332 
GLEANINGS  FROM  GERMAN  JOURNALS. 
concentrated  as  possible,  and  evaporated  at  a  very  gentle  heat ; 
a  few  drops  of  a  concentrated  solution  yields  a  better  result 
than  a  large  quantity  of  a  diluted  one. — (N.  Jahrb.  f.  Ph.  xiv. 
129—134  ) 
Ammonium-Iron  The  galvanoplastic  deposit  from  protosalts 
of  iron  in  presence  of  an  ammonia  salt,  resembles  polished  steel, 
and  adheres  well  when  in  very  thin  layers,  but  peels  off  in  scales 
when  thicker.  After  washing  with  water,  the  precipitate  loses 
ammonia  over  caustic  potassa,  and  when  ignited,  and  in  boiling 
water,  an  evolution  of  hydrogen  is  observed.  Dr.  Meidinger 
views  this  as  a  compound  of  iron,  with  the  hypothetic  metal 
ammonium.  The  quantity  of  combined  ammonium  is  very 
small ;  in  one  sample  he  proved  not  over  lj  per  ct. — (N.  Jahrb. 
f.  Ph.  xvi.  295.  296.) 
Estimation  of  Chlorine  in  organic  compounds  Dr.  Carius 
has  modified  his  method  of  estimating  the  inorganic  elements  in 
organic  compounds  (heating  in  a  sealed  glass-tube  with  ni- 
tric acid  and  estimating  the  products  of  oxidation)  for  chlorine, 
bromine  and  iodine,  by  adding  a  small  excess  of  nitrate  of  silver. 
The  decomposition  is,  with  the  exception  of  the  aromatic  series, 
readily  effected,  frequently  at  ordinary  temperature  ;  the  bodies 
just  mentioned  are  best  decomposed  in  presence  of  bichromate 
of  potassa,  when  the  resulting  chromate  of  silver  is  removed  by 
diluting  the  acid  liquor  and  boiling.  Excess  of  silver  salt  has 
no  effect  on  the  accuracy  of  the  analysis  ;  but  a  large  amount 
of  even  dilute  nitric  acid  dissolves  chloride  of  silver,  and  ren- 
ders the  neutralization  with  carbonate  of  soda  requisite. —  (N. 
Jahrb.  f.  Ph.  xvi.  283,  284.) 
Reaction  of  Hydr iodic  Acid  with  Qlycerin, — Dr.  Erlenmeyer 
states  that  the  distillate  obtained  from  glycerin,  with  little 
hydriodic  acid,  contains  much  iodide  of  allyle ;  on  increasing 
the  acid,  the  allyle  iodide  diminishes,  and  in  its  place  iodide  of 
propyle  appears  in  the  distillate,  which  boils  between  85  and 
90°  C,  is  very  refractive,  and  resembles  in  odor  iodide  of 
ethyle.  The  supernatant  liquid  of  the  crude  distillate  yields 
sometimes  iodoform  on  neutralizing  with  potassa.  The  residue 
in  the  retort  is  black  resinous,  and  yields,  when  distilled  with 
