162  Bismuthyl  Iodide.  {^AiXim"11' 
only  very  meagre,  but  very  unsatisfactory,  indeed.  Although  con- 
siderable has  been  written  on  the  mode  of  preparation,  yet,  after  a 
great  number  of  experiments,  no  one  seems  to  have  obtained  a  thor- 
oughly satisfactory  result.  None  of  the  products  obtained  were  of 
sufficient  purity,  and  none  of  the  methods  employed  were  without 
some  serious  objection ;  yet  these  investigations  were  made  by  some 
of  the  best  pharmacists  in  our  land.  How  far  I  may  have  been  suc- 
cessful in  my  efforts  in  this  direction  I  leave  for  others  to  judge.  At 
the  time  of  Dr.  Reynolds'  experiments  the  high  cost  of  the  compound 
prevented  its  general  adoption  ;  therefore  the  main  point  for  consider- 
ation was  a  process  by  which  a  chemically  pure  compound  could  be 
obtained  at  a  price  sufficiently  reasonable  to  bring  it  into  general 
use. 
The  first  commercial  sample  which  I  examined,  was  of  a  very  dark 
brown,  almost  chocolate  color,  with  nothing  of  the  characteristic 
brick  red  color  which  it  should  have,  indicating  the  presence  of  a 
considerable  quantity  of  iodine  in  other  form  of  combination  than 
BiOI,  most  probably  as  Bil3.  When  boiled  with  an  excess  of  water 
it  assumed  a  much  lighter  color,  finally  a  bright  brick  red,  owing  to 
more  perfect  oxidation,  one  atom  of  oxygen  from  the  hot  water  re- 
placing two  of  iodine  forming  a  molecule  of  BiOI.  When  heated  to 
100°  C.  no  apparent  change  took  place,  only  a  slight  odor  of  iodine 
becoming  perceptible.  As  the  heat  was  slowly  raised  to  cause  partial 
decomposition  and  as  the  iodine  was  slowly  liberated  the  compound 
gradually  assumed  the  brick  red  color.  By  analysis  I  found  that  it  con- 
tained 48*36  per  cent,  of  iodine,  or  about  12  per  cent,  more  than  a 
pure  article  should  contain,  and  we  may  justly  draw  the  conclusion 
that  this  is  a  very  indefinite  and,  therefore,  unsatisfactory  compound. 
The  next  sample  examined  was,  like  the  first,  of  American  manu- 
facture. It  was  dark-red  in  color,  dense  and  heavy,  and  exhibited  a 
few  lumps  of  a  lighter  color.  It  contained  91 '83  per  cent.  BiOI, 
with  a  small  amount  as  BiON03.H20.  One  other  sample  was  exam- 
ined, but  it  did  not  differ  from  the  one  just  spoken  of,  except  that  it 
had  been  more  carefully  powdered  and  contained  92*61  per  cent. 
BiOI,  and  a  small  proportion  of  BiON03.H20. 
Of  the  various  processes  set  forth  in  journals  and  books  of  refer- 
ence, I  have  tried  several  with  varied  success.  The  first  tried  was 
the  so-called  method  of  "  precipitation,"  proposed  by  Jos.  W.  Eng- 
land, in  Amer.  Jour.  Phar.,  Jan.,  1887,  pp.  9-15.    The  product 
