﻿9S 
  E. 
  V. 
  Shannon 
  — 
  New 
  Description 
  of 
  Amesite. 
  

  

  Table 
  I, 
  Amesite, 
  Chester, 
  Mass. 
  

  

  Si0 
  2 
  20-95 
  

  

  A1 
  2 
  3 
  35-21 
  

  

  FeO 
  8-28 
  

  

  CaO 
  58 
  

  

  MgO 
  % 
  22-88 
  

  

  MnO 
  trace 
  

  

  H 
  9 
  0— 
  110°C 
  -23 
  

  

  H 
  2 
  O+110°C 
  ■ 
  1302 
  

  

  Total 
  101-15 
  

  

  This 
  analysis 
  yields 
  the 
  following 
  simple 
  ratios 
  : 
  

  

  SiO, 
  -3474 
  or 
  3-01 
  or 
  ± 
  3 
  or 
  1 
  

  

  A1 
  2 
  3 
  -3445 
  2-99 
  3 
  1 
  

  

  FeO 
  -1152 
  100 
  ) 
  

  

  MgO 
  ( 
  ' 
  5779 
  5 
  -° 
  2 
  > 
  

  

  H 
  2 
  -7355 
  6-38 
  6 
  2 
  

  

  This 
  gives 
  the 
  formula 
  

  

  2(Fe,Mg)0,Al 
  2 
  8 
  ,Si0 
  2 
  .2H 
  2 
  

  

  or 
  Pisani's 
  formula 
  

  

  H 
  4 
  (Mg,Fe) 
  2 
  Al 
  2 
  Si0 
  9 
  . 
  

  

  This 
  analysis 
  differs 
  from 
  that 
  of 
  Pisani 
  only 
  in 
  the 
  

   ratio 
  of 
  ferrous 
  iron 
  to 
  magnesia. 
  The 
  definite 
  ratio 
  of 
  

   MgO 
  : 
  FeO 
  = 
  1:5 
  shown 
  by 
  this 
  analysis 
  may 
  be 
  acci- 
  

   dental 
  and 
  the 
  percentages 
  of 
  these 
  two 
  oxides 
  probably 
  

   vary 
  reciprocally 
  in 
  different 
  specimens. 
  The 
  close 
  

   agreement 
  between 
  the 
  values 
  found 
  and 
  the 
  theoretical 
  

   values 
  is 
  brought 
  out 
  in 
  the 
  following 
  table 
  : 
  

  

  Table 
  II, 
  Amesite. 
  

  

  I. 
  II. 
  III. 
  

  

  Si0 
  2 
  20-95 
  20-82 
  21-40 
  

  

  Al 
  2 
  6 
  3 
  35-21 
  35-28 
  32-30 
  

  

  FeO 
  8-28 
  8-27 
  15-80 
  

  

  MgO(+CaO) 
  23-46 
  23-20 
  19-90 
  

  

  H 
  2 
  13-25 
  12-43 
  10-90 
  

  

  101-15 
  100-00 
  100-30 
  

  

  I. 
  Amesite, 
  Chester, 
  Mass., 
  anal, 
  by 
  Shannon. 
  

   II. 
  Amesite, 
  values 
  to 
  conform 
  with 
  formula 
  H 
  4 
  (5Fe,Mg) 
  2 
  

  

  Al 
  2 
  Si0 
  9 
  . 
  

   III. 
  Amesite, 
  Chester, 
  Mass., 
  anal, 
  by 
  Pisani. 
  

  

  