SULPHOCYANIDE  OF  MERCURY,  ETC. 
101 
Before  Combustion.  After  Combustion. 
Hg-,12,  passing  off  in  vapor. 
N4  ,  evolved  in  a  free  state. 
5(N4  C6  ),  mellon,  forming  the  chief  bulk  of 
the  snake. 
18(CS2  ).  The  elements  of  18  equiv.  of  bi- 
sulphuret  of  carbon,  which,  by  assuming 
108  eq.  oxygen  from  the  air,  become 
carbonic  and  sulphurous  acid  gases. 
12(HgS),  cinnabar,  which  partially  remains  in 
the  suake,  and  is  partly  consumed  and 
volatilized  on  the  surface. 
Hg24 
N24 
24(HgCyS2  )= 
C48 
S48 
While  on  the  subject  of  chemical  toys,  we  may  as  well  refer 
to  another.  Philosophers,  as  well  as  children,  may  be  amused 
and  instructed  by  blowing  bubbles.  Several  years  ago,  an 
account  was  published  of  the  capacity  of  a  solution  of  oleate  of 
soda  to  yield  bubbles  of  extraordinary  dimensions  and  of 
gorgeous  coloring.  Our  correspondent  has  taken  some  pains  to 
investigate  this  property,  and  finds  that  the  success  of  the 
experiment  depends  largely  upon  the  purity  of  the  oleate  used. 
The  commercial  oleic  acid  made  by  the  manufacturers  of 
stearic  acid  does  not  afford  an  oleate  of  soda  that  answers  the 
purpose  intended,  even  though  it  be  purified  by  combination  with 
oxide  of  lead,  and  separation  by  ether,  etc. 
The  best  results  were  obtained  as  follows  : — Dissolve  two 
ounces  of  good  white  Castile  soap  in  20  fluidounces  of  boiling 
water,  and  add  about  one  ounce  of  sulphuric  acid,  diluted  with 
two  fluidounces  of  water,  and  stir  together;  the  fatty  acids  of 
the  soap  are  separated  and  rise  to  the  surface,  where  they  collect 
and  float  as  a  clear  yellowish  oily  layer.  The  vessel  is  now 
removed  from  the  fire,  and,  with  a  syphon,  decant  the  acid 
solution  of  sulphate  of  soda  constituting  the  inferior  layer  of 
liquid,  carefully  avoiding  the  loss  of  the  oily  part  by  stopping 
in  time.  The  oily  acids  are  then  well  washed  three  successive 
times  in  hot  water,  separating  them  as  before,  after  which,  by 
exposure  to  cold,  they  solidify.  The  mass  is  then  weighed,  put 
in  a  suitable  dish,  and  half  its  weight  of  finely-powdered  litharge 
added,  and  the  mixture  digested  at  a  beat  of  212°  to  225°,  until 
complete  union  is  effected.    The  resulting  oleo-margarate  of 
