Amsi°ptf;Sarm'}         Oil  of  Erigeron  Canadense.  423 
residue  above  2200  was  viscid  and  resinous.  The  fraction  boiling 
below  1800,  of  which  there  were  1053*0  gm.  of  the  specific  gravity 
0-853  at  1 50  C,  was  distilled  with  water  vapors,  to  free  it  from  the 
resin,  which  remained  in  the  flask  as  a  viscid  cherry  red  liquid.  The 
oil  was  separated  from  the  water  and  dried  at  the  temperature  of 
the  water-bath  with  caustic  potash.  The  dry  oil  was  then  repeatedly 
subjected  to  fractional  distillation  with  the  aid  of  a  column.  The 
following  table  gives  the  fractions  obtained,  their  specific  gravity, 
and  action  upon  polarized  light : 
Fract.  B.  P. 
Sp.  G.  at 
20°  C. 
a  for  100 
mm. 
Aprox.  Amt. 
I,  
1 70° 
0-8521 
+  79-2° 
+  92-9° 
50  cc. 
II,  .... 
1 70-1 72° 
0-8503 
+  82770 
+  97'3° 
120  cc. 
Ill,  .... 
172-174° 
0-8510 
+  8579° 
+  ioo-S°* 
250  cc. 
IV,  ...  . 
1 74-i 75° 
0-8460 
+  90-64° 
+  107-1° 
250  cc. 
V,  .... 
175-176° 
0.8476 
4-92770 
4- 109-4°* 
200  cc. 
VI,   ...  . 
1 76- 1 78° 
0-8450 
+  95' 94° 
+  112-35° 
75  cc. 
VII,.  .  .  . 
178-1800 
0-8485 
+  93 '34° 
+  1107° 
50  cc. 
*  Of  fractions  III  and  V  the  rotatory  power  of  solutions  was  also  ascertained. 
Fraction  III. 
Fraction  V. 
S  -  2-9684 
S  =  2-199 
L  (ale.)  =  58-4220 
L  (ale.)  =  46-6506 
p.  =  4*83  per  cent. 
p.  =  4-5  per  cent. 
d.  =  0-816 
d.  =0-816 
t.  =  20 
t.  =  20 
1=1  d.m. 
1=1  d.m. 
«  =  +  37i 
0=  +  3-81 
)b  —  +  94*i 
(«)d  =  +  103-75 
It  will  be  seen  from  this  table  that,  with  the  increase  of  the  boil- 
ing point  of  the  fractions  up  to  the  sixth,  there  is  on  the  whole  a 
diminution  of  the  specific  gravity,  but  an  increase  of  the  rotatory 
power.  With  fraction  VII,  the  increase  in  temperature  is  accom- 
panied by  an  increase  of  specific  gravity,  but  there  is  a  diminution 
of  the  rotatory  power. 
Fraction  I  (/700). — This  fraction  was  obtained  chiefly  between 
168-1700  C.    Its  high  specific  gravity  led  to  the  suspicion  that 
