﻿132 
  Z. 
  C. 
  Jones 
  — 
  Method 
  for 
  Estimation 
  of 
  Borio 
  Acid. 
  

  

  The 
  solution 
  is 
  again 
  brought 
  to 
  saturation, 
  if 
  necessary, 
  by 
  

   mannite 
  and 
  after 
  standing 
  in 
  a 
  cool 
  place 
  for 
  40-60 
  minutes, 
  

   titrated 
  with 
  decinormal 
  iodine 
  to 
  determine 
  the 
  excess 
  of 
  

   thiosulphate 
  present. 
  In 
  the 
  manner 
  described, 
  specimens 
  of 
  

   crude 
  calcium 
  borate 
  and 
  crystals 
  of 
  colemanite 
  were 
  analyzed 
  

   with 
  the 
  results 
  given 
  below. 
  

  

  The 
  solution 
  of 
  thiosulphate 
  used 
  was 
  0'19939 
  and 
  the 
  

   iodine 
  0*0996 
  normal. 
  

  

  

  

  

  Table 
  III. 
  

  

  

  

  

  

  

  

  Calcium 
  borate 
  

  

  

  

  

  

  Thio 
  

  

  Iodine 
  

  

  

  Volume 
  of 
  

  

  B2O3 
  

  

  

  Mineral. 
  

  

  taken. 
  

  

  taken. 
  

  

  Time 
  

  

  solutions. 
  

  

  found. 
  

  

  Per 
  

  

  grtn. 
  

  

  cm^. 
  

  

  cm^. 
  

  

  standing. 
  

  

  cm^. 
  

  

  grm. 
  

  

  cent. 
  

  

  0-4015 
  

  

  35-05 
  

  

  4-75 
  

  

  1:00 
  

  

  40 
  

  

  0-2280 
  

  

  56-92 
  

  

  0-4010 
  

  

  35-34 
  

  

  5-23 
  

  

  2:00 
  

  

  Colemanite. 
  

  

  45 
  

  

  0-2283 
  

  

  56-94 
  

  

  0-4002 
  

  

  3200 
  

  

  5-50 
  

  

  1:30 
  

  

  50 
  

  

  0-2043 
  

  

  51-04 
  

  

  0-2513 
  

  

  B201 
  

  

  7-36 
  

  

  1:00 
  

  

  40 
  

  

  0-1279 
  

  

  50-91 
  

  

  0-4007 
  

  

  33-03 
  

  

  7-72 
  

  

  : 
  50 
  

  

  65 
  

  

  0-2036 
  

  

  50-81 
  

  

  These 
  results 
  show 
  little 
  variation 
  and 
  in 
  the 
  case 
  of 
  cole- 
  

   manite 
  correspond 
  closely 
  to 
  the 
  theory 
  50'9T 
  per 
  cent. 
  The 
  

   process 
  is 
  convenient, 
  generally 
  applicable 
  and 
  accurate 
  within 
  

   the 
  ordinary 
  limits 
  of 
  analysis. 
  

  

  