Am.  Jour.  Phaem.  ) 
Dec.  1, 1873.  J 
On  Tea. 
551 
ON  TEA. 
By  J.  Alfred  Wanklyn. 
There  is  no  doubt  that  tea  is  sometimes  adulterated  with  iron-filings 
and  other  preparations  of  iron,  and  when  public  analysts  have  found 
that  iron  had  been  put  into  tea  leaves  they  have  doubtless,  in  some 
instances,  found  that  which  had  really  taken  place. 
The  ash  of  genuine  tea  leaves,  however,  contains  iron,  and  by  no 
means  a  small  proportion  of  it.  In  a  paper  by  Zoller  (Liebig's  An- 
nalen,  May,  1871),  the  percentage  of  oxide  of  iron  in  the  ash  of  tea 
leaves  is  given  as  4-38  per  cent.  The  importance  of  this  determina- 
tion depends  upon  the  circumstance  of  the  tea  having  been  received 
direct  from  the  growers,  who  were  personal  friends  of  Liebig's ;  in 
that  instance,  therefore,  there  could  be  no  question  of  adulteration. 
It  may  be  interesting  to  reproduce  Zoller's  analysis,  which  is  as  fol- 
lows : — 
Potash,  .....  39-22 
Soda,       ......  0-65 
Magnesia,       .....  6-47 
Lime,       ......  4-24 
Oxide  of  iron,  ....  4-38 
Protoxide  of  manganese,  ....  1*03 
Phosphoric  acid,  .  14*55 
Sulphuric  acid,     .....  trace 
Chlorine,        ....  .  0*81 
Silica,      ......  4-35 
Carbonic  acid,  ....  24*30 
100-00 
From  this  it  is  abundantly  manifest  that' the  mere  qualitative  de- 
tection of  oxide  of  iron  in  the  ash  of  tea  is  no  valid  proof  of  adultera- 
tion ;  and  that  in  order  to  make  out  a  case  it  is  necessary  to  show 
sensibly  more  than  4  per  cent,  of  oxide  of  iron  in  the  ash. 
On  the  present  occasion  I  wish  to  call  the  attention  of  public  ana- 
lysts to  the  importance  of  investigating  the  ash  of  samples  of  tea. 
Zoller  found  the  ash  of  tea  leaves  to  be  5-63  per  cent.,  using  in  his 
investigation  tea  leaves  of  guaranteed  purity.  I  find  that  commercial 
tea  yields  a  very  similar  result,  as  is  seen  from  the  following  analysis 
made  in  my  own  laboratory  : — 
