528  TO  PREVENT  THE  BUMPING  OP  LIQUIDS. 
own  experience,  that  his  proposition  to  run  a  constant  stream  of 
some  gas  through  the  boiling  liquid  would  answer,  at  least  in 
most  cases.  If  you  work  with  acids,  however,  such  as  nitric, 
sulphuric,  or  with  other  corrosive  liquids,  chloride  of  antimony, 
etc.,  where  the  bumping  is  sometimes  so  strong  that  your  cork  o^* 
india-rubber  stopper,  by  which  you  fit  your  glass  tube  into  the 
tubulus  of  the  retort,  will  not  resist  the  action  of  the  hot  vapors, 
and  consequently  the  whole  arrangement  will  not  be  applicable. 
There  is  another  objection  :  the  operation  of  condensation  is 
certainly  rendered  more  difficult,  where  a  permanent  gas  is  mixed 
with  the  vapors,  consequently  an  imperfect  condensation  and  an 
escape  of  some,  perhaps  not  unimportant,  part  of  the  liquid  is  to 
be  feared. 
In  distilling  acids  and  other  liquids  I  used  to  proceed  in  the 
following  manner,  by  far  in  the  most  cases  with  perfectly  satis- 
factory results  ;  once  or  twice,  however,  I  cannot  help  stating,  the 
result  has  been  unaccountably  dissatisfactory. 
The  end  of  an  ordinary  glass  pipe  of  about  J  inch  opening  is 
shut  at  one  end  and  this  end  bent  into  a  little  hook.  The  glass 
pipe  is  then  cut  exactly  so  long  as  to  reach  from  the  bottom  of 
a  glass  retort  to  within  J  inch  or  an  inch  of  the  stopper  of  the 
tubulus.  By  means  of  the  hook  and  a  piece  of  twine  or  a  little 
hook  of  thin  wire  this  glass  pipe  is  placed  into  the  retort,  the 
open  end  at  the  bottom,  and  the  retort  can  be  filled,  or  the  re- 
tort is  filled  first,  and  the  glass  pipe  entered  afterwards,  which 
will  probably  be  preferable.  If  the  liquid  now  is  warmed,  the 
air  in  the  glass  pipe  is  expanded,  and  constantly  bubbles  out  at 
the  open  end,  and  if  the  boiling  point  is  reached,  vapors  of  the 
tension  of  the  atmosphere  are  created  at  the  spot  where  the 
glass  pipe  stands  on  the  bottom  of  the  retort,  and  the  boiling 
continues  regularly  and  quietly  in  far  the  most  cases  for  days. 
If  the  retort  is  to  be  refilled,  the  glass  pipe  is  to  be  taken  out, 
in  order  to  empty  it,  and  then  is  replaced  again,  also  when  the 
operation  is  not  finished  the  first  day,  but  the  retort  cooled  and 
operation  resumed  next  morning. 
You  would  greatly  oblige  me  by  giving  the  above  a  space  in 
your  valuable  journal.  Yours,  respectfully, 
Theo.  Schumann, 
Newark,  N.  J.,  Sept.  25,  1869.  Apothecary, 
