﻿56 
  

  

  Mr. 
  W. 
  G. 
  Hormell 
  on 
  the 
  

  

  position 
  of 
  maximum 
  glow 
  is 
  reached 
  ; 
  this 
  will 
  be 
  27*80 
  cm. 
  

   from 
  the 
  first 
  bridge. 
  When 
  the 
  bridge 
  is 
  in 
  the 
  proper 
  

   position, 
  the 
  maximum 
  glow 
  of 
  the 
  tube 
  may 
  be 
  easily 
  noted 
  

   from 
  the 
  extension 
  of 
  the 
  glow 
  into 
  the 
  sealing-off 
  tube. 
  

  

  Coolidge 
  * 
  found 
  it 
  necessary 
  to 
  connect 
  the 
  first 
  bridge 
  

   with 
  the 
  earth 
  in 
  order 
  to 
  lead 
  off 
  the 
  irregular 
  vibrations 
  

   of 
  the 
  oscillator 
  which 
  otherwise 
  masked 
  the 
  position 
  of 
  the 
  

   node 
  of 
  the 
  fundamental 
  wave. 
  

  

  I 
  have 
  not 
  found 
  this 
  necessary, 
  however, 
  and 
  attribute 
  it 
  

   largely 
  to 
  the 
  accurately 
  symmetrical 
  arrangement 
  of 
  the 
  

   primary 
  and 
  secondary. 
  

  

  Table 
  I. 
  contains 
  a 
  set 
  of 
  readings 
  which 
  were 
  taken 
  for 
  

   the 
  determination 
  of 
  the 
  line 
  constants. 
  In 
  this, 
  as 
  in 
  all 
  

   other 
  cases, 
  ten 
  readings 
  were 
  taken 
  in 
  locating 
  the 
  position 
  

   of 
  a 
  node. 
  The 
  average 
  of 
  two 
  or 
  three 
  such 
  groups 
  for 
  the 
  

   same 
  node 
  never 
  varied 
  beyond 
  ^ 
  of 
  1 
  per 
  cent. 
  

  

  Table 
  I. 
  

  

  

  

  2nd 
  Node 
  

  

  

  1 
  

  

  1st 
  Node. 
  

  

  2nd 
  Node. 
  

  

  with 
  balance- 
  

   tube. 
  

  

  3rd 
  Node. 
  

  

  4th 
  Node. 
  

  

  centim. 
  

  

  centim. 
  

  

  centim. 
  

  

  centim. 
  

  

  centim. 
  

  

  2765 
  

  

  58-85 
  

  

  58-15 
  

  

  89-25 
  

  

  120-75 
  

  

  27-65 
  

  

  58-95 
  

  

  58-00 
  

  

  89-55 
  

  

  120-45 
  

  

  27-80 
  

  

  59-15 
  

  

  58-30 
  

  

  89-50 
  

  

  120-65 
  

  

  27-75 
  

  

  58-75 
  

  

  58-00 
  

  

  89-50 
  

  

  120-55 
  

  

  27-80 
  

  

  59-00 
  

  

  58-20 
  

  

  89-25 
  

  

  12100 
  

  

  27-80 
  

  

  58-80 
  

  

  58-20 
  

  

  89-60 
  

  

  120-80 
  

  

  27*90 
  

  

  59-15 
  

  

  58-35 
  

  

  89-55 
  

  

  120-80 
  

  

  27-70 
  

  

  59-15 
  

  

  58-15 
  

  

  89-40 
  

  

  120-50 
  

  

  28-00 
  

  

  . 
  58-60 
  

  

  58-10 
  

  

  89-55 
  

  

  120-30 
  

  

  27-95 
  

  

  5900 
  

  

  58-00 
  

  

  89-75 
  

  

  120-50 
  

  

  27-80 
  

  

  58-94 
  

  

  58-14 
  

  

  89-49 
  

  

  120-60 
  

  

  The 
  readings 
  for 
  the 
  nodes 
  most 
  distant 
  from 
  the 
  first 
  

   bridge 
  are 
  not 
  so 
  concordant, 
  but 
  the 
  percentage 
  of 
  error 
  is 
  

   no 
  greater. 
  Generally 
  a 
  careful 
  adjustment 
  of 
  the 
  three 
  

   spark-gaps 
  will 
  lead 
  to 
  a 
  more 
  brilliant 
  and 
  a 
  more 
  constant 
  

   glow 
  of 
  the 
  tube. 
  Frequently, 
  for 
  various 
  reasons, 
  the 
  tube 
  

   will 
  cease 
  to 
  glow 
  in 
  the 
  dark. 
  If 
  on 
  these 
  occasions 
  white 
  

   light 
  from 
  an 
  incandescent 
  lamp 
  or 
  a 
  lighted 
  match 
  be 
  per- 
  

   mitted 
  to 
  fall 
  on 
  the 
  tube, 
  it 
  will 
  instantly 
  begin 
  to 
  glow. 
  

   This 
  is 
  no 
  doubt 
  " 
  the 
  effect 
  of 
  ultra-violet 
  light 
  upon 
  the 
  

  

  * 
  Annaltn 
  der 
  Physik, 
  lxvii. 
  p. 
  582 
  (1899). 
  

  

  