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  LVI. 
  Hie 
  Temperature 
  Variations 
  of 
  the 
  Specific 
  Molecular 
  

   Conductivity 
  and 
  of 
  the 
  Fluidity 
  of 
  Sodium 
  Chloride 
  

   Solutions. 
  By 
  Prof. 
  Thomas 
  R. 
  Lyle 
  and 
  Mr. 
  Richard 
  

   Hosking, 
  University 
  of 
  Melbourne*. 
  

  

  [Plates 
  XI, 
  & 
  XII.] 
  

  

  HE 
  statement 
  lias 
  often 
  been 
  made 
  that 
  the 
  temperature 
  

  

  T 
  

  

  variations 
  of 
  electrical 
  conductivity 
  and 
  fluidity 
  (the 
  

   inverse 
  of 
  viscosity) 
  are 
  identical 
  for 
  a 
  given 
  electrolytic 
  

   solution. 
  In 
  order 
  partly 
  to 
  test 
  the 
  accuracy 
  of 
  the 
  state- 
  

   ment 
  in 
  a 
  particular 
  case, 
  and 
  generally 
  to 
  obtain 
  a 
  set 
  of 
  

   accurate 
  values 
  for 
  the 
  two 
  quantities 
  mentioned, 
  the 
  experi- 
  

   ments 
  which 
  yielded 
  the 
  following 
  results 
  were 
  undertaken 
  

   by 
  us. 
  

  

  Previously 
  one 
  of 
  us 
  had 
  obtained 
  values 
  of 
  the 
  Viscosity 
  

   of 
  Sodium 
  Chloride 
  solutions 
  over 
  a 
  considerable 
  range 
  of 
  

   temperature 
  (Phil. 
  Mag. 
  March 
  1900, 
  p. 
  274) 
  ; 
  but 
  the 
  effect 
  

   of 
  change 
  of 
  density 
  and 
  temperature 
  on 
  the 
  viscosity 
  is 
  so 
  

   great 
  that 
  it 
  was 
  determined 
  that 
  portions 
  of 
  the 
  solution 
  to 
  

   be 
  experimented 
  upon 
  should 
  be 
  run 
  into 
  suitable 
  instruments 
  

   fixed 
  in 
  the 
  same 
  bath, 
  and 
  that 
  the 
  observations 
  necessary 
  

   for 
  calculating 
  the 
  density, 
  fluidity, 
  and 
  electrical 
  resistance 
  

   should 
  be 
  made 
  at 
  the 
  same 
  time, 
  the 
  temperature 
  being 
  

   kept 
  constant 
  until 
  all 
  the 
  readings 
  had 
  been 
  taken 
  for 
  that 
  

   particular 
  temperature. 
  

  

  From 
  the 
  results 
  so 
  obtained, 
  we 
  are 
  able, 
  by 
  interpolation, 
  

   to 
  compare 
  the 
  electric 
  conductivity 
  and 
  the 
  fluidity 
  over 
  the 
  

   range 
  of 
  temperature 
  between 
  0°C. 
  and 
  100° 
  C. 
  of 
  solutions 
  

   of 
  constant 
  concentration; 
  that 
  is, 
  we 
  compare 
  the 
  conductivity 
  

   and 
  the 
  fluidity 
  at 
  different 
  temperatures 
  of 
  such 
  solutions 
  as 
  

   contain, 
  say, 
  1 
  gram 
  molecule 
  per 
  litre 
  at 
  each 
  of 
  these 
  

   temperatures. 
  This 
  we 
  are 
  enabled 
  to 
  do 
  by 
  means 
  of 
  the 
  

   values 
  of 
  the 
  density 
  at 
  the 
  different 
  temperatures 
  of 
  any 
  

   particular 
  solution 
  experimented 
  with, 
  which 
  we 
  determine 
  

   simultaneously 
  with 
  its 
  electric 
  resistance 
  and 
  viscosity. 
  

  

  The 
  bath 
  was 
  a 
  large 
  beaker 
  of 
  water, 
  contained 
  in 
  the 
  

   upper 
  compartment 
  of 
  an 
  iron 
  jacket 
  provided 
  at 
  the 
  front 
  

   and 
  back 
  with 
  glass 
  windows, 
  and 
  inclosed 
  at 
  the 
  top 
  by 
  a 
  

   thick 
  wooden 
  cover. 
  The 
  two 
  compartments 
  were 
  separated 
  

   by 
  a 
  plate 
  of 
  asbestos 
  on 
  which 
  the 
  beaker 
  rested, 
  and 
  the 
  

   lower 
  one 
  contained 
  the 
  gas-jet 
  used 
  for 
  heating 
  the 
  bath 
  and 
  

   the 
  very 
  small 
  controlling 
  flame 
  which 
  was 
  used 
  for 
  keeping 
  

   the 
  bath 
  from 
  cooling 
  while 
  readings 
  were 
  being 
  taken. 
  The 
  

   cover 
  was 
  pierced 
  with 
  the 
  holes 
  necessary 
  for 
  holding 
  the 
  

  

  * 
  Communicated 
  by 
  the 
  Authors. 
  

  

  