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Gasometric  Analysis. 
f  Am.  Jour.  Pharm. 
\     August,  1900. 
GASOMETRIC  ANALYSIS.1 
By  Frank  X.  Moerk. 
In  the  present  Pharmacopoeia  only  the  nitrites  are  estimated  by 
a  gasometric  process,  although  a  number  of  other  official  and  unof- 
ficial substances  can  be  estimated  by  similar  methods.  As  the 
nitrometer  is  an  expensive  piece  of  apparatus,  and  requires  care 
and  some  experience  in  its  manipulation,  an  effort  was  made  during 
the  past  winter  to  devise  a  simple  and  inexpensive  apparatus  suita- 
ble for  use  in  the  laboratory  and  store  for  the  estimation  of  sweet 
spirit  of  nitre ;  the  greatest  difficulty  encountered  was  in  perfectly 
removing  the  air  from  the  apparatus,  as  this  will  react  with  the  lib- 
erated nitrogen  dioxide  and  cause  low  results ;  this  was  accom- 
plished by  the  little  device,  described  below,  which  is  recommended 
in  numerous  text-books  on  volumetric  methods  to  regulate 
the  flow  of  liquids  from  burettes.  After  overcoming  this  dif- 
ficulty and  having  the  apparatus  in  good  working  order,  this 
appeared  so  simple  that  the  literature  was  looked  up  on  the 
subject,  and  it  was  found  that  Dr.  E.  R.  Squibb  had  covered  some 
of  the  same  points  in  an  apparatus  described  in  Ephemeris,  Vol.  Ill, 
p.  1 200.  In  the  use  of  Squibb's  apparatus  the  air  is  not  perfectly 
removed  and  mercury  is  used  as  the  liquid  to  be  displaced,  for,  as 
Dr.  Squibb  states,  "  several  fluids,  including  brine,  were  tried  in 
endeavoring  to  avoid  the  use  of  mercury,  but  none  would  answer." 
The  apparatus  to  which  I  now  call  your  attention  has  the  follow- 
ing advantages  over  that  of  Dr.  Squibb  :  No  retort  stand  or  sup- 
port of  any  kind  and  no  spring  clamp  are  needed,  and,  lastly, 
the  apparatus  is  charged  with  brine. 
As  can  be  seen  from  the  illustration,  Fig.  1,  the  apparatus  con- 
sists of  a  4-ounce  saltmouth  bottle,  with  doubly  perforated  stopper ; 
a  short  piece  of  glass  tubing,  flush  with  the  lower  end  of  the  cork, 
is  connected  by  a  small  piece  of  rubber  tubing  with  a  small  funnel; 
in  this  rubber  tubing  at  a  is  placed  a  very  small  section  of  glass  rod 
(i^-^-inch)  with  fused  ends,  and  having  about  the  same  diameter 
as  the  tubing,  so  that  it  can  be  introduced  without  much  difficulty, 
and,  at  the  same  time,  tightly  close  the  rubber  tubing.  A  long 
glass  tube  bent  twice  at  right  angles,  passing  through  the  other 
1  Read  at  the  meeting  of  the  Pennsylvania  State  Pharmaceutical  Association, 
June,  1900. 
