I 
362 
Colored  Insect  Powder. 
r  Am,  Jour.  Pharm. 
\      July,  1883. 
investigation  has  proceeded^  finding  chemical  method  more  exact  and 
trustworthy. 
I  have  examined  about  twenty  samples,  none  of  which  was  supplied 
to  me  specially  for  examination,  but  purchased  in  packets,  or  obtained 
as  bond  fide  samples  offered  by  Avholesale  dealers  to  retailers  in  the 
ordinary  way  of  business.  With  the  exception  of  l^o.  3  following, 
all  are  powders  from  well-known  firms,  most  of  whom  claim  to  be 
grinders.  Selecting  twelve  as  typical,  both  as  to  source  and  general 
character,  I  placed  them  side  by  side  and  arranged  them  according  to 
their  depth  of  yellow  color,  with  the  following  result: 
Vendor's  Definition. 
No. 
1.  Insect  powder- 
2. 
Color. 
Drab. 
3   Olive  drab. 
4.  From  closed  flowers   YeUowish  . 
5.  All  closed  flowers   j  " 
6.  Open  flowers   ;  " 
7.  Packet  powder   Yellow  
9.  Opt   "   
10.  All  closed  flowers   "   
11.  Foreign   j  "   
12.  Dalmatian   i  Very  yellow. 
Adulterant. 
(Genuine. 
Chrome. 
Turmeric  and  chrome. 
Chrome. 
Turmeric. 
After  arranging  the  powders  in  this  manner  by  the  eye,  it  was 
apparent  that  between  the  colors  of  6  and  7  there  was  a  perceptible 
gap,  and  when  by  testing  it  was  proved  that  Nos.  7  to  12  were  arti- 
ficially colored,  it  will  be  seen  that  appearance  is  some  indication  of 
genuineness. 
For  further  examination  I  discarded  the  first  suggested  plan  of 
igniting  the  powder  with  potassium  nitrate  and  testing  the  residue, 
and  prefer  what  I  think  a  more  delicate  and  easy,  if  somewhat  crude 
method.  Incinerate  say  20  grains  of  the  suspected  powder  on  plati- 
num foil,  and  carefully  weigh  the  ash  as  well  as  note  its  character. 
For  example,  take  No.  3,  which  had  been  reduced  to  powder  in  a  mor- 
tar by  myself  from  authenticated  flowers.    The  ash  was  grey  in  color 
