CRYOLITE  AND   ITS  PRODUCTS. 
71 
of  caustic  soda,  that  the  precipitate  produced  thereby  from  4 
ounces  of  the  liquid,  when  dried,  weighed  35  'grains  ;  therefore 
each  ounce  contains  a  little  less  than  9  grains  of  magnesia. 
The  superiority  over  the  corresponding  solutions  of  soda  and 
lime  as  a  remedial  agent,  consists  in  the  base  (magnesia)  which 
it  contains  not  being  caustic  in  its  nature.  Therefore  particularly 
adapted  either  for  internal  use  or  as  an  application  to  delicate 
tissues  where  the  effect  of  chlorine  or  its  compounds  only  is 
required. — Jour.  Franklin  Institute,  Oct.,  1867. 
CRYOLITE  AND  ITS  PRODUCTS. 
By  Evan  T.  Ellis. 
This   remarkable   mineral,  which,  as  you  will  observe,  is 
partially  transparent,  of  a  vitreous  lustre,  and  brittle  texture,  is 
a  fluoride  of  sodium  and  aluminum,  containing — 
13  per  cent,  aluminum, 
34      "  sodium, 
53      "  fluorine. 
100 
It  is  found  in  an  immense  deposit  in  Greenland,  at  Iviktout, 
at  the  head  of  Arksut  Bay,  near  Cape  Farewell.  The  first  dis- 
covery was  made  by  one  of  the  missionaries,  who  carried  a  spe- 
cimen with  him  to  Copenhagen.  Its  true  composition  was  de- 
termined by  Vanquelin. 
There  is  a.  bed  eighty  feet  thick,  and  three  hundred  feet  long, 
at  the  above-mentioned  place. 
It  is  frequently  associated  with  the  salts  of  metals,  and  beauti- 
ful crystals  of  galena,  or  sulphide  of  lead,  chalybite,  or  brown 
spathic  carbonate  of  iron,  resembling  spar  in  lustre,  copper  py- 
rites with  silver,  iron  pyrites,  &c,  are  found  therein,  arranged 
in  masses  segregated  from  the  white,  transparent,  ice-like  cryo- 
lite. 
It  remained  for  the  "  Pennsylvania  Salt  Company"  to  intro- 
duce to  our  country  this  valuable  material.  This  energetic 
Company,  whose  works  are  in  western  Pennsylvania,  has  secured 
the  privilege  of  using  a  large  part  of  all  that  is  mined,  and  has, 
