﻿Self- 
  Recording 
  Electrometer. 
  205 
  

  

  passing 
  through 
  the 
  instrument. 
  Instead 
  of 
  using 
  charts 
  

   ruled 
  with 
  a 
  time-scale, 
  blank 
  forms 
  are 
  used, 
  and 
  the 
  time 
  

   is 
  given 
  by 
  an 
  arrangement 
  which 
  brings 
  a 
  small 
  rod 
  under 
  

   the 
  depressor 
  bar 
  for 
  about 
  6 
  minutes 
  before 
  the 
  hour. 
  

   This 
  rod 
  gives 
  a 
  dot 
  near 
  the 
  edge 
  of 
  the 
  chart 
  every 
  two 
  

   minutes 
  while 
  it 
  is 
  under 
  the 
  bar, 
  and 
  it 
  is 
  so 
  adjusted 
  that 
  

   the 
  last 
  dot 
  of 
  the 
  series 
  gives 
  the 
  hour 
  mark. 
  These 
  marks 
  

   are 
  shown 
  on 
  the 
  chart 
  (fig. 
  5, 
  p. 
  208). 
  

  

  Suspetision. 
  — 
  Phosphor-bronze 
  suspensions 
  are 
  employed 
  

   in 
  the 
  usual 
  manner, 
  and 
  it 
  is 
  found 
  that 
  wire 
  0'002 
  in. 
  in 
  

   diameter 
  inves 
  o-ood 
  stability. 
  

  

  Automatic 
  zero. 
  — 
  The 
  drum 
  Q 
  makes 
  two 
  revolutions 
  in 
  

   25 
  hours, 
  and 
  advantage 
  was 
  taken 
  of 
  this 
  to 
  attach 
  an 
  

   arrangement 
  whereby 
  the 
  needle 
  was 
  earthed 
  for 
  about 
  12 
  

   minutes, 
  during 
  each 
  revolution 
  of 
  the 
  drum. 
  The 
  zero 
  

   position 
  is 
  thus 
  automatically 
  given 
  twice 
  a 
  day. 
  

  

  Results. 
  

  

  Fig. 
  2 
  gives 
  an 
  actual 
  trace 
  of 
  the 
  instrument 
  for 
  a 
  

   leakage 
  test. 
  This 
  shows 
  that 
  the 
  insulation 
  is 
  of 
  a 
  very 
  

   hieh 
  order. 
  

  

  

  

  Fig. 
  -2. 
  

  

  

  

  

  Re 
  

  

  ■crr/t 
  

  

  1 
  9 
  . 
  u 
  ro 
  m 
  

  

  eCer 
  

  

  

  Mr^.a-?j*JJi^_L?jL. 
  

  

  

  S* 
  

  

  rnhLr 
  Rccor 
  J 
  . 
  

  

  

  

  

  

  

  Dam/i 
  

  

  atr 
  admitted 
  

  

  ^Leafcaoe 
  of 
  Condenser 
  

  

  Tim?. 
  Marker. 
  

  

  Table 
  III. 
  gives 
  some 
  of 
  the 
  tests 
  made 
  on 
  the 
  sensibility. 
  

   One 
  pair 
  of 
  quadrants 
  was 
  connected 
  to 
  the 
  positive 
  terminal 
  

   of 
  the 
  battery, 
  the 
  other 
  pair 
  to 
  the 
  negative, 
  and 
  the 
  centre 
  

   of 
  the 
  battery 
  was 
  earthed. 
  

  

  