364  MANUFACTURE  OF  CARBONATE  OF  MAGNESIA. 
MANUFACTURE  OF  CARBONATE  OF  MAGNESIA. 
Native  Carbonate  of  Magnesia, — Native  carbonate  of  magne- 
sia, or  magnesite,  has  been  found  at  Hrubschitz,  district  of  Gro- 
mau,  in  Moravia  ;  at  Baudissero  and  Castellamonte,  villages  in 
the  vicinity  of  Turin,  Piedmont ;  in  the  East  Indies ;  and  in  the 
district  of  Kironile,  in  the  Eubsea.  Specimens  of  the  Piedmon- 
tese  magnesite  were  exhibited  under  the  name  of  Giobertite,  in 
the  Sardinian  section  of  the  Exhibition  of  I85I.  It  takes  its 
name  of  Giobertite  from  Giobert,  who  established  its  true  nature, 
it  having  passed  for  a  long  time  for  pure  alumina.  The  magne- 
site from  Baudissero  contains  68  per  cent  of  magnesia,  and  that 
of  Castellamonte  26.3  per  cent.  The  native  carbonate  from 
Moravia  contains  about  46  per  cent,  of  magnesia.  The  analysis  by 
Dr.  Henry  of  a  sample  of  native  carbonate  from  a  cargo  imported 
by  Mr.  Babbington  from  India,  also  gave  46  per  ct.  of  magnesia.  It 
constitutes  a  range  of  low  hills  in  Hindostan.  In  the  Eubsea  there 
are  entire  hills  of  it.  The  mines  or  quarries  are  situated  in  the  vil- 
lages of  Limni,  Kotsikir,  and  Matondi ;  the  produce  of  the  last 
named  village  is  the  best  in  quality.  It  is  stated  that  upwards 
of  2000  tons  are  annually  exported  to  Smyrna  and  England. 
The  Eubaean  magnesite  contains  44  per  cent,  of  magnesia.  It  is 
used  for  the  manufacture  of  pure  magnesia,  and,  as  mentioned 
in  our  last  number,  Epsom  salt.  It  is  a  very  useful  ingredient 
in  the  composition  of  bricks  for  refractory  furnaces,  on  account 
of  its  property  of  resisting  the  heat  of  fire.  Specimens  of  native 
carbonate  of  magnesia  from  Madras,  and  of  Epsom  salt  manu- 
factured therefrom,  were  shown  in  the  exhibition  of  1851 ;  also 
specimens  of  magnesite  from  Eubaea. 
In  England,  carbonate  of  magnesia  is  found  in  combination 
with  carbonate  of  lime,  forming  what  is  called  magnesian  limestone 
or  dolomite.  The  magnesian  limestone  extends  from  Newcastle 
to  Nottingham.    Annexed  are  the  analyses  of  five  specimens  : 
1. 
2. 
3. 
4. 
5. 
57.50 
55.70 
54.19 
51.10 
54.05 
"      Magnesia  .  . 
39.40 
41.60 
41.37 
40.20 
38.58 
0.80 
2.53 
3.60 
1.80 
Oxide  of  Iron  .  .  . 
0.70 
0.40 
0.30 
1.80 
1.36 
"      "  Manganese 
trace 
1.50 
Water  and  loss  .  . 
1.60 
2.30 
1.61 
3.30 
2.71 
100.00  100.00     100.00    100.00  100.00 
