﻿266 
  

  

  Mr. 
  G. 
  B. 
  Bryan 
  on 
  the 
  Determination 
  of 
  

  

  Alcohol 
  (absolute). 
  

   Table 
  XT. 
  

  

  d, 
  

  

  turns. 
  

  

  d, 
  mm. 
  

  

  r, 
  ohms. 
  

  

  Sp. 
  R 
  

  

  C.G.S.xlO" 
  12 
  - 
  

  

  Differ- 
  

   ences. 
  

  

  Resist, 
  of 
  

   1 
  turn. 
  

  

  •1 
  

   •2 
  

   •3 
  

   •5 
  

   10 
  

   20 
  

  

  •127 
  

   •254 
  

   •381 
  

   •635 
  

   1-27 
  

   254 
  

  

  572 
  

   921 
  

   1286 
  

   2005 
  

   3815 
  

   7410 
  

  

  915 
  

   737 
  

   686 
  

   641 
  

   610 
  

   592 
  

  

  349 
  

  

  365 
  

  

  719 
  

  

  1810 
  

  

  3595 
  

  

  3490 
  

   3650 
  

   3595 
  

   3620 
  

   3595 
  

  

  

  

  

  

  3590 
  mean. 
  

  

  Here 
  again 
  there 
  is 
  a 
  great 
  increase 
  in 
  the 
  specific 
  

   resistance 
  in 
  the 
  thin 
  layers, 
  whilst, 
  the 
  differences 
  between 
  

   the 
  layers 
  give 
  an 
  approximately 
  constant 
  value 
  for 
  the 
  

   resistance 
  of 
  one 
  turn, 
  as 
  was 
  the 
  case 
  with 
  water. 
  For 
  this 
  

   reason 
  it 
  was 
  expected 
  that 
  by 
  improving 
  the 
  apparatus 
  the 
  

   differences 
  in 
  the 
  apparent 
  conductivity 
  of 
  the 
  layers 
  could 
  

   be 
  considerably 
  reduced. 
  

  

  Design 
  of 
  New 
  Apparatus. 
  

  

  The 
  chief 
  improvements 
  to 
  be 
  made 
  were 
  : 
  — 
  

  

  (1) 
  To 
  make 
  the 
  upper 
  plate 
  move 
  parallel 
  to 
  itself 
  without 
  

   turning 
  with 
  the 
  screw. 
  This 
  would 
  increase 
  the 
  accuracy 
  of 
  

   the 
  adjustment 
  as 
  well 
  as 
  reduce 
  the 
  time 
  required 
  for 
  it. 
  

  

  (2) 
  To 
  so 
  fix 
  the 
  plates 
  that 
  they 
  could 
  be 
  removed 
  after 
  

   adjusting, 
  to 
  be 
  cleaned, 
  and 
  replaced 
  without 
  spoiling 
  the 
  

   adjustment. 
  The 
  liquid 
  could 
  then 
  be 
  poured 
  into 
  the 
  vessel 
  

   immediately 
  after 
  refixing 
  the 
  plates, 
  so 
  that 
  there 
  would 
  be 
  

   much 
  less 
  time 
  for 
  them 
  to 
  get 
  dirty 
  again 
  than 
  in 
  the 
  old 
  

   arrangement. 
  

  

  (3) 
  To 
  improve 
  the 
  surface 
  of 
  the 
  plates. 
  

  

  (4) 
  To 
  increase 
  the 
  rapidity 
  of 
  alternation 
  of 
  the 
  current 
  

   so 
  as 
  to 
  reduce 
  the 
  polarization. 
  

  

  With 
  the 
  rate 
  of 
  alternation 
  already 
  used 
  (about 
  60 
  per 
  

   sec.) 
  the 
  balance-point 
  with 
  the 
  very 
  thin 
  layers 
  of 
  water 
  

   was 
  not 
  quite 
  steady, 
  and 
  it 
  was 
  thought 
  that 
  this 
  was 
  prob- 
  

   ably 
  due 
  to 
  slight 
  polarization. 
  

  

  The 
  new 
  arrangement 
  for 
  holding 
  the 
  plates 
  is 
  shown 
  in 
  

   fig. 
  5. 
  My 
  best 
  thanks 
  are 
  due 
  to 
  Professors 
  Heaton 
  and 
  

   Robinson, 
  of 
  University 
  College, 
  Nottingham, 
  for 
  the 
  use 
  of 
  

   their 
  workshops 
  while 
  I 
  was 
  making 
  this 
  apparatus. 
  

  

  