410 
Ferric  Chlorides. 
f  Am.  Jour.  Tharm. 
\     August,  1884. 
35  per  cent.,  may  be  beneficial,  any  large  excess  may  be  fairly  judged 
as  a  species  of  impurity,  aside  from  being  a  positive  waste. 
In  the  "Pharmacist"  for  July,  1869,  the  writer  advocated  the  use 
of  potassium  chlorate  for  the  development  of  ferric  salts.  With  this 
process  a  slight  impurity  is  incurred  in  the  form  of  potassium  chloride. 
From  a  therapeutical  aspect,  as  well  as  viewed  from  the  side  of  phar- 
macy, this  contamination  is  absolutely  unobjectionable.  Recently, 
however,  the  writer  has  used  barium  chlorate  in  this  operation  with 
great  success.  By  its  employment  a  more  than  practically  pure  product 
is  obtained.  In  this  new  process  chloric  acid  in  moderately  concen- 
trated solution  is  first  prepared  either  by  dissolving  the  chlorate  in 
about  five  times  its  weight  of  warm  water  and  then  gradually  adding 
sulphuric  acid  in  slight  excess,  but  previously  diluted  by  pouring  it 
into  about  five  times  its  weight  of  water.  Or  the  sulphuric  acid  may 
first  be  mixed  with  water  equal  to  five  times  the  weight  of  the  chlorate 
before  the  addition  of  the  latter.  In  such  cases  the  precipitated  barium 
sulphate  is  separated  by  filtration  through  paper.  It  stands  to  reason 
that  contact  of  strong  sulphuric  acid  with  the  chlorate  must  be  cautiously 
avoided  if  dangerous  explosions  are  not  to  occur.  Should  this  process 
become  popular  the  chloric  acid  in  proper  form  and  quantity  would 
soon  be  furnished  by  the  manufacturers  at  appropriate  prices.  The 
writer,  however,  prefers  to  add  the  chlorate  directly  to  the  acidified 
solution  of  the  ferrous  salt  and  then  precipitate  the  barium  as  sulphate 
with  a  slight  excess  of  sulphuric  acid,  diluted  or  not.  If  any  barium 
sulphate  remains  dissolved  at  all  it  is  an  indiscernable  trace. 
The  term  peroxidation  as  applied  to  the  transformation  of  valence  from 
a  lower  to  a  higher  degree  and  perfectly  appropriate  in  the  older  chem- 
istry has  now  become  very  awkward  and  meaningless.  A  new  term 
is  highly  desirable,  and  hence  the  writer  proposes  "valeation"  as  indi- 
cative of  the  transformation  of  valence.  In  place  of  the  antiquated 
terms,  deoxidation  and  peroxidation,  the  new  forms,  devaleation  and 
pervaleation  are  properly  substituted.  Consequently  changing  the 
valence  to  a  diad  will  be  called  divaleation,  to  a  triad,  trivaleation,  etc. 
Xow  to  effect  the  trivaleation  of  the  iron  in  400  parts  of  the  official 
solution  of  ferric  chloride  requires  25  parts  of  barium  chlorate,  as  is 
seen  from  the  following  proportion : 
12(FeCl3),  12(162-1)  :  Ba(C10s)2  Aq.,  321-6  ::  4(37-8)  :  25. 
The  amount  of  sulphuric  acid  necessary  to  precipitate  the  barium  as 
