202  OLEUM  iETHEREUM  AND  SPIRITUS  iETHERIS  COMPOSITUS. 
the  ingredients  must  be  resorted  to.  Whichever  course  is  adopted^ 
however,  no  collateral  product  is  lost,  and  the  preparations  are 
practically  identical. 
The  officinal  compound  spirit  of  ether  consists  of 
Ethereal  oil,   3  f.3,       .       .       or    1-56  per  cent. 
Ether,  8  f.3,       .       .       "  32-81  « 
Alcohol,       16  f.|,       .       .       «  65-62  « 
The  mixing  of  these  ingredients  causes  a  diminution  of  volume 
about  equal  to  the  measure  of  the  oil,  so  that  the  finished  pre- 
paration has  the  volumetric  composition  given,  and  each  fluid 
drachm  contains  nearly  one  minum  of  the  heavy  oil  of  wine. 
The  weight  of  24  f.g  of  it,  at  60°  is  about  8640  grains,  hence 
1  f.3  weighs  360  grains.  The  weight  of  3  f.3  of  ethereal  oil  is 
188  grains,  hence  the  proportion  of  the  latter  ingredient  by 
weight  amounts  to  2-17  per  cent. 
Compound  spirit  of  ether  thus  made  is  a  colorless  bright  mobile 
liquid,  of  a  fruity  ethereal  odor,  of  s.  g.  -812  to  -816,  and  neutral 
or  very  slightly  acid  to  litmus  paper.  It  usually  gives  a  very 
faint  cloudiness  with  solution  of  chloride  of  barium  after  some 
months  keeping. 
Five  drops  =  2^1  of  the  compound  spirit,  well  stirred  into  one 
pint  of  water  give  a  distinct  oily  surface  on  standing  for  a 
moment,  and  yields  the  characteristic  fruity  odor  of  the  oil  free 
from  that  of  the  ether  and  alcohol. 
Sixteen  drops  =6^1,  stirred  in  a  like  manner  into  one  pint  of 
water  visibly  affects  the  transparency  of  the  water. 
Sixty  drops=23m,  renders  the  water  decidedly  milky,  but 
not  properly  opalescent,  for  the  milkiness  is  of  a  dull  leaden 
color,  and  not  bluish  or  pearly  as  in  the  appearance  generally 
called  opalescent. 
Two  fluid  drachms  renders  the  pint  of  water  so  turbid 
that  the  bottom  of  the  pint  beaker  in  which  the  mixture  is  made 
can  be  but  just  distinctly  seen  on  looking  down  through  the  long 
axis.  With  four  fluid  drachms  the  bottom  cannot  be  seen.  The 
odor  and  appearance  of  this  mixture  are  very  characteristic.  A 
few  minutes  after  the  stirring  has  ceased  the  minute  globules 
of  oil  begin  to  collect  at  the  bottom  of  the  beaker  in  the  form  of 
a  fine,  very  scanty  white  precipitate,  while  the  surface  is  but 
little  more  greasy  in  appearance  than  when  one  or  two  fluid 
drachms  had  been  stirred  in. 
