﻿16 
  Brackett 
  and 
  Williams 
  — 
  JVewtonite 
  and 
  Rectorite. 
  

  

  In 
  addition 
  to 
  this 
  there 
  is 
  a 
  white 
  rim 
  about 
  the 
  edges 
  which 
  

   gives 
  them 
  the 
  appearance 
  of 
  being 
  higher 
  than 
  the 
  rest 
  of 
  the 
  

   surface. 
  The 
  cause 
  of 
  this 
  is, 
  however, 
  not 
  due 
  to 
  any 
  mark- 
  

   ing 
  or 
  relief 
  on 
  the 
  surface 
  but 
  probably 
  to 
  internal 
  reflec- 
  

   tions 
  whose 
  origin 
  it 
  is 
  hard 
  to 
  detect. 
  

  

  In 
  polarized 
  light 
  the 
  rhombs 
  extinguish 
  sharply 
  parallel 
  to 
  

   their 
  diagonals, 
  thus 
  showing 
  that 
  they 
  are 
  faces 
  of 
  some 
  

   anisotropic 
  material 
  and 
  not, 
  as 
  might 
  be 
  supposed, 
  sections 
  of 
  

   cubes 
  which 
  had 
  been 
  cut 
  more 
  or 
  less 
  obliquely. 
  

  

  If 
  these 
  rhombs 
  and 
  squares 
  are 
  sections 
  of 
  rhombohedrons 
  

   then 
  one 
  would 
  expect 
  to 
  find 
  also 
  plane 
  triangles 
  correspond- 
  

   ing 
  to 
  sections 
  perpendicular 
  to 
  the 
  principal 
  axis. 
  This, 
  how- 
  

   ever, 
  is 
  not 
  the 
  case 
  and 
  only 
  in 
  a 
  very 
  few 
  instances 
  have 
  any 
  

   triangular 
  forms 
  been 
  found 
  and 
  even 
  then 
  they 
  are 
  very 
  in- 
  

   distinct 
  and 
  appear 
  to 
  be 
  not 
  in 
  the 
  upper 
  surface 
  of 
  the 
  plate 
  

   but 
  somewhat 
  lower 
  down. 
  It 
  is 
  probable 
  that 
  in 
  making 
  sec- 
  

   tions 
  of 
  this 
  material 
  the 
  individual 
  crystals 
  are 
  not 
  cut, 
  but 
  

   are 
  either 
  rubbed 
  away 
  entirely, 
  or 
  are 
  left 
  undisturbed, 
  so 
  that 
  

   what 
  are 
  seen 
  under 
  the 
  microscope 
  are 
  not 
  sections 
  but 
  crystal 
  

   faces. 
  By 
  means 
  of 
  a 
  selenite 
  plate 
  the 
  positions 
  of 
  the 
  axes 
  

   of 
  greatest 
  and 
  least 
  elasticity 
  were 
  determined, 
  and 
  were 
  

   found 
  to 
  lie 
  respectively 
  parallel 
  to 
  the 
  shorter 
  and 
  longer 
  

   diagonals 
  of 
  the 
  rhomb. 
  

  

  By 
  powdering 
  some 
  of 
  the 
  material 
  and 
  allowing 
  it 
  to 
  settle 
  

   out 
  from 
  water, 
  similar 
  rhombohedral 
  crystals 
  were 
  obtained. 
  

  

  JReetorite. 
  

  

  The 
  second 
  hydrous 
  silicate 
  of 
  alumina, 
  which 
  is 
  also 
  to 
  be 
  

   regarded 
  as 
  new, 
  is 
  found 
  in 
  the 
  Blue 
  Mountain 
  mining 
  dis- 
  

   trict 
  in 
  Marble 
  Township, 
  Garland 
  county, 
  2 
  North, 
  19 
  West, 
  

   section 
  27, 
  about 
  24 
  miles 
  nearly 
  north 
  of 
  Hot 
  Springs. 
  It 
  

   occurs 
  in 
  deposits 
  which 
  are 
  very 
  narrow 
  near 
  the 
  surface 
  but 
  

   increase 
  to 
  the 
  thickness 
  of 
  a 
  foot 
  or 
  more 
  in 
  descending 
  nine 
  

   feet. 
  Several 
  such 
  deposits 
  have 
  been 
  found. 
  The 
  wall 
  rock 
  

   is 
  sandstone 
  probably 
  of 
  Lower 
  Silurian 
  age. 
  Specimens 
  of 
  

   this 
  mineral 
  have 
  been 
  furnished 
  by 
  Messrs. 
  Ware 
  and 
  Arnold 
  

   of 
  Hot 
  Springs, 
  who 
  are 
  interested 
  in 
  developing 
  the 
  deposit. 
  

  

  We 
  propose 
  the 
  name 
  Rectorite 
  for 
  this, 
  the 
  first 
  member 
  of 
  

   the 
  Kaolinite 
  Series, 
  in 
  honor 
  of 
  Hon. 
  E. 
  W. 
  Rector, 
  of 
  Hot 
  

   Springs, 
  Ark., 
  who 
  originated 
  and 
  has 
  so 
  unceasingly 
  supported 
  

   in 
  the 
  State 
  Legislature 
  the 
  bills 
  providing 
  for 
  the 
  Geological 
  

   Survey 
  of 
  Arkansas. 
  

  

  Rectorite, 
  when 
  pure, 
  is 
  a 
  soft, 
  white 
  mineral 
  occurring 
  in 
  

   large 
  leaves 
  or 
  plates 
  and 
  resembling 
  very 
  closely 
  in 
  form 
  that 
  

   variety 
  of 
  asbestos 
  known 
  as 
  "mountain 
  leather," 
  and 
  at 
  the 
  

   same 
  time 
  having 
  somewhat 
  the 
  soapy 
  appearance 
  of 
  steatite. 
  

   Parts 
  of 
  it 
  are 
  often 
  pure 
  white, 
  while 
  other 
  portions 
  are 
  

  

  