106  A  Chemical  Problem.  {Ara're°bUrmiiarm' 
V 
A  CHEMICAL  PROBLEM.1 
By  W.  Lloyd  Williams,  A.I.C. 
In  September  of  the  present  year  a  friend  wrote  me  as  follows : 
R    Ammonii  chlorid 
Sodii  bibor.,  .  . 
Sodii  bicarb.,  . 
Acid  carbolici, 
Aquae,  
The  above  is  the  form  for  a  lotion  which  always  goes  black  on 
being  kept,  even  when  put  in  a  glass-stoppered  bottle.  Can  you 
explain  it? 
The  reply  to  this  query  forms  the  subject  matter  of  this  short 
note. 
It  has  probably  been  noticed  by  each  one  present  that  when 
solutions  of  salicylate  of  sodium  and  an  alkaline  bicarbonate  are 
mixed  and  kept  for  some  time  a  blackening  occurs,  and  reasoning 
by  the  letter  of  the  inquiry  and  the  light  of  experience  I  conjectured 
that  the  coloration  might  be  traced  to  some  action  of  the  sodium 
bicarbonate  upon^he  phenol.  To  test  the  value  of  this  conjecture 
I  made  up  the  lotion  according  to  the  prescription  and  watched  its 
behavior. 
I  was  speedily  undeceived  ;  in  the  course  of  some  four  and  twenty 
hours  a  distinct  change  was  perceptible,  but  the  direction  of  the 
change  was  not  in  accordance  with  the  symptoms  exhibited  by  the 
salicylate  mixture. 
The  tint  gradually  assumed  by  the  lotion  is  of  a  bluish-purple 
color,  that  of  the  salicylate  mixture  proceeds  through  yellow  and 
brown  to  inky  black. 
Besides,  it  is  stated  that  there  is  no  reaction  between  alkaline 
carbonates  and  phenol,  and  I  find  no  coloration  attends  an  admix- 
ture of  sodium  bicarbonate  and  phenol,  nor  yet  of  borax  and 
phenol. 
I  next  put  together  the  borax,  soda,  phenol  and  water.  Beyond 
the  development  of  a  faint  yellow  tint  no  change  was  observed. 
The  passage  of  a  considerable  volume  of  air  did  not  intensify  the 
3J- 
24  grs. 
ad  5  vj. 
1  Read  before  the  Chemists'  Assistants'  Association  ;  reprinted  from  Phar. 
Jour,  and  Trans.,  January  3,  p.  592. 
