﻿386 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  r 
  

  

  Mortar 
  

  

  The 
  use 
  of 
  lime 
  as 
  a 
  mortar 
  has 
  been 
  known 
  for 
  many 
  years, 
  

   and 
  the 
  ancients 
  were 
  familiar 
  with 
  the 
  fact 
  that 
  by 
  means 
  of 
  

   simply 
  burning 
  limestone 
  and 
  soaking 
  the 
  burnt 
  mass 
  in 
  water 
  

   they 
  could 
  obtain 
  a 
  stiff 
  paste 
  which 
  possessed 
  valuable 
  prop- 
  

   erties. 
  

  

  Lime 
  is 
  extensively 
  utilized 
  for 
  mortar 
  making 
  at 
  the 
  present 
  

   day. 
  

  

  Pure 
  CaO 
  has 
  71.4$ 
  Ca 
  and 
  28.6$ 
  O. 
  It 
  is 
  a 
  porous, 
  earthy, 
  

   white 
  solid, 
  which 
  when 
  pure 
  resists 
  a 
  high 
  degree 
  of 
  heat. 
  It 
  

   absorbs 
  both 
  moisture 
  and 
  carbonic 
  acid 
  from 
  the 
  air 
  with 
  the 
  

   greatest 
  avidity. 
  ; 
  

  

  Richardson 
  gives 
  the 
  following 
  requirements 
  for 
  caustic 
  lime 
  

   used 
  for 
  mortar. 
  a 
  

  

  Except 
  when 
  made 
  from 
  coarsely 
  crystalline 
  marble 
  or 
  from 
  

   marl 
  or 
  shells 
  it 
  should 
  be 
  in 
  hard 
  lumps. 
  

  

  It 
  should 
  be 
  white, 
  or 
  nearly 
  so, 
  in 
  color. 
  Lime 
  of 
  a 
  yellow 
  

   or 
  brownish 
  color 
  with 
  veins 
  of 
  siliceous 
  matter 
  is 
  inferior. 
  

  

  It 
  should 
  be 
  free 
  from 
  fused 
  or 
  semi-fused 
  stone 
  which 
  shows 
  

   over 
  burning, 
  and 
  from 
  unburnt 
  ash 
  of 
  fuel 
  or 
  clinker. 
  

  

  It 
  should 
  contain 
  less 
  than 
  10$ 
  of 
  impurities 
  but 
  often 
  has 
  

   more. 
  

  

  It 
  should 
  slake 
  rapidly, 
  showing 
  that 
  it 
  is 
  rich 
  and 
  fresh. 
  

  

  Good 
  lime 
  in 
  lumps 
  should 
  weigh, 
  as 
  packed, 
  with 
  about 
  40$ 
  of 
  

   voids, 
  60 
  lb. 
  a 
  cubic 
  foot, 
  75 
  lb. 
  a 
  bushel 
  and 
  from 
  220 
  to 
  

   230 
  lb. 
  a 
  bbl. 
  of 
  3 
  bushels. 
  If 
  ground 
  or 
  in 
  powder 
  it 
  will 
  

   weigh 
  less 
  when 
  packed 
  loosely, 
  but 
  when 
  well 
  shaken 
  down 
  it 
  

   will 
  weigh 
  as 
  much 
  as 
  270 
  lb. 
  a 
  bbl. 
  A 
  lump 
  of 
  hard 
  lime 
  1 
  

   foot 
  cube 
  would 
  weigh 
  about 
  95 
  lb. 
  having 
  a 
  density 
  of 
  1.52. 
  

  

  Slaking 
  

  

  Lime 
  combines 
  with 
  water 
  with 
  evolution 
  of 
  heat 
  and 
  every 
  

   100 
  parts 
  lime 
  take 
  32 
  parts 
  of 
  water. 
  

  

  ©Brickbuilder, 
  1897, 
  p. 
  78. 
  

  

  