﻿LIMESTONES 
  OF 
  NEW 
  YORK 
  AND 
  THEIR 
  ECONOMIC 
  VALUE 
  391 
  

  

  C0 
  2 
  . 
  The 
  best 
  hydraulic 
  lime 
  known 
  is 
  the 
  celebrated 
  Chaux 
  du 
  

   Theil 
  whose 
  composition 
  according 
  to 
  Dr 
  Michaelis 
  is 
  

  

  Silica 
  22.588 
  

  

  Alumina 
  2.629 
  

  

  Iron 
  oxid 
  ■ 
  . 
  .837 
  

  

  Lime 
  65.624 
  

  

  Magnesia 
  1 
  . 
  536 
  

  

  Potash 
  124 
  

  

  Soda 
  065 
  

  

  Sulfuric 
  acid 
  523 
  

  

  Ignition 
  6 
  . 
  421 
  

  

  Hydraulic 
  limes 
  generally 
  have 
  a 
  yellow 
  color. 
  Their 
  specific 
  

   gravity 
  is 
  about 
  2.9 
  and 
  on 
  ignition 
  they 
  lose 
  about 
  8$. 
  They 
  

   harden 
  slowly 
  and, 
  by 
  themselves 
  their 
  hardness 
  is 
  small. 
  On 
  

   the 
  other 
  hand 
  if 
  mixed 
  with 
  sand 
  they 
  get 
  a 
  high 
  degree 
  of 
  

   tensile 
  strength. 
  

  

  2 
  Roman 
  cement. 
  This 
  is 
  also 
  a 
  natural 
  product 
  and 
  of 
  the 
  

   hydraulic 
  limes 
  has 
  the 
  highest 
  silica 
  percentage. 
  In 
  addition 
  

   the 
  roman 
  cement 
  always 
  has 
  a 
  certain 
  percentage 
  of 
  free 
  quick- 
  

   lime 
  which 
  among 
  other 
  things 
  distinguishes 
  it 
  from 
  portland 
  

   cement. 
  The 
  following 
  analysis 
  of 
  roman 
  cement 
  will 
  serve 
  as 
  

   a 
  type 
  (Schoch 
  p. 
  74) 
  

  

  Silica 
  25 
  .00 
  

  

  Alumina 
  9.00 
  

  

  Ferric 
  oxid 
  4 
  . 
  39 
  

  

  Lime 
  58.02 
  

  

  Magnesia 
  1 
  . 
  08 
  

  

  Alkalies 
  62 
  

  

  The 
  ultimate 
  composition 
  approaches 
  somewhat 
  that 
  of 
  port- 
  

   land 
  cement. 
  The 
  burning 
  of 
  roman 
  cement 
  must 
  never 
  ex- 
  

   ceed 
  a 
  certain 
  temperature, 
  in 
  order 
  to 
  prevent 
  sintering, 
  but 
  

   while 
  the 
  hydraulic 
  lime 
  naturally 
  slakes 
  in 
  water 
  the 
  roman 
  

   cement 
  must 
  as 
  in 
  the 
  case 
  of 
  portland 
  be 
  ground 
  to 
  the 
  finest 
  of 
  

   flour. 
  Burned 
  and 
  ground 
  roman 
  cement 
  is 
  ^generally 
  a 
  light, 
  

   yellow 
  powder 
  with 
  a 
  specific 
  gravity 
  of 
  2.7. 
  The 
  time 
  of 
  hard- 
  

   ening 
  varies 
  but 
  it 
  is 
  quite 
  rapid. 
  In 
  mixing 
  it 
  with 
  water 
  it 
  

  

  