﻿CLAYS 
  OF 
  NEW 
  YORK 
  761 
  

  

  The 
  red 
  owes 
  its 
  color 
  to 
  the 
  higher 
  state 
  of 
  oxidation 
  of 
  the 
  

   iron; 
  the 
  lower 
  percentage 
  of 
  lime 
  is 
  due 
  probably 
  to 
  its 
  having 
  

   been 
  leached 
  out 
  of 
  the 
  red 
  clay 
  by 
  percolating 
  surface 
  waters. 
  

  

  Elm 
  Point, 
  L. 
  I. 
  This 
  clav 
  was 
  used 
  for 
  a 
  time 
  bv 
  the 
  i!^ew 
  

   York 
  architectural 
  terra 
  cotta 
  co., 
  and 
  also 
  for 
  stoneware, 
  under 
  

   which 
  head 
  it 
  is 
  described. 
  

  

  Terra 
  cotta 
  manufacture 
  

  

  It 
  rarely 
  happens 
  that 
  terra 
  cotta 
  is 
  made 
  from 
  one 
  clay, 
  it 
  

   being 
  usually 
  found 
  necessary 
  to 
  mix 
  several 
  different 
  ones 
  to 
  get 
  

   the 
  best 
  results. 
  In 
  addition 
  to 
  this 
  a 
  certain 
  amount 
  of 
  sand 
  or 
  

   ground, 
  brick 
  is 
  added 
  to 
  prevent 
  excessive 
  shrinkage. 
  

  

  The 
  clay 
  and 
  fire 
  brick 
  are 
  ground 
  in 
  a 
  dry 
  pan; 
  and 
  the 
  mixing 
  

   is 
  done 
  in 
  a 
  pug 
  mill. 
  The 
  clay 
  is 
  then 
  stored 
  in 
  bins 
  till 
  used; 
  

   and 
  before 
  the 
  clay 
  is 
  sent 
  up 
  to 
  the 
  molding 
  room 
  it 
  is 
  put 
  through 
  

   another 
  pugging. 
  

  

  A 
  model 
  is 
  first 
  made 
  of 
  every 
  object 
  to 
  be 
  constructed. 
  For 
  

   simple 
  forms 
  of 
  straight 
  outline 
  this 
  can 
  be 
  done 
  with 
  the 
  aid 
  of 
  

   a 
  templet. 
  Thus, 
  if 
  a 
  cornice 
  is 
  to 
  be 
  modeled, 
  the 
  ground 
  form 
  

   of 
  the 
  piece 
  is 
  constructed 
  by 
  putting 
  together 
  several 
  slabs 
  of 
  

   plaster 
  of 
  paris; 
  over 
  these 
  a 
  mass 
  of 
  soft 
  plaster 
  is 
  poured 
  and 
  

   the 
  templet 
  is 
  then 
  run 
  along 
  the 
  surface, 
  the 
  pattern 
  of 
  it 
  being 
  

   the 
  same 
  as 
  the 
  profile 
  of 
  the 
  cornice. 
  In 
  the 
  case 
  of 
  complicated 
  

   or 
  elaborate 
  forms, 
  the 
  model 
  has 
  to 
  be 
  molded 
  entirely 
  or 
  'in 
  part 
  

   by 
  hand, 
  requiring 
  the 
  services 
  of 
  a 
  skilled 
  modeler. 
  When 
  the 
  

   straight 
  edge 
  and 
  elaborated 
  center 
  of 
  a 
  panel 
  or 
  similar 
  piece 
  

   are 
  desired, 
  the 
  latter 
  is 
  modeled, 
  while 
  the 
  former 
  is 
  obtained 
  by 
  

   means 
  of 
  a 
  templet. 
  

  

  The 
  model 
  completed, 
  a 
  mold 
  of 
  plaster 
  is 
  next 
  made 
  from 
  it. 
  

   This 
  is 
  made 
  of 
  several 
  parts, 
  which 
  are 
  held 
  together 
  by 
  an 
  iron 
  

   band, 
  tightened 
  with 
  a 
  wooden 
  wedge. 
  In 
  filling 
  the 
  mold 
  the 
  

   soft, 
  plastic 
  clay 
  is 
  forced 
  into 
  all 
  the 
  corners, 
  till 
  it 
  forms 
  a 
  layer 
  

   about 
  2 
  inches 
  thick 
  all 
  over 
  the 
  interior. 
  The 
  mold 
  is 
  allowed 
  

   to 
  stand 
  for 
  a 
  short 
  time, 
  while 
  the 
  clay 
  dries 
  sufficiently 
  to 
  per- 
  

   mit 
  the 
  parts 
  of 
  the 
  mold 
  to 
  be 
  lifted 
  off, 
  when 
  the 
  edges 
  of 
  the 
  

  

  