556 
PREPARATION  OF  LACTATE  OF  PROTOXIDE  OF  IRON. 
powder  in  grains  burns  between  270°  and  320°,  while  powder 
pulverized,  burns  between  265°  and  270°. 
In  view  of  the  facts,  M.  Yiolette  concludes  that  it  is  necessary 
to  revise  the  charges  employed,  taking  into  consideration  the 
actual  composition  of  the  charcoal.  Trials  made  with  this  in 
view  upon  hunting  powder,  with  charges  calculated  according  to 
the  actual  composition  of  the  charcoal,  have  given  a  range  much 
beyond  the  standard  rate  obtained  with  the  ordinary  powder. — 
J.  Nickles,  in  Amer.  Jour,  of  Science  and  Arts,  Sept.  1853. 
ON  THE  PREPARATION  OF  LACTATE  OF  PROTOXIDE  OF  IRON. 
By  M.  C.  J.  Thirault. 
In  the  preparation  of  lactate  of  iron  by  the  processes  described 
in  chemical  works,  difficulties  are  frequently  encountered,  espe- 
cially in  the  concentration  of  the  liquor  for  the  purpose  of  ob- 
taining the  salt  in  crystals.  Even  should  a  first  crystallization 
be  obtained  without  difficulty,  on  concentrating  the  mother-li- 
quors in  order  to  obtain  a  second  crystallization,  the  liquid  ac- 
quires a  reddish  tint  owing  to  the  peroxidation  of  the  salt,  which 
now  refuses  to  crystallize.  Another  difficulty  presents  itself  in 
drying  the  lactate  of  iron  when  obtained.  If  certain  precautions 
be  not  taken,  the  salt,  instead  of  being  a  yellowish  white  with  a 
tinge  of  green,  acquires  a  reddish-yellow  color,  in  which  case  it 
is  in  great  measure  peroxidized. 
All  these  difficulties,  which  I  have  experienced  in  making  the 
salt  for  the  first  time,  in  addition  to  the  facility  with  which  lac- 
tic acid,  combined  with  lime  may  be  artificially  prepared,  induce 
me  to  publish  the  processes  which  I  have  always  found  success- 
ful. 
There  are  two  process  for  obtaining  solution  of  lactate  of  pro- 
toxide of  iron,  either  of  which  may  be  employed  with  equal  suc- 
cess. The  one  consists  in  the  direct  action  of  lactic  acid  on  iron 
filings,  and  the  other  in  the  double  decomposition  of  protosulphate 
of  iron  and  lactate  of  lime.  But  to  whichever  of  these  the  pref- 
erence is  given,  it  is  essential,  in  carrying  out  the  process  accord- 
ing to  my  mode  of  operating,  to  have  a  small  quantity  of  lactic 
acid  in  reserve. 
