The  whole  is  evaporated  to  dryness,  and
submitted  to  a  dull  red  heat.  The  re-
siduum is  next  powdered  and  mixed  with
pure  peroxide  of  manganese;  the  mixture
haying  been  placed  in  a  retort,  sulphuric  acid
(diluted  with  half  its  weight  of  water)  is
poured  in.  Red  vapours  immediately  arise,
and  condense  into  drops  of  bromine,  which
are  collected  by  plunging  the  neck  of  the
retort  nearly  to  the  bottom  of  a  small  receiver


362


BEOMINE


containing  a  little  vevy  cold  water.  The  bro-
mine forms  a  stratum  beneath  the  water,  and
may  be  collected  and  at  once  put  into  a  stop-
pered bottle;  or  it  may  be  further  purified  by
distillation  from  dry  chloride  of  calcium.
2.  Leislcr's  patent  for  a  method  of  obtain-
ing bromine  consists  in  decomposing  the  lye
containing  the  bromine  salt  by  heating  it  with
hydrochloric  acid  and  bichromate  of  potash  in
a  leaden  still  having  an  earthenware  head.
The  volatilised  bromine  with  the  vapour  of
water  is  conducted  into  a  receiver  containing
iron  turnings,  bromide  of  iron,  which  dis-
solves in  the  water  contained  in  the  receiver,
being  formed.  The  bromide  of  iron  so  pro-
duced is  either  converted  into  other  metallic
bromides  by  the  usual  processes,  or  the  bromine
is  obtained  in  a  separate  state  from  the  iodide
by  treatment  with  sulphuric  acid  and  bichro-
mate of  potash.
