rochleder's  proximate  analysis. 
277 
the  oxygenated  oils,  in  many  mixed  oils.  Frequently  the  oxygenated  oils 
afford,  by  this  treatment,  colored  decomposition  products.  Thus  the  dis- 
tillate of  the  oil  of  calamus  over  soda-lime  is  at  first  colorless,  so  long 
as  the  lighter  volatile  oils  distil  over  unaltered.  Later,  a  blue  distillate 
appears,  arising  from  the  decomposition  of  the  less  volatile  oxygenated 
portion  of  the  oil  of  calamus,  by  the  alkali  at  a  higher  temperature. 
We  turn  back  to  the  aqueous  solution  of  the  baryta  salt  or  salts,  which 
was  obtained  by  agitating  the  oil  with  baryta  water,  which  oil  had  collect- 
ed Or)  the  surface,  or  at  the  bottom  of  the  watery  distillate.  The  solution 
is  divided  into  two  parts.  The  first  is  introduced  into  a  retort,  into  which 
a  little  hydrate  of  baryta  is  placed.  The  retort  is  connected  with  a  re- 
frigerator, and  the  greater  part  of  the  water  is  distilled  off.  If  an  acid 
ether  was  present,  this  is  decomposed.  The  corresponding  alcohol  is  sep- 
arated, and  is  found  in  the  distillate,  and  the  acid  in  combination  with  the 
baryta  is  in  the  residue  of  the  distillation.  The  second  part  of  the  solution 
is  mixed  with  dilute  sulphuric  acid,  as  long  as  a  precipitate  of  sulphate  of 
baryta  is  formed.  The  sulphate  of  baryta  is  separated  by  filtration,  and 
the  filtrate  distilled  off  until  a  small  residue  remains.  As  the  fluid  must 
contain  a  tolerably  large  quantity  of  volatile  acid  compounds,  it  may  be 
ascertained  whether  an  aldehyde  of  an  acid  character  is  present  or  not,  by 
the  addition  of  a  highly  concentrated  solution  of  alkaline  bisulphites,  and 
a  sufficiently  large  quantity  of  anhydrous  alcohol.  If  this  is  not  the  case, 
then  only  a  volatile  acid,  or  a  mixture  of  several  such  acids,  is  present. 
It  was  previously  mentioned  that  the  oil  separated  from  the  distillate, 
when  before  or  after  treatment  with  baryta  it  reacted  alkaline,  should  be 
shaken  with  dilute  sulphuric  acid  that  the  base  or  bases  present  may  be 
obtained  dissolved  as  sulphates.  The  solution  of  sulphates  is  then  mixed 
with  baryta  water  as  long  as  a  precipitate  of  sulphate  of  baryta  ensues  ; 
for  certainty,  one  or  two  drops  of  baryta  water  is  added  in  excess,  and  the 
liquid  distilled  from  a  retort  which  is  covmected  with  a  refrigeratory  ap- 
paratus, as  long  as  the  distillate  has  an  alkaline  reaction.  The  distillate 
is  now  exactly  neutralized  with  dilute  sulphuric  acid  and  evaporated  to 
dryness.  The  residue  is  treated  with  alcohol,  which  dissolves  the  sul- 
phates of  the  bases.  If  a  residue  remains,  either  ammonia  or  methylamine 
is  present,  or  a  mixture  of  both,  in  the  form  of  sulphates.  After  the  ex- 
pulsion of  the  alcohol  from  the  alcholic  extract  in  the  water-bath,  the  salts 
of  the  other  bases  perchance  present  remain  behind.  They  may  be  easily 
obtained  therefrom,  by  distillation  with  a  solution  of  caustic  potash,  in  an 
isolated  form,  or  by  mixing  the  salts  with  a  solution  of  caustic  potash  aifd 
agitating  with  ether,  by  which  an  ethereal  solution  of  the  bases  is  obtained, 
from  which  the  ether  can  be  distilled  off.  If  by  the  examination  of  the 
separated  oil  no  bases,  acids,  or  aldehydes  have  been  found  ;  if  no  com- 
pound ethers  are  present,  or  if  these  bodies  have  been  removed  ;  further, 
if  the  oxygenated  indifferent  volatile  oils  sometimes  present  have  been  sep- 
arated from  the  hydrocarbons  by  distillation  over  soda  lime,  in  so  far  as 
