800 
NOTE  TO  HAIR  DYE. 
Extemporaneous  Drop  Machine. 
I  have  for  some  time  been  using  the  following  method  in 
"  dropping,"  and  gaining  thereby  uniformity  in  the  size  of  drops 
(of  the  same  liquid)  I  think  it  is  worth  a  corner  in  your  Journal, 
so  much  the  more  as  every  druggist  has  the  machine  at  hand. 
I  simply  take  a  half  ounce  glass  measure  (graduated),  measure 
off  one  drachm  of  the  liquid,  and  drop  from  the  measure.  Every 
druggist  has  at  least  a  one  ounce  measure.  In  always  dropping 
from  the  same  measure  from  a  same  quantity  of  liquid^  uni- 
formity will  be  insured. 
For  obvious  reasons  the  above  method  cannot  well  be  applied 
to  the  dropping  of  essential  oils. 
Very  respectfully  yours,  H.  M.  W. 
Philadelphia,  May  26,  1870. 
 / 
NOTE  TO  HAIR  DYE,  {^age  227  of  May  No.) 
Cairo,  III.,  May  Ath,  1870. 
Editor  Journal  of  Pharmacy,  Philadelphia  : 
I  saw  this  evening,  for  the  first  time,  a  notice  from  a  party  in 
New  York  who  manufactures  an  article  which  he  calls  Egyp- 
tian Hair  Coloring,"  cautioning  persons  who  buy  "  hair-restor- 
ers," to  have  their  druggists  first  test  them  for  lead  and  mer- 
cury by  means  of  potassa  iodide,  and  as  the  preparation  men- 
tioned in  the  article  I  sent  you  last  month  possesses  the  property 
of  not  yielding  a  precipitate  on  the  addition  of  that  salt,  you 
would  oblige  me,  if  it  is  not  too  late,  by  adding  to  or  inserting  in 
the  article  in  question  the  remarks  enclosed  with,  this  note. 
Yours  respectfully,  Geo.  McDonald. 
(The  reader  will  consider  the  following  in  connection  with  page  227  of 
the  May  number,  it  having  arrived  too  late  for  the  May  number.) 
This  preparation  has  the  singular  property  of  not  indicating 
the  presence  of  lead  on  the  addition  of  iodide  of  potassium. 
When  iodide  of  potassium  is  added  to  a  solution  of  the  ordinary 
salts  of  lead,  a  bright  yellow  precipitate  of  iodide  of  lead  is  im- 
mediately formed,  but  when  added  to  this  preparation,  no  change 
whatever  ensues.  The  reaction  is  completely  masked.  Sulphuric 
acid,  however,  readily  indicates  the  presence  of  the  poison,  by 
the  formation  of  a  heavy,  white,  insoluble  precipitate  of  sulphate 
of  lead. 
