﻿20 
  Brackett 
  and 
  Williams 
  — 
  Newtonite 
  and 
  Bectorite. 
  

  

  Many 
  points 
  of 
  similarity 
  appear 
  between 
  rectorite 
  and 
  kao- 
  

   linite, 
  but 
  in 
  view 
  of 
  the 
  peculiarity 
  of 
  the 
  form 
  which 
  it 
  

   assumes, 
  and 
  on 
  account 
  of 
  its 
  chemical 
  composition, 
  it 
  is 
  prob- 
  

   able 
  that 
  it 
  should 
  be 
  considered 
  as 
  a 
  separate 
  mineral. 
  

  

  In 
  confirmation 
  of 
  the 
  above 
  opinion 
  the 
  statements 
  of 
  two 
  

   manufacturers 
  of 
  ceramics 
  to 
  whom 
  specimens 
  of 
  rectorite 
  were 
  

   sent 
  for 
  firing 
  may 
  be 
  quoted. 
  

  

  Homer 
  Laughlin, 
  Esq., 
  of 
  East 
  Liverpool, 
  Ohio, 
  writes: 
  

   " 
  The 
  sample 
  of 
  what 
  you 
  call 
  kaolinite, 
  sent 
  me, 
  was 
  duly 
  

   received, 
  and 
  carefully 
  examined 
  and 
  tested 
  under 
  fire. 
  The 
  

   mineral 
  is 
  neither 
  kaolin 
  nor 
  kaolinite, 
  but 
  just 
  what 
  it 
  should 
  

   be 
  called 
  I 
  am 
  unable 
  to 
  say, 
  never 
  in 
  all 
  my 
  experience 
  hav- 
  

   ing 
  seen 
  any 
  mineral 
  of 
  its 
  kind. 
  Unlike 
  kaolin 
  it 
  will 
  not 
  

   dissolve* 
  in 
  water. 
  It 
  burns 
  a 
  white 
  color 
  and 
  becomes 
  very 
  

   vitreous 
  and 
  strong. 
  It 
  cannot 
  be 
  finished 
  with 
  a 
  smooth 
  face 
  

   or 
  skin, 
  but 
  roughs 
  up 
  like 
  a 
  blotting 
  pad. 
  It 
  is 
  certainly 
  a 
  

   very 
  interesting 
  and 
  curious 
  mineral, 
  but 
  I 
  can 
  think 
  of 
  no 
  

   use 
  for 
  it 
  in 
  ceramic 
  manufacture 
  unless 
  it 
  could, 
  after 
  careful 
  

   experiments, 
  be 
  made 
  into 
  novel 
  ornaments." 
  

  

  Messrs. 
  Oliphant 
  & 
  Company 
  of 
  the 
  Delaware 
  Pottery,. 
  

   Trenton^ 
  New 
  Jersey, 
  write: 
  "Your 
  sample 
  of 
  kaolinite 
  came 
  

   out 
  of 
  the 
  kiln 
  to-day, 
  and 
  would 
  say 
  that 
  we 
  are 
  unable 
  to 
  

   make 
  any 
  report 
  upon 
  it. 
  We 
  do 
  not 
  know 
  just 
  what 
  it 
  is, 
  

   therefore 
  cannot 
  say 
  anything 
  about 
  its 
  quality 
  or 
  market 
  

   value." 
  

  

  It 
  appears 
  therefore 
  from 
  the 
  above 
  that 
  its 
  physical 
  proper- 
  

   ties 
  when 
  subjected 
  to 
  heat 
  do 
  not 
  correspond 
  to 
  those 
  of 
  

   kaolin. 
  

  

  Experiments 
  were 
  made 
  in 
  the 
  laboratory 
  on 
  the 
  relative 
  

   solubility 
  of 
  newtonite 
  and 
  rectorite, 
  and 
  at 
  the 
  same 
  time 
  

   upon 
  some 
  specimens 
  of 
  true 
  kaolin 
  in 
  the 
  following 
  manner 
  : 
  

  

  "The 
  fine 
  powder 
  of 
  the 
  various 
  substances, 
  was 
  boiled 
  with 
  

   10 
  cc 
  of 
  concentrated 
  sulphuric 
  acid 
  for 
  five 
  minutes, 
  after 
  hav- 
  

   ing 
  been 
  digested 
  with 
  it 
  for 
  three 
  hours 
  on 
  a 
  sand 
  bath. 
  It 
  

   was 
  then 
  diluted, 
  decanted, 
  treated 
  with 
  a 
  strong 
  solution 
  of 
  

   potassium 
  carbonate, 
  washed 
  with 
  water 
  and 
  hydrochloric 
  acid, 
  

   filtered 
  and 
  weighed. 
  In 
  all 
  the 
  cases, 
  the 
  results 
  were 
  very 
  

   similar, 
  so 
  much 
  so 
  in 
  fact 
  that 
  no 
  characteristic 
  differences 
  

   could 
  be 
  detected. 
  

  

  When 
  treated 
  with 
  caustic 
  potash 
  the 
  results 
  were 
  somewhat 
  

   different 
  in 
  the 
  different 
  cases. 
  Powder 
  from 
  each 
  specimen 
  

   was 
  boiled 
  with 
  10 
  cc 
  of 
  a 
  saturated 
  solution 
  of 
  caustic 
  potash 
  

   for 
  20 
  minutes, 
  diluted, 
  filtered, 
  washed 
  and 
  treated 
  with 
  dilute 
  

   hydrochloric 
  acid. 
  The 
  white 
  fiocculent 
  residue 
  which 
  re- 
  

   mained 
  after 
  the 
  treatment 
  of 
  the 
  powder 
  with 
  caustic 
  potash 
  

  

  * 
  Mr. 
  Laughlin 
  does 
  not 
  mean 
  dissolve 
  in 
  the 
  chemical 
  sense 
  of 
  the 
  word, 
  but 
  

   disintegrate 
  into 
  a 
  fine 
  powder 
  which 
  remains 
  partly 
  in 
  suspension. 
  

  

  