^octo>berr,^fm'}  Microscopical  Examination  of  Cloves.  481 
a  =  weight  of  benzoyl  eugenol. 
b  =  weight  of  oil  taken. 
c  =  4-  01 10  gram  for  every  5  cubic  centimetres  of  alcohol  used 
(being  the  weight  of  benzoyl  eugenoldissolved  in  90  per 
cent,  alcohol). 
x  =  per  cent,  of  eugenol. 
Molecular  weight  of  eugenol  =  164. 
Molecular  weight  of  benzoyl  eugenol  =  268. 
Then 
268  :  164  =      4-  c)  :  weight  of  eugenol. 
Weight  of  eugenol  =  I_^4L(^_+_f) 
268 
r    164  (a  4-  c) 
0  :  — ?  y  1 — I  -    100  :  x 
.268 
164  (a  4-  c)  100 
.  268^ 
x 
4100  (0  4-  c) 
The  following  results  have  been  obtained  by  this  method  from  the 
commercial  samples  of  powdered  cloves  and  clove  oil : 
Powd.  Cloves.  Per  Cent.  Oil.       Per  Cent.  Eugenol. 
No.  1   17-50  5974 
No.  2    1775  60-45 
No.  31  12-75  66"  16 
1  This  sample  was  determined  by  the  microscope  to  contain  powdered  clove  stems,  although 
sold  by  a  large  house  in  New  York  as  powdered  cloves. 
Clove  Oil.  Per  Cent.  Eugenol. 
No.  1    ....<■   76  06 
No.  2   78-12 
No.  3   8345 
Coming  to  the  subject  of  quantitative  microscopical  analysis,  while 
accurate  results  may  be  possible,  so  far,  only  approximate  figures 
have  been  obtained.  These  may  not  be  without  interest  and  value, 
and  it  seems  probable  that  an  analyst  who  is  able  to  use  the  micro- 
scope may,  by  a  few  moments'  careful  examination,  obtain  evidences 
that  will  materially  aid  him  in  subsequent  chemical  analysis.  Re- 
garding the  statements  made  by  some  that  "  the  results  of  micro- 
scopical examination  are  not  always  uniform,"  I  must  refer  them  to 
