TO  PREVENT  THE  BUMPING  OF  LIQUIDS. 
527 
represent  one  ounce  of  the  crude  drug,  I  will  testify  (from 
actual  proof)  can  be  made  by  Mr.  Campbell's  process.  But  that 
we  can  in  all  cases  by  that  process  reach  the  definite  results  re- 
quired by  our  standard  I  am  not  prepared  to  admit. 
I  hope,  however,  that  the  subject  may  be  more  fully  discussed  ; 
hope  in  fact  that  its  "  thorough  exhaustion  "  may  result  in  con- 
firming Mr.  Campbell's  views  and  refuting  my  own  doubts. 
H.  P.  Reynolds. 
Plainfield,  N.  J.,  Sept.  29,  1869. 
Note  by  Editor. — Mr.  Campbell,  instating  his  process  in  the  Septem- 
ber number,  does  not  make  his  meaning  clear  as  regards  moistening  the 
powder.  We  also  think  he  has  erred  in  directing  the  cork  to  be  inserted 
before  the  air  has  been  expelled  by  the  descending  fluid  after  pouring  ou 
the  menstruum.  When  a  pound  of  powder  is  moistened  and  properly 
packed  in  a  funnel  and  the  balance  of  the  pint  of  menstruum  poured  on 
it,  the  first  portion  of  the  latter,  descending  gradually  from  layer  to  layer, 
carries  a  large  part  of  the  more  soluble  constituents  with  it  to  the  lower 
part  of  the  funnel,  leaving  the  last  portion  of  the  menstruum  much  less 
toextract.  When,  therefore,  the  displacing  liquid  is  added  after  four  days 
maceration,  the  strength  of  the  absorbed  liquid  in  the  top  layer  of  the 
powder  is  very  much  l^ss  than  if  the  powder  and  menstruum  had  been 
uniformly  mixed  and  left  to  macerate  for  four  days,  and  consequently,  if 
any  of  it  gets  admixed  with  the  displacing  liquid  it  will  occasion  a  less 
final  deficiency.  Theoretically  it  is  safer  to  use  only  about  14  fluidounces  of 
menstruum  for  each  16  troyounces  of  ingredients  for  maceration,  because 
as  the  extracted  matter  occupies  space,  it  follows  that  the  original  16 
fluidounces  of  menstruum  cannot  possibly  be  all  included  in  the  16  fluid- 
ounces  of  finished  fluid  extract. 
The  quantity  of  fluid  required  to  moisten  a  powder  for  percolation  is 
only  that  quantity  that  is  necessary  to  slightly  soften  the  tissues  so  as  to 
facilitate  packing  and  invite  the  descent  of  the  second  portion  of  liquid. 
This  portion  is  not  always  the  same,  but  it  is  rarely  necessary  to  make 
it  more  than  one-fourth  or  one-third  of  the  pint  when  a  pound  of  pov;der 
is  treated.  W.  P.  Jr. 
TO  PREVENT  THE  BUMPING  OF  LIQUIDS. 
Editor  American  Journal  of  Pharmacy. 
Bear  Sir : — The  bumping  of  liquids  when  submitted  to  distil- 
lation has  often  annoyed  me,  and  I  have  sought  for  means  to 
prevent  it  in  compendiums  and  journals  od  Chemistry  and  Tech- 
nology, but  without  finding  entirely  reliable  ones.  When  I  saw 
the  article  of  Hugo  Miiller  on  this  subject  in  the  last  number  of 
your  valuable  journal,  I  conceived  at  once,  supported  by  my 
