196 
SOLUBILITY  OF  CAMPHOR  IN  WATER. 
ployed  to  determine  the  amount  of  camphor  taken  up  from  its 
mixture  with  carbonate  of  magnesia,  nor  do  the  authors  of  the 
United  States  Dispensatory  state  how  they  prove  the  presence 
of  "  fifty  grains"  of  camphor  in  each  pint  of  officinal  water. 
The  only  hints,  contained  in  the  standard  works,  that  suggest 
a  method  by  which  the  quantity  of  camphor  in  the  officinal  water 
might  be  determined,  are  the  statements  that  "  solution  of  po- 
tassa"  sulphate  of  magnesia  and  some  other  salts  will  separate 
camphor  from  its  aqueous  solution. 
To  test  the  truth  of  these  assertions  the  following  experi- 
ments were  instituted  : 
1st  exp.  Two  pints  of  camphor  water  were  treated  with  solu- 
tion of  potassa,  which  threw  down  a  bulky  flocculent  precipi- 
tate, which  was  collected  on  a  small  filter  and  dried  between 
folds  of  bibulous  paper,  by  which  treatment  it  lost  nearly  all 
its  bulk,  leaving  a  very  small  quantity  of  a  light-brown  colored 
substance  on  the  filter,  which  was  insoluble  in  water  and  alco- 
hol, but  the  greater  part  readily  dissolved  in  dilute  hydrochloric 
acid  with  effervescence. 
2d  exp.  Sulphate  of  magnesia  was  added  to  two  pints  of 
camphor  water  as  long  as  it  caused  a  separation  of  camphor, 
and  a  few  grains  were  obtained  floating  on  the  surface  of  the 
liquid. 
3d  exp.  Four  ounces  of  chloride  of  calcium  were  added  to 
two  pints  of  "  camphor  water,"  and  the  camphor  which  rose  to 
the  surface  was  collected  on  a  filter.  Two  more  ounces  of  the 
chloride  were  added  to  the  filtrate  without  causing  the  separa- 
tion of  an  additional  quantity  of  camphor.  The  camphor  on 
the  filter  was  washed  with  camphor  water,  dried  between  folds 
of  bibulous  paper,  dissolved  in  a  very  little  chloroform,  the  so- 
lution evaporated  spontaneously,  and  the  camphor  obtained 
weighed  six  grains. 
4th  exp.  One  pint  of  camphor  water  was  shaken  with 
stronger  ether,  and  set  aside  to  let  the  ether  separate.  When 
this  was  accomplished,  it  was  carefully  decanted  from  the  water 
and  then  evaporated  spontaneously,  but  without  yielding  cam- 
phor. 
5th  exp.  One  pint  of  camphor  water  was  treated  with  chloro- 
form with  negative  results. 
