Am,ia?.r'i87h6arm'}  Ammonium  in  Diluted  Phosphoric  Acid.  1 13 
plains  the  fact  why  the  sodio-ferric  pyrophosphate  precipitated  by  alco- 
hol should  yield  only  2(Na4P207)  (Fe43(P207),  instead  of  3(Na4P207) 
(Fe43(P207)),  as  which  it  exists  in  solution.  For  if  we  represent  the 
sodium  salt  in  solution  by  3(Na3H(P207)NaOH)  the  first  effect  of  the 
alcohol  will  be  a  tearing  away  of  the  exposed  alkali ;  the  immediate 
result  of  this  is  the  formation  of  a  corresponding  amount  of  acid  salt, 
which  also  dissolves,  while  in  the  mean  time  the  remnant  precipitates 
in  the  anhydrous  condition.  The  decomposition  is  clearly  illustrated 
by  the  following : 
3(Na5P2Or)+3(OH2=3(Na3H(P207)NaOH). 
Na9H3(P207)3(NaOH)3-2(Na4P207)+NaH4(P207)+3(NaOH). 
NaH3(P207)+3(NaOH)=Na4P207-r-3(OH2),  or, 
Na3H(P207)(NaOH)+2(OH2). 
AMMONIUM  IN  DILUTED  PHOSPHORIC  ACID. 
BY  HENRY  TRIMBLE. 
{Read  at  the  Pharmaceutical  Meeting,  February  15  ) 
The  process,  recently  offered  by  Prof.  Markoe,  for  making  diluted 
phosphoric  acid,  has  been  a  fruitful  source  of  controversy  among 
pharmacists  during  the  past  few  months,  and  many  objections  have 
been  advanced,  and  advantages  claimed,  with  the  addition  of  but  few 
facts  to  sustain  them. 
I  have  endeavored,  under  the  direction  of  Prof.  Maisch,  to  fully 
investigate  one  of  these  objections,  namely,  that  in  reference  to  the 
amount  of  ammonium  generated  during  the  process. 
Two  lots  of  the  acid  were  prepared,  one  in  the  proportion  of  12 
ounces  of  nitric  acid,  4  cubic  centimetres  of  bromine  and  2  ounces  of 
phosphorus.  The  bromine  was  dissolved  in  the  nitric  acid  and  the 
phosphorus  afterward  added.  The  reaction  commenced  at  650  F., 
and  was  allowed  to  continue  until  the  temperature  reached  950,  when 
the  flask  was  placed  in  water  of  6o°,  where  it  remained  for  24  hours. 
The  phosphorus  not  then  being  entirely  dissolved,  heat  was  applied  and 
very  gradually  increased  until  it  reached  1400,  at  which  degree  it  was 
maintained  for  2  hours  before  the  solution  was  completed.  The  usual 
process  was  then  employed  of  heating  in  a  capsule  until  free  from  nitric 
acid,  and  diluting  with  water  to  bring  it  to  the  officinal  strength.  In 
the  second  experiment,  the  same  proportions  were  adopted  with  the 
addition  of  12  ounces  of  water.    Little  or  no  reaction  occurred,  unless 
8 
