﻿LIMESTONES 
  OF 
  NEW 
  YORK 
  AND 
  THEIR 
  ECONOMIC 
  VALUE 
  399 
  

  

  In 
  color 
  there 
  is 
  a 
  very 
  great 
  variation 
  among 
  the 
  rock 
  

   cements, 
  varying 
  all 
  the 
  way 
  from 
  a 
  light 
  cream 
  color 
  to 
  a 
  very 
  

   dark 
  drab 
  color, 
  which 
  is 
  a 
  characteristic 
  of 
  the 
  cements 
  of 
  the 
  

   Rosendale 
  district. 
  There 
  is 
  no 
  standard 
  in 
  this 
  regard 
  and 
  the 
  

   color 
  indicates 
  nothing 
  in 
  regard 
  to 
  the 
  quality 
  of 
  the 
  cement. 
  

   There 
  is 
  also 
  a 
  considerable 
  variation 
  in 
  the 
  specific 
  gravity 
  of 
  

   the 
  cements, 
  though 
  generally 
  it 
  is 
  about 
  two 
  sixths. 
  It 
  depends 
  

   chiefly 
  on 
  the 
  percentage 
  of 
  iron 
  in 
  the 
  material, 
  the 
  greater 
  the 
  

   amount 
  of 
  iron 
  the 
  higher 
  the 
  specific 
  gravity. 
  

  

  Vast 
  quantities 
  of 
  natural 
  cement 
  are 
  used 
  in 
  the 
  middle 
  west- 
  

   ern 
  states 
  from 
  the 
  gulf 
  to 
  the 
  lakes 
  and 
  from 
  Ohio 
  to 
  the 
  

   Rocky 
  mountains. 
  This 
  demand 
  is 
  supplied 
  chiefly 
  from 
  brands 
  

   made 
  near 
  Milwaukee, 
  Wis. 
  Louisville, 
  Ky. 
  and 
  Utica, 
  111. 
  while 
  

   lesser 
  amounts 
  come 
  from 
  Fort 
  Scott, 
  Kan. 
  and 
  Mankato, 
  Minn. 
  

   All 
  these 
  are 
  cements 
  but 
  their 
  character 
  and 
  composition 
  vary 
  

   considerably. 
  Richardson 
  gives 
  a 
  number 
  of 
  tests 
  of 
  these. 
  

  

  Large 
  quantities 
  of 
  cement 
  are 
  made 
  along 
  the 
  Lehigh 
  river 
  

   near 
  Ooplay 
  and 
  other 
  places. 
  This 
  cement 
  is 
  in 
  some 
  respects 
  

   very 
  similar 
  to 
  that 
  of 
  the 
  Potomac 
  valley, 
  it 
  is 
  quite 
  free 
  from 
  

   magnesia, 
  sets 
  very 
  quickly 
  and 
  is 
  as 
  a 
  rule 
  what 
  is 
  known 
  as 
  

   fiery. 
  While 
  it 
  gives 
  great 
  initial 
  strength 
  it 
  is 
  quite 
  inferior 
  to 
  

   the 
  Potomac 
  cement. 
  The 
  rock 
  from 
  which 
  it 
  is 
  now 
  made 
  has 
  a 
  

   much 
  more 
  important 
  application 
  for 
  the 
  manufacture 
  of 
  portland 
  

   cement. 
  Richardson 
  makes 
  the 
  following 
  classifications 
  of 
  natural 
  

   cement 
  based 
  on 
  the 
  examination 
  of 
  those 
  made 
  in 
  various 
  por- 
  

   tions 
  of 
  the 
  United 
  States.® 
  

  

  1 
  Lime 
  cement 
  with 
  only 
  2$ 
  or 
  3$ 
  of 
  magnesia, 
  13 
  to 
  15$ 
  of 
  iron 
  

   and 
  aluminum 
  oxid 
  and 
  20$ 
  of 
  combined 
  silica. 
  

  

  2 
  Lime 
  cements 
  with 
  as 
  little 
  magnesia 
  but 
  with 
  less 
  silicates 
  

   than 
  class 
  1, 
  and 
  consequently 
  less 
  satisfactory 
  and 
  more 
  fiery. 
  

  

  3 
  Magnesia 
  cements 
  with 
  a 
  maximum 
  of 
  not 
  more 
  than 
  15# 
  

   of 
  magnesia, 
  the 
  same 
  amount 
  of 
  iron 
  and 
  aluminum 
  oxid 
  and 
  

   15 
  to 
  20$ 
  of 
  combined 
  silica, 
  and 
  in 
  addition 
  considerable 
  un- 
  

   combined 
  silicates 
  as 
  they 
  are 
  not 
  thoroughly 
  burned. 
  

  

  a 
  Brickbuilder, 
  Jan. 
  1898, 
  p. 
  14. 
  

  

  