﻿882 
  Messrs. 
  T. 
  H. 
  Laby 
  and 
  G. 
  W. 
  C. 
  Kaye 
  on 
  

  

  Two 
  stout 
  circular 
  aluminium 
  plates 
  1\1 
  cm. 
  apart, 
  separated 
  

   by 
  a 
  ring 
  of 
  brass, 
  were 
  fastened 
  together 
  by 
  six 
  bolts. 
  The 
  

   brass 
  ring 
  was 
  let 
  into 
  a 
  circular 
  groove 
  cut 
  in 
  each 
  of 
  the 
  

   plates. 
  A 
  central 
  disk 
  of 
  aluminium 
  1 
  mm. 
  thick 
  was 
  mounted 
  

  

  Fiff. 
  2. 
  

  

  I 
  

  

  , 
  tm, 
  . 
  

  

  £ 
  l£CTRQM£T^H 
  

  

  midwav 
  between 
  the 
  plates 
  and 
  surrounded 
  by 
  an 
  earthed 
  

   aluminium 
  guard-ring 
  held 
  in 
  place 
  by 
  three 
  small 
  ebonite 
  

   blocks 
  (B). 
  Three 
  small 
  dumb-bell 
  shaped 
  pieces 
  of 
  ebonite 
  

   (A) 
  insulated 
  the 
  central 
  disk 
  from 
  the 
  guard-ring 
  : 
  these 
  

   pieces 
  could 
  be 
  slipped 
  into 
  place 
  when 
  the 
  disk 
  was 
  eccentric 
  

   and 
  afterwards 
  moved 
  around 
  in 
  the 
  slot 
  into 
  position. 
  The 
  

   central 
  disk 
  was 
  joined 
  to 
  the 
  electrometer 
  quadrants 
  by 
  

   a 
  wire 
  and 
  an 
  insulated 
  rod 
  which 
  passed 
  through 
  the 
  

   wall 
  of 
  the 
  vessel 
  ; 
  the 
  insulation 
  was 
  of 
  ebonite 
  and 
  was 
  

   provided 
  with 
  the 
  usual 
  earthed 
  guard-tube 
  to 
  which 
  the 
  

   guard-ring 
  was 
  connected 
  by 
  a 
  wire. 
  The 
  different 
  parts 
  of 
  

   the 
  ebonite 
  plug 
  were 
  each 
  fitted 
  with 
  a 
  shoulder 
  on 
  the 
  

   inside 
  surface, 
  to 
  withstand 
  the 
  high 
  pressures, 
  and 
  for 
  the 
  

   same 
  reason 
  the 
  end 
  of 
  the 
  glass 
  capillary 
  connecting 
  tube, 
  

   which 
  was 
  let 
  into 
  the 
  opposite 
  face, 
  was 
  expanded. 
  

  

  All 
  the 
  joints 
  were 
  made 
  gas-tight 
  with 
  a 
  mixture 
  of 
  bees- 
  

   wax 
  and 
  resin 
  in 
  proportions 
  that 
  yielded 
  a 
  flexible 
  cement 
  

   which 
  held 
  up 
  to 
  20 
  atmospheres 
  pressure. 
  The 
  bolts 
  were 
  

   tightened 
  up 
  with 
  the 
  apparatus 
  hot 
  enough 
  to 
  keep 
  the 
  

  

  