136 
ATTAR  OF  ROSE. 
which  it  is  poured  off  after  standing  one  day.  The  washed  oil  is 
then  placed,  in  shallow  saucers  exposed  as  much  as  possible  to  the 
sun  and  air,  whereby  it  gradually  loses  its  objectionable  odor. 
The  spring  and  early  summer  are  the  seasons  most  suitable  for 
this  operation,  the  period  required  for  it  varying,  according  to 
the  quality  of  the  oil  and  the  weather,  from  two  to  four  weeks. 
Artificial  bleaching  agents  could  doubtless  be  used  for  depriving 
the  oil  of  its  color,  but  not  for  refining  its  odor.  Those  who 
have  tried  them  have  always  returned  to  the  old  method  of  ex- 
posure to  solar  light ;  and  though  the  resources  of  art  may  not 
have  been  exhausted,  they  have  certainly  not  yet  been  success- 
fully applied  for  the  improvement  of  this  oil. 
Refined  Geranium  oil  constitutes  a  bright  yellow,  somewhat 
viscid  liquid,  of  an  odor  remotely  suggestive  of  roses,  and  not 
over-strong  ;  its  sp.  gr.  varies  according  to  the  degree  of  insola- 
tion (resinification)  from  Q'88  to  0-92.  When  the  oil  is  good  and 
the  refining  process  has  been  well  conducted,  a  considerably  lar- 
ger quantity  may  be  added  to  the  attar  without  diminishing  its 
disposition  to  congeal  than  when  the  oil  is  of  inferior  quality. 
To  this  the  consistence  or  sp.  gr.  of  an  oil  chiefly  contributes, 
for  the  more  geranium  oil  accords  in  sp.  gr.  with  the  attar  with 
which  it  is  mixed,  the  more  fully  does  the  latter  retain  its  own 
peculiar  qualities.  If  geranium  oil  be  re-distilled,  whereby  it  is 
rendered  lighter,  or  if  with  the  bleached  oil,  resin  etc.  is  mixed 
so  as  to  make  it  heavier  and  more  viscid,  the  congealing  power 
of  attar  with  which  either  of  such  oils  is  mixed,  is  impaired. 
Geranium  oil  does  not  solidify  at  —  20°  C.  (—  4°  Fahr.),  but 
becomes  at  that  temperature  turbid  and  thick.  Like  attar,  it 
takes  up  ozone  from  the  air  and  shows  an  energetic  reaction  with 
iodine  ;  it  is  easily  soluble  in  ordinary  spirit  of  wine,  and  affords 
like  attar  a  well-crystallized  compound  with  Ca  CI.  It  is  quite 
inactive  to  a  ray  of  polarized  light. 
Geranium  oil  is  mixed  with  attar  in  almost  any  proportion, 
from  a  few  parts  per  cent,  up  to  80  or  90.  The  differences  in 
congealing  point  are  not  quite  in  proportion  to  the  relative 
volumes  of  the  two  oils  which  are  mixed,  apart  from  the  varia- 
ble properties  of  each  ;  and  to  calculate  the  amount  of  mixture 
that  is  required  to  suit  a  particular  market,  one  has  always  to 
