PREPARATION  OF  PURE  SULPHURIC  ACID. 
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tained  a  small  quantity  of  alumina,  and  the  proportion  of  sul- 
phate of  lime  soluble  in  water. 
The  solution  was  evaporated  to  as  small  a  volume  as  possible, 
as  sulphate  of  lithia  is  very  soluble  in  water.  By  this  means  a 
»  considerable  portion  of  the  much  less  soluble  sulphate  of  potash 
crystallized  out,  as  did  also  nearly  all  the  sulphate  of  lime.  The 
filtered  fluid  was  mixed  with  ammonia,  a  little  sulphuret  of  am- 
monium, and  oxalate  of  ammonia.  The  precipitate  thus  produced, 
consisting  of  alumina,  sulphuret  of  manganese  and  oxalate  of 
lime,  was  separated,  and  all  the  lithia  was  then  thrown  down  as 
carbonate,  by  means  of  carbonate  of  ammonia,  assisted  by  heat, 
and  washed  with  cold  water.  To  purify  it  completely  from  potash, 
it  is  well  to  repeat  the  last  operation  once  more,  by  dissolving 
the  carbonate  of  lithia  in  an  acid,  and  precipitating  it  again  by 
carbonate  of  ammonia.— Chem.  Gazette,  Oct.  15,  1856,  from 
Journ.  fur  Prakt.  Chem, 
ON  THE  PREPARATION  OF  CHEMICALLY  PURE  SULPHURIC 
ACID. 
By  F.  Vorwerk. 
Some  time  ago  Kussegger  described  a  method  in  which,  by  a 
particular  arrangement  of  the  retorts,  sulphuric  acid  may  be 
distilled  by  boiling  without  thumping,  and  the  rectification  of 
the  crude  acid  may  be  effected  without  the  employment  of  plati- 
num wire.  Instead  of  this  the  author  recommends  the  following 
process,  which  fulfils  the  same  purpose,  and  dispenses  with  all 
further  particular  arrangements. 
Into  a  long-necked  plain  retort,  which  had  already  served 
several  times  for  the  preparation  of  nitric  acid,  5  lbs.  of  slightly 
brown  English  sulphuric  acid,  of  spec,  grav.  1-832  and  free  from 
arsenic,  were  put.  The  retort  was  put  upon  a  layer  of  sand  of 
the  depth  of  a  finger  in  the  sand-bath,  and  surrounded  with 
sand,  so  that  it  was  buried  up  to  the  neck.  A  long-necked  flask 
served  as  a  receiver;  it  was  simply  pushed  over  the  neck  of  the 
retort  without  any  luting.  Commencing  with  a  moderate  heat, 
this  was  gradually  raised  until  the  sand-bath  became  red-hot,  du- 
ring which  the  distillation  went  on  quite  regularly  without  any 
thumping.    Notwithstanding  the  heat  to  which  the  retort  was 
