AmjLnuri87^arni'}      Acidum  Phosphoeicum  Dilutum.  n 
only  deficient  in  strength,  which  varies  accordingly  with  the  amount  of 
sodic  salt  contained  therein,  but  the  presence  of  the  pyrophosphate 
precipitates  the  corresponding  ferric  salt  when  the  acid  is  added  to 
solutions  containing  iron. 
A  third  process,  which  is  known  as  "  Markoe's  process,"  consists 
in  acting  upon  phosphorus  with  bromine  in  the  presence  of  water. 
With  care  the  process  is  esteemed  a  safe  one,  but  the  fact  remains  that 
at  least  one  experienced  experimenter  has  had  proof  positive  of  the 
contrary,  and  we  would  not  recommend  the  process  as  one  to  be  left 
in  the  hands  of  the  inexperienced,  though  that  it  does  furnish  excellent 
results  at  a  limited  cost  is  undeniable. 
The  fourth  process  is  the  one  we  propose  for  the  next  u  Pharmaco- 
poeia." It  is  not  designed  for  the  manufacturer,  but  for  the  pharmacist. 
Its  chief  feature  is  simplicity,  combined  with  ease  and  rapidity  of  exe- 
cution. Its  simplicity  depends  upon  the  ease  with  which  amorphous 
phosphorus  is  converted  into  orthophosphoric  acid  by  the  action  of 
nitric  acid,  and  we  would  propose  the  following  modification  of  the 
first  officinal  process : 
Take  of  Phosphorus  (amorphous),      .       370  grains; 
Nitric  acid,     .       .       5  troyounces  or  q.  s. ; 
Water,  sufficient  quantity. 
Add  the  nitric  acid  to  eight  fluidounces  of  water  in  a  porcelain  cap- 
sule, arid  to  this  add  the  amorphous  phosphorus  ;  raise  the  temperature 
of  the  mixture  to  boiling,  and  evaporate  until  the  solution  has  lost  the 
odor  of  nitric  acid.  (It  would  be  almost  superfluous  to  caution  the 
operator  at  this  period  regarding  the  passage  of  ortho-  to  pyrophosphoric 
acid  by  increased  temperature.)  When  perfectly  free  from  nitric  acid 
it  should  be  diluted  to  the  measure  of  twenty  fluidounces,  or  to  the 
requisite  specific  gravity,  the  arsenic  and  other  impurities,  if  present, 
having  been  previously  removed. 
Of  a  sample  of  acid  prepared  by  this  process  one  hundred  grains 
were  neutralized  by  twenty-four  and  six-tenths  grains  of  perfectly  dry 
crystals  of  acid  potassium  carbonate  ;  solution  of  ammonic  nitrate  gave 
a  yellow  precipitate  \  it  did  not  coagulate  albumen  or  precipitate  with 
tincture  of  the  ferric  chloride  when  mixed  in  various  proportions. 
The  operation  is  finished  in  fifty  minutes,  and  if  judicious  note  of 
temperature  is  taken  the  finished  product  is  free  from  pyro-  or  meta- 
acids,  perfectly  free  from  danger  either  to  person  or  property,  no  gauze 
