154  Oil  of  Bitter  Almonds.  {^mAJprn;S 
Sodium  Thiosul-  H3PO4  abs.  in 
H3PO4  phate,  V.  S.  Original  Sample. 
5  c.c  21 -9  85*24  per  cent. 
5    "  21-8  85-84   "  " 
5    "    217  84*44   "  " 
5    "  21-8  84-84   "  " 
5    "  .  •  •  •  2r'9  84  24   "  " 
5    "  21-8  84-84   "  " 
Exposure  to  temperatures  above  65 0  C.  entail  a  loss  in  iodine 
through  failure  of  (even  specially  constructed)  pressure  vials  to  seal 
securely.  Digestion  for  longer  periods,  at  lower  temperatures, 
cause  a  further  liberation  of  iodine  due  to  secondary  reaction. 
Experiments  were  then  made  to  determine  the  feasibility  of  a  cold 
method  whereby  the  objectionable  features  of  the  above  might  be 
avoided.  It  was  found  that  the  reaction  (according  to  theory],  is 
complete  after  a  period  of  2-5  to  3  hours,  when  the  securely  stop- 
pered flask  and  contents  are  exposed  to  a  room  temperature  of  20°  C. 
These  conditions  must  be  strictly  followed,  otherwise  low  or  high 
results  will  be  obtained. 
Sodium  Thiosul-  ^PO^  abs.  in 
H3PO4  phate,  V.  S.  Original  Sample. 
5  c.c.  ,3     hours  287   c.c.  84-44  per  cent. 
5    "    3        "   21-8    "  84-84   "  " 
5    "    3        "   21-8    "  84  84  "  " 
5    "    2/2      "  ........  21-8    "  84-84  "  " 
5    «    2/2      "  ........  21-85  "  85-00   "  " 
The  gravimetric  estimation  of  abs.  H3P04  in  the  original  sample 
being  84.84  per  cent.,  further  comparisons  are  unnecessary  to 
demonstrate  the  value  of  this  method  for  the  accurate  titrimetric 
estimation  of  phosphoric  acid. 
OIL  OF  BITTER  ALMONDS. 
By  Frank  O.  Taylor. 
It  is  well  known  that  the  oil  of  bitter  almonds  of  commerce  is 
largely  substituted  by  artificial  benzaldehyde,  and  even  that  which 
is  natjral  is  not  often  derived  from  the  almond,  but  from  the  kernel 
of  the  apricot ;  but  the  extent  of  this  substitution  of  benzaldehyde 
for  the  genuine  oil  is  frequently  not  realized,  and  many  times  oil  of 
bitter  almonds  may  be  purchased  by  retail  dealers  which  is,  in  truth, 
nothing  more  than  the  much  cheaper  product,  benzaldehyde.  The 
