Am.  Jour.  Phai  ni. ) 
Oct.,  1881.  I 
British  Phai'maceutiml  Conference. 
533 
the  results  of  a  comparison  of  the  old  potassium  iodide  and  starch  test 
with  the  metaphenylaminediamin  and  the  naplithylamin  tests  for  iiit- 
I'ous  acid.  He  found  that  a  solution  containing  1  part  of  nitrogen  as  nitrous 
;acid  in  a  hundred  millions  gives  with  the  potassium  iodide  test  a  distinct 
blue  in  twelve  hours,  and  1  part  in  ten  millions  gives  the  color  in  a  few 
minutes,  showing  that  this  test  has  at  least  delicacy  equal  to  the  naplithyl- 
amin test.  In  regard  to  the  significance  of  the  presence  of  nitrous  acid  in 
water,  Mr.  Ekin  remarked  that  the  importance  of  estimating  nitrites  is  not 
.sufficiently  realized,  some  analysts  omitting  to  determine  them  separately, 
while  others  disregard  them  altogether.  He,  on  the  contrary,  considers 
this  determination  to  be  one  of  the  most  important  items  of  water  analysis, 
having  never  met  with  well  or  spring  water  containing  nitrites  that  was 
not  proved  to  be  unfit  for  drinking  jiurposes,  nor  any  such  water  known 
to  be  unpolluted  which  yields  even  a  trace  of  nitrites.  He  was  not  sure 
now  far  this  applied  to  river  water,  but  after  frequent  examination  of 
water  containing  nitrates,  from  uncontaminated  streams  in  whicii  aquatic 
vegetation  was  abundant,  he  had  never  detected  the  presence  of  nitrites, 
although  from  the  presence  of  nitrous  acid  in  rain  water  it  might  reason- 
ably be  supposed  that  the  water  of  rivers  and  open  reservoirs  would  give 
evidence  of  their  presence.  Mr.  J.  Williams  referred  to  the  liability  to 
error  arising  from  the  presence  of  iodate  in  the  iodide  of  potassium  and 
chlorine  in  hydrochloric  acid,  which  he  had  found  it  impossible  to  get  rid 
of  entirely.  Mr.  Groves  asked  whether  the  liberation  of  iodine  might  not 
be  due  to  the  presence  of  iron  in  the  ferric  state.  Mr,  M.  AV.  Williams 
expressed  the  opinion  that  the  presence  of  nitrites  showed  that  the  con- 
tamination by  organic  matter  was  very  recent.  Prof.  Attfield  said  that 
he  had  recognized  the  presence  of  nitrites  in  water  from  deep  wells  in  which 
no  organic  matter  could  be  detected,  and  he  referred  to  the  observation  by 
Mr.  Deane,  that  old  infusion  of  senna  gave  off  nitrous  fufties  when  mixed 
with  sulphuric  acid,  as  showing  the  reducing  action  of  organic  matter 
upon  nitrates.  In  reply,  Mr.  Ekin  expressed  the  opinion  that  the  organic 
nitrogen  was  always  first  converted  into  ammonia,  and  then  oxidized  to 
nitrates,  and  that  nitrites  always  resulted  from  reduction.  In  regard  to 
the  iDOssibility  of  error  arising  from  the  presence  of  impurities  in  the  test, 
he  stated  that  this  had  been  provided  against  by  making  blank  experi- 
ments, and  as  to  the  alleged  presence  of  nitrites  in  water  from  deep  wells, 
he  said  if  Prof.  Attfield  would  specify  the  locality  he  would  be  willing  to 
travel  a  few  hundred  miles  to  obtain  evidence  of  the  fact. 
In  a  note  on  the  Solubility  of  Carbonio  Anhydride  in  Certain  Aromatic  - 
Waters,  Mr.  C.  H.  Bothamley  described  the  results  of  some  experiments 
made  to  ascertain  whether  carbonic  anhydride  is  more  soluble  in  pepper- 
mint than  in  pure  water.  He  found  that  the  difference  was  very  slight. 
This  w^as  also  the  case  with  dill  water.  With  cinnamon  water  a  somewhat 
more  marked  increase  of  solubility  was  observed.  In  comi^aring  the  quan- 
tities of  carbonic  anhydride  given  ofi'  from  sodium  bicarbonate  and  citric 
acid,  dissolved  respectively  in  distilled  water  and  peppermint  water,  he 
found  that  more  gas  was  given  off"  from  the  mixture  with  aromatic  water 
than  when  distilled  water  used  ;   showing   that,  contrary  to  what  has 
