﻿LIMESTONES 
  OF 
  NEW 
  YORK 
  AND 
  THEIR 
  ECONOMIC 
  VALUE 
  400 
  

  

  A 
  clay 
  or 
  Med 
  way 
  mud 
  from 
  Gillingham 
  is 
  as 
  follows: 
  

  

  Silica 
  ; 
  - 
  . 
  ; 
  .... 
  88 
  - 
  413 
  Uand 
  

  

  Alumina 
  and 
  ferric 
  oxid 
  , 
  1 
  . 
  856 
  ) 
  

  

  Silica 
  25.2491 
  

  

  Alumina 
  14 
  . 
  244 
  

  

  Ferric 
  oxid 
  :..,.-.. 
  6 
  . 
  744 
  

  

  Lime 
  • 
  81 
  ° 
  

  

  Magnesia 
  1 
  .727 
  Y 
  s 
  ni 
  ca 
  tes 
  

  

  Potash 
  2.957 
  j 
  

  

  Soda 
  773 
  ' 
  

  

  Water 
  3.384 
  

  

  Pyrite 
  214 
  

  

  Clay 
  used 
  for 
  the 
  manufacture 
  of 
  portland 
  cement 
  should 
  not 
  

   contain 
  an 
  excess 
  of 
  sand 
  nor 
  iron. 
  Clays 
  low 
  in 
  iron 
  are 
  usually 
  

   of 
  a 
  gray 
  or 
  blue 
  color 
  and 
  light 
  yellow 
  on 
  weathering. 
  The 
  clay 
  

   should 
  be 
  fairly 
  siliceous, 
  and 
  the 
  more 
  amorphous 
  silica 
  present 
  

   the 
  better. 
  Michaelis 
  (Hydraulische 
  Mortel 
  u. 
  Portland-Cemente, 
  

   p. 
  99) 
  gives 
  the 
  following 
  typical 
  examples: 
  

  

  12 
  3 
  4 
  5 
  6 
  

  

  Silica 
  60.06 
  59.25 
  60.00 
  62.48 
  68.45 
  64.72 
  

  

  Alumina 
  17.79 
  23.12 
  22.22 
  20.00 
  11.64 
  24.27 
  

  

  Ferric 
  oxid 
  7.08 
  8.53 
  8.99 
  7.33 
  14.80 
  7.64 
  

  

  Lime 
  9.92 
  . 
  ... 
  4.18 
  6.30 
  .75 
  1.89 
  

  

  Magnesia.. 
  ...... 
  1.89 
  2.80 
  1.60 
  1.16 
  

  

  Potash 
  2.50 
  1.87 
  1.49 
  1.74 
  1.90 
  ..... 
  

  

  Soda 
  73 
  1.60 
  .72 
  .37 
  2.10 
  

  

  Calcium 
  sulfate 
  . 
  . 
  .60 
  2.73 
  .89 
  .60 
  

  

  1 
  Province 
  of 
  Saxony 
  4 
  Mark 
  Brandenburg 
  

  

  2 
  Yorpommern 
  , 
  * 
  I 
  Medway 
  

  

  3 
  Oberharz 
  6 
  f 
  

  

  Cements 
  high 
  in 
  alumina 
  have 
  a 
  tendency 
  to 
  expand 
  and 
  to 
  

   blow 
  or 
  to 
  check. 
  Magnesia 
  is 
  also 
  supposed 
  to 
  cause 
  expansion 
  

   after 
  a 
  lapse 
  of 
  a 
  considerable 
  interval, 
  while 
  sulfates 
  are 
  looked 
  

   on 
  as 
  causes 
  of 
  disintegration 
  of 
  portland 
  cement 
  when 
  exposed 
  

   to 
  sea 
  water. 
  Cements 
  low 
  in 
  lime 
  and 
  without 
  an 
  excess 
  of 
  

   alumina 
  but 
  high 
  in 
  silica 
  are 
  simply 
  of 
  low 
  strength 
  as 
  under 
  

   burned 
  cements. 
  If 
  the 
  alumina 
  goes 
  above 
  8$ 
  it 
  is 
  considered 
  

  

  