302  Pelargonium-Oil.  { Am' M™y  §21 rm' 
The  passing  away  of  this  great  man  undoubtedly  leaves  a  void 
that  can  be  scarcely  filled  and  the  sterling  example  of  him  amply 
blazes  the  trail  for  those  who  are  eager  to  follow  in  the  prints  of  his 
climbing  foot-steps. 
I.  G. 
ORIGINAL  PAPERS 
PELARGONIUM-OIL. 
Professor  Richard  Knuth, 
charlottenburg,  germany. 
The  rose-oil  which  plays  a  prominent  part  in  the  manufacture 
of  the  best  perfumes  and  is  used  pure  as  perfume  and  as  an  ingre- 
dient in  the  manufacture  of  soap,  is  produced  not  only  from  the 
petals  of  Rosa  damascena  Mill,  but  often  from  other  plants,  which 
have  a  similar  odor.  Such  substitutes  of  the  best  sort  are  the  pelargo- 
nium-, the  palmarosa-  and  the  gingergrass-oil.  The  latter  two,  ac- 
cording to  Stapf  (Kew  Bull.,  1906,  p.  297),  are  respectively  termed 
Andropogon  schoenanthus  Fliick.  et  Hanb.,  non  L.  and  Schoenan- 
thus  var.  Martini  Hook  f .  This  plant,  which  is  widely  distributed  in 
India,  is  used,  according  to  his  reports,  as  an  oil-plant  in  Kandesh 
of  the  Presidency  of  Bombay,  in  the  districts  of  Nagpur,  Sagar, 
Qabalpur,  and  Karnul,  and  in  Ajmere  of  Radschputana.  Ac- 
cording to  one  opinion,  the  two  oils  are  produced  by  different  stages 
of  development,  according  to  another  by  different  varieties  of  the 
same  species. 
The  most  valuable  substitute  for  rose-oil  is  undoubtedly  the 
pelargonium-oil,  which  is  obtained  from  the  rose- geranium.  The 
name  of  this  geranium  dates  from  the  time  when  the  two  genera 
geranium  and  pelargonium  had  not  yet  been  separated.  Linne  classed 
most  of  the  geraniaceae  as  geranium ;  l'Heritier  was  the  first  to  sepa- 
rate, in  1 787- 1 788,  the  species  pelargonium  and  erodium  from 
geranium. 
CLASSIFICATION  OF  THE  PLANT. 
Gintl  (p.  268)  pointed  out  in  1879  that  the  French  rose-oil  is 
manufactured  from  Pelargonium  radula,  that  of  Algeria  from  P. 
roseum  and  P.  odoratissimum.  The  French  oil  is  said  to  polarize 
light  to  the  right,  the  Algerian,  to  the  left.  According  to  Heuze  (p. 
