﻿746 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  brick 
  should 
  be, 
  and 
  if 
  possible 
  to 
  adopt 
  a 
  set 
  of 
  standard 
  specifica- 
  

   tions, 
  a 
  committee 
  was 
  appointed 
  by 
  the 
  National 
  brickmakers 
  

   association 
  two 
  years 
  ago. 
  After 
  a 
  series 
  of 
  exhaustive 
  tests 
  their 
  

   report 
  has 
  recently 
  been 
  submitted. 
  

  

  The 
  subjects 
  which 
  the 
  committee 
  took 
  up 
  for 
  consideration 
  were: 
  

  

  1 
  Rattling, 
  as 
  a 
  measure 
  of 
  toughness 
  and 
  wearing 
  power 
  

  

  2 
  Absorption, 
  as 
  a 
  measure 
  of 
  vitrification 
  and 
  resistance 
  to 
  

   freezing 
  

  

  3 
  Cross-breaking, 
  as 
  a 
  measure 
  of 
  structural 
  perfection 
  and 
  

   freedom 
  from 
  defects 
  due 
  to 
  manufacture 
  

  

  4 
  Crushing, 
  as 
  a 
  farther 
  indication 
  of 
  the 
  same 
  factor 
  

  

  5 
  Hardness, 
  as 
  a 
  confirmatory 
  test 
  of 
  vitrification 
  

  

  6 
  Specific 
  gravity, 
  as 
  a 
  guide 
  to 
  the 
  density 
  and 
  fineness 
  of 
  the 
  

   material 
  

  

  The 
  rattler. 
  A 
  series 
  of 
  experiments 
  made 
  by 
  varying 
  the 
  

   charge, 
  size 
  of 
  rattler, 
  number 
  of 
  revolutions 
  a 
  minute, 
  and 
  time 
  

   of 
  rattling 
  showed 
  that 
  

  

  1 
  Not 
  less 
  than 
  10^ 
  nor 
  more 
  than 
  15^ 
  of 
  the 
  volume 
  of 
  the 
  

   rattler 
  need 
  be 
  filled 
  with 
  the 
  cubic 
  contents 
  of 
  the 
  charge. 
  

  

  2 
  It 
  must 
  be 
  rattled 
  for 
  not 
  less 
  than 
  1000 
  and 
  preferably 
  not 
  

   less 
  than 
  2000 
  revolutions. 
  

  

  3 
  The 
  length 
  of 
  the 
  chamber 
  is 
  immaterial. 
  

  

  4 
  The 
  diameter 
  of 
  the 
  chamber 
  must 
  be 
  between 
  26 
  and 
  30 
  

   inches. 
  

  

  5 
  The 
  speed 
  of 
  revolution, 
  between 
  24 
  and 
  36 
  revolutions 
  a. 
  

   minute, 
  is 
  immaterial 
  if 
  the 
  test 
  is 
  terminated 
  when 
  the 
  requisite 
  

   number 
  of 
  revolutions 
  have 
  been 
  made. 
  

  

  The 
  use 
  of 
  cast 
  iron 
  and 
  granite 
  as 
  abrasive 
  and 
  filling 
  materials 
  

   was 
  also 
  tested 
  and 
  found 
  to 
  be 
  unsatisfactory. 
  Large 
  bricks 
  showed 
  

   less 
  wear 
  than 
  small 
  ones; 
  normally 
  burned, 
  less 
  than 
  overbumed 
  

   or 
  underburned 
  ones. 
  ^ 
  

  

  Absorption 
  test. 
  A 
  series 
  of 
  tests 
  showed 
  that 
  even 
  after 
  dry- 
  

   ing 
  48 
  hours 
  at 
  above 
  110° 
  C. 
  a 
  brick 
  continued 
  to 
  lose 
  water, 
  and 
  

   that 
  immersed 
  brick 
  showed 
  redundant 
  gain 
  in 
  weight 
  even 
  after 
  

  

  