440 
RUBIDIUM  IN  VEGETABLE  SUBSTANCES,  ETC. 
times  its  volume  of  ether.  In  a  little  time  the  whole  of  the 
ether  was  found  floating  upon  the  water,  and  had  carried  with 
it  the  whole  of  the  iodine,  leaving  the  iodide  of  iron  dissolved  in 
the  water,  from  which  carbonate  of  ammonium  threw  down  the 
white  carbonate  of  iron.  This  experiment  pretty  conclusively 
proves  what  our  President  asserted  in  the  "  Philosophical  Maga- 
zine," in  July,  1836,  viz.  that  the  periodide  of  iron  had  no  ex- 
istence, and  that  the  brown  solution  obtained  by  exposing  a  so- 
lution of  iodide  of  iron  to  the  air  was  nothing  more  than  a  solu- 
tion of  iodide  of  iron  with  some  free  iodine. — London  Pharm. 
Journ.,  Mai/,  1862. 
ON  THE  PRESENCE  OF  RUBIDIUM  IN  CERTAIN  VEGETABLE 
SUBSTANCES  (BEET-ROOT,  TOBACCO,  TEA,  COFFEE,  GRAPES). 
By  M.  L.  Grandeau. 
On  the  24th  of  February  last,  I  had  the  honor  to  communi- 
cate to  the  Academy  the  results  of  my  researches  on  the  pres- 
ence of  rubidium  in  the  salts  from  beet-root,  and  in  the  mother- 
liquors  obtained  from  treating  them  for  the  extraction  of  chloride 
of  potassium.  Since  then  I  have  actively  pursued  this  research, 
both  in  the  laboratory  of  the  upper  Ecole  Normale  and  also  in 
the  important  factory  of  M.  Lefebvre,  distiller  at  Corbehem, 
who  has  kindly  placed  at  my  disposal  the  substances  necessary 
for  extracting  chloride  of  rubidium  on  a  larger  scale. 
Thanks  to  this  assistance,  I  now  possess  400  grammes  of  pure 
chloride  of  rubidium,  about  half  of  which  has  been  prepared  at 
the  factory  at  Corbehem,  according  to  my  instructions,  by  the 
assistance  of  M.  Martel,  a  skilful  young  chemist  attached  to  M. 
Lefebvre's  establishment. 
When  presenting  to  the  Academy,  at  a  subsequent  sitting, 
the  new  salts  of  rubidium  which  I  had  been  able  to  prepare 
from  the  pure  chloride  at  my  disposal,  I  will  describe  the  pro- 
cesses which  I  have  employed  for  the  extraction  of  the  chloride, 
and  will  show  by  the  aid  of  a  few  figures  that  the  quantity  of 
rubidium  annually  removed  from  one  hectare  of  land  by  beet- 
root is  an  amount  not  to  be  neglected  from  an  agricultural  point 
of  view. 
I  now  propose  to  submit  to  the  Academy  some  new  results, 
