NEW  METHOD  OF  DETECTING  IODINE  AND  BROMINE.  449 
to  that  of  the  gas  employed.  This  remarkable  reaction  accu- 
rately establishes  its  composition  CaO-f-CS=CaS -f  CO,  no  car- 
bonate of  lime  being  produced. 
At  a  red  heat  it  is  feebly  decomposed — 1st,  by  a  spongy  pla- 
tinum; 2ndly,  by  the  vapor  of  water  into  HS  and  CO  ;  3rdly? 
very  readily  by  hydrogen  into  HS  and  CH  ;  4thly,  by  copper 
into  graphitoid  carbon  and  sulphide  of  copper  ;  and,  finally,  by 
exposure  to  the  sun  with  an  equal  volume  of  chlorine,  a  reaction 
takes  place,  a  partial  condensation  and  formation  of  compounds, 
which  I  am  at  present  investigating.  Analysed  by  oxygen  in 
the  eudiometer,  it  gives  equal  volumes  of  carbonic  acid  and  sul- 
phurous acid,  from  which  we  may  deduce  the  formula  CS  as 
representing  its  composition.  The  composition  is  also  estab- 
lished by  the  action  of  lime  water,  which,  as  I  have  stated, 
resolves  it  completely  into  carbonic  oxide  and  sulphide  of  calcium 
without  the  production  of  any  carbonate  of  lime.  We  also 
arrive  at  the  same  conclusion  from  determining  the  quantities 
of  carbon  and  sulphide  of  copper,  produced  by  its  decomposition 
with  that  metal. 
Many  chemists  have  attempted  to  discover  this  body ;  and  its 
having  escaped  their  investigations,  is  attributable,  without 
doubt,  to  its  reaction  upon  water  and  the  solutions  of  the  alka- 
lies, which  resolve  it  into  carbonic  oxide  and  sulphuretted  hydro- 
gen London  Pharm.  Journal,  July  1st,  1857,  from  Compter 
Hendus. 
NEW  METHOD  OF  DETECTING  IODINE  AND  BROMINE. 
By  MM.  0.  Henry,  Jr.,  and  E.  Humbert, 
The  authors  employed  this  process  with  the  view  of  determin- 
ing the  presence  of  iodine  in  the  waters  of  Vichy,  in  which  its 
existence  was  a  matter  of  dispute.  It  presents  great  analogy 
with  that  recommended  by  them  for  detecting  traces  of  hydro- 
cyanic acid  in  cases  of  poisoning,  and  is  applicable  in  all 
possible  circumstances.  In  the  case  of  a  mineral  water  it  is  as 
follows : — 
The  water  (or  the  more  or  less  concentrated  residue  of  its 
evaporation)  is  treated  with  acid  nitrate  of  silver.    The  pre- 
27 
