NEW  METHOD  OF  ANALYSING  OIL  CAKE.  265 
the  iodide  mixed  with  eight  or  ten  times  its  weight  of  the  cya- 
nide, and  lime  is  next  introduced  ;  then  a  layer  of  the  cyanide 
and  lime  is  added  ;  and  lastly,  a  little  carbonate  of  magnesia  is 
placed  on  the  top  •  the  tube  is  now  drawn  out  and  bent,  and 
the  extremity  is  made  to  dip  into  a  receiver  containing  water. 
Heat  is  now  applied  to  the  mixture,  beginning  at  the  top,  and 
the  mercury  distils  over. 
Other  mercuric  compounds  may  be  decomposed  in  the  same 
manner. 
According  to  Carius,  iodide  of  mercury  is  completely  decom- 
posed by  digestion  with  nitrate  of  silver  in  a  not  very  acid  so- 
lution. The  reaction  is  definite  enough  to  allow  of  its  being 
utilised  for  an  estimation.  Iodide  of  silver,  like  iodide  of  mer- 
cury, is  slightly  soluble  in  nitrate  of  mercury. 
The  red  iodide  of  mercury  may  be  reduced  by  a  solution  of 
protochloride  of  tin,  but  the  reduction  is  not  complete.  With 
an  excess  of  hydrochloric  acid  the  reduction  is  impossible,  and 
the  iodide  becomes  yellow  when  the  mixture  is  heated.  When, 
however,  the  mixture  is  supersaturated  with  potash,  the  reduc- 
tion takes  place.  Iodide  of  potassium  will  also  prevent  the  re- 
duction with  protochloride  of  tin,  unless  an  excess  of  potash  is 
present. 
Metallic  zinc  completely  decomposes  iodide  of  mercury  in  the 
presence  of  water,  forming  iodide  of  zinc. — Lond.  Chem.  News, 
February  27,  1864. 
ON  A  NEW  METHOD  OF  ANALYSING  OIL  CAKE. 
By  W.  B.  Tegetmeier. 
Some  time  since  I  was  requested  to  examine  the  products 
and  report  upon  the  process  of  a  new  method  of  extracting  oil 
from  crushed  seeds  by  means  of  bisulphide  of  carbon  in  place 
of  pressure.  I  found  that  the  oils  obtained  by  this  plan  were 
of  very  superior  quality,  bright,  free  from  albuminous  and  mu- 
cilaginous matters,  and  destitute  of  the  slightest  trace  of  the 
bisulphide. 
The  residuary  mass  of  ground  seed  was  also  much  more  free 
from  oil  than  that  left  after  pressure. 
Being  desirous  of  verifying  my  own  opinion,  I  forwarded  a 
sample  of  the  crushed  seeds  after  extraction  to  professor  A. 
