AmsS>tr 'i889arm'}    Hypophosphorous  Acid  and  Hypophosphites.  463 
specific  gravity  at  15*5°  C.  it  was  diluted  to  a  40,  30,  20  and  10  per 
cent,  acid  respectively,  and  the  specific  gravities  taken. 
With  Oxalic  Acid.       With  Tartaric  Acid. 
60  per  cent,  acid,  1*2813   
50      "  "  1-2308  1-3277 
40      "          "  1-1803  1-2517 
30      "          "  1-1319  -  •  1*1812 
20      "  "  1-0861  1-1161 
10      "          "  1-0427  1-0567 
The  National  Formulary  quotes  the  specific  gravity  of  the  50  per 
cent,  as  1*400  and  of  the  10  per  cent,  acid  1*060 ;  these  higher  figures 
may  be  better  understood  after  the  analysis  of  the  10  per  cent,  acid 
is  given.  After  neutralizing  the  acid  the  addition  of  calcium  chloride 
produced  a  heavy  white  precipitate  of  calcium  tartrate.  The  neutral- 
ization value  was  found  to  be  10'63  per  cent,  while  the  reducing 
value  was  only  8*35  per  cent.,  indicating  the  presence  of  tartaric  acid 
equivalent  to  2.28  per  cent.  H3P02. 
2H3P02  :  H2C4H406 
132     :     150       :  :  2*28  :  x=2'60  per  cent,  tartaric  acid. 
The  potassium  hypophosphite  employed  contained  98*21  per  cent. 
KH2P02  and  the  low  results  in  the  acid  are  possibly  explained  by 
the  precipitation  of  some  of  the  potassium  hypophosphite  when  the 
aqueous  and  alcoholic  solutions  were  mixed,  leaving  some  of  the  tartaric 
acid  in  solution.  It  is  the  tartaric  acid  then  to  which  is  due  the 
higher  specific  gravities  of  the  acid  prepared  by  this  process,  and  the 
specific  gravities  given  in  the  National  Formulary  would  indicate 
that  the  sample  of  acid  used  in  their  determination  contained  even 
more  tartaric  acid  than  the  sample  made  by  me.  The  process  is 
about  as  expensive  as  any  that  could  be  devised,  and  judging  from 
the  composition  of  this  one  sample,  yields  an  inferior  preparation  to 
the  one  made  with  the  use  of  oxalic  acid. 
In  concluding  this  work  the  results  may  be  summed  in  compara- 
tively few  words.  1.  The  hypophosphites  and  the  acid  are  not 
prone  to  as  rapid  oxidation  as  has  hitherto  been  believed.  2.  With 
ordinary  precautions  and  observation  of  the  several  suggestions 
offered  in  these  papers,  the  preparation  of  medicinally  pure  salts  and 
of  the  acid  need  be  no  more  difficult  than  those  of  other  substances. in 
the  U.  S.  P.  3.  Should  the  acid  be  made  officinal,  one  of  50  per 
cent,  would  be  the  most  desirable  strength  and  which  can  easily  be 
