﻿740 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  tion 
  at 
  1, 
  with 
  16 
  fo 
  shrinkage. 
  Viscosity 
  at 
  5. 
  Percentage 
  of 
  solu- 
  

   ble 
  salts, 
  .20^. 
  

  

  About 
  one 
  mile 
  north 
  of 
  the 
  depot 
  is 
  the 
  yard 
  of 
  the 
  Garden 
  

   City 
  brick 
  company. 
  This 
  is 
  on 
  the 
  site 
  of 
  the 
  old 
  Stewart 
  yard^ 
  

   but 
  the 
  plant 
  is 
  a 
  modern 
  one. 
  The 
  clay 
  however 
  is 
  obtained 
  

   from 
  the 
  opening 
  that 
  supplied 
  Stewart.'s 
  yard. 
  

  

  In 
  the 
  mining 
  of 
  the 
  clay 
  three 
  kinds 
  are 
  recognized: 
  1) 
  top 
  

   sandy 
  clay; 
  2) 
  middle 
  clay 
  and 
  3) 
  black 
  bottom 
  clay. 
  (For 
  sec- 
  

   tion 
  of 
  bankj 
  see 
  chapter 
  on 
  " 
  Geology 
  of 
  clay 
  deposits 
  in 
  I^ew 
  

   York 
  '', 
  p. 
  60'5) 
  

  

  ISTo 
  analyses 
  of 
  the 
  clay 
  have 
  been 
  made, 
  but 
  no. 
  1 
  and 
  a 
  mix- 
  

   ture 
  of 
  2 
  and 
  3 
  have 
  been 
  tested. 
  JSTo. 
  1 
  is 
  a 
  red 
  burning, 
  gi'itty 
  

   clay, 
  with 
  an 
  abundance 
  of 
  fine 
  mica 
  scales. 
  With 
  31^ 
  of 
  water 
  

   it 
  worked 
  up 
  to 
  a 
  very 
  plastic 
  mass, 
  that 
  had 
  an 
  air 
  shrinkage 
  of 
  

   5^. 
  The 
  tensile 
  strength 
  was 
  low 
  and 
  ranged 
  from 
  50 
  to 
  60 
  pounds 
  

   a 
  square 
  inch. 
  The 
  mechanical 
  analysis 
  gave 
  16.44 
  sand, 
  83.75 
  

   clay 
  substance 
  and 
  silt. 
  In 
  burning, 
  incipient 
  fusion 
  occurred 
  at 
  

   cone 
  .03, 
  with 
  11^ 
  shrinkage; 
  vitrification 
  at 
  cone 
  2, 
  with 
  14^ 
  

   shrinkage, 
  and 
  viscosity 
  at 
  cone 
  5. 
  Soluble 
  salts, 
  .54^. 
  

  

  The 
  mixture 
  of 
  2 
  and 
  3 
  showed 
  similar 
  properties, 
  but 
  hardened 
  

   at 
  a 
  somewhat 
  lower 
  temperature. 
  The 
  tensile 
  strength 
  was 
  from 
  

   40 
  to 
  50 
  pounds 
  a 
  square 
  inch; 
  the 
  clay 
  was 
  slightly 
  more 
  gritty 
  

   than 
  the 
  top 
  part, 
  but 
  was 
  equally 
  plastic; 
  33^ 
  of 
  water 
  was 
  re- 
  

   quired 
  to 
  temper 
  it; 
  the 
  air 
  shrinkage 
  was 
  Q^ 
  at 
  cone 
  .04 
  ; 
  incipient 
  

   fusion 
  occurred 
  with 
  a 
  shrinkage 
  of 
  12^; 
  vitrification 
  began 
  at 
  1, 
  

   the 
  shrinkage 
  was 
  16^. 
  The 
  clay 
  grew 
  viscous 
  at 
  5. 
  The 
  color 
  of 
  

   the 
  burned 
  clay 
  is 
  light 
  red, 
  but 
  deepens 
  on 
  hard 
  firing. 
  The 
  solu- 
  

   ble 
  salts 
  amounted 
  to 
  .2^. 
  

  

  The 
  bricks 
  made 
  at 
  these 
  works 
  are 
  all 
  dry 
  pressed 
  ; 
  the 
  product 
  

   is 
  used 
  chiefly 
  in 
  Brooklyn. 
  

  

  By 
  mixing 
  the 
  clays, 
  with 
  addition 
  of 
  manganese, 
  and 
  by 
  hard 
  

   or 
  soft 
  burning, 
  the 
  colors 
  buff, 
  pink, 
  gray, 
  brown, 
  red, 
  and 
  speck- 
  

   led, 
  are 
  produced. 
  

  

  