﻿210 
  M. 
  Austin 
  — 
  Double 
  Ammonium 
  Phosphates. 
  

  

  excess 
  of 
  ammonium 
  chloride 
  be 
  present. 
  When 
  there 
  is 
  an 
  

   abundance 
  of 
  the 
  precipitant 
  the 
  results 
  are 
  all 
  in 
  excess 
  of 
  the 
  

   theory, 
  which 
  may 
  be 
  accounted 
  for 
  on 
  the 
  supposition 
  that 
  

   foreign 
  material 
  is 
  included 
  — 
  the 
  chloride 
  of 
  ammonia 
  and 
  the 
  

   soluble 
  phosphate 
  — 
  to 
  a 
  greater 
  or 
  less 
  extent 
  by 
  the 
  precipi- 
  

   tate. 
  The 
  formation 
  of 
  a 
  phosphate 
  of 
  beryllium 
  containing 
  

   too 
  much 
  ammonia 
  and 
  phosphoric 
  acid, 
  or, 
  in 
  case 
  of 
  the 
  pre- 
  

   cipitations 
  by 
  microcosmic 
  salt 
  or 
  sodium 
  by 
  the 
  formation 
  of 
  

   a 
  sodium 
  ammonium 
  beryllium 
  phosphate 
  and 
  sodium 
  beryl- 
  

   lium 
  phosphate 
  (known 
  salts) 
  is 
  not 
  definitely 
  proved. 
  

  

  The 
  Ammonium 
  Zinc 
  Phosphate. 
  

  

  Debray,* 
  Bettef 
  and 
  Heintz;}: 
  separately 
  found 
  that 
  ammo- 
  

   nium 
  zinc 
  phosphate 
  is 
  formed 
  by 
  boiling 
  a 
  solution 
  of 
  zinc 
  

   sulphate 
  with 
  ammonium 
  phosphate. 
  This 
  salt 
  was 
  investi- 
  

   gated 
  later 
  by 
  A. 
  Guyard 
  (Hugo 
  Tamm),§ 
  who 
  found 
  that 
  if 
  

   to 
  a 
  solution 
  of 
  a 
  zinc 
  salt 
  of 
  an 
  organic 
  or 
  a 
  mineral 
  acid 
  

   supersaturated 
  with 
  ammonia 
  until 
  all 
  the 
  zinc 
  oxide 
  is 
  dis- 
  

   solved 
  and 
  made 
  faintly 
  acid 
  with 
  hydrochloric 
  acid, 
  sodium 
  

   phosphate 
  be 
  added, 
  a 
  flocky 
  precipitate 
  resulted, 
  which 
  on 
  

   being 
  kept 
  near 
  the 
  boiling 
  point 
  for 
  some 
  seconds 
  was 
  con- 
  

   verted 
  to 
  crystalline 
  zinc 
  ammonium 
  phosphate, 
  which 
  filtered 
  

   readily 
  and 
  was 
  washed 
  free 
  from 
  impurities 
  with 
  the 
  greatest 
  

   facility. 
  He 
  found 
  that 
  all 
  the 
  zinc 
  in 
  solution 
  was 
  thrown 
  down 
  

   as 
  the 
  ammonium 
  zinc 
  phosphate, 
  which 
  on 
  ignition 
  yielded 
  

   the 
  zinc 
  pyrophosphate. 
  With 
  care 
  in 
  handling 
  this 
  process 
  to 
  

   avoid 
  an 
  excess 
  of 
  the 
  precipitant, 
  and 
  the 
  presence 
  of 
  sodium 
  

   and 
  potassium 
  salts 
  (on 
  account 
  of 
  the 
  danger 
  of 
  occlusion) 
  the 
  

   precipitation 
  of 
  the 
  ammonium 
  zinc 
  phosphate, 
  ignition, 
  and 
  

   weighing 
  as 
  the 
  pyrophosphate 
  made, 
  Guyard 
  believed, 
  an 
  ideal 
  

   process 
  for 
  the 
  estimation 
  of 
  zinc. 
  Although 
  there 
  was 
  slight 
  

   solubility 
  of 
  the 
  salt, 
  it 
  made 
  an 
  insignificant 
  loss 
  when 
  the 
  

   process 
  was 
  handled 
  properly. 
  Acids 
  present, 
  or 
  certain 
  alka- 
  

   lies 
  to 
  any 
  great 
  extent, 
  increased 
  the 
  solubility 
  of 
  the 
  salt 
  so 
  

   much 
  that 
  the 
  loss 
  became 
  appreciable. 
  Another 
  source 
  of 
  

   error 
  was 
  to 
  Guyard's 
  mind 
  loss 
  of 
  zinc 
  during 
  the 
  ignition 
  of 
  

   the 
  zinc 
  ammonium 
  phosphate 
  with 
  the 
  paper 
  on 
  which 
  the 
  

   precipitate 
  had 
  been 
  collected. 
  Garriguesf 
  found, 
  in 
  estimat- 
  

   ing 
  zinc 
  in 
  a 
  practical 
  way, 
  that 
  this 
  process 
  advocated 
  by 
  

   Guyard 
  gives 
  in 
  solutions 
  of 
  zinc 
  free 
  from 
  salts 
  of 
  all 
  metals, 
  

   even 
  alkaline 
  salts 
  — 
  solutions 
  that 
  from 
  previous 
  steps 
  in 
  

   analysis, 
  however, 
  must 
  have 
  contained 
  ammonium 
  chloride 
  in 
  

   large 
  amount 
  — 
  as 
  satisfactory 
  results 
  as 
  Guyard 
  claimed 
  for 
  it. 
  

  

  * 
  Comptes 
  Rendus, 
  lix, 
  40, 
  + 
  Liebig 
  s 
  Anualen, 
  xv, 
  129. 
  

  

  :}: 
  Liebig's 
  Aunalen, 
  cxliii, 
  156. 
  § 
  Chemical 
  Xews, 
  xxiv, 
  148. 
  

  

  II 
  Jour. 
  Am. 
  Cliem. 
  Soc, 
  xix, 
  936. 
  

  

  