﻿56 
  Austin 
  — 
  Constitution 
  of 
  the 
  

  

  ignited 
  in 
  a 
  crucible 
  held 
  in 
  a 
  second 
  protecting 
  crucible, 
  after 
  

   treating 
  with 
  nitric 
  acid 
  and 
  ammonium 
  nitrate, 
  he 
  obtained 
  

   concordant 
  results. 
  Brauner* 
  followed 
  this 
  method 
  with 
  

   success. 
  

  

  As 
  has 
  been 
  shown 
  by 
  Dr. 
  Hugo 
  Neubauer,f 
  ammonium 
  

   chloride 
  tends 
  to 
  form 
  a 
  phosphate 
  of 
  magnesium 
  too 
  rich 
  in 
  

   ammonia, 
  and 
  in 
  papers^ 
  from 
  this 
  laboratory 
  it 
  has 
  been 
  shown 
  

   that 
  the 
  tendency 
  of 
  ammonia 
  and 
  ammonium 
  chloride 
  is 
  to 
  

   cause 
  the 
  replacement 
  of 
  some 
  of 
  the 
  metal 
  in 
  the 
  ammonium 
  

   phosphate 
  of 
  manganese, 
  of 
  magnesium 
  and 
  of 
  other 
  metals 
  in 
  

   the 
  second 
  group 
  of 
  Mendeleeff, 
  giving 
  phosphates 
  too 
  rich 
  in 
  

   ammonia 
  for 
  the 
  ideal 
  constitution. 
  The 
  marked 
  similarity 
  as 
  

   to 
  behavior 
  between 
  the 
  phosphates 
  and 
  the 
  arseniates 
  led 
  to 
  

   the 
  investigation 
  of 
  the 
  constitution 
  of 
  the 
  ammonium 
  mag- 
  

   nesium 
  arseniate 
  under 
  the 
  usual 
  conditions 
  imposed 
  in 
  analy- 
  

   sis, 
  and, 
  further, 
  to 
  the 
  effect 
  of 
  ammonium 
  chloride 
  on 
  the 
  

   salt 
  of 
  ideal 
  constitution. 
  

  

  In 
  the 
  table 
  which 
  follows 
  are 
  recorded 
  a 
  set 
  of 
  qualitative 
  

   tests, 
  in 
  which 
  the 
  hot 
  filtrates 
  were 
  tested 
  by 
  hydrogen 
  sul- 
  

   phide 
  in 
  presence 
  of 
  hydrochloric 
  acid. 
  These 
  tests 
  were 
  

   made 
  to 
  show 
  under 
  what 
  conditions 
  of 
  volume, 
  given 
  amounts 
  

   of 
  arsenic 
  acid 
  can 
  be 
  entirely 
  removed 
  by 
  magnesia 
  mixture 
  

   from 
  ammoniacal 
  solutions 
  alone, 
  or 
  from 
  ammoniacal 
  solutions 
  

   containing 
  ammonium 
  chloride. 
  The 
  ammonium 
  chloride 
  for 
  

   this 
  work 
  was 
  carefully 
  purified 
  by 
  heating 
  it 
  to 
  boiling 
  tem- 
  

   perature 
  in 
  concentrated 
  solution 
  — 
  1 
  grm. 
  to 
  8 
  cm3 
  — 
  with 
  

   ammonia 
  in 
  slight 
  excess. 
  The 
  magnesia 
  mixture 
  was 
  prepared 
  

   by 
  dissolving 
  one 
  hundred 
  and 
  ten 
  grams 
  of 
  the 
  crystallized 
  

   magnesium 
  chloride 
  in 
  a 
  small 
  volume 
  of 
  water, 
  filtering 
  and 
  

   adding 
  to 
  it 
  fifty-eight 
  grams 
  of 
  ammonium 
  chloride 
  in 
  solu- 
  

   tion, 
  purified 
  by 
  adding 
  bromine 
  water 
  and 
  bleaching 
  with 
  

   ammonia, 
  filtering 
  and 
  then 
  dilating 
  to 
  a 
  volume 
  of 
  two 
  liters, 
  

   adding 
  enough 
  ammonia 
  — 
  10 
  cc 
  — 
  to 
  make 
  this 
  solution 
  smell 
  

   distinctly 
  of 
  ammonia. 
  

  

  The 
  results 
  (1) 
  to 
  (3) 
  recorded 
  in 
  the 
  table 
  were 
  obtained 
  by 
  

   precipitating 
  the 
  arsenic 
  present 
  in 
  solution 
  by 
  means 
  of 
  the 
  

   magnesia 
  mixture 
  prepared 
  as 
  described 
  and 
  rendering 
  the 
  

   solution 
  distinctly 
  ammoniacal. 
  After 
  standing 
  until 
  the 
  pre- 
  

   cipitate 
  subsided, 
  the 
  solution 
  was 
  filtered 
  and 
  tested 
  for 
  

   arsenic 
  by 
  hydrogen 
  sulphide. 
  Within 
  certain 
  limits 
  of 
  vol- 
  

   ume 
  all 
  the 
  arsenic 
  is 
  removed 
  from 
  solution 
  by 
  the 
  magnesia 
  

   mixture. 
  In 
  case 
  of 
  (3) 
  two 
  additional 
  amounts 
  of 
  the 
  pre- 
  

   cipitant 
  had 
  to 
  be 
  made 
  in 
  order 
  to 
  remove 
  the 
  arsenic, 
  the 
  

  

  * 
  Zeitschr. 
  f. 
  Anal. 
  Chem., 
  xvi, 
  57. 
  

  

  f 
  Zeitschr. 
  f. 
  Anorg. 
  Chem.; 
  ii, 
  45; 
  iv, 
  251; 
  x, 
  60. 
  Zeitschr. 
  f. 
  Angen 
  Chem., 
  

   1896, 
  435. 
  Jour. 
  Amer. 
  Chem. 
  Soc, 
  xiv, 
  289. 
  

   \ 
  This 
  Journal, 
  vi, 
  233 
  ; 
  vii, 
  187 
  ; 
  viii, 
  206. 
  

  

  