﻿On 
  the 
  Source 
  of 
  the 
  x-Mays. 
  

  

  185 
  

  

  disk 
  A, 
  due 
  to 
  torsion, 
  no 
  click 
  will 
  be 
  heard, 
  since 
  D 
  and 
  E 
  

   do 
  not 
  touch 
  the 
  conductors 
  H 
  and 
  K 
  at 
  the 
  same 
  instant. 
  

  

  2)C 
  

  

  Now, 
  in 
  order 
  to 
  hear 
  the 
  click 
  again, 
  the 
  brush- 
  holder 
  F 
  

   must 
  be 
  moved 
  through 
  an 
  angle 
  equal 
  to 
  that 
  of 
  the 
  angle 
  of 
  

   advance 
  of 
  C 
  on 
  A, 
  and 
  this 
  is 
  the 
  angle 
  of 
  torsion 
  which 
  is 
  

   found. 
  It 
  is 
  shown 
  on 
  a 
  divided 
  scale 
  Gr. 
  

  

  The 
  author 
  has 
  applied 
  the 
  method 
  to 
  find 
  the 
  torsional 
  

   angle 
  of 
  an 
  ergometer 
  in 
  which 
  a 
  solenoidal 
  spiral 
  spring 
  is 
  

   used 
  instead 
  of 
  a 
  shaft 
  as 
  shown 
  in 
  the 
  figure. 
  

  

  The 
  couple 
  due 
  to 
  any 
  angle 
  is 
  found 
  by 
  fixing 
  A 
  and 
  

   suspending 
  known 
  weights 
  from 
  a 
  thin 
  steel 
  tape 
  attached 
  to 
  

   a 
  pulley 
  of 
  known 
  radius 
  keyed 
  on 
  to 
  the 
  shaft 
  close 
  to 
  the 
  

   disk 
  C. 
  

  

  XIX. 
  The 
  Source 
  of 
  the 
  x-Rays. 
  

   By 
  John 
  Trowbridge 
  and 
  John 
  E. 
  Burbank*. 
  

  

  THE 
  experiments 
  described 
  in 
  this 
  paper 
  were 
  conducted 
  

   with 
  Crookes 
  tubes 
  containing 
  no 
  interval 
  between 
  

   the 
  anode 
  and 
  the 
  cathode: 
  and 
  no 
  discharge, 
  therefore, 
  

   in 
  the 
  usual 
  sense 
  occurred 
  in 
  the 
  tubes. 
  A 
  continuous 
  

   conductor 
  was 
  led 
  through 
  the 
  rarefied 
  tube, 
  and 
  it 
  was 
  dis- 
  

   covered 
  that 
  the 
  arrays 
  were 
  given 
  off 
  from 
  every 
  element 
  of 
  

   this 
  conductor 
  at 
  right 
  angles 
  to 
  its 
  surface 
  when 
  a 
  disruptive 
  

   discharge 
  occurred 
  in 
  the 
  circuit 
  of 
  which 
  the 
  tube 
  formed 
  a 
  

   part. 
  This 
  remarkable 
  result 
  was 
  obtained 
  by 
  means 
  of 
  the 
  

   very 
  high 
  electromotive 
  force 
  furnished 
  by 
  a 
  Plante 
  rheostatic 
  

   machine 
  which 
  was 
  charged 
  by 
  ten 
  thousand 
  storage-cells. 
  

   We 
  shall 
  describe 
  our 
  experiments 
  with 
  the 
  various 
  tubes 
  we 
  

   employed, 
  and 
  in 
  conclusion 
  state 
  our 
  results. 
  

  

  * 
  Communicated 
  by 
  the 
  Authors. 
  

  

  