﻿852 
  NEW 
  YOEK 
  STATE 
  MUSEUM 
  

  

  Filling 
  paper 
  

  

  Clay 
  is 
  one 
  of 
  the 
  several 
  substaiice© 
  used 
  for 
  tliis 
  purpose. 
  

   It 
  is 
  mixed 
  in 
  with 
  the 
  paper 
  pulp 
  during 
  the 
  process 
  of 
  manufac- 
  

   ture, 
  the 
  object 
  of 
  this 
  being 
  that 
  the 
  fibers 
  of 
  the 
  pulp 
  shall 
  enmesh 
  

   a 
  certain 
  amount 
  of 
  the 
  clay 
  particles 
  which 
  are 
  in 
  suspension 
  in 
  

   the 
  water 
  in 
  which 
  the 
  pulp 
  is. 
  The 
  plasticity 
  and 
  sandiness 
  of 
  the 
  

   clay 
  no 
  doubt 
  exert 
  some 
  influence 
  on 
  the 
  degree 
  of 
  success 
  ^f 
  the 
  

   operation, 
  for 
  it 
  is 
  found 
  that 
  a. 
  given 
  paper 
  will 
  often 
  retain 
  a 
  much 
  

   greater 
  proportion 
  of 
  some 
  clays 
  than 
  fothers, 
  those; 
  of 
  which 
  the 
  

   greatest 
  quantity 
  is 
  retained 
  being 
  the 
  most 
  plastic, 
  of 
  the 
  several 
  

   tried. 
  Sand 
  is 
  an 
  undesirable 
  constituent 
  of 
  paper 
  clay 
  for 
  the 
  rea- 
  

   son 
  that 
  the 
  sand 
  grains 
  tend 
  to 
  wear 
  out 
  the 
  wires 
  of 
  the 
  screens 
  

   through 
  which 
  the 
  materials 
  have 
  to 
  pass. 
  In 
  certain 
  lines 
  at 
  least 
  

   clay 
  is 
  not 
  used 
  as 
  much 
  for 
  filling 
  as 
  it 
  formerly 
  was. 
  The 
  color 
  

   of 
  the 
  clay 
  in 
  its 
  raw 
  condition 
  is 
  all 
  important 
  for 
  the 
  higher 
  

   grades 
  of 
  paper. 
  For 
  the 
  best 
  quality 
  a 
  very 
  fine 
  white 
  kaolin 
  or 
  

   sedimentary 
  clay 
  is 
  used, 
  it 
  being 
  first 
  carefully 
  washed, 
  but 
  for 
  

   the 
  commoner 
  grades, 
  specially 
  the 
  colored 
  ones, 
  the 
  manufacturer 
  

   does 
  not 
  as 
  a 
  rule 
  have 
  to 
  search 
  very 
  far 
  in 
  order 
  tO' 
  find 
  the 
  right 
  

   material, 
  as 
  the 
  requirements 
  are 
  not 
  so 
  strict. 
  

  

  Food 
  adulterants 
  

  

  This 
  use 
  of 
  clay 
  is 
  self-evident. 
  It 
  is 
  used 
  as 
  an 
  adulterant 
  of 
  

   those 
  food 
  products 
  which 
  it 
  resembles 
  in 
  color, 
  and 
  which 
  are 
  used 
  

   either 
  in 
  a 
  powdered 
  condition 
  or 
  caked 
  form, 
  either 
  of 
  which 
  

   would 
  tend 
  to 
  hide 
  the 
  presence 
  of 
  the 
  adulterant. 
  

  

  Ultramarine 
  manufacture 
  

  

  Kaolin 
  in 
  its 
  washed 
  condition 
  or 
  even 
  very 
  fine-grained, 
  white 
  

   sedimentary 
  clays 
  are 
  used 
  in 
  the 
  manufacture 
  of 
  ultramarine 
  to 
  

   serve 
  as 
  a 
  nucleus 
  for 
  the 
  coloring 
  material 
  to 
  gather 
  round. 
  For 
  

   this 
  work 
  the 
  clay 
  should 
  be 
  as 
  low 
  in 
  iron 
  and 
  lime 
  as 
  possible, 
  

   and 
  an 
  excess 
  of 
  silica 
  is 
  undesirable, 
  but 
  if 
  too 
  little 
  is 
  present 
  it 
  

   may 
  be 
  added 
  in 
  the 
  form 
  of 
  finely 
  powdered 
  quartz. 
  

  

  Polishing 
  and 
  abrasive 
  materials 
  

   Many 
  clays 
  exert 
  a 
  combined 
  polishing 
  and 
  abrasive 
  action 
  on 
  

   account 
  of 
  the 
  very 
  finely 
  divided 
  grains 
  of 
  sand 
  which 
  they 
  con- 
  

   tain. 
  The 
  well-known 
  Bath 
  brick 
  which 
  has 
  such 
  an 
  extensive 
  

  

  