﻿382 
  Scientific 
  Intelligence. 
  

  

  carbon 
  dioxide 
  had 
  been 
  given 
  off, 
  the 
  liquid 
  had 
  a 
  strong 
  odor 
  

   of 
  vanillin, 
  and 
  100 
  g. 
  of 
  sugar 
  had 
  produced 
  21-3 
  g. 
  of 
  glycerine 
  

   as 
  an 
  average 
  of 
  several 
  experiments. 
  — 
  Helvetica 
  Chimica 
  Acta, 
  

   2, 
  167. 
  h. 
  l. 
  w. 
  

  

  2. 
  The 
  Determination 
  of 
  Nitrons 
  Acid 
  and 
  Nitrites. 
  — 
  J. 
  S. 
  

   Laird 
  and 
  T. 
  C. 
  Simpson, 
  of 
  the 
  University 
  of 
  Michigan, 
  have 
  

   found 
  that 
  the 
  methods 
  given 
  in 
  the 
  literature 
  for 
  these 
  deter- 
  

   minations 
  are 
  not 
  satisfactory, 
  and 
  they 
  suggest 
  a 
  modification 
  

   of 
  Raschig's 
  method, 
  which 
  they 
  have 
  found 
  to 
  give 
  excellent 
  

   results. 
  An 
  excess 
  of 
  standard 
  permanganate 
  solution 
  is 
  placed 
  

   in 
  a 
  flask 
  and 
  acidified 
  with 
  10-20 
  cc. 
  of 
  1 
  : 
  4 
  sulphuric 
  acid. 
  

   The 
  nitrite 
  solution 
  is 
  run 
  in 
  slowly 
  with 
  constant 
  shaking. 
  In 
  

   this 
  way 
  there 
  is 
  no 
  danger 
  of 
  loss 
  of 
  nitrite 
  due 
  to 
  decomposition 
  

   upon 
  acidifying. 
  Excess 
  of 
  ferrous 
  sulphate, 
  hydrogen 
  peroxide 
  

   or 
  sodium 
  oxalate, 
  in 
  the 
  form 
  of 
  a 
  standardized 
  solution, 
  is 
  then 
  

   added, 
  and 
  the 
  clear 
  solution 
  is 
  then 
  titrated 
  with 
  the 
  perman- 
  

   ganate 
  solution. 
  It 
  was 
  found 
  that 
  this 
  method 
  is 
  not 
  interfered 
  

   with 
  by 
  moderate 
  amounts 
  of 
  chlorides 
  or 
  small 
  amounts 
  of 
  bro- 
  

   mides. 
  

  

  In 
  the 
  course 
  of 
  their 
  investigation 
  the 
  authors 
  found 
  that 
  

   silver 
  nitrite, 
  which 
  has 
  been 
  highly 
  recommended 
  for 
  the 
  pur- 
  

   pose, 
  is 
  not 
  a 
  satisfactory 
  material 
  for 
  use 
  as 
  a 
  standard 
  in 
  nitrate 
  

   determinations. 
  They 
  prefer 
  to 
  use 
  a 
  sodium 
  nitrite 
  solution 
  

   standardized 
  either 
  by 
  the 
  volumetric 
  method 
  given 
  above, 
  or 
  

   gravimetrically 
  by 
  the 
  reduction 
  of 
  silver 
  bromate 
  to 
  bromide 
  

   according 
  to 
  the 
  method 
  of 
  Busvold. 
  — 
  Jour. 
  Amer. 
  Chem. 
  Soc, 
  

   41, 
  524. 
  h. 
  l. 
  w. 
  

  

  3. 
  The 
  Natural 
  Organic 
  Colouring 
  Matters; 
  by 
  Arthur 
  

   George 
  Perkin 
  and 
  Arthur 
  Ernest 
  Everest. 
  8vo, 
  pp. 
  655. 
  

   London, 
  1918 
  (Longmans, 
  Green 
  & 
  Co., 
  New 
  York. 
  Price 
  $9 
  net). 
  

   — 
  This 
  book 
  is 
  one 
  of 
  the 
  exceedingly 
  important 
  ' 
  ' 
  Monographs 
  on 
  

   Industrial 
  Chemistry" 
  which 
  are 
  in 
  course 
  of 
  publication 
  under 
  

   the 
  editorship 
  of 
  Sir 
  Edward 
  Thorpe. 
  It 
  gives 
  a 
  comprehensive 
  

   discussion 
  of 
  the 
  present 
  knowledge 
  of 
  natural 
  organic 
  coloring 
  

   matters, 
  particularly 
  from 
  a 
  chemical 
  point 
  of 
  view, 
  but 
  with 
  

   many 
  statements 
  concerning 
  their 
  properties 
  as 
  dyes. 
  

  

  The 
  authors 
  state 
  that 
  prior 
  to 
  the 
  year 
  1880, 
  excepting 
  in 
  the 
  

   cases 
  of 
  madder 
  and 
  indigo, 
  very 
  little 
  was 
  known 
  of 
  the 
  chemical 
  

   structure 
  of 
  these 
  coloring 
  matters, 
  and, 
  in 
  fact, 
  it 
  is 
  only 
  during 
  

   the 
  lasl 
  30 
  years 
  that 
  a 
  large 
  amount 
  of 
  information 
  in 
  regard 
  

   to 
  them 
  has 
  been 
  obtained. 
  In 
  looking 
  through 
  this 
  volume 
  one 
  

   is 
  much 
  impressed 
  with 
  the 
  vast 
  amount 
  of 
  knowledge 
  that 
  has 
  

   been 
  gained 
  in 
  this 
  recent 
  period 
  by 
  observing 
  the 
  hundreds 
  of 
  

   complex 
  structural 
  formulas 
  that 
  are 
  presented 
  as 
  representing 
  

   these 
  chemical 
  com 
  pounds. 
  The 
  great 
  industry 
  and 
  success 
  of 
  the 
  

   organic 
  chemists 
  who 
  have 
  labored 
  in 
  this 
  field 
  is 
  well 
  shown 
  by 
  

   the 
  fad 
  thai 
  the 
  'discussion 
  of 
  the 
  coloring 
  matters 
  of 
  unknown 
  

  

  