Amju°ne?i?o2.arin'}         Copper  in  Powdered  Drugs.  289 
The  incentive  to  the  development  of  this  practical  contact  process 
was  the  need  of  anhydrous  or  fuming  sulphuric  acid  for  the  cheaper 
manufacture  of  organic  products  like  alizarine,  and  especially  the 
new  synthetic  indigo,  but  the  process  now  developed  is  able  to  com- 
pete advantageously  with  the  chamber  process  for  all  grades  of 
sulphuric  acid,  and  the  close  of  the  nineteenth  century  undoubtedly 
sees  the  old  and  familiar  lead  chamber  doomed  to  early  replace- 
ment by  a  simpler  form  of  plant. 
THE  PRESENCE  OF  COPPER  IN  POWDERED  DRUGS 
AND  CHEMICALS.1 
By  B.  H.  Gane. 
From  time  to  time,  the  author  has  been  somewhat  puzzled  over 
the  origin  of  small  amounts  of  copper  which  have  been  detected  in 
various  powdered  drugs  and  chemicals.  Traces  of  copper  have 
been  found  by  investigators  in  the  ash  of  various  drugs,  and  have 
generally  been  attributed  to  absorption  of  copper  by  the  plant  from 
the  soil,  notwithstanding  the  fact  that  the  place  of  growth  of  the 
drug  may  have  been  far  removed  from  any  known  source  of  copper. 
That  this  is  not  the  source  of  the  copper  in  all  cases  is  shown  by 
the  fact  that  the  metal  could  not  be  detected  in  the  whole  drug, 
and  in  the  case  of  chemicals,  the  process  of  manufacture  precluded 
copper  contamination.  As  the  amount  of  metal  found  was 
extremely  small,  and  its  occurrence  quite  casual,  no  detailed  effort 
was  made  for  some  time  to  trace  the  source  of  the  contamination, 
it  being  attributed  either  to  careless  handling  or  to  the  use  of  cop- 
per utensils  for  transferring  the  powder  from  the  grinding  mill. 
The  rejection,  however,  of  several  consignments  of  powdered 
ammonium  carbonate,  which  had  developed  a  blue  mottled  appear- 
ance, rendered  it  necessary  to  ascertain  definitely  the  origin  of  the 
copper,  so  as  to  avoid  further  trouble  from  this  cause.  The  search 
was  not  without  difficulties.  Every  possible  source  of  copper  was 
eliminated,  such  as  brass  work  around  the  mill,  and  close  watch  was 
kept  over  the  grinding  and  sifting,  so  as  to  avoid  contamination 
during  these  processes.  The  use  of  brass  sieves  and  copper  or 
tinned  copper  scoops  was  also  abandoned  in  the  milling  room. 
1  Reprinted  from  the  Journal  of  the  Society  of  Chemical  Industry,  February 
28  1902.    No.  4,  Vol.  XXI. 
