^November^t92™: }    Who  Invented  the  Tall  Percolator'^  799 
study  of  the  process  of  fractional  percolation  and  whether  it 
possessed  any  advantages  over  simple  percolation  properly  carried 
out,  and  concluded  that  the  object  aimed  at  in  fractional  percolation 
could  be  obtained  by  simple  percolation  "if  we  increase  the  height 
of  the  column  without  increasing  its  diameter."  In  order  to  per- 
form his  experiments  he  states:  "Being  well  aware,  however,  of  the 
difficulties  attending  the  percolation  of  high  columns  of  vegetable 
powders,  and  particularly  of  narrow  columns  of  such,  I  had  some 
glass  percolators  constructed  which,  while  of  the  same  diameter  at 
the  upper  and  lower  end  as  those  ordinarily  constructed,  should  be 
twice  the  usual  height." 
The  figure  illustrating  his  conception  of  a  tall,  narrow  percolator 
for  this  purpose  is  reproduced  herewith. 
It  is  evident  from  these  quotations  that  Dr.  Oldberg  followed 
very  closely  the  ideas  of  Prof.  Diehl  and  repeated  substantially  the 
latter 's  recommendations  as  to  the  approved  type  for  percolators. 
As  a  fact  established  by  historical  records,  Diehl  should  be  given 
credit  in  the  pharmaceutical  literature  as  the  inventor  of  this  form 
of  percolator. 
The  writer  is  aware  that,  although  Prof.  Diehl  made  no  pub- 
lished claims  regarding  the  priority  of  his  paper,  he  nevertheless 
felt  rather  keenly  that  credit  had  not  been  given  where  it  was  justly 
due.  In  a  heretofore  unpublished  letter  he  wrote,  under  date  of 
December  9,  19 10: 
"It  does  not  take  long  to  forget  what  has  been  done  in  previous 
years,  and  we  daily  discover,  as  new,  facts  which  years  ago  have  been 
practically  demonstrated. 
"How  little  time  it  takes  to  forget,  or  to  overlook  observations  or 
recommendations  made,  is  exemplified  by  the  question  of  tall, 
narrow  percolators  recommended  by  me  for  preparing  fiuidextracts 
(and  for  extraction  by  percolation  in  general).  Take  a  look  at  the 
percolator.  Fig.  67  on  p.  729  of  my  report  in  the  Proceedings  (Amer- 
ican Pharmaceutical  Association)  1879,  and  then  compare  with  the 
percolator  described  and  illustrated  by  Prof.  Oldberg  in  the  Pro- 
ceedings 1884,  pp.  388-392,  which  is  now  generally  designated  as 
the  "Oldberg  Percolator."  Leaving  the  exact  shape  out  of  con- 
sideration, does  not  this  open  a  question  of  precedence  regarding  the 
suggestion  of  'tall  narrow  percolators;'  and  yet  it  had  taken  but  a 
short  five  years  to  practically  obliterate  any  modest  claim  I  may 
have  held  for  the  suggestion  made?" 
