358 
ACIDUM  PHOSPHORICUM  DILUTUM. 
Y/ould  not  answer  for  this  purpose,  since  they  would  in  course  of 
time  cause  an  oxydation  of  the  copper.  Wax,  and  especially 
paraffine,  appear  better  adapted  for  this  purpose.  He  states 
that  0.5  per  cent,  of  either  substance,  mixed  with  the  bronze 
powder  in  a  shallow  pan,  is  sufficient. 
The  mechanical  subdivision  of  the  alloy  is  effected  by  rolling 
and  hammering,  as  in  the  preparation  of  gold  leaf,  and  then 
grinding  the  leaves  of  metal  with  water,  between  stones. 
Hr.  Konig  has  endeavored  to  prepare  these  bronzes  in  the 
wet  way,  by  reducing  the  metal,  but  has  not  succeeded  in  ob- 
taining any  satisfactory  results.  The  only  substance  of  this 
kind  which  he  was  able  to  prepare  in  the  wet  way,  is  that  called 
"  iron  black,"  which  is  used  for  coating  gypsum  figures,  in  order 
to  give  an  appearance  similar  to  grey  cast  iron.  This  consists 
of  very  finely  divided  antimony,  precipitated  from  solution  by 
means  of  zinc. — London  Pharm.  Journ.,  Aug.,  1857. 
ACIDUM  PHOSPHORICUM  DILUTUM. 
To  the  Editor  of  the  PharaiaceuticalJoumal. 
Sir, — Without  being  able  of  my  own  knowledge  to  answer 
the  query  of  Mr.  Whipple,  I  gladly  seize  an  opportunity  of  say- 
ing something  respecting  the  preparation  of  Acidum  Phosphori- 
cum  Dilutum,  P.L. ;  but  in  order  to  be  somewhat  relevant,  will 
first  quote  from  M.  Personne's  original  paper  [Journ.  de  Ph.  et 
de  Ch.,  tome  32,  Oct.  1851)  some  paragraphs  bearing  on  the 
question  of  the  poisonous  or  non-poisonous  action  of  phosphorous 
acid. 
M.  Personne  begins  by  saying  that  his  communication  is  not 
for  the  purpose  of  describing  red  phosphorus,  already  so  fully 
described  by  Schroetter,  but  of  making  known  certain  facts  that 
had  escaped  that  able  chemist,  and  at  the  same  time  of  proving 
that  the  highly  poisonous  action  attributed  to  (P03  by  Woehler 
and  Frerichs  is  far  from  being  so  well  founded  as  those  chemists 
appear  to  think. 
He  proceeds  to  show  that  red  phosphorus,  even  after  very  care- 
ful purification,  is,  like  the  ordinary  variety,  attacked  by  atmos- 
pheric oxygen,  and  converted  into  (P03)  and  P05),  but  very 
slowly ;  the  action,  moreover,  being  the  more  rapid,  the  more 
finely-divided  the  phosphorus. 
