VALERIANATE  OP  IRON.  535 
I  had  no  time  to  ascertain  the  quantity  of  valerianic  acid 
actually  present  in  the  salt ;  but  assuming  that  the  loss  from 
ignition  was  due  to  this  acid  alone,  the  formula  of  the  salt  would 
be  as  near  as  possible  Fe203+3  Va,  or  a  neutral  anhydrous  vale- 
rianate of  peroxide  of  iron,  containing  three  equivalents  of  vale- 
rianic acid  =  279,  and  one  equivalent  of  oxide  of  iron  —  80 ; 
and  this  is  the  formula  given  by  Wittstein,  but  which  he  says  he 
was  not  able  to  produce,  his  explanation  being  as  follows  :  "  If 
a  neutral  solution  of  valerianate  of  soda  is  added  to  one  of  per- 
chloride  or  any  persalt  of  iron,  a  dark  brick-red  precipitate  of 
valerianate  of  iron  is  formed,  together  with  a  sulphate  or  chloride 
of  sodium,  according  to  whichever  iron  salt  has  been  used.  In 
the  case  of  perchloride  of  iron — 
3  atoms  NaO-f  Va  and  1  atom  Fe2Cl3 
form 
1  atom  Fe203-{-3  Va  and  3  atoms  NaCl. 
The  neutral  compound  of  valerianic  acid  described  above  does 
not,  however,  precipitate,"  he  goes  on  to  say,  "but  decomposes 
as  soon  as  formed  into  a  basic  salt,  in  which,  if  the  formula  of 
the  neutral  salt  is  tripled,  two  atoms  of  acid  are  replaced  by  two 
atoms  of  water,  forming  a  salt  3  Fe203-(-7Va-j-2HO  and  free 
valerianic  acid,  which,  holding  a  portion  of  the  basic  salt  in  solu- 
tion, gives  to  the  supernatant  liquor  a  slightly  yellowish-red  color." 
This  basic  salt  is  therefore  the  substance  generally  found  in  com- 
merce, and  I  suppose  is  the  only  valerianate  of  iron  which  it  has 
been  hitherto  thought  could  be  obtained.  The  neutral  valeri- 
anate is  in  ruby  scales,  will  dissolve  in  its  own  weight  of  alcohol, 
and  will  bear  heating  to  a  temperature  of  212°  without  decompo- 
sition. Not  only  in  these  respects  but  in  appearance  it  differs 
completely  from  the  brick-red  powder  hitherto  known  to  us,  and 
I  doubt  not  will  be  found  a  much  more  reliable  article  for  medi- 
cinal use. 
The  next  question  for  our  consideration  is  the  preparation  of  the 
salt,  and  herein  seems  to  lie  the  secret  of  the  difference  between 
one  salt  and  the  other.  My  experiments  in  this  matter  have  not 
been  so  extensive  as  I  could  wish,  but  so  far  as  they  go  they  seem 
to  show  that  the  use  of  dilute  solutions  of  valerianate  of  soda  and 
iron  necessitate  the  production  of  the  basic  salt,  and  vice  versa, 
