ON  SOME  OF  THE  APPLICATIONS  OF  GLYCERINE.  159 
neutral  fats  by  water  under  great  pressure  coming  under  our 
notice,  led  us  to  look  again  more  closely  into  our  old  distilling 
processes ;  and  the  doing  this  showed,  what  we  had  often  been 
on  the  brink  of  discovering,  that  glycerine  might  be  distilled. 
In  our  new  process  the  only  chemical  agents  employed  for 
decomposing  the  neutral  fat,  and  separating  its  glycerine,  are 
steam  and  heat ;  and  the  only  agents  used  in  purifying  the  gly- 
cerine 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. 
Steam,  at  a  temperature  of  from  550^  to  600*^  Fah.,  is  intro- 
duced 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,  other- 
wise the  elements  of  the  glycerine  do  not  take  up  their  equiva- 
lent of  water,  and  acroleine  is  evolved, — -a  body  of  a  very  differ- 
ent character,  an  acrid  eye-inflaming  vapor,  appreciated  only 
by  those  who  have  had  the  misfortune  of  an  experimental  ac- 
quaintance with  it. 
In  an  ordinary  apparatus  the  glycerine  distilled  from  the  neu- 
tral fat  is  not  in  a  sufficiently  concentrated  state  for  most  pur- 
poses :  it  should  therefore  be  concentrated,  and,  if  discolored, 
be  redistilled.  It  is  then  obtained  of  sp.  gr.  1.240,  and  con- 
tains 94  per  cent,  of  anhydrous  glycerine.  It  can  be  concen- 
trated to  sp.  gr.  1.260,  or  to  contain  98  per  cent. 
Mr.  Wilson  then  described  attempts  which  had  been  made  to 
process  is  alluded  to  by  the  author,  and  who  8oId  his  patent  to  Price's  Can- 
dle Company,  where  Mr.  Wilson  is  engaged.  To  Mr.  Tilghraan  is  due  the 
credit  of  discovering  that  the  exposure  of  fats  and  water  to  a  temperature 
above  500°  resolved  them  into  hydrated  acids  and  glycerine,  and  Mr.  Wil- 
son extended  this  idea  to  the  application  of  the  water  as  super-heated  steam, 
and  thus  arrived  at  the  result  of  the  volatility  of  glycerine  without  de- 
composition when  aided  by  watery  vapor  in  the  absence  of  atmospheric 
air.  Why  did  not  Mr.  Wilson  mention  Mr.  Tilghman  ? — Editor  Am. 
Journ.  Pharm/j 
