Am.  Jour.  Pharm. 
Feb.,  1887. 
Terebene. 
67 
purpose  of  ascertaining  the  correctness  of  this  assumption  we  pur- 
chased samples  from  the  leading  drug  houses  of  this  city.  We  found 
it  popularly  believed  that  the  European  articles  were  the  purest  to  be 
had.  We  purchased,  among  others,  a  very  fine  looking  English 
preparation,  which  is  recommended  by  an  authority  on  throat  affec- 
tions, but  as  our  table  shows  this  was  one  of  the  poorest  in  the 
market. 
The  following  table  was  prepared  after  a  careful  examination  of  the 
material  for  sale  by  first-class  druggists;  great  care  being  exercised 
in  each  case  to  obtain  the  terebene  in  its  original  packages  so  as  to  in- 
sure its  authenticity.  The  rotation  in  the  following  is  for  10  cm.  of 
liquid  and  the  mean  of  six  readings.  The  gravities  were  taken  at 
14°  C. 
No. 
Origin . 
Rotation. 
Gravity 
155° 
160° 
165° 
170° 
175° 
180° 
185°  190° 
1 
Turpentine. 
14°  11' 
0-8T2 
3> 
84$ 
91$ 
96$ 
2 
12°  8' 
0-882 
15 
71 
86 
87 
88 
3 
li°  17' 
0-872 
0 
85 
91 
96 
4 
9°  54' 
0-872 
0 
85 
92 
96 
5 
German. 
9°  8' 
8°  I  V 
0910 
4 
50 
64 
74 
79 
82 
6 
7 
i?) 
English. 
7°  bS' 
0 
57 
78 
86 
92 
96 
8 
American. 
1°  44' 
0-865 
0  . 
10 
31 
58 
76 
86 
90  92 
9 
<< 
l°2u' 
6 
16 
43 
70 
83 
90 
10 
German. 
0°  58' 
0875 
0 
59 
78 
87 
9i 
96 
11 
0°  26' 
0 
48 
72 
82 
92 
12 
IP  18' 
0-860 
0 
0 
0 
36 
74 
87 
91  95 
13 
American. 
0°  3' 
0-860 
0 
0 
0 
40 
78 
91 
96 
For  convenience  of  comparison  we  have  added  the  tests  of  four 
commercial  turpentines.  No.  5  is  a  terebene,  slightly  yellow,  with 
smell  of  turpentine;  above  183°  this  sample  decomposed  and  left  a 
thick  resin. 
No.  7,  a  very  clear  water-white  article,  smells  of  turpentine. 
No.  13  was  prepared  by  ourselves. 
It  will  be  seen  by  a  careful  inspection  of  the  above  table  that  the 
determination  of  the  specific  gravity  and  boiling  points  are  of  little 
value  in  estimating  the  purity  of  terebene.  The  smell  also  has  no 
direct  bearing  on  the  purity,  as  the  odor  of  turpentine  is  masked  when 
mixed  with  its  own  weight  of  terebene.  The  only  reliable  determina- 
tion of  purity  is  the  test  with  the  polariscope  together  with  the  ab- 
sence of  fractions  above  190°  C. 
If  we  take  the  mean  rotation  of  commercial  turpentines  at  12°, 
then  the  samples  Nos.  7  and  8  would  contain  respectively  about  75, 
65  and  15  per  cent,  of  turpentine  oil.    No  reliance,  however,  can  be 
