118 
Volatile  Oil  of  Monarda  Fanddin. 
( \m.  Jour.  Pharm. 
V     March,  18gH. 
The  results  of  six  experiments  with  the  hydrocarbon  found  are  as 
follows : 
1.  O'lOO  gram  of  substance  vaporized  replaced  17.6  cbc.  of  air. 
2.  0-090  ^  16-2 
3.  0-057  "  "  10-1 
4.  0-068  "  "  12-2 
o.  0.089  "  15-6 
6.  0.117  20.6 
These  figures  with  the  observation  of  the  barometric  pressure,  the 
temperature  of  tlie  water,  and  also  the  tension  of  vapor  of  water,  gave 
on  calculation  the  following  vapor  densities  : 
Calculated  vapor.  Found. 
Density  for  C'lo  H„. 
'=  4-71. 
1-  1 
3. 
4. 
5. 
6. 
481 
4-65 
4-74 
4-73 
4-S2 
4-75 
These  all  correspond  sufficiently  close  to  that  of  C^q  H^g. 
The  vapor  densities  of  the  oxygenated  compounds  are  as  follows 
I.  Thymol,  C\q  H^^  0. 
Calculated  mpor. 
Found. 
Density  for  Cio  H,^  0. 
"  =  5-19. 
1. 
2. 
3. 
5-22 
5-14 
516 
These  figures  correspond  also  very  well  with       H^^  O,  and  upon 
calculation  that  formula  was  arrived  at. 
11.  Higher  compound  C\^,  H^^  O. 
Calculated  vapor.  Found. 
Density  for  Cio  H^,  O. 
=5-33. 
1. 
5-30 
5-35 
5-3< 
On  calculation  with  these  results,  this  showed  also  the  formula  of 
that  body  to  be  C^o  H^^  O. 
Polarization.  The  action  of  polarized  light  upon  the  compounds 
obtained  was  noted  ;  that  of  the  hydrocarbon  and  of  the  oxygenated 
compounds.   With  a  200  mm.  tube  the  following  readings  were  made  : 
