280 
DISCOVERY  OF  EMERY  IN  CHESTER,  MASS. 
ore,  distinct  from  the  ore  accompanying  the  emery,  occur,  the 
ore  yielding  54j  per  cent,  of  metallic  iron.  This  ore  is  mined, 
and  is  smelted  into  bar  iron  by  forge  fires,  and  is  also  sold  to 
mix  with  the  hematites  and  carbonates  of  iron  worked  at  the 
Lenox  and  Stockbridge  furnaces. 
Digesting  the  South  mountain  emery  in  fine  powder  with 
nitro-muriatic  acid  and  sulphuric  acid  for  a  long  time,  it  was 
found  that  73  per  cent,  of  it  was  wholly  insoluble  in  acids  ;  and 
on  microscopic  examination  the  grains  were  seen  to  be  translu- 
cent, and  exactly  like  the  Naxos  emery  prepared  in  the  same 
way ;  but  these  translucent  grains  are  readily  taken  up  by  the 
magnet.  I  therefore  infer  that  protoxyd  of  iron  is  a  chemical 
constituent  of  true  emery. 
Chemical  analysis  of  the  coarsely  crystalline  emery  of  the 
North  Mountain,  Chester.    Sp.  gr.  3*75.    II. =9. 
Alumina,  .....  46-50 
Protoxyd  of  iron,  ....  44-00 
Titanic  acid,  ....  5-00 
Silica  and  loss,  ,  4-50 
100-00 
Emery  of  the  South  hill.*    Sp.  gr.  4-02.    II. =9. 
Alumina,        -.        .        .        .        .  45-50 
Protoxyd  of  iron,     ....  43-00 
Silica  and  titanic  acid,      .        .        .  11-50 
100-00 
Kegarding  the  oxyd  of  iron  which  can  be  dissolved  out  from 
emery  by  acids  as  accidental,  and  that  which  cannot  be  so  re- 
moved as  an  essential  constituent,  we  shall  have  for  the  compo- 
sition of  three  samples  of  emery  analysed,  after  digestion  in 
acids, 
Naxos  best 
Chester,  1,  Chester,  2.  selected  emery. 
Alumina,  60-4  59-05  62-3 
Protoxyd  iron,       39-6  40-95  37-7 
100-0  100-0  100-0 
*  The  highest  specific  gravity  of  any  sample  from  the  South  mountain 
was  4-3734. 
