350 
NATIVE  CARBONATE  OF  SODA. 
a  small  quantity  of  water,  it  may  be  from  not  having  been  pro- 
perly dried  after  being  washed,  or  from  its  being  combined  with 
it  constitutionally  as  a  hydrate. 
This  additional  impurity,  together  with  those  already  referred 
to,  make  the  difference  between  the  oxide  and  carbonate  greater 
than  it  really  appears  to  be  from  a  mere  comparison  of  their  re^ 
spective  equivalent  weights. — Pharm.  Jour.,  May  1,  1853. 
Prince  Street,  Kilmarnock,  March  22,  1853. 
NOTICE  OF  A  NATIVE  CARBONATE  OF  SODA  FOUND  IN  THE 
TERRITORY  OF  THE  NIZAM,  INDIA. 
By  W.  H.  Bradley,  Esq. 
Surgeon  in  His  Highness  the  Nizam's  Service. 
(Communicated  by  Mr.  H.  Deane.) 
The  salt  in  question  is  found  at  the  Loonar  Lake,  which  is 
situated  in  about  20°  N.  lat.  and  77°  long.  There  can  be  no 
doubt  whatever,  that  the  lake  is  an  ancient  volcano,  long  ago  burnt 
out ;  and  I  have  fancied  that  from  this  vent  have  streamed  the 
peculiar  trachytic  rocks  to  be  traced  east  and  west  for  100  miles, 
but  this  is  purely  conjecture. 
It  is  placed  just  within  the  borders  (south-east)  of  the  Great 
Trap  formation  of  Central  India,  is  cup-shaped,  the  edge  well- 
defined  and  continuous,  being  nearly  five  miles  in  circumference, 
with  a  depth  averaging  500  feet,  sloping  at  a  great  angle.  The 
outer  edge  of  the  crater  is  flush  with  the  surrounding  country  on 
the  east  and  south-east  side,  and  banked  on  the  north,  south,  and 
west.  The  rocks  are  observed  to  be  disposed  in  a  stratiform 
manner,  the  result  of  the  successive  pourings  forth  of  the  molten 
matter,  and  of  subsequent  upheavals.  The  point  of  exit  for  the 
boiling  lava  was  evidently  at  the  north-east  angle. 
Some  have  imagined  the  hollow  to  have  resulted  from  a  sub- 
sidence of  the  crust  of  the  earth,  but  such  is  not  the  case.  I 
found  decided  proofs  of  its  once  volcanic  energies  in  a  hill  covered 
with  scoriae,  close  upon  the  southern  side.  Besides,  were  it  a 
case  of  subsidence,  the  dip  of  the  stratiform  masses  of  rock 
would  indicate  it,  which  they  do  not,  being  all  in  the  usual  di- 
rection of  these  trap  rocks,  dipping  away  slightly  to  the  north- 
east. 
