GLEANINGS — CHEMICAL  AND  PHYSIOLOGICAL.  525  . 
for  the  poppy,  almond  and  olive  oils;  about  a  month  for  the  butter, 
whale  oil  and  decolorized  English  cod-liver  oil,  and  a  month's 
use  of  the  brown  cod-liver  oil  caused  no  'perceptible  increase  in 
the  fatty  matter  of  the  excrement.  He  therefore  divides  the  fatty 
bodies  into  three  classes:  1st,  the  difficultly  assimilable,  (vege- 
table oils.)  2d,  the  assimilable,  as  butter,  whale  oil,  &c.  3d, 
very  assimilable,  brown  cod  liver  oil  Chemist. 
Detection  of  Picric  Acid  in  Beer  M.  Pohl,  of  Vienna,  states 
that  carbazotic  (picric)  acid  may  be  detected  in  beer,  when  in 
the  proportion  of  one-eight  millionth,  by  boiling  a  little  very 
white  wool,  unmordanted,  in  the  suspected  beer  for  six  or  eight 
minutes,  when,  if  present,  the  wool  contracts  a  more  or  less  deep 
canary  yellow  color. — Chemist. 
New  Process  for  Arresting  the  Escape  of  Corrosive  Vapors 
from  Chimnies. — By  M.  Tessier. — The  process  consists  essen- 
tially in  causing  the  gases  from  the  manufactory  to  pass  through 
an  oven  containing  lime,  or  its  carbonate  heated  to  a  tempera- 
ture favorable  to  the  absorption  of  the  gases,  before  they  can 
pass  into  the  chimney.  Hydrochloric  acid  and  corrosive  chlo- 
rides are  thus  arrested  in  the  author's  aluminium  works,  near 
Rouen. — Chemist. 
Chrysophanie  Acid. — M.  Rochleder  has  extracted  chrysopha- 
nic  acid,  C20  H8  0s,  identical  with  rheine,  from  wall  lichen  (Par- 
melia  parietina)  or  from  rhubarb,  by  the  following  process  : — 
These  substance  are  exhausted  by  weak  alcohol,  with  the  ad- 
dition of  a  small  quantity  of  caustic  potassa.  It  is  strained 
through  a  cloth  with  pressure,  filtered,  and  a  current  of  washed 
carbonic  acid  passed  through  the  solution.  A  precipitate  is 
formed,  which  is  collected  and  dissolved  in  spirits  of  wine,  at 
122°  F.,  to  which  a  little  potassa  has  been  added.  The  solution 
is  filtered  and  precipitated  with  acetic  acid,  the  precipitate  re- 
dissolved  in  boiling  alcohol,  mixed  with  water  and  filtered,  when 
the  liquid  deposits  chrysophanic  acid  in  yellow  flocks,  which  may 
be  obtained  in  crystals  from  alcohol. — Jour,  fur  Prac.  Chem. 
ON  IODISED  OIL.    By  M.  Hugounenq. 
Various  processes  have  been  proposed  for  the  preparation  of 
iodised  oil. 
The  first,  published  by  M.  Personne,  consists  in  passing  a 
