386 
Oxy  Salts  of  Bismuth. 
Am.  Jour.  Pharm. 
Aup:.,1888. 
Calculating  the  amount  of  subnitrate  from  the  N2O- 
BiONOg 
Bi^Oa 
H2O 
BiONOs-HaO 
94-12 
5-88 
No.  1. 
85-23  • 
11-71 
2-95 
No.  2. 
86-40 
10-50 
302 
No.  3. 
85-55 
10-84 
3-62 
No.  4. 
84-11 
13-51 
2-35 
It  will  be  seen  that  the  amount  of  water  present  is  generally  less 
than  half  of  that  required  in  the  formula  BiONOg.  Hfi.  The 
anhydrous  samples  are  very  hygroscopiCj  regaining  during  twelve  hours 
exposure  almost  the  entire  amount  present  in  the  sample  before  heat- 
ing, (No.  1.  regained  2.39  per  cent,  moisture).  The  oxide  is  con- 
sidered as  being  produced  by  washing  the  salt,  and  a  few  experiments 
in  this  direction  may  be  interesting.  Ten  gm.  of  the  subnitrate  (No.  1 .) 
were  placed  in  a  small  percolator  and  water  poured  over  it,  the  per- 
colate was  caught  in  portions  of  10  cc.  and  the  acid  present  estimated 
hj  means  of  dilute  soda  solution ;  the  quantity  indicated  was  surpris- 
ingly constant,  equaling  0.03  per  cent,  and  containing  bismuth  in  solu- 
tion. If  the  percolate  was  returned,  it  contained  acid  to  the  extent  of 
0.06  per  cent,  and  a  correspondingly  larger  quantity  of  bismuth  in  solu- 
tion; on  allowing  the  percolator  to  stand  over  night  and  then  displac- 
ing the  liquid  by  fresh  additions  of  water,  the  quantity  of  acid  in- 
creased to  0.15  per  cent.  This  is  certainly  of  interest  and  might 
suggest  that  in  the  preparation  of  subnitrate  the  portion  of  water  into 
which  the  acid  solution  of  bismuth  is  poured,  should  be  sufficient  to 
furnish  an  acidulated  water  containing  the  above  amount  of  acid.  If 
the  strength  of  the  acid  solution  is  less,  the  tendency  is  to  make  a 
more  basic  salt  by  abstraction  of  acid.  The  bismuth  dissolved  in  the 
0.15  per  cent,  acid  can,  after  draining  the  precipitate,  be  collected  after 
addition  of  sodium  carbonate  and  be  used  in  the  preparation  of  the  next 
lot.  It  would  be  desirable  not  to  wash  the  precipitate,  but  fo  absorb  the 
excessive  liquid  by  some  porous  material  after  thorough  draining.  The 
U.  S.  P.  (1870)  process  furnished  an  acid  liquid — before  the  addition 
of  the  ammonia  water — containing  0.04  fo  HXO3,  which  the  ammonia 
water  reduced  to  about  0.01  per  cent,  and  at  the  same  time  formed  a 
solution  containing  approximately  0.04  per  cent,  ammonium  nitrate. 
Although  it  is  known  that  the  latter  salt  prevents  (if  present  to  the 
extent  of  0.2  per  cent.)  the  removal  of  nitric  acid  from  basic  bismuth 
salts,  still  it  is  doubtful  if  any  favorable  results  are  to  be  had  from  its 
