﻿488 
  Prof. 
  Lyle 
  and 
  Mr. 
  Hosking 
  on 
  the 
  Conductivity 
  

  

  various 
  instruments 
  in 
  position 
  in 
  the 
  bath, 
  namely 
  : 
  the 
  

   glischrometer, 
  dilatometer, 
  electrolytic 
  cell, 
  thermometer, 
  and 
  

   siphon. 
  The 
  stirring 
  was 
  managed 
  by 
  a 
  swiftly 
  rotating 
  

   propeller. 
  The 
  thermometers 
  were 
  standardized 
  before 
  being 
  

   used. 
  They 
  were 
  graduated 
  in 
  tenths, 
  and 
  their 
  readings 
  

   were 
  observed 
  through 
  a 
  cathetometer. 
  The 
  sample 
  of 
  

   sodium 
  chloride 
  used 
  in 
  the 
  solutions 
  was 
  specially 
  purified 
  

   for 
  the 
  purpose 
  by 
  David 
  Avery, 
  Esq., 
  M.Sc, 
  Instructor 
  in 
  

   Chemistry 
  at 
  the 
  Working 
  Men's 
  College, 
  Melbourne. 
  

  

  Figures 
  1, 
  2, 
  and 
  3 
  are 
  drawings 
  of 
  the 
  glischrometer, 
  

   dilatometer, 
  and 
  electrolytic 
  cell 
  used. 
  The 
  formula 
  used 
  

   in 
  determining 
  the 
  viscosity 
  was 
  

  

  where 
  A 
  and 
  B 
  are 
  constants, 
  p 
  is 
  the 
  density 
  and 
  T 
  the 
  

   transpiration 
  time 
  of 
  the 
  solution. 
  The 
  constants 
  A 
  and 
  B 
  

   were 
  obtained, 
  from 
  known 
  values 
  of 
  rj 
  supplied 
  from 
  the 
  

   original 
  curves 
  at 
  two 
  temperatures 
  for 
  which 
  T 
  had 
  been 
  

   observed 
  with 
  the 
  new 
  glischrometer, 
  the 
  liquid 
  used 
  being 
  

   water. 
  The 
  values 
  obtained 
  were 
  

  

  A 
  = 
  0-00002834, 
  B 
  = 
  0'0360 
  ; 
  

  

  and 
  the 
  new 
  determinations 
  of 
  the 
  viscosity 
  of 
  water 
  were 
  

   identical 
  with 
  the 
  old 
  ones 
  up 
  to 
  70° 
  C. 
  Above 
  that 
  there 
  

   were 
  very 
  slight 
  variations. 
  With 
  the 
  new 
  form 
  of 
  glis- 
  

   chrometer 
  the 
  liquid 
  flowed 
  through 
  the 
  capillary-tube 
  under 
  

   a 
  pressure 
  due 
  to 
  the 
  difference 
  of 
  level 
  of 
  its 
  two 
  surfaces 
  

   only. 
  No 
  external 
  pressure 
  was 
  used. 
  Moreover, 
  measure- 
  

   ments 
  could 
  only 
  be 
  made 
  with 
  the 
  liquid 
  flowing 
  in 
  the 
  one 
  

   direction 
  through 
  the 
  capillary-tube, 
  so 
  that 
  we 
  could 
  not 
  

   eliminate 
  errors 
  due 
  to 
  this 
  tube 
  not 
  being 
  quite 
  horizontal. 
  

   For 
  these 
  reasons 
  the 
  new 
  values 
  obtained 
  as 
  absolute 
  values 
  

   are 
  not 
  quite 
  so 
  reliable 
  as 
  the 
  original 
  ones. 
  However, 
  we 
  

   took 
  all 
  precautions 
  to 
  get 
  as 
  accurate 
  values 
  as 
  possible. 
  

   The 
  amount 
  of 
  solution 
  before 
  each 
  reading 
  was 
  adjusted 
  so 
  

   that 
  the 
  two 
  surfaces 
  were 
  at 
  the 
  marks 
  A 
  and 
  B 
  in 
  the 
  same 
  

   horizontal 
  line. 
  The 
  solution 
  w 
  r 
  as 
  then 
  forced 
  up 
  into 
  the 
  

   left 
  limb 
  until 
  its 
  surface 
  was 
  just 
  above 
  C. 
  The 
  time 
  of 
  

   flow 
  when 
  the 
  meniscus 
  passed 
  from 
  C 
  to 
  D 
  gave 
  the 
  tran- 
  

   spiration 
  time 
  (T), 
  usually 
  from 
  2 
  to 
  6 
  minutes. 
  

  

  The 
  cylindrical 
  bulb 
  of 
  the 
  dilatometer 
  (figure 
  2) 
  was 
  

   about 
  5 
  c.c. 
  in 
  capacity, 
  and 
  the 
  remaining 
  portion 
  had 
  an 
  

   internal 
  diameter 
  of 
  2 
  mm. 
  approximately. 
  Between 
  A 
  and 
  

   C 
  were 
  graduations 
  etched 
  in 
  the 
  glass. 
  The 
  graduations 
  

   above 
  B 
  in 
  the 
  other 
  limb 
  were 
  much 
  further 
  apart, 
  and 
  were 
  

  

  