ON  THE  PREPARATION  OF  SMELLINa  SALTS. 
351 
solution  to  convert  the  whole  of  the  ferrocyanide  employed  into 
ferridcyanide  ;  this  number  taken  from  50  leaves  31-5  divisions 
of  ferrocyanide,  which  were  converted  into  ferridcyanide  by  the 
chlorine  of  chloride  of  lime  ;  and  as  each  division  represents 
0-1  grain  of  chlorine,  31 will  be  equivalent  to  3-15  grains  of 
chlorine,  which  is  the  amount  contained  in  10  grains  of  the 
sample  ;  consequently  100  grains  will  contain  31-5  grains  of 
chlorine,  which  is  the  same  amount  as  is  obtained  by  simply  de- 
ducting the  number  of  divisions  of  bichromate  solution  employed 
from  50  of  ferrocyanide  used  in  the  estimation." 
Though  this  process  appears  a  long  one,  from  the  details 
which  are  necessary  to  explain  its  principle,  yet  in  practice  it  is 
very  expeditious,  and  requires  only  a  very  few  minutes  for  its 
performance,  and  is  much  quicker  than  either  Gay.Lussac's  or 
Otto's  method. 
The  great  purity  of  commercial  ferrocyanide  of  potassium, 
its  definite  composition,  and  the  little  tendency  it  has  to  change 
by  keeping,  constitute  the  advantages  of  this  process. 
Dr.  Davy  also  suggests  in  his  paper  the  use  of  dried  ferrocyan- 
ide as  a  reducing  flux.  He  finds  that  it  is  quite  as  delicate,  if 
not  more  so,  than  black  flux,  or  cyanide  of  potassium,  for  the 
reduction  of  minute  quantities  of  arsenic  or  mercury,  while  it 
has  the  greatadvantage  of  not  being  at  all  deliquescent.  It 
does  not  require  any  admixture  with  a  carbonated  alkali. — 
London  Pharm.  Journ.  May,  1861. 
ON  THE  PREPARATION  OF  SMELLING  SALTS. 
By  Mr.  Alfred  Allchin, 
There  is,  no  operation  in  our  daily  avocations  that  we  are 
more  frequently  called  upon  to  perform  than  that  of  preparing 
smelling-salts,  and  yet  I  do  not  recollect  to  have  seen  any 
formula  published  that  would  convey  the  means  of  doing  so  in  a 
perfectly  satisfactory  manner. 
I  have  for  some  years  been  in  the  habit  of  making  smelling- 
salts  by  a  process  which,  I  believe,  possesses  so  many  advan- 
tages, that  I  venture  to  bring  it  before  the  notice  of  the  Pharma- 
