510 
GLEANINGS  FROM  FOREIGN  JOURNALS. 
tion  with  disengagement  of  heat,  which,  added  to  the  production 
of  nitrogen,  occasions  a  loss.  But  if  the  operation  is  performed 
in  a  Woulf's  apparatus,  of  earthenware,  with  an  excess  of  am- 
monia, the  loss  of  bromine  vapor  is  entirely  avoided.  The 
evaporation  of  the  liquors  is  elFected  in  a  cast-iron  retort  ar- 
ranged with  an  earthenware  recepient  to  collect  the  excess  of 
ammonia.  The  decomposition  oi  the  bromide  by  carbonate  of 
soda  may  also  be  executed  on  a  large  scale  in  cast-iron  vessels. 
— Journ.  de  Pliarm.^  Sept.,  1870. 
Preparation  of  Caustic  Soda  from  Sodium.  The  great  reduc- 
tion in  price  of  sodium  enables  it  to  be  used  for  obtaining  pure 
caustic  soda,  which,  thus  made,  is  now  an  article  of  commerce. 
The  process  is  as  follows  :  Into  a  deep,  hemispherical,  silver 
vessel,  capable  of  holding  20  litres  (5J  gallons)  introduce  a  drop 
of  distilled  water,  and  then  lay  above  it  a  morsel  of  sodium, 
about  a  square  centimetre.  The  silver  vessel,  which  should 
dip  in  cool  water  to  prevent  an  explosion,  is  then  shaken  so 
as  to  produce  contact  between  the  water  and  sodium,  which  \f 
transformed  to  a  milky  liquid.  To  this  is  added,  with  constant 
stirring,  other  fragments  of  sodium  and  drops  of  water  until 
three  or  four  pounds  of  sodium  have  been  converted  into  a  thick 
milky  liquid.  This  is  deprived  of  the  water  it  contains  by  ex- 
posure on  a  gas  furnace  at  a  red  heat  and  cast  into  moulds. — 
Journ.  de  Pharm  ,  Sept.,  1870. 
On  the  infiuenee  of  Sugar  on  Magnesia  used  as  an  Antidote. 
In  1846,  M.  Bussy,  and  afterwards  Christison  and  others,  recom- 
mended magnesia  as  an  antidote  for  arsenic  and  other  metallic 
poisons.  M.  Carles,  supposing  that  sugar  (as  in  the  case  of  lime) 
would,  by  rendering  magnesia  soluble,  increase  its  efficacy,  tried 
the  mixture  of  sugar,  water  and  magnesia,  but,  to  his  surprise, 
found  that  it  rendered  the  arsenite  of  magnesia  soluble,  and  that 
sugar  tends  to  prevent  the  formation  of  arsenite  of  magnesia, 
and  is,  therefore,  useless  and  pernicious.  When,  however,  sac- 
charated  magnesia  is  used  with  the  salts  of  lead,  copper,  anti- 
mony and  mercury  it  hastens  and  facilitates  their  decomposition 
without  uniting  with  them,  and  in  some  instances  the  sugar  of 
itself  acts  by  reducing  the  oxides.  For  this  last  reason  it  may 
be  better  to  use  honey  in  lieu  of  sugar. 
