134  Granular  Effervescent  Powders.  {^J^M^' 
The  volatile  oil  of  mustard. — In  the  Amer.  Jour,  of  Pharm.,  1888, 
556,  the  presence  of  carbon  disulphide  in  unadulterated  oil  of  mustard 
was  noticed.  Recently  Paul  Birkenwald  proved  that  the  action  of 
acid  potassium  sulphate  (one  of  the  decomposition  products  of 
myronate  of  potassium)  upon  the  oil  will  produce  CS2 ;  also  that  if 
the  seed  be  distilled  with  steam  under  pressure,  decomposition  of 
the  oil  may  take  place  with  formation  of  CS2. 
The  yellowish  brown  flocculent  precipitate  that  forms  in  the  oil, 
especially  upon  exposure  to  light  or  air  gave  the  following  analyti- 
cal results  I,  compared  with  those  from  pure  oil  II : 
C.  H.  N.  S.  O. 
I.    44*28  5-67  I3'09  2174  15-22  (by  difference) 
II.    48-49  5-05  14-14  32-32 
Comparing  these  results  it  would  seem  that  the  oxidation  of  the 
oil  is  accompanied  by  the  separation  of  carbon  and  sulphur,  prob- 
ably as  CS2. 
If  in  the  distillation  of  oil  of  mustard  a  copper  condensing-worm 
be  used,  there  is  often  deposited  a  compound  of  copper,  which  after 
washing  with  alcohol  approximates  the  formula  Cu2S,C3H5CNS, 
a  combination  of  the  oil  with  cuprous  sulphide. 
Myronate  of  potassium,  C10HlsKNS2O10  in  its  decomposition  by 
ferments,  breaks  up  without  uniting  with  elements  of  water ;  while 
all  other  glucosides  unite  with  water  under  the  condition  named. 
The  author,  however,  found  that,  while  myronate  of  potassium  dried 
over  H2S04  agreed  to  the  above  formula,  by  heating  it  carefully  to 
temperatures  not  exceeding  100°  C,  almost  enough  water  was  lost 
to  equal  one  molecule,  and  it  is,  therefore,  probable  that  the  formula 
of  the  anhydrous  myronate  of  potassium  is  C10H16KNS2O9,  and  that 
in  its  decomposition  H.,0  is  necessary  as  in  the  case  of  all  other 
glucosides.  This  would  make  the  rule  absolute  that  H20  is 
essential  to  the  decomposition  of  all  glucosides. — Pharm.  Ztschr.f. 
Russl.,  1890,  737,  etc. 
^    GRANULAR  EFFERVESCENT  POWDERS.1 
By  Hedley  Pattinson. 
Let  us  look  at  "the  theory  of  granulation  first.    It  is  the  citric 
acid  in  the  mixed  powder  which  is  the  chief  factor  in  the  process  of 
granulation,  assisted  to  a  small  extent  by  the  moisture  in  the  sugar. 
1  From  a  paper  read  before  the  Chemists'  Assistants'  Association,  Newcastle- 
on-Tyne  ;  Phar.  Jour,  and  Trans.,  February  7,  1891,  p.  712. 
\ 
