Am.  Jour.  Pharm. ) 
July,  1881.  J 
Otto  of  Rose. 
369 
tillation  are  spread  out  in  cellars,  but  all  are  treated  within  the  day  on 
which  they  are  plucked.  Baur  states  that,  if  the  buds  develop  slowly,  by 
reason  of  cool  damp  weather,  and  are  not  much  exposed  to  sun  heat  when 
about  to  be  collected,  a  rich  yield  of  otto,  having  a  low  solidifying  point, 
is  the  result,  whereas,  should  the  sky  be  clear  and  the  temperature  high  at 
or  shortly  before  the  time  of  gathering,  the  product  is  diminished  and  is 
more  easily  congealable.  Hanbury,  on  the  contrary,  when  distilling  roses 
in  London,  noticed  that  when  they  had  been  collected  on  fine  dry  days 
the  rose  water  had  most  volatile  oil  floating  upon  it,  and  that,  when  gath- 
ered in  cool  and  rainy  weather,  little  or  no  volatile  oil  separated. 
The  flowers  are  not  salted,  nor  subjected  to  any  other  treatment,  before 
being  conveyed  in  baskets  on  the  heads  of  men  and  women,  and  backs  of 
animals,  to  the  distilling  apj^aratus.  This  consists  of  a  tinned-copper  still, 
erected  on  a  semicircle  of  bricks,  and  heated  by  a  wood  fire;  from  the  top 
passes  a  straight  tin  pipe,  which  obliquely  traverses  a  tub  kept  constantly 
filled  with  cold  water,  by  a  spout,  from  some  convenient  rivulet,  and  con- 
stitutes the  condenser.  Several  such  stills  are  usually  placed  together, 
often  beneath  the  shade  of  a  large  tree.  The  still  is  charged  with  25  to  50 
lbs.  of  roses,  not  previously  deprived  of  their  calyces,  and  double  the  vol- 
ume of  spring  water.  The  distillation  is  carried  on  for  about  one  hour  and  " 
a  half,  the  result  being  simply  a  very  oily  rose  water  {ghyul-suyu) .  The 
exhausted  flowers  are  removed  from  the  still,  and  the  decoction  is  used  for 
the  next  distillation  instead  of  fresh  water.  The  first  distillates  from  each 
apparatus  are  mixed  and  distilled  by  themselves,  one-sixth  being  drawn 
off;  the  residue  replaces  spring  water  for  subsequent  operations.  The  dis- 
tillate is  received  in  long-necked  bottles,  holding  about  1^  gallon.  It  is 
kept  in  them  for  a  day  or  two,  at  a  temperature  exceeding  59°F.,  by  which 
time  most  of  the  oil,  fluid  and  bright,  will  have  reached  the  surface.  It  is 
skimmed  off  by  a  small,  long-handled,  fine-orificed  tin  funnel,  and  is  then 
ready  for  sale.  The  last-run  rose  water  is  extremely  fragrant,  and  is  much 
prized  locally  for  cvilinary  and  medicinal  purposes.  The  quantity  and 
qualitiy  of  the  otto  are  much  influenced  by  the  character  of  the  water  used 
in  distilling.  When  hard  spring  water  is  employed,  the  otto  is  rich  in 
stearopten,  but  less  transparent  and  fragrant.  The  average  quantity  of  the 
product  is  estimated  by  Baur  at  0*037  to  0-040  per  cent. ;  another  authority 
says  that  3,200  kilograms  of  roses  give  1  kilogram  of  oil. 
Pure  otto,  carefully  distilled,  is  at  first  colorless,  but  speedily  becomes 
yellowish  ;  its  specific  gravity  is  0'87  at  72'5°F. ;  its  boiling  point  is  444°F.  ; 
it  solidifies  at  5r8°  to  60'8°F.  or  still  higher;  it  is  soluble  in  absolute  alco- 
hol and  in  acetic  acid.  The  most  usual  and  reliable  tests  of  the  quality  of 
an  otto  are  (1)  its  odor,  (2)  its  congealing  point,  (3)  its  crystallization. 
The  odor  can  be  judged  only  after  long  experience.  A  good  oil  should 
congeal  well  in  five  minutes  at  a  temperature  of  54-5°F. ;  fraudulent  addi- 
tions lower  the  congealing  point.  The  crystals  of  rose-stearopten  are 
light,  feathery,  shining  plates,  filling  the  whole  liquid.  Almost  the  only 
material  used  for  artificially  heightening  the  apparent  proportion  of  stear- 
opten is  said  to  be  spermaceti,  which  is  easily  recognizable  from  its  liabil- 
ity to  settle  down  in  a  solid  cake,  and  from  its  melting  at  122°F.,  whereas 
24 
