A,ujuOner;i90h6arm'}  American  Pharmacopoeia.  255 
cyanic  acid  between  2  and  4  per  cent.;1  d25Q  1-045  to  i*o6o;2  aD  ± 
O0;3  boiling  point  about  1800;  soluble  in  every  proportion  in  alco- 
hol, also  in  an  equal  volume  70. per  cent,  alcohol  ;4  test  for  absence 
of  chlorinated  products. 
Cajeput  Oil  {Oleum  cajuputi). — Colorless  or  greenish ,  cineol- 
content  at  least  55  per  cent,  by  volume;5  d25Q  0-915  to  925  ;6  laevo- 
rotatory,  aD250  not  above  —  2°  ;7  soluble  in  every  proportion  in 
alcohol,  also  in  1  part  80  per  cent,  alcohol. 
Camphor  (Camphora). — White,  transparent  mass  ;  d25Q  o  990  ; 
aD  to  the  right  ;  melting  point  1 75 0  ;  boiling  point  2040. 
Caraway  Oil  {Oleum  cart). — Colorless  or  pale  yellow  ;  d25Q  o  905 
to  0-915  ;8  aD250  -f-  70  to  -f-  8o°  ;  soluble  in  an  equal  volume  alcohol, 
and  in  3  to  10  volumes  80  per  cent,  alcohol. 
Cassia  Oil9  (Oleum  cinnamomi). — Yellowish  or  brownish;  content 
of  cinnamic  aldehyde  at  least  75  per  cent,  by  volume;  d25Q  1-045  to 
1  Such  a  content  of  hydrocyanic  acid  cannot  always  be  guaranteed. 
2  The  specific  gravity  given  is  for  a  temperature  of  15  °,  but  it  should  be 
taken  into  consideration  that  even  in  the  case  of  absolutely  normal  oils,  it  often 
amounts  to  1*070;  for  250  the  following  figures  apply:  1*038  to  1*063  (comp. 
table. 
3  Occasionally  a  feeble  optical  activity  is  also  observed. 
4  Of  70  per  cent,  alcohol  1  to  2  volumes  are  required  to  dissolve  the  oil. 
5  The  estimation  of  cineol  is  accomplished  by  means  of  phosphoric  acid  in  the 
following  manner  :  10  c.c.  oil  are  dissolved  in  50  c.c.  petroleum  ether,  and  to 
the  well  cooled  solution  (freezing  mixture)  is  gradually  added,  whilst  stirring, 
concentrated  phosphoric  acid,  until  the  white  compound  separating  off  acquirea 
a  yellowish  (or  reddish)  shade.  The  crystalline  mass  is  then  filtered  off  with 
a  suction  pump,  washed  with  petroleum  ether,  pressed  to  remove  the  last  liquid 
portions,  and  decomposed  with  water.  The  cineol  separated  off  is  estimated 
volumetrically  and  the  percentage  calculated. 
We  have  again  convinced  ourselves  by  estimations  of  mixtures  of  a  known 
cineol-content,  that  this  method  does  not  always  give  reliable  results.  This 
applies  specially  to  oils  Jess  rich  in  cineol  ;  for  example,  in  mixtures  of  50  per 
cent.,  the  content  of  cineol  found  was  up  to  8  per  cent,  too  little,  although  we 
endeavored  by  different  small  improvements,  to  avoid  sources  of  error  as  much 
as  possible.  For  this  reason,  the  cineol  estimations  can  only  lay  claim  to 
approximate  accuracy. 
6  As  lower  limit  of  value,  0*913  is  to  be  recommended  (comp.  table). 
7  With  pure  distillates,  we  have  observed  rotations  up  to  —  2C  40'. 
8  The  specific  gravity  given  applies  to  a  temperature  of  150  ;  it  should  read  : 
d25o  0*899  to  0*909  (comp.  table). 
9  Only  the  rectified  oil  answers  the  requirements  given. 
