﻿334 
  Trowbridge 
  and 
  Richards 
  — 
  Temperature 
  and 
  

  

  observed 
  in 
  the 
  photographs 
  of 
  argon 
  at 
  1, 
  2, 
  and 
  3 
  mm 
  pres- 
  

   sure 
  contained 
  in 
  tubes 
  with 
  very 
  fine 
  capillaries, 
  while 
  six 
  

   half 
  oscillations 
  were 
  observed. 
  in 
  tubes 
  about 
  like 
  those 
  used 
  

   for 
  nitrogen 
  and 
  hydrogen. 
  This 
  shows 
  that 
  the 
  form 
  of 
  the 
  

   tube 
  influences 
  very 
  materially 
  the 
  resistance. 
  As 
  a 
  very 
  small 
  

   jar 
  will 
  provide 
  enough 
  electricity 
  to 
  give 
  the 
  blue 
  spectrum 
  

   of 
  argon, 
  the 
  resistance 
  of 
  a 
  tube 
  containing 
  the 
  gas 
  at 
  l 
  mm 
  

   pressure 
  was 
  determined 
  with 
  a 
  capacity 
  of 
  about 
  1,000 
  as 
  well 
  

   as 
  with 
  the 
  usual 
  capacities 
  6,000, 
  12,000 
  and 
  18,000 
  electro- 
  

   static 
  units. 
  Somewhat 
  over 
  six 
  half 
  oscillations 
  were 
  observed 
  

   in 
  each 
  case, 
  corresponding 
  to 
  resistance 
  of 
  about 
  thirteen, 
  

   eight, 
  six-and-a-half, 
  and 
  five 
  ohms 
  respectively. 
  In 
  all, 
  about 
  

   a 
  thousand 
  photographs 
  of 
  sparks 
  through 
  the 
  various 
  gases 
  

   were 
  made. 
  

  

  The 
  Resistance 
  of 
  Nitrogen. 
  

  

  Pressure 
  

  

  of 
  gas 
  in 
  

  

  millimeters. 
  

  

  9'5 
  

  

  5-0 
  

  

  4-2 
  

  

  2-7 
  

  

  2* 
  

  

  1*7 
  

  

  1-3 
  

  

  1-04 
  

  

  0-70 
  

  

  0-50 
  

  

  0'30 
  

  

  0-26 
  

  

  0-22 
  

  

  0*15 
  

  

  0-07 
  

  

  005 
  

  

  0-03 
  

  

  0'02 
  

  

  0-01 
  

  

  0*005 
  

  

  Number 
  of 
  half 
  oscillations. 
  

  

  Capacity^ 
  

   6,000 
  

   units. 
  

  

  1 
  (faint) 
  

  

  2 
  

   2 
  

  

  3* 
  

  

  Capacity 
  = 
  Capacity: 
  

   12,000 
  18,000 
  

  

  units. 
  units. 
  

  

  1 
  

  

  H 
  

   i* 
  

  

  2 
  

   3 
  

   3 
  

   4 
  

   4 
  

   5 
  

  

  8* 
  

  

  5 
  8 
  

  

  7 
  

   8 
  

   5 
  

   5 
  

   no 
  spark 
  | 
  no 
  spark 
  

  

  3 
  

   3(f) 
  

  

  H 
  

  

  5i(?) 
  

  

  Resistance 
  in 
  ohms. 
  

  

  no 
  spark 
  

  

  Capacity 
  = 
  

   6,000 
  

  

  Capacity 
  = 
  

   12,000 
  

  

  Capacity^ 
  

   18,000 
  

  

  ohms. 
  

  

  ohms. 
  

   30 
  

  

  ohms. 
  

  

  35 
  

  

  25 
  

   25 
  

  

  23 
  

  

  20 
  

  

  

  10? 
  

  

  20 
  

  

  20 
  

   15 
  

   15 
  

  

  15 
  

  

  15 
  

  

  10 
  

   10 
  

  

  8 
  

  

  

  8 
  

  

  7 
  

  

  12 
  

  

  4-5 
  

  

  5 
  

   5-5 
  

  

  7 
  

  

  4 
  

  

  

  10 
  

  

  4-5 
  

  

  5 
  

  

  4'5 
  

  

  8 
  

   8 
  

  

  

  

  

  — 
  

  

  — 
  

  

  The 
  evidence 
  of 
  all 
  these 
  experiments 
  is 
  unequivocal, 
  and 
  

   may 
  be 
  summed 
  up 
  under 
  the 
  following 
  heads: 
  

  

  L 
  The 
  resistance 
  of 
  a 
  gas 
  at 
  low 
  pressure 
  to 
  the 
  oscillatory 
  

   discharge 
  is 
  equivalent 
  to 
  only 
  a 
  very 
  small 
  ohmic 
  resistance. 
  

  

  II. 
  This 
  resistance 
  is 
  in 
  general 
  greater, 
  the 
  less 
  the 
  quan- 
  

   tity 
  of 
  electricity. 
  

  

  