340 
DETECTION  OF  ADULTERATED  ESSENTIAL  OILS. . 
To  show  this  calculation  by  an  example,  the  power  of  rotation 
is  supposed  to  be — 
of  the  pure  oil  of  lemon,  =+80°-573 
"       "     "      turpentine,  =—40° -275 
"     mixture,  =+18°-70 
the  quantity  of  the  mixture,      —20  c.  cm. 
(20— x)  80-573— 40-275*      =20  x  18-70 
7611-46— 80-573z—70-275z  =  374 
1237-46  =  122-848* 
10-0  =x. 
The  mixture  contains  equal  parts  of  the  pure  oil  and  the  adul- 
terating oil  of  turpentine. 
Optical  behaviour  of  several  essential  oils. 
Specific 
gravity. 
Power  of 
rotation. 
0-973 
+  20°-67 
0-835 
+  127°-43 
0-837 
0-850(?) 
+  125°-59 
-j-  29°-28 
0-850 
-f  49°-396 
0-877 
0-897 
0-848 
0-852 
—  6°-573 
—  ll°-7 
+  80°-484 
+  80°-573 
0-844 
+  79°-749 
0-853 
0-854 
0.881 
-f  78°-156 
-f-  80°-916 
—  34°-18 
0-898 
0.929 
—  28°-553 
—  40°-159 
0-914 
0.852 
0-855 
0-858 
0-8722(?) 
0  860 
0-865 
—  39°-40 
—  90° -30 
—  3°-521 
—  3°-479 
—  39°  9.50 
—  43°-38 
—  42°-25 
Tested  Oils. 
Oil  of  absinth  
Oil  of    orange  b 
first  product  
Oil  of   orange  b 
second  product. 
Oil  of  bergamot.... 
duct. 
duct  
Oil  of  caraway  seed  
Oil  of  lemon  
Oil  of  lemon  
Oil   of   lemon,  (Grasse, 
first  product, 
Oil  of  lemon,  (Grasse,) 
last  product  
Oil  of  lemon,  rectified  
Oil  of  copaiva  balsam  
Oil  of  copaiva  basam, 
(Para,)  
Oil  of  cubebs  
Oil  of  cubebs,  free  from 
water  
Oil  of  elemi  
Oil  of  juniper  
Oil  of  juniper  
Oil  of  turpentine  
Oil  of  turpentine  
Oil  of  turpentine  
Observer. 
|  Soubeiran 
J-  and 
|  Capitaine. 
J 
Biot. 
} Soubeiran 
and 
Capitaine. 
Maier. 
Biot. 
Maier. 
Soubeiran 
and 
Capitaine. 
Deville. 
Soubeiran  and  Capitaine, 
Maier. 
Biot. 
Soubeiran  and  Capitaine, 
Maier. 
Gladstone  (Chem.  Soc.  Jour.,  [2],  ii;  1,)  has  given  a  more 
complete  table  on  the  power  of  rotation  of  most  of  the  essential 
oils.  My  researches  were  restricted  to  the  few  above  mentioned. 
— Amer.  Jour.  Science  and  Arts,  May,  1863. 
