﻿400 
  Oberhelman 
  and 
  Browning 
  — 
  Tellurous 
  Acid. 
  

  

  just 
  described, 
  which 
  from 
  its 
  intensity 
  of 
  color 
  was 
  considered 
  

   to 
  contain 
  the 
  maximum 
  amount 
  of 
  copper, 
  gave 
  the 
  following 
  

   analysis: 
  

  

  Te0 
  2 
  83-84 
  

  

  CuO 
  4-63 
  

  

  NH 
  3 
  5-22 
  

  

  HO 
  _.- 
  6-10 
  

  

  99-19 
  

  

  The 
  Te0 
  2 
  was 
  determined 
  by 
  the 
  permanganate 
  method. 
  

   Copper 
  was 
  estimated 
  colorimetrically 
  by 
  comparing 
  in 
  Nessler 
  

   tubes 
  ammoniacal 
  copper 
  solutions 
  of 
  known 
  strength 
  with 
  

   weighed 
  amounts 
  of 
  the 
  compound 
  dissolved 
  in 
  acid 
  and 
  made 
  

   ammoniacal. 
  This 
  method 
  was 
  found 
  to 
  be 
  accurate 
  to 
  2/10ths 
  

   of 
  a 
  mg. 
  The 
  ammonia 
  was 
  determined 
  by 
  distillation 
  from 
  an 
  

   alkaline 
  solution 
  into 
  standard 
  acid. 
  The 
  water 
  eould 
  not 
  be 
  

   determined 
  by 
  difference 
  on 
  ignition, 
  owing 
  to 
  a 
  slight 
  reduction 
  

   of 
  the 
  tellurium. 
  So 
  the 
  compound 
  was 
  heated 
  at 
  140°, 
  and 
  the 
  

   residual 
  ammonia 
  was 
  determined 
  after 
  weighing. 
  From 
  the 
  

   weights 
  of 
  the 
  total 
  ammonia 
  and 
  of 
  the 
  residual 
  ammonia 
  at 
  

   140°, 
  together 
  with 
  the 
  total 
  loss 
  on 
  heating 
  at 
  140°, 
  the 
  weight 
  

   of 
  the 
  water 
  was 
  determined. 
  The 
  loss 
  of 
  ammonia 
  which 
  

   resulted 
  from 
  heating 
  at 
  140° 
  proved 
  to 
  be 
  about 
  constant 
  and 
  

   amounted 
  to 
  a 
  third 
  of 
  the 
  total 
  ammonia. 
  The 
  color 
  of 
  the 
  

   substance 
  changed 
  on 
  heating 
  at 
  140° 
  from 
  reddish-purple 
  to 
  

   blue. 
  

  

  It 
  was 
  thought 
  that 
  compounds 
  of 
  a 
  similar 
  nature 
  containing 
  

   bases 
  other 
  than 
  copper 
  might 
  be 
  formed 
  in 
  a 
  similar 
  manner. 
  

   Nickel, 
  cobalt, 
  zinc, 
  cadmium, 
  and 
  silver 
  were 
  tried 
  but 
  with 
  

   no 
  success. 
  Silver 
  gave 
  a 
  yellow 
  precipitate, 
  but 
  this 
  proved 
  

   to 
  be 
  the 
  ordinary 
  silver 
  tellurite. 
  

  

  