﻿Salts 
  of 
  Caesium 
  and 
  Rubidium. 
  465 
  

  

  while 
  with 
  an 
  excess 
  of 
  bismuth 
  the 
  color 
  was 
  more 
  of 
  a 
  red- 
  

   dish 
  brown. 
  

  

  Methods 
  of 
  Analysis. 
  — 
  The 
  methods 
  here 
  given 
  were 
  nsed 
  

   in 
  both 
  the 
  double 
  chlorides 
  and 
  iodide 
  of 
  bismuth. 
  

  

  Halogens 
  were 
  determined 
  as 
  the 
  silver 
  salts 
  being 
  precipi- 
  

   tated 
  from 
  a 
  solution 
  acidified 
  with 
  tartaric 
  and 
  nitric 
  acids 
  

   and, 
  after 
  standing, 
  filtered 
  and 
  weighed 
  on 
  a 
  G-ooch 
  crucible. 
  

   As 
  Remsen 
  and 
  Brigham 
  had 
  mentioned 
  a 
  difficulty 
  in 
  de- 
  

   termining 
  bismuth, 
  we 
  made 
  a 
  few 
  determinations 
  of 
  it 
  in 
  

   Bi 
  2 
  3 
  , 
  which 
  was 
  made 
  by 
  precipitating 
  BiON0 
  3 
  with 
  water 
  

   from 
  a 
  nitric 
  acid 
  solution 
  of 
  "Bi(N0 
  8 
  ) 
  8 
  , 
  and 
  heating 
  the 
  pre- 
  

   cipitate 
  to 
  constant 
  weight 
  in 
  a 
  platinum 
  dish. 
  The 
  method 
  

   finally 
  adopted 
  was 
  to 
  dissolve 
  the 
  substance 
  in 
  water 
  slightly 
  

   acidified 
  with 
  hydrochloric 
  acid 
  and 
  precipitate 
  Bi 
  2 
  S 
  3 
  from 
  the 
  

   cold 
  solution 
  with 
  hydrogen 
  sulphide. 
  The 
  precipitate 
  was 
  

   filtered 
  and 
  immediately 
  dissolved 
  in 
  nitric 
  acid 
  and 
  digested 
  

   for 
  some 
  time 
  on 
  the 
  water 
  bath 
  until 
  completely 
  decomposed. 
  

   The 
  sulphur 
  was 
  filtered 
  off 
  and 
  the 
  filtrate, 
  diluted 
  to 
  about 
  

   300-400 
  cc 
  , 
  was 
  heated 
  and 
  ammonium 
  carbonate 
  added 
  in 
  slight 
  

   excess. 
  It 
  was 
  placed 
  on 
  the 
  water 
  bath 
  for 
  an 
  hour 
  or 
  two, 
  

   until 
  the 
  liquid 
  had 
  become 
  nearly 
  clear 
  and 
  the 
  excess 
  of 
  

   ammonium 
  carbonate 
  had 
  been 
  driven 
  off, 
  and 
  it 
  was 
  then 
  fil- 
  

   tered 
  on 
  a 
  Gooch 
  crucible 
  and 
  ignited 
  strongly 
  over 
  a 
  Bunsen 
  

   burner 
  and 
  weighed 
  as 
  Bi 
  2 
  3 
  . 
  

  

  Two 
  determinations 
  on 
  Bi 
  2 
  3 
  gave 
  the 
  following 
  results 
  : 
  ' 
  

  

  I 
  Amt. 
  Bi 
  2 
  3 
  taken 
  = 
  0-1979^ 
  Amt. 
  Bi 
  2 
  3 
  found 
  = 
  0-1974^ 
  

   II 
  " 
  •" 
  " 
  =0-3604 
  " 
  " 
  " 
  =0-3617 
  

  

  The 
  filtrate 
  from 
  the 
  bismuth 
  precipitation 
  was 
  evaporated 
  

   with 
  sulphuric 
  acid 
  and 
  ignited 
  in 
  a 
  stream 
  of 
  air 
  containing 
  

   ammonia. 
  The 
  residue 
  was 
  weighed 
  as 
  Cs 
  2 
  S0 
  4 
  . 
  

  

  The 
  results 
  obtained 
  from 
  the 
  analysis 
  of 
  the 
  double 
  iodide 
  

   were 
  as 
  follows 
  : 
  

  

  Calculated 
  for 
  

   I. 
  II, 
  Cs 
  3 
  Bi 
  2 
  I 
  9 
  . 
  

  

  Bi 
  . 
  21-34 
  21-15 
  21-25 
  

  

  Cs_. 
  20-75 
  20-31 
  20*38 
  

  

  I 
  58-02 
  58-37 
  

  

  Sheffield 
  Chemical 
  Laboratory, 
  New 
  Haven, 
  January, 
  1897. 
  

  

  