534 
VALERIANATE  OF  IRON. 
About  three  weeks  ago  I  resolved  to  make  a  closer  examina- 
tion of  these  two  preparations  of  valerianate  of  iron,  namely,  Mr. 
Hanbury's  and  my  own,  in  order  to  see  wherein  they  differed 
from  the  powdery  kind  usually  found  in  the  market.  As  they 
were  both  found  to  be  identical  in  composition  eventually,  the 
description  of  one  of  them  will  suffice.  I  will  describe  the  sample 
sent  by  Mr.  Hanbury. 
A  small  quantity  of  it  was  spread  out  thinly  upon  the  lid  of  a 
platinum  basin  and  weighed.    The  quantity  was  13*42  grains  ; 
the  first  thing  to  be  done  with  it  was  to  remove  any  excess  of 
moisture  in  the  compound.    Fearing  that  heat  might  dissipate 
some  of  the  valerianic  acid,  the  vessel  was  placed  under  the  re- 
ceiver of  a  large  air-pump,  together  with  a  dish  of  sulphuric  acid, 
and  kept  in  vacuo  for  twenty-four  hours,  when  the  loss  was  found 
to  be  2*7  grains,  equal  to  20  per  cent.    It  was  then  exposed  to 
the  same  influences  twelve  hours  longer,  but  with  no  further  loss. 
In  order  to'ascertain  whether  any  acid  would  be  lost  by  artificial 
heat,  it  was  then  transferred  to  a  water-bath,  and  kept  at  a 
temperature  of  212°  until  the  weight  remained  constant ;  the 
loss  was  then  3*41  grains,  or  very  nearly  25  per  cent.,  but  no 
change  had  taken  place  in  the  appearance  of  the  substance,  and 
no  apparent  loss  of  acid  by  smell  or  otherwise.    It  had  now  lost 
all  stickiness  and  become  quite  firm,  so  that  it  might  readily  be 
chipped  off  the  vessel  in  thin  transparent  scales,  like  the  usual 
citrate  or  tartrate  of  iron.    A  few  of  these  scales  were  treated 
with  alcohol,  and  were  found  to  dissolve  readily  to  a  clear  deep 
ruby  liquid,  but  they  were  quite  insoluble  in  water,  and  if  water 
is  added  to  the  alcoholic  solution  the  valerianate  is  immediately 
precipitated. 
A  quantity  of  the  dry  scales,  weighing  9*1  grains,  were  then 
gently  heated  over  a  gas  lamp,  when  they  immediately  began  to 
melt,  and  give  off  copious  fumes  of  valerianic  acid,  which  readily 
ignited  and  gave  a  yellow  brilliant  flame.  The  residue,  which 
appeared  to  consist  of  oxide  of  iron,  weighed  2*31  grains ;  this 
was  dissolved  in  a  little  hydrochloric  acid,  and  the  oxide  of  iron 
precipitated  with  ammonia.  The  weight  of  precipitate  so  ob- 
tained was  2*03  grains  ;  the  loss  of  weight  between  this  and  the 
ignited  residue  was  due  to  sulphate  of  soda  not  thoroughly 
washed  out  of  the  valerianate. 
