Am-/u°1^-1f8h9arm-}  Notes  on  Essential  Oils.  373 
Two  samples  of  Italian  peppermint  oil  examined  gave  the  following  re- 
sults :— (1)  "  Foglie  de  Menta :"  sp.  gr.  0-921  at  19° ;  boiling  point  about  195°- 
222°  ;  44  per  cent,  distilled  between  195°  and  210° ;  37  per  cent,  between  210° 
and  222° ;  residue  19  per  cent.  (2)  "  Fiori  di  Menta :"  sp.  gr.  0.915  at  190° ; 
boiling  point  about  195°-222° ;  57  per  cent,  distilled  between  195°  and  210°  ; 
36  per  cent,  between  210°  and  225° ;  residue  19  per  cent.  Neither  sample 
gave  a  separation  of  menthol  upon  being  placed  in  a  freezing  mixture.  It 
is  considered  that  according  to  these  results  both  these  oils  range  in  quality 
below  line  American  oils.  A  sample  of  Russian  peppermint  oil  gave : — Sp. 
gr.  0  908  at  20° ;  boiling  point  about  195°-222° ;  46  per  cent,  distilled  be- 
tween 195°  and  210° ;  40  per  cent,  between  210°  and  222° ;  residue  14  per 
cent.  Placed  in  a  cooling  mixture  the  oil  formed  a  thin  paste;  it  contained 
consequently  a  small  quantity  of  menthol. 
Rose  Oil. — Information  is  given  as  to  the  properties  of  a  pure  rose  oil,  and 
especially  as  to  the  characteristic  stearoptene  and  the  possible  introduction 
of  spermaceti.  The  stearoptene  of  rose  oil  is  a  hydrocarbon,  CnH2n,  which 
is  not  altered  by  boiling  with  alcoholic  potash  solution,  whilst  spermaceti, 
which  is  essentially  palmitic-cetyl-ether,  is  saponified  by  that  reagent,  with 
the  formation  of  potassium  palmitate  and  cetyl  alcohol.  Upon  this  fact 
Messrs.  Schimmel  have  based  a  method  for  the  examination  of  the  oil. 
(1)  Isolation  and  determination  of  the  stearoptene.  Fifty  grams  of  oil  are 
heated  with  500  grams  of  75  per  cent,  spirit  to  a  temperature  of  70°  to  80°. 
Upon  cooling  the  stearoptene  separates  nearly  entirely.  It  is  removed  from 
the  liquid  and  treated  similarly  with  200  grams  more  of  75  per  cent,  spirit, 
and  this  operation  is  repeated  until  the  stearoptene  is  obtained  perfectly 
odorless,  a  second  treatment  of  the  crude  stearoptene  being  usually  sufficient. 
In  this  way  the  following  results  were  obtained  with  different  samples  of 
German  and  Turkish  oil. 
Grams 
Grams  oil.  stearoptene.  Per  cent. 
German,  1887   50  gave  16-2  =32% 
1888   50  "  16-9  =34 
Turkish,  1887   50  6  "3  •  =12-13 
1888   50  "       6-9  =14 
(2)  Determination  of  an  Admixture  of  Spermaceti. — 3-5  grams  of  the 
stearoptene  are  boiled  for  five  or  six  hours  in  a  return  condenser  with  20  to 
25  grams  of  5  per  cent,  alcoholic  potash  solution;  the  alcohol  is  then  driven 
off  and  the  residue  treated  with  hot  water.  Upon  cooling  the  greater  part 
of  the  stearoptene  separates  on  the  surface  as  a  crystalline  mass.  The  alka- 
line liquor  is  then  poured  off,  the  stearoptene  washed  with  some  cold  water, 
then  again  melted  down  with  hot  water,  allowed  to  cool  and  the  water  poured 
off,  and  this  is  repeated  until  the  wash- water  is  neutral.  The  united  aqueous 
liquor  is  shaken  twice  with  ether,  to  remove  suspended  stearoptene,  and 
after  separation  of  the  ether  is  acidulated  with  dilute  sulphuric  acid  and 
again  extracted  with  ether,  which  upon  evaporation  should  leave  no  residue 
(fat  acid).  As  a  check  the  stearoptene,  including  that  withdrawn  from  the 
alkaline  liquid,  is  dried  at  90°  and  weighed.  There  will,  however,  be  a  small 
loss  due  to  the  volatilization  of  some  stearoptene.    In  a  control  experiment 
