22 
ON  COMMERCIAL   IRCN  BY  HYDROGEN. 
the  heated  acid  ;  the  evolved  hydrogen  had  the  odor  of  sul- 
phuretted hydrogen  and  turned  sugar  of  lead  paper  black. 
No.  2  of  American  make  had  a  blackish  grey  color,  some- 
what lighter  when  rubbed  on  white  paper ;  it  ignited  with 
great  facility  and  burned  rapidly,  yielding  a  product  of  a  pur- 
plish black,  with  a  small  portion  of  the  original  color,  the 
latter  igniting  as  soon  as  touched  with  the  match.  Cold  and 
boiling  nitric  and  hydrochloric  acids  dissolved  a  portion  ;  nitro- 
muriatic  acid  when  cold,  did  not  dissolve  all,  but  after  some 
boiling  yielded  a  perfectly  clear  solution.  The  gas  evolved  from 
digesting  it  with  diluted  sulphuric  acid  had  a  slight  odor  of 
carburetted  hydrogen  and  was  free  from  sulphhydric  acid. 
No.  3  of  French  origin  had  a  grey  color,  lighter  than  No. 
2,  and  appeared  similar  to  it  when  rubbed  on  paper  ;  it  ignited 
very  readily  and  burned  rapidly  and  entirely  to  a  dull  reddish 
brown  oxide.  It  was  but  partly  soluble  in  cold  or  boiling 
muriatic,  nitric  and  nitro-muriatic  acid,  but  dissolved  in  the 
latter  by  repeated  boiling  with  fresh  portions.  The  gas, 
evolved  by  diluted  sulphuric  acid,  had  a  strong  odor  of  car- 
buretted hydrogen  and  likewise  contained  some  sulphuretted 
hydrogen. 
Ten  grs.  of  each  of  the  three  specimens  were  dissolved  in  ni- 
tromuriatic  acid,  evaporated  to  near  dryness,  redissolved  in 
water  and  precipitated  by  ammonia  ;  the  precipitate  was  well 
washed,  dried,  incinerated  and  weighed,  after  deducting  the 
ashes  of  the  filter.  Ten  grs.  of  each  specimen  vv'ere  subjected 
to  red  heat,  repeatedly  moistened  with  nitric  acid  and  heated, 
until  they  ceased  to  gain  Vveight.    The  results  were  as  follows  : 
No.  1.    No.  2.    No.  3. 
Weight  of  Fe^  Oo  by  precipitation     11-8     12-75     12-8  grains. 
^      heating  11.55   12-6      12-9  " 
The  sesquioxide  of  iron  obtained  from  10  grs.  of  pure  iron, 
ought  to  have  weighed  14-286  grs.  whereby  a  deficiency  of 
2-486,  1-536  and  1-486  grs.  respectively  is  shown.  The  pre- 
cipitated and  incinerated  oxide  of  iron  as  obtained  above,  is 
equivalent  to  8-26,  8-89  and  8-96  grs.  of  pure  iron  ;  if  the  small 
percentage  of  carbon  and  sulphur  be  neglected,  or  rather  calcu- 
lated as  oxygen  not  entirely  removed,  the  specimens  would  con- 
tain 1-74,  I'll  and  1-04  grs.  0.     If  this  ox^^gen  was  retained 
