﻿806 
  NEW 
  YOKK 
  STATE 
  MUSEUM 
  

  

  water 
  pitchers 
  and 
  many 
  other 
  articles 
  of 
  a 
  liollow 
  nature 
  are 
  

   molded 
  in 
  this 
  manner. 
  

  

  Casting. 
  Casting 
  consists 
  in 
  pouring 
  a 
  slip 
  of 
  clay 
  into 
  a 
  porous 
  

   mold, 
  which 
  absorbs 
  some 
  of 
  the 
  water, 
  and 
  causes 
  a 
  thin 
  layer 
  of 
  

   the 
  clay 
  to 
  adhere 
  to 
  the 
  interior 
  surface 
  of 
  the 
  mold. 
  When 
  this 
  

   layer 
  is 
  sufficiently 
  thick, 
  the 
  mold 
  is 
  inverted 
  and 
  the 
  remaining^ 
  

   slip 
  is 
  poured 
  out. 
  After 
  a 
  few 
  hours 
  the 
  mold 
  can 
  be 
  removed. 
  

   This 
  method 
  is 
  extensively 
  used 
  in 
  making 
  thin 
  porcelain 
  orna- 
  

   ments; 
  many 
  white 
  earthenware 
  objects 
  can 
  be 
  formed 
  by 
  the 
  same 
  

   process. 
  Much 
  of 
  the 
  success 
  of 
  molding 
  depends 
  on 
  the 
  proper 
  

   consistency 
  and 
  composition 
  of 
  the 
  plaster 
  mold. 
  

  

  Drying 
  

  

  The 
  ware 
  after 
  it 
  has 
  been 
  molded 
  is 
  usually 
  set 
  aside 
  on 
  shelves 
  

   in 
  steam-heated 
  rooms 
  to 
  dry. 
  

  

  From 
  this 
  point 
  on, 
  the 
  method 
  of 
  manufacture 
  varies 
  somewhat, 
  

   depending 
  on 
  the 
  kind 
  of 
  ware 
  that 
  is 
  to 
  be 
  produced. 
  

  

  Glazing 
  stoneware 
  

  

  Stoneware 
  is 
  most 
  commonly 
  glazed 
  either 
  with 
  salt, 
  or 
  by 
  means 
  

   of 
  slip 
  clays. 
  Slip 
  clays, 
  which 
  are 
  really 
  natural 
  glazes, 
  are 
  very 
  

   impure, 
  easily 
  fusible 
  clays. 
  The 
  clay 
  is 
  mixed 
  with 
  water 
  to 
  the 
  

   consistency 
  of 
  cream, 
  and 
  the 
  ware 
  before 
  burning 
  is 
  either 
  dipped 
  

   into 
  this 
  slip, 
  or 
  the 
  slip 
  is 
  put 
  on 
  the 
  ware 
  by 
  a 
  brush. 
  

  

  The 
  most 
  desirable 
  thing 
  in 
  a 
  slip 
  clay 
  is 
  that 
  it 
  shall 
  fuse 
  

   at 
  a 
  low 
  temperature, 
  form 
  a 
  glaze 
  of 
  a 
  uniform 
  color, 
  and 
  this 
  

   glaze 
  shall 
  not 
  crack 
  or 
  craze. 
  Many 
  fine-grained 
  impure 
  clays 
  

   fulfil 
  the 
  first 
  requirement 
  but 
  are 
  seldom 
  able 
  to 
  comply 
  with 
  the 
  

   second 
  and 
  the 
  third 
  condition. 
  

  

  Slip 
  clays 
  have 
  been 
  supplied 
  to 
  a 
  considerable 
  extent 
  by 
  several 
  

   different 
  states, 
  but 
  the 
  most 
  important 
  and 
  the 
  best 
  thiis 
  far 
  used 
  

   is 
  obtained 
  from 
  the 
  Champlain 
  deposit 
  at 
  Albany, 
  N". 
  Y. 
  This 
  

   Albany 
  slip 
  makes 
  a 
  splendid, 
  even 
  colored, 
  natural 
  glaze, 
  and 
  one 
  

   which 
  does 
  not 
  crack. 
  It 
  not 
  only 
  works 
  well 
  by 
  itself 
  but 
  gives 
  

  

  