Am  Jour.  Pharm,  \ 
July,  1883.  J 
Colored  Insect  Powder. 
363 
and  weighed  1*2  grain.  This  is  placed  in  a  test-tube,  and  a  few  drops 
of  strong  hydrochloric  acid  added,  which  causes  some  effervescence ; 
heat  is  then  applied  to  dissolve  the  ash,  which  consists  chiefly  of  pot- 
ash salts.  The  solution  is  colorless  and  the  addition  of  a  little  water 
prepares  it  for  the  application  of  the  usual  tests. 
Sulphuretted  hydrogen  gives  no  precipitate  nor  potassium  iodide  a 
yellow  color  nor  precipitate ;  but  it  ought  to  be  here  noted  that  ammo- 
nium sulphide  and  potassium  ferrocyanide  give  the  characteristic  reac- 
tions indicating  iron,  which  I  found  in  small  quantity  in  the  ash  of 
the  genuine  flowers,  as  well  as  in  all  the  powders.  This  metal  seems 
to  exist  in  gi eater  abundance  in  the  florets,  and  in  much  less  propor- 
tion in  the  seeds,  and  the  indications  of  iron  must  be  noted,  as  I  have 
found  two  powders  containing  it  in  such  quantity  as  to  suggest  that 
some  ferruginous  earth,  such  as  ochre,  had  been  used  to  make  weight 
or  color.  One  of  these  powders  is  a  proprietary  article,  and  the  other 
a  small  odd  sample,  which  I  cannot  replace,  therefore  neither  appears 
amongst  the  selected  twelve. 
The  behavior  of  a  powder  colored  with  the  usual  adulterant,  viz.^ 
yellow  chrome,  is  quite  different.  The  ash  is  brownish,  or  showing 
brown  patches  at  the  most  exposed  parts,  and  the  weight  is  greater ; 
thus  No.  7  yielded  2*1  grains.  There  is  the  same  effervescence  with 
HCl ;  but  part  is  insoluble,  and  the  solution  on  heating  becomes  dis- 
tinctly green,  which  with  a  black  precipitate  with  HgS  may  be  taken 
as  conclusive  proof  of  the  presence  of  lead  chromate.  KI  gives  a 
yellow  color,  and  if  the  HCl  be  not  in  excess  a  yellow  crystalline  pre- 
cipitate separates. 
Any  attempt  to  judge  of  the  amount  of  added  chrome  by  estima- 
tion of  the  lead  present  I  found  futile,  which  is  readily  understood 
when  it  is  remembered  that  the  finer  chromes  are  said  to  be  "  struck 
on  magnesia,  and  undoubtedly  the  alkaline  earths  are  found  to  bulk 
largely  in  the  composition  of  many. 
No.  12,  although  of  a  strikingly  deep  yellow  color,  gave  only  1*2 
grain  of  grey  ash,  and  thus  suggested  that  some  vegetable  coloring 
had  been  used,  and  on  the  sample  being  tested  by  the  method  devised 
by  myself  for  the  detection  of  artificial  coloring  in  rhubarb  and  other 
powders  ('^  Pharm.  Journ.''  [3],  vol.  iv,  354)  the  supposition  proved 
to  be  correct. 
Pieces  of  white  blotting  paper  corresponding  to  the  number  of  sam- 
ples are  taken  and  named  or  numbered,  and  a  few  grains  of  the  sus- 
