A  AuJg0usus9s.rm"}    Recent  Literature  Relating  to  Pharmacy.  409 
zero  of  absolute  temperature,  and  its  use  will  open  up  an  entirely 
new  field  of  scientific  inquiry. 
During  the  whole  course  of  the  low-temperature  work  carried 
out  at  the  Royal  Institution,  the  invaluable  aid  of  Mr.  Robert  Len 
nox  has  been  at  the  author's  disposal,  and  it  is  not  too  much  to  say 
that,  but  for  his  engineering  skill,  manipulative  ability  and  loyal 
perseverance,  the  present  successful  issue  might  have  been  indefi- 
nitely delayed.  The  author's  thanks  are  also  due  to  Mr.  J.  W.  Heath 
for  valuable  assistance  in  the  conduct  of  these  experiments. 
BISMUTH  SUBNITRATE. 
In  an  article  on  the  composition  and  tests  for  bismuth  subnitrate, 
Thorns  (in  Ber.  d.  Deutsche  Pharm.  Ges.,  1898,  Heft  4)  says  that 
according  to  the  amount  of  water  employed,  and  the  temperature 
at  which  the  salt  is  precipitated,  as  also  according  to  the  tempera- 
ture at  which  the  preparation  is  dried,  does  it  consist  of  the  fol- 
lowing products  in  varying  proportions  as  Bi(OH)(ON02)2,BiO 
(ON02),  BiO(OH)  and  water.  Thorns  recommends  the  Pharmaco- 
poeia to  direct  that  upon  heating  the  salt  to  redness  100  parts  should 
yield  79  to  80  5  parts  of  bismuth  oxide.  Further,  if  2  grammes  of 
the  nitrate  are  mixed  with  a  number  of  cubic  centimeters  of  water 
in  a  100  c.c.  measuring  flask,  and  treated  with  10  c.c.  of  normal 
KOH  solution  for  several  minutes,  and  the  flask  then  filled  up  to 
the  100  c.c.  mark,  50  c.c.  of  the  clear  liquid  should  not  require  less 
than  21  c.c.  normal  hydrochloric  acid  (21  c.c.  —  normal  hydro- 
10 
chloric  acid)  or  more  than  2-4  c.c.  normal  hydrochloric  acid  (24  c.c. 
—  normal  hydrochloric  acid). 
10  J 
The  author  gives  the  following  method  for  determining  the 
amount  of  nitric  acid  contained  in  the  salt.  Into  a  100  c.c.  gradu- 
ated flask  is  introduced  2  grammes  of  bismuth  subnitrate  ;  this  is 
mixed  with  a  few  cubic  centimeters  of  water  and  shaken.  To  this 
is  then  added  10  c.c.  normal  KOH  solution,  and  the  mixture  shaken 
for  about  five  minutes.  The  flask  is  then  filled  to  the  100  c.c.  mark 
with  distilled  water,  well  shaken  and  allowed  to  stand  until  the  mix- 
ture has  settled  so  that  the  supernatant  liquid  is  clear,  50  c.c.  of  the 
latter  is  removed  by  means  of  a  pipette,  and  titrated  with  normal 
hydrochloric  acid,  using  phenolphthalein  or  litmus  as  an  indicator. 
