 
  one 
  is 
  used. 
  This 
  method 
  works 
  best 
  

   where 
  the 
  kiln 
  is 
  placed 
  in 
  the 
  lower 
  story 
  of 
  the 
  factory, 
  while 
  the 
  

   molding 
  machine 
  is 
  on 
  the 
  second 
  floor, 
  or 
  in 
  other 
  words 
  on 
  the 
  

   same 
  level 
  as 
  the 
  top 
  of 
  the 
  kiln. 
  The 
  bricks 
  when 
  molded 
  are 
  

   set 
  on 
  the 
  cars, 
  and 
  wheeled 
  directly 
  to 
  the 
  pallet 
  racks. 
  When 
  

   dry, 
  they 
  are 
  loaded 
  on 
  barrows 
  or 
  cars, 
  and 
  sent 
  down 
  to 
  the 
  kiln 
  

   on 
  an 
  elevator. 
  The 
  one 
  disadvantage 
  in 
  this 
  method 
  lies 
  in 
  the 
  

   extra 
  handling 
  of 
  the 
  bricks. 
  The 
  cost 
  of 
  the 
  drying 
  tunnel 
  is- 
  

   however 
  done 
  away 
  with. 
  

  

  Burning 
  

  

  In 
  the 
  burning 
  of 
  clay, 
  the 
  chemically 
  combined 
  water 
  and 
  also 
  

   any 
  carbonic 
  acid 
  which 
  may 
  be 
  present 
  are 
  driven 
  off, 
  while 
  the 
  

   organic 
  materials 
  contained 
  in 
  the 
  clay 
  are 
  also 
  burned. 
  As 
  a 
  re- 
  

   sult 
  of 
  this, 
  the 
  clay 
  loses 
  more 
  or 
  less 
  weight, 
  which 
  in 
  calcareous, 
  

   clays 
  may 
  be 
  as 
  much 
  as 
  20;^^, 
  and 
  the 
  porosity 
  increases 
  as 
  a 
  rule 
  

   with 
  the 
  amount 
  of 
  loss 
  on 
  ignition; 
  but, 
  if 
  the 
  temperature 
  is 
  ele- 
  

   vated 
  enough 
  to 
  soften 
  any 
  of 
  the 
  clay 
  particles, 
  the 
  various 
  grains 
  

   of 
  the 
  mass 
  will 
  draw 
  together, 
  more 
  or 
  less, 
  and 
  the 
  porosity 
  will 
  

   be 
  diminished. 
  The 
  hardness 
  of 
  the 
  material 
  will 
  also 
  be 
  increased, 
  

   and 
  this 
  is 
  specially 
  true 
  of 
  calcareous 
  clays. 
  In 
  the 
  case 
  of 
  com- 
  

   mon 
  brick 
  it 
  is 
  always 
  the 
  finest 
  particles 
  of 
  the 
  clay 
  that 
  soften 
  

   when 
  a 
  temperature 
  of 
  about 
  1000° 
  F. 
  is 
  reached, 
  but 
  the 
  small 
  

   particles 
  of 
  quartz 
  sand 
  do 
  not 
  soften, 
  and 
  therefore 
  form 
  the 
  skele- 
  

   ton 
  of 
  the 
  mass, 
  thus 
  enabling 
  the 
  brick 
  to 
  hold 
  its 
  form. 
  As 
  at 
  this 
  

   temperature 
  the 
  quartz 
  sand 
  expands 
  as 
  much 
  as 
  16^, 
  and 
  conse- 
  

   quently 
  decreases 
  in 
  specific 
  gravity, 
  there 
  will 
  be 
  a 
  certain 
  amount 
  

   of 
  decrease 
  in 
  the 
  porosity 
  from 
  this 
  cause. 
  We 
  therefore 
  can 
  

   obtain 
  thoroughly 
  dense 
  brick 
  from 
  sandy 
  clays, 
  without 
  the 
  burn- 
  

   ing 
  process 
  being 
  accompanied 
  by 
  any 
  material 
  amount 
  of 
  shrink- 
  

   age, 
  the 
  quartz 
  having 
  aided 
  in 
  rendering 
  the 
  clays 
  more 
  dense. 
  

  

  In 
  the 
  burning 
  the 
  clay 
  changes 
  from 
  a 
  comparatively 
  soft 
  con- 
  

   dition 
  to 
  one 
  of 
  rock-like 
  hardness. 
  The 
  amount 
  of 
  heat 
  applied 
  

   in 
  burning 
  and 
  the 
  temperature 
  to 
  which 
  the 
  kiln 
  is 
  raised 
  depend 
  

  

  