﻿636 
  NEW 
  YOEK 
  STATE 
  MUSEUM 
  

  

  USES 
  OF 
  CLAY 
  

   Characters 
  of 
  brick 
  clays 
  

  

  Under 
  this 
  head 
  is 
  included 
  a 
  very 
  wide 
  range 
  of 
  materials, 
  de- 
  

   pending 
  on 
  the 
  quality 
  of 
  the 
  product 
  to 
  be 
  made. 
  

  

  For 
  common 
  building 
  brick 
  almost 
  any 
  clay 
  of 
  good 
  plasticity 
  

   will 
  do, 
  and 
  this 
  very 
  fact 
  has 
  been 
  most 
  extensively 
  abused 
  by 
  

   brick 
  manufacturers, 
  encouraged 
  by 
  indifference 
  on 
  the 
  part 
  of 
  con- 
  

   tractors 
  who 
  are 
  very 
  often 
  inclined 
  to 
  regard 
  common 
  brick 
  as 
  

   simply 
  so 
  many 
  cubic 
  feet 
  of 
  burned 
  clay, 
  little 
  attention 
  being 
  

   paid 
  to 
  the 
  quality 
  of 
  the 
  product. 
  

  

  As 
  the 
  different 
  kinds 
  of 
  brick 
  can 
  not 
  all 
  be 
  made 
  from 
  the 
  

   same 
  kind 
  of 
  clay, 
  it 
  will 
  be 
  best 
  to 
  consider 
  separately 
  the 
  requisites 
  

   of 
  the 
  clays 
  used 
  for 
  these 
  different 
  types. 
  

  

  Clays 
  for 
  common 
  bricks. 
  For 
  this 
  purpose 
  the 
  more 
  impure 
  clays 
  

   are 
  generally 
  utilized, 
  and 
  in 
  general 
  those 
  which 
  bum 
  to 
  a 
  red 
  

   color. 
  Calcareous 
  clays 
  are 
  often 
  employed, 
  specially 
  around 
  Chi- 
  

   cago. 
  Such 
  clays 
  produce 
  a 
  buff 
  product. 
  Many 
  morainic 
  clay 
  a 
  

   of 
  south 
  central 
  ISTew 
  York 
  are 
  of 
  this 
  nature. 
  

  

  Clays 
  for 
  making 
  common 
  brick 
  should 
  burn 
  to 
  a 
  good 
  red 
  color 
  

   at 
  a 
  temperature 
  not 
  greater 
  than 
  2000° 
  F. 
  or 
  2100° 
  F. 
  They 
  

   should 
  also 
  have 
  sufficient 
  fluxes 
  to 
  cement 
  the 
  clay 
  particles 
  to- 
  

   gether, 
  forming 
  a 
  hard 
  dense 
  body, 
  when 
  subjected 
  to 
  the 
  above 
  

   amount 
  of 
  heat. 
  From 
  5^ 
  to 
  Y^ 
  of 
  iron 
  is 
  desirable, 
  as 
  this 
  amount 
  

   has 
  been 
  found 
  to 
  exert 
  the 
  best 
  coloring 
  action. 
  A 
  large 
  amount 
  

   of 
  lime 
  is 
  undesirable, 
  for 
  it 
  brings 
  the 
  temperatures 
  of 
  fusion 
  and 
  

   incipient 
  vitrification 
  too 
  close 
  together, 
  though 
  with 
  care 
  a 
  good 
  

   brick 
  can 
  be 
  made 
  from 
  a 
  clay 
  containing 
  20^ 
  to 
  25^ 
  of 
  carbonate 
  

   of 
  lime. 
  ( 
  Soger's 
  Ges. 
  Schrift. 
  p. 
  265) 
  The 
  celebrated 
  Mil- 
  

   waukee 
  brick 
  contain 
  22^ 
  of 
  lime 
  carbonate 
  and 
  the 
  clays 
  used 
  for 
  

   making 
  front 
  brick 
  at 
  Canandaigua, 
  N. 
  Y., 
  have 
  20^-23^. 
  

  

  The 
  tendency 
  of 
  lime 
  as 
  previously 
  stated 
  is 
  to 
  lessen 
  the 
  shrink- 
  

  

  