198] 
CRYOLITE. 
nearly  pure  lime  readily,  free  from  silicates,  &c,  being  the  only 
obstacle  in  the  way  of  absolute  chemical  purity. 
The  amount  of  cryolite  imported  into  the  United  States  in 
1867  was  8000J  tons,  all  of  which  was  entered  through  the  port 
of  Philadelphia.  The  two  principal  uses  to  which  cryolite  is 
applied  in  this  country  are  as  follows  :  1st,  the  preparation  of 
the  salts  of  soda  and  of  alumina  from  the  sodium  and  aluminum 
contained  in  it;  2d,  the  manufacture  of  opaque  "white  glass," 
or,  as  it  is  sometimes  called,  "  hot-cast  porcelain."  Having 
dwelt  at  some  length  on  its  first  use,  as  designated,  I  will  now 
endeavor  to  state  its  second. 
The  application  of  cryolite  to  the  manufacture  of  the  new 
porcelain,  or  opaque  glass,  promises  to  be  one  of  those  discover- 
ies, simple  in  themselves,  that  at  times  almost  subvert  the  course 
of  trade  and  manufacture.  From  this  material  (which  is  simply 
glass,  so  far  as  the  mode  of  working  is  concerned)  is  furnished, 
at  less  than  the  cost  of  the  cheapest  ordinary  white  or  flint  glass, 
and  with  the  facility  attending  working  common  blown  or  pressed 
glass,  any  article  of  any  shape  that  can  be  made  from  glass  ; 
exactly  resembling  the  finest  French  porcelain  in  appearance  and 
beauty,  but  far  surpassing  it,  as  well  as  glass,  in  toughness, 
strength,  and  capability  of  standing  sudden  changes  of  tempera- 
ture. The  ingredients  used  in  its  manufacture  consist  of  cryo- 
lite 10  lbs.,  white  sand  20  lbs.,  and  oxide  of  zinc  5  lbs., — the 
dirty  discolored  oxide,  worth  less  than  half  the  price  of  the  white 
oxide  of  commerce,  answering  well  for  this  purpose.  The  fusion 
of  the  ingredients  is  effected  at  the  same  heat,  and  in  the  usual 
manner  practised  in  the  flint  glass  factories.  In  this  manner 
can  be  made  not  only  the  articles  ordinarily  made  of  glass  or 
porcelain,  but  also  tiles,  mantel-pieces,  mouldings,  statuary  ware, 
mortars,  pill  tiles,  evaporating  dishes,  funnels,  ointment  jars, 
and  in  fact  any  and  everything  capable  of  being  cast,  blown  or 
moulded  'whilst  in  a  melted  state,  and  at  a  mere  trifling  cost. 
The  ousiness  of  making  these  articles  from  cryolite  is  as  yet 
in  its  infancy.  One  establishment  in  this  city  alone,  and  I  be- 
lieve this  is  the  only  one  anywhere,  is  working  exclusively  on  it, 
consuming  from  500  to  1000  tons  of  cryolite  per  annum ;  but  its 
use  will  necessarily  become  general,  either  as  a  speciality,  or  in 
