﻿3?8 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  For 
  the 
  manufacture 
  of 
  lime 
  many 
  different 
  types 
  of 
  limer<K-ks 
  

   are 
  available, 
  those 
  only 
  being 
  excluded 
  which 
  are 
  contaminated 
  

   with 
  clay, 
  for 
  this 
  latter 
  substance 
  often 
  affects 
  their 
  most 
  im- 
  

   portant 
  properties. 
  It 
  is 
  only 
  in 
  later 
  years 
  that 
  the 
  applica- 
  

   bility 
  of 
  limestone 
  with 
  a 
  large 
  amount 
  of 
  clay 
  has 
  been 
  recog- 
  

   nized. 
  

  

  The 
  lime 
  made 
  from 
  pure 
  or 
  nearly 
  pure 
  limestone 
  may 
  be 
  

   called 
  air-lime 
  in 
  contradistinction 
  to 
  hydraulic 
  lime 
  made 
  from 
  

   aluminous 
  or 
  clayey 
  limestones. 
  

  

  As 
  before 
  stated 
  pure 
  limestone 
  consists 
  of 
  56$ 
  of 
  oxid 
  of 
  

   lime 
  (CaO) 
  and 
  44$ 
  of 
  carbonic 
  acid. 
  The 
  change 
  from 
  car- 
  

   bonate 
  of 
  lime 
  to 
  oxid 
  of 
  lime 
  occurs 
  during 
  the 
  burning, 
  the 
  

   carbonic 
  acid 
  being 
  driven 
  off 
  at 
  a 
  higher 
  temperature. 
  In 
  this 
  

   process 
  the 
  lime 
  loses 
  about 
  44$ 
  by 
  weight. 
  

  

  As 
  it 
  is 
  generally 
  in 
  a 
  somewhat 
  moist 
  condition 
  when 
  it 
  is 
  

   put 
  into 
  the 
  kiln, 
  due 
  to 
  water 
  in 
  its 
  pores, 
  the 
  loss 
  in 
  weight 
  

   may 
  be 
  still 
  greater 
  than 
  mentioned 
  above. 
  

  

  The 
  percentage 
  of 
  moisture 
  in 
  limestone 
  is 
  very 
  variable 
  and 
  

   depends 
  largely 
  on 
  the 
  hardness 
  and 
  density 
  of 
  the 
  rock. 
  The 
  

   denser 
  a 
  limestone 
  the 
  less 
  porous 
  it 
  will 
  be 
  and 
  the 
  lower 
  will 
  

   be 
  the 
  percentage 
  of 
  quarry 
  moisture 
  in 
  it. 
  

  

  The 
  looser 
  or 
  more 
  spongy 
  it 
  is 
  the 
  more 
  moisture 
  will 
  it 
  ab- 
  

   sorb. 
  Marl 
  or 
  chalk 
  may 
  be 
  looked 
  on 
  as 
  the 
  loosest 
  form 
  of 
  

   limestone 
  and 
  in 
  them 
  the 
  moisture 
  may 
  reach 
  36$ 
  or 
  40$, 
  and 
  in 
  

   marls 
  and 
  bituminous 
  limestones 
  the 
  loss 
  in 
  burning 
  may 
  be 
  still 
  

   farther 
  increased 
  by 
  driving 
  off 
  organic 
  matter. 
  

  

  A 
  dense 
  limestone 
  is 
  much 
  harder 
  to 
  burn 
  than 
  a 
  loose 
  grained 
  

   one, 
  and 
  requires 
  more 
  fuel, 
  but 
  this 
  increased 
  consumption 
  is 
  

   more 
  than 
  made 
  up 
  for 
  by 
  the 
  quality 
  of 
  the 
  lime 
  obtained. 
  

  

  In 
  a 
  clean, 
  dense 
  limestone 
  the 
  percentage 
  of 
  quicklime 
  may 
  

   be 
  54$ 
  while 
  in 
  a 
  bituminous 
  one 
  it 
  may 
  only 
  amount 
  to 
  30 
  or 
  

   35$. 
  

  

  In 
  addition 
  to 
  the 
  decrease 
  in 
  weight 
  in 
  burning 
  the 
  limestone 
  

   also 
  decreases 
  somewhat 
  in 
  volume 
  as 
  much 
  as 
  12 
  to 
  21$ 
  but 
  

   usually 
  16 
  to 
  18$.° 
  

  

  aC. 
  Schoch. 
  Die 
  Aufbereitung 
  der 
  Mortel-materialien, 
  p. 
  57. 
  

  

  