70 
Chemical  Notes. 
f  Am.  Jour.  Pharuk 
\      Feb.,  1882. 
deep  red  color  in  alkaline  carbonates,  ammonia  and  dilute  alkalies. 
The  solutions,  moreover,  show  a  striking  fluorescence  like  that  seen 
with  resorcin-phtalein.  The  bromine  compound,  obtained  by  adding 
alcoholic  bromine  to  an  alcoholic  solution  of  the  color,  dissolves  in 
alkaline  carbonates  with  a  fine  crimson-red  color. 
The  corresponding  citric  acid  compound  was  obtained  in  a  similar 
manner.  The  magnificent  blue  fluorescence  of  the  red  alkaline  solu- 
tion is  even  more  intense  than  in  the  tartaric  acid  compound.  The 
reaction  with  tartaric  acid  will  take  place  even  without  the  addition  of 
sulphuric  acid.  Fraude  calls  these  compounds  tartreins  and  citreins, 
analogous  to  phtaleins. 
Adolph  Claus  has  also  obtained  resorcin-oxalein.  This  compound 
only  forms  under  strong  pressure.  By  heating  anhydrous  oxalic  acid 
and  resorcin  in  open  vessels  it  cannot  be  produced,  and  even  in  closed 
tubes  the  mixture  has  to  be  heated  to  200°C.  to  produce  the  desired 
reaction.  One  molecule  of  oxalic  acid  and  one  of  resorcin  were  used. 
The  oxalein  was  precipitated  from  the  dilute  alcoholic  solution  by 
addition  of  water  or  was  gotten  by  evaporation  as  a  red  powder  toler- 
ably soluble  in  ether  and  possessing  a  formula  CjoHj^O^.  It  dissolves 
in  alkalies  whether  in  aqueous  solution  or  in  alcoholic  with  an 
intensely  red  or  brownish  color.  In  dilute  solutions  of  light  yellowish 
color  it  shows  a  strong  moss-green  fluorescence.  A  penta-bromine 
derivation  was  gotten  as  a  dark-fiery  red  powder. — Ber.  der  Chem.  Ges., 
xiv,  pp.  2558  and  2563. 
On  Pejpi^ermint  Camphor  [Menthol)  and  soyne  of  its  Derivatives. — 
R.  W.  Atkinson  and  H.  Yoshida  have  given  menthol  a  careful  exa- 
mination. After  repeated  purification  by  distillation,  careful  pressing 
between  filter-jiaper,  etc.,  the  authors  obtained  menthol  melting  at 
42-2°C.,  solidifying  at  40-3°C.,  and  boiling  at  212°C.  Mr.  Moriga 
has  shown  that  menthol,  when  heated  with  acid  bichromate  solution 
at  120°C.,  yields  an  oil  boiling  at  404°C.,  having  the  composition  of 
menthone,  CjoHigO  ("Jour.  Chem.  Soc.,''  March,  1881).  The  authors 
have  repeated  these  experiments,  using  larger  quantities.  Menthone 
is  a  colorless  mobile  liquid,  neutral  to  test  paper,  soluble  in  alcohol, 
chloroform,  benzene  and  bisulphide  of  carbon;  insoluble  in  water. 
If  a  solution  of  menthone  in  petroleum  naphtha  be  heated  with 
sodium,  the  solution  formed  decomposed  by  carbonic  acid,  the  product 
shaken  with  water,  rapidly  separated  from  the  oily  layer,  and  set  aside,, 
minute  crystals  of  menthol  are  obtained.    Menthol,  therefore,  stands- 
