PROCESS  FOR  OBTAINING  AND  PURIFYING  GLYCERINE.  37 
thus  obtained  are  heat  and  steam.  Thus  all  trouble  from  earthy 
salts  or  lead  is  escaped. 
Distillation,  however,  purifies  the  impure  glycerine  of  the  old 
sources. 
On  the  table  is  a  series  of  products  of  palm  oil,  which  will 
serve  to  illustrate  the  process.  Steam,  at  a  temperature  of  from 
550°  to  600°  Fahr.,  is  introduced  into  a  distillatory  apparatus, 
containing  a  quantity  of  palm  oil.  The  fatty  acids  take  up  their 
equivalents  of  water,  and  the  glycerine  takes  up  its  equivalent  ; 
they  then  distil  over  together.  In  the  receiver,  the  condensed 
glycerine,  from  its  higher  specific  gravity,  sinks  below  the  fat 
acids.  Sufficient  steam  must  be  supplied,  and  the  temperature 
regulated,  otherwise  the  elements  of  the  glycerine  do  not  take  up 
their  equivalents  of  water,  and  acroleine  is  evolved — a  body  of  a 
very  different  character,  an  acrid  eye  inflaming  vapor,  appreci- 
ted  only  by  those  who  have  had  the  misfortune  of  an  experimen- 
tal acquaintance  with  it. 
In  an  ordinary  apparatus  the  glycerine  distilled  from  the  neu- 
tral fat  is  not  in  a  sufficiently  concentrated  state  for  most 
purposes  ;  it  should  therefore  be  concentrated,  and,  if  discolored, 
be  redistilled.  It  is  then  obtained,  in  the  state  of  the  specimen 
on  the  table,  at  the  temperature  of  60°  Fahr.  ;  it  is  of  sp.  gr. 
1-260,  or  to  contain  98  per  cent. 
I  have  now  to  mention  some  uses  for  glycerine,  which  I  be- 
lieve to  be  new,  or  to  which  I  have  seen  distilled  glycerine  ap- 
plied. 
A  possible  use  which  appears  worthy  of  experiment  is  to  in- 
ject it  into  the  bladder,  for  the  purpose  of  dissolving  calculous 
deposits  ;  from  its  blandness  it  should  not  cause  irritation,  while, 
as  it  is  a  solvent  of  urea  and  phosphate  of  lime,  it  might  dis- 
solve them  when  in  the  bladder.  Some  of  the  high  authorities 
have  received  glycerine  for  the  purpose  of  the  experiment. 
The  use  of  glycerine  in  photography  having  been  suggested, 
some  distilled  glycerine  has  been  sent  to  several  of  the  best 
photographers  and  makers  of  photographic  preparations.  It  was 
very  well  received,  and  considered  to  promise  well,  and  is  still 
the  subject  of  many  experiments;  but  as  yet  it  does  not  appear 
that  any  great  results  have  been  arrived  at.  It  is,  however,  ex- 
pected to  supersede  the  honey  and  Shadbolt's  process. 
