﻿Ammonium 
  Magnesium 
  Arseniate 
  of 
  Analysis. 
  57 
  

  

  solution 
  being 
  ammoniacal. 
  Results 
  (4) 
  to 
  (10) 
  of 
  the 
  table 
  

   were 
  obtained 
  in 
  the 
  same 
  manner 
  as 
  (1) 
  to 
  (3), 
  the 
  amount 
  of 
  

   arsenic 
  acid 
  present 
  being 
  increased 
  ten 
  times. 
  In 
  (9) 
  and 
  (10), 
  

   where 
  the 
  smaller 
  amounts 
  of 
  magnesia 
  mixture 
  were 
  used, 
  

  

  

  

  

  Table 
  I. 
  

  

  

  

  

  

  Arsenic 
  

  

  

  

  

  

  

  

  present 
  

  

  

  

  

  Indications 
  

  

  

  

  in 
  terms 
  

  

  Magnesia 
  

  

  

  of 
  arsenic 
  in 
  

  

  Volume. 
  

  

  of 
  As 
  2 
  5 
  . 
  

  

  mixture. 
  

  

  NH 
  4 
  OH. 
  

  

  NH 
  4 
  C1. 
  

  

  trie 
  filtrate 
  by 
  

  

  

  cc. 
  

  

  grm. 
  

  

  cc. 
  

  

  cc. 
  

  

  grm. 
  

  

  H 
  2 
  S. 
  

  

  (0 
  

  

  100 
  

  

  •05 
  

  

  20 
  

  

  slight 
  excess 
  

  

  

  none 
  

  

  (2) 
  

  

  200 
  

  

  •05 
  

  

  20 
  

  

  cc 
  cc 
  

  

  

  cc 
  

  

  (3) 
  

  

  300 
  

  

  •05 
  

  

  x 
  20 
  

  

  11 
  20 
  

   m 
  20 
  

  

  cc 
  cc 
  

  

  " 
  

  

  1 
  present 
  

   11 
  present 
  

   111 
  none 
  

  

  (*) 
  

  

  200 
  

  

  •5 
  

  

  50 
  

  

  cc 
  cc 
  

  

  

  none 
  

  

  (5) 
  

  

  300 
  

  

  •5 
  

  

  50 
  

  

  cc 
  cc 
  

  

  

  present 
  

  

  (6) 
  

  

  300 
  

  

  •5 
  

  

  50 
  

  

  2 
  

  

  

  cc 
  

  

  (<) 
  

  

  200 
  

  

  •5 
  

  

  50 
  

  

  4 
  

  

  

  cc 
  

  

  (8) 
  

  

  200 
  

  

  •5 
  

  

  30 
  

  

  2 
  

  

  

  present 
  

  

  (») 
  

  

  200 
  

  

  •5 
  

  

  x 
  30 
  

   11 
  10 
  

  

  4 
  

  

  -- 
  

  

  1 
  present 
  

   11 
  none 
  

  

  (10) 
  

  

  100 
  

  

  •5 
  

  

  x 
  30 
  

   11 
  10 
  

  

  2 
  

  

  -- 
  

  

  1 
  present 
  

   11 
  none 
  

  

  (11) 
  

  

  130 
  

  

  •5 
  

  

  50 
  

  

  excess 
  

  

  10 
  

  

  present 
  

  

  (12) 
  

  

  200 
  

  

  "5 
  

  

  50 
  

  

  cc 
  

  

  10 
  

  

  cc 
  

  

  (13) 
  

  

  150 
  

  

  •5 
  

  

  75 
  

  

  cc 
  

  

  10 
  

  

  none 
  

  

  (14) 
  

  

  250 
  

  

  "5 
  

  

  75 
  

  

  cc 
  

  

  10 
  

  

  present 
  

  

  (15) 
  

  

  300 
  

  

  *5 
  

  

  75 
  

  

  2 
  

  

  10 
  

  

  trace 
  

  

  (16) 
  

  

  400 
  

  

  •5 
  

  

  75 
  

  

  • 
  2 
  

  

  10 
  

  

  present 
  

  

  (11) 
  

  

  285 
  

  

  •5 
  

  

  100 
  

  

  excess 
  

  

  10 
  

  

  none 
  

  

  (18) 
  

  

  215 
  

  

  •5 
  

  

  100 
  

  

  cc 
  

  

  20 
  

  

  none 
  

  

  (19) 
  

  

  335 
  

  

  "5 
  

  

  100 
  

  

  cc 
  

  

  60 
  

  

  present 
  

  

  (20) 
  

  

  360 
  

  

  •5 
  

  

  125 
  

  

  cc 
  

  

  60 
  

  

  present 
  

  

  (21) 
  

  

  360 
  

  

  '5 
  

  

  150 
  

  

  cc 
  

  

  60 
  

  

  none 
  

  

  additional 
  portions 
  had 
  to 
  be 
  added 
  before 
  all 
  the 
  arsenic 
  was 
  

   removed 
  from 
  solution. 
  When 
  the 
  larger 
  amounts 
  of 
  ammonia 
  

   were 
  used 
  the 
  results 
  did 
  not 
  seem 
  to 
  be 
  influenced, 
  (7) 
  and 
  

   (9). 
  The 
  results 
  recorded 
  in 
  (11) 
  to 
  (21) 
  were 
  obtained 
  by 
  pre- 
  

   cipitating 
  the 
  arsenic 
  in 
  solution 
  in 
  presence 
  of 
  ammonium 
  

   chloride 
  by 
  the 
  magnesia 
  mixture. 
  It 
  is 
  evident 
  that 
  the 
  

   presence 
  of 
  ammonium 
  chloride 
  causes 
  some 
  arsenic 
  to 
  be 
  dis- 
  

   solved 
  and 
  further 
  that 
  this 
  solvent 
  effect 
  is 
  overcome 
  by 
  the 
  

   magnesia 
  mixture 
  added 
  in 
  larger 
  amounts, 
  even 
  when 
  the 
  

   ammonium 
  chloride 
  present 
  amounts 
  to 
  sixty 
  grams 
  in 
  weight, 
  

   as 
  in 
  (21). 
  

  

  