﻿52 
  

  

  Mr. 
  R. 
  F. 
  Earhart 
  on 
  the 
  Discharge 
  

  

  Table 
  II. 
  — 
  Air 
  37 
  cm. 
  Pressure. 
  

   Point 
  + 
  . 
  

  

  Distances 
  

  

  Least 
  P. 
  D. 
  

  

  Distances 
  

  

  Least 
  P.D. 
  

  

  in 
  

  

  required 
  

  

  in 
  

  

  required 
  

  

  wave-lengths 
  

  

  for 
  discharge. 
  

  

  wave-lengths 
  

  

  for 
  discharge. 
  

  

  Na 
  light. 
  

  

  Volts. 
  

  

  Na 
  light. 
  

  

  Volts. 
  

  

  1 
  

  

  347 
  

  

  15 
  

  

  446 
  

  

  1 
  

  

  376 
  

  

  20 
  

  

  526 
  

  

  3 
  

  

  395 
  

  

  20 
  

  

  456 
  

  

  5 
  

  

  364 
  

  

  25 
  

  

  517 
  

  

  5 
  

  

  426 
  

  

  30 
  

  

  503 
  

  

  10 
  

  

  409 
  

  

  40 
  

  

  508 
  

  

  10 
  

  

  395 
  

  

  50 
  

  

  503 
  

  

  12 
  

  

  428 
  

  

  75 
  

  

  564 
  

  

  15 
  

  

  446 
  

  

  92 
  

  

  611 
  

  

  Table 
  III. 
  — 
  Air 
  25 
  cm. 
  Pressure. 
  

   Point 
  + 
  . 
  

  

  Distances 
  

  

  Least 
  P.D. 
  

  

  Distances 
  

  

  Least 
  P.D. 
  

  

  in 
  

  

  required 
  

  

  in 
  

  

  required 
  

  

  wave-lengths 
  

  

  for 
  discharge. 
  

  

  wave-lengths 
  

  

  for 
  discharge. 
  

  

  Na 
  light. 
  

  

  Volts. 
  

  

  Na 
  light. 
  

  

  Volts. 
  

  

  1 
  

  

  376 
  

  

  2 
  

  

  409 
  

  

  2-5 
  

  

  385 
  

  

  20 
  

  

  423 
  

  

  2-5 
  

  

  390 
  

  

  25 
  

  

  446 
  

  

  5 
  

  

  390 
  

  

  30 
  

  

  461 
  

  

  10 
  

  

  351 
  

  

  35 
  

  

  456 
  

  

  10 
  

  

  395 
  

  

  40 
  

  

  475 
  

  

  10 
  

  

  381 
  

  

  45 
  

  

  475 
  

  

  15 
  

  

  395 
  

  

  50 
  

  

  488 
  

  

  Table 
  IV.— 
  Air 
  75 
  cm. 
  

   Point 
  - 
  

  

  pressure. 
  

  

  Distances 
  

  

  Least 
  P.D. 
  

  

  Distances 
  

  

  Least 
  P.D. 
  

  

  in 
  

  

  required 
  

  

  m 
  

  

  required 
  

  

  wave-lengths 
  

  

  for 
  discharge. 
  

  

  wave-lengths 
  

  

  for 
  discharge. 
  

  

  Na 
  light. 
  

  

  Volts. 
  

  

  Na 
  light. 
  

  

  Volts. 
  

  

  0-5 
  

  

  268 
  

  

  18 
  

  

  376 
  

  

  1 
  

  

  329 
  

  

  20 
  

  

  ■123 
  

  

  1 
  

  

  338 
  

  

  26 
  

  

  137 
  

  

  25 
  

  

  820 
  

  

  25 
  

  

  446 
  

  

  4 
  

  

  329 
  

  

  80 
  

  

  451 
  

  

  5 
  

  

  319 
  

  

  35 
  

  

  460 
  

  

  12 
  

  

  338 
  

  

  40 
  

  

  171 
  

  

  12 
  

  

  329 
  

  

  50 
  

  

  494 
  

  

  i;» 
  

  

  376 
  

  

  50 
  

  

  517 
  

  

  IS 
  

  

  385 
  

  

  

  

  