550       Estimation  of  Sulphur  in  Iron  and  Steel.  {%ec!tm3BM" 
for  magnesium,  in  the  usual  way,  by  phosphate  of  sodium,  when  an 
abundant  precipitate  was  obtained,  proving  the  presence  of  magne- 
sium as  silicate. — Chemical  News,  Oct.  24,  1873. 
ESTIMATION  OF  SULPHUR  IN  IKON  AND  STEEL. 
By  T.  J.  M.ORRELL. 
The  more  common  method  of  estimating  sulphur  in  iron  and  steel 
consists  in  acting  on  the  metal  with  sulphuric  or  hydrochloric  acid, 
and  precipitating  some  metallic  sulphide  by  the  evolved  sulphuretted 
hydrogen.  It  would  be  a  desideratum,  in  point  of  time,  if  this  sul- 
phide could  be  directly  weighed. 
By  passing  the  evolved  gases  through  an  ammoniacal  solution  of 
cadmium  oxide  (or  a  solution  of  sulphate  to  which  an  excess  of  ammo- 
nia has  been  added),  a  precipitate  of  cadmium  sulphide  is  obtained, 
which  can  be  at  once  collected  upon  a  small  filter,  dried  at  212°  F. 
and  weighed. 
The  phosphoretted  hydrogen,  evolved  in  a  solution  of  the  metal 
together  with  the  sulphuretted  hydrogen,  causes  no  precipitate  in  the 
solution. 
The  presence  of  ammoniacal  salts  would  also  prevent  any  precipi- 
tation of  carbonate  of  cadmium  by  the  traces  of  carbonic  acid  in  the 
air  drawn  through  the  apparatus  by  the  aspirator  after  the  metal  is 
dissolved.  However,  the  aspirated  air  could  easily  be,  passed  through 
potash  solution,  to  remove  its  carbonic  acid. 
To  prevent  the  precipitation  of  oxide  of  cadmium  on  the  filter,  the 
precipitate  should  be  washed  with  distilled  water  containing  diminish- 
ing quantities  of  ammonia. 
If,  in  very  accurate  estimations,  it  is  necessary  to  estimate  the 
minute  quantity  of  sulphur  left  in  the  solution  and  residue  of  the 
metal,  this  can  be  done  as  usual  and  added  to  that  found  as  above. 
Five  test  analyses  of  a  piece  of  Bessemer  steel  known  to  contain 
•13  per  cent,  of  sulphur,  gave  as  fellows:  (1)  0-124  per  cent. ;  (2)  0*125 
per  cent.  ;  (3)  9*137  per  cent. :  (4)  0-125  per  cent. ;  (5)  0*124  per 
cent. 
Cambria  Iron  Works,  Johnstown,  Pa. 
— Am.  Chemist. 
