30  Abstracts  from  the  French  Journals.  {Amjin%^arm- 
intensity  of  the  coloration  through  comparison  with  solutions  of 
known  strength. 
The  generation  of  oxygen  by  plants  has  been  studied  by  Henri 
Jumelle  [Compt.  rend.,  cxii,  1462)  at  very  low  temperatures  and  he 
found  that  carbonic  acid  is  decomposed  at  low  temperatures,  at  which 
respiration  has  completely  ceased,  by  plants  the  vitality  of  which  is 
not  affected  by  a  high  degree  of  cold.  Thus  the  assimilation  of 
atmospheric  carbonic  acid  gas  is  effected  in  the  light  at — 350  and — 
400  C.  by  Picea,  Juniperus  and  other  coniferae,  and  by  lichens  like 
Evernia  Prunastri. 
Compounds  of  camphor  with  aldehydes. — A.  Haller  has  found  the 
following  process  to  yield  good  results  [Compt.  rend.,  ciii,  22) :  Dissolve 
1 5  gm.  sodium  in  a  solution  of  150  gm.  camphor  and  400  gm.  toluol, 
allow  to  cool,  pour  off  the  liquid,  wash  the  crystals  of  sodium 
camphor  with  a  little  benzol,  and  then  heat  with  100  gm,  toluol  and 
105  gm.  benzaldehyde ;  after  washing  with  water  the  oily  liquid 
contains  toluol,  camphor,  borneol,  borneol  benzoate  and  benzal 
camphor  (dextro) ;  the  latter  melts  at  95 0  C.  Lsevocamphor  yields 
lsevo-benzalcamphor  having  identical  properties  except  in  behavior 
to  polarized  light.  A  mixture  of  equal  parts  of  the  two  is  inactive 
and  melts  at  780  C.  Analogous  crystalline  compounds  have  been 
obtained  as  follows :  Cuminalcamphor  C20H26O,  melting  point,  620; 
methylsalicylalcamphor,  m.  p.  93 °;  ethylsalicylalcamphor,  m.  p.  65 °; 
cinnamalcamphor  C19H220,  boils  at  280  to  2900  C.- 
Reaction  of  oil  of  turpentine  with  manganous  salts  — Commercial 
oil  of  turpentine,  on  being  agitated  with  an  ammoniacal  solution  of 
a  manganous  salt,  acquires  a  blackish  brown  color ;  the  reaction  is 
facilitated  by  the  application  of  heat.  L.  Crismer  [Bull.  Soc.  chim. 
[3]  vi,  25)  ascertained  that  this  reaction  depends  not  only  upon  the 
presence  of  hydrogen  dioxide,  but  likewise  of  a  small  quantity  of  a 
water-insoluble  acid,  which  was  produced  by  the  prolonged  influence 
of  air  upon  the  oil.  The  same  reaction  takes  place  with  pure  oil  of 
turpentine,  by  adding  to  it  a  little  oleic  acid,  followed  by  the  man- 
ganous solution,  and  agitating  the  mixture  with  air.  Oil  of  lemon 
shows  a  similar  behavior.  On  distilling  the  brown  oil  in  vacuo,  a 
resinous  residue  is  left,  soluble  in  chloroform  and  containing  man- 
ganese and  formic  acid,  the  latter  apparently  produced  by  the 
oxidation  of  the  terpene.  This  behavior  may  be  used  for  the 
detection  of  oil  of  turpentine  in  various  mixtures. 
