﻿Chemistry 
  and 
  Physics. 
  67 
  

  

  SCIENTIFIC 
  INTELLIGENCE. 
  

  

  I. 
  Chemistry 
  and 
  Physics. 
  

  

  1. 
  On 
  the 
  Absorption 
  Spectra 
  of 
  Iodine 
  and 
  Bromine 
  solutions 
  

   <tt 
  Temperatures 
  above 
  the 
  Critical 
  Temperature 
  of 
  the 
  Solvent.— 
  

   It 
  is 
  well 
  known 
  that 
  the 
  absorption 
  spectrum 
  of 
  iodine 
  in 
  carbon 
  

   disulphide 
  consists 
  of 
  a 
  narrow 
  band 
  in 
  the 
  red 
  and 
  a 
  broad 
  one 
  

   in 
  the 
  violet, 
  while 
  that 
  of 
  iodine 
  vapor 
  consists 
  of 
  numerous 
  fine 
  

   lines. 
  Wood 
  has 
  investigated 
  the 
  question 
  whether 
  a 
  rise 
  of 
  

   temperature 
  will 
  convert 
  the 
  absorption 
  spectrum 
  into 
  the 
  line 
  

   spectrum, 
  by 
  heating 
  solutions 
  of 
  iodine 
  in 
  varying 
  quantities 
  of 
  

   carbon 
  disulphide 
  in 
  closed 
  tubes 
  to 
  above 
  300°, 
  the 
  concentration 
  

   of 
  the 
  iodine 
  being 
  varied 
  until 
  the 
  line 
  spectrum 
  becomes 
  visible. 
  

   At 
  this 
  point 
  the 
  density 
  of 
  the 
  carbon 
  disulphide 
  vapor 
  and 
  the 
  

   concentration 
  of 
  the 
  iodine 
  were 
  calculated 
  and 
  the 
  results 
  plot- 
  

   ted. 
  In 
  the 
  case 
  of 
  iodine 
  the 
  numbers 
  obtained 
  gave 
  a 
  curve 
  

   consisting 
  of 
  two 
  consecutive 
  straight 
  lines 
  making 
  an 
  angle 
  with 
  

   one 
  another, 
  while 
  the 
  results 
  of 
  similar 
  experiments 
  with 
  bromine 
  

   gave 
  a 
  curve 
  concave 
  to 
  the 
  axis 
  representing 
  the 
  concentration 
  

   of 
  the 
  bromine. 
  The 
  ratio 
  of 
  the 
  content 
  of 
  bromine 
  to 
  that 
  of 
  

   iodine 
  at 
  similar 
  solvent 
  density 
  varied 
  from 
  6*1 
  to 
  9-4 
  and 
  

   increased 
  with 
  the 
  concentration. 
  The 
  author 
  points 
  out 
  the 
  

   analogy 
  between 
  these 
  results 
  and 
  those 
  obtained 
  by 
  Ilannay 
  and 
  

   Hogarth 
  for 
  solutions 
  of 
  solids 
  at 
  temperatures 
  above 
  the 
  critical 
  

   temperature 
  of 
  the 
  solvent. 
  — 
  Zeitschr. 
  phy 
  sikalische 
  Chem., 
  xix, 
  

   689-695, 
  May, 
  1896. 
  G. 
  r. 
  b. 
  

  

  2. 
  On 
  Boiling 
  Points 
  in 
  a 
  Crookes 
  Vacuum. 
  — 
  Keafft 
  and 
  

   Weilandt 
  have 
  studied 
  the 
  effect 
  of 
  very 
  high 
  exhaustions 
  upon 
  

   the 
  boiling 
  point 
  of 
  several 
  organic 
  substances. 
  The 
  pump 
  used 
  

   was 
  that 
  of 
  v. 
  Babo, 
  a 
  combination 
  of 
  the 
  Bunsen 
  w 
  r 
  ater-pump 
  with 
  

   the 
  mercury 
  pump 
  of 
  Sprengel, 
  w 
  T 
  orking 
  automatically 
  and 
  exhaust- 
  

   ing 
  even 
  a 
  large 
  vessel 
  in 
  a 
  quarter 
  to 
  half 
  an 
  hour, 
  so 
  that 
  a 
  mercury 
  

   manometer 
  shows 
  no 
  difference 
  of 
  level 
  on 
  the 
  two 
  sides. 
  To 
  the 
  

   distillation 
  apparatus 
  was 
  attached 
  a 
  Hittorf 
  tube, 
  so 
  that 
  when 
  the 
  

   induction 
  current 
  was 
  passed 
  between 
  its 
  terminals 
  the 
  production 
  

   upon 
  the 
  glass 
  of 
  the 
  well 
  known 
  green 
  fluorescence 
  indicated 
  

   approximately 
  a 
  vacuum 
  of 
  one 
  millionth 
  of 
  an 
  atmosphere. 
  The 
  

   substance 
  was 
  heated 
  in 
  a 
  flask 
  having 
  a 
  capacity 
  of 
  about 
  15 
  cc 
  , 
  

   which 
  formed 
  with 
  the 
  receiver 
  a 
  single 
  piece. 
  It 
  was 
  connected 
  

   to 
  the 
  pump 
  and 
  the 
  Hittorf 
  tube 
  by 
  a 
  ground 
  joint, 
  the 
  ther- 
  

   mometer 
  passing 
  through 
  a 
  rubber 
  stopper 
  in 
  the 
  neck 
  of 
  the 
  flask. 
  

   When 
  in 
  use, 
  the 
  receiver 
  was 
  covered 
  with 
  filter 
  paper 
  on 
  which 
  

   lumps 
  of 
  ice 
  were 
  placed. 
  The 
  substances 
  experimented 
  on, 
  of 
  

   course, 
  were 
  only 
  those 
  which 
  at 
  this 
  temperature 
  have 
  no 
  vapor- 
  

   pressure 
  ; 
  such 
  as 
  the 
  higher 
  paraffins, 
  cetyl 
  alcohol, 
  chloride 
  and 
  

   iodide; 
  the 
  higher 
  fatty 
  acids 
  and 
  their 
  amides; 
  the 
  higher 
  acids 
  

   of 
  the 
  oleic 
  and 
  oxalic 
  series 
  ; 
  alkylbenzenes 
  of 
  high 
  molecular 
  

   mass; 
  mixed 
  aliphatic 
  aromatic 
  ketones 
  of 
  high 
  molecular 
  mass; 
  

  

  