﻿the 
  Cathodic 
  Rays 
  and 
  those 
  of 
  Rontgen. 
  167 
  

  

  fixed 
  in 
  the 
  posterior 
  part 
  of 
  the 
  tube, 
  but 
  high 
  np 
  in 
  front 
  of 
  

   the 
  spherical 
  reflector 
  S' 
  and 
  at 
  some 
  distance 
  from 
  the 
  axis 
  

   of 
  this 
  same 
  reflector. 
  

  

  The 
  cathodic 
  rajs 
  reflected 
  by 
  the 
  plane 
  reflector 
  on 
  the 
  

   spherical 
  one 
  S', 
  were 
  by 
  this 
  thrown 
  back 
  with 
  the 
  same 
  

   luminous 
  appearances 
  as 
  surrounded 
  the 
  spherical 
  reflector 
  

   exposed 
  to 
  the 
  direct 
  cathodic 
  rays 
  in 
  the 
  2nd 
  experiment 
  ; 
  

   but 
  the 
  small 
  pencil 
  which 
  showed 
  sufficiently 
  in 
  said 
  2nd 
  

   experiment 
  was 
  scarcely 
  visible 
  in 
  front 
  of 
  S' 
  and 
  could 
  only 
  

   be 
  followed 
  up 
  to 
  a 
  very 
  limited 
  distance 
  from 
  the 
  reflector. 
  

  

  The 
  photographic 
  cylinder 
  received 
  then 
  a 
  much 
  more 
  

   vivid 
  impression 
  on 
  the 
  part 
  facing 
  the 
  reflector 
  than 
  on 
  any 
  

   other 
  portion 
  of 
  it. 
  

  

  The 
  two 
  experiments, 
  3rd 
  and 
  4tb, 
  show 
  that 
  the 
  cathode 
  

   rays 
  reflected 
  by 
  the 
  reflector 
  of 
  a 
  focus-tube 
  can 
  subsequently 
  

   undergo 
  a 
  new 
  anomalous 
  reflexion 
  similar 
  to 
  the 
  first 
  re- 
  

   flexion 
  of 
  the 
  same 
  rays. 
  

  

  5th 
  Experiment. 
  — 
  In 
  this 
  experiment 
  two 
  bulbs 
  of 
  equal 
  

   size, 
  with 
  the 
  reflector 
  and 
  the 
  small 
  cylinder 
  disposed 
  as 
  in 
  

   fig. 
  1, 
  were 
  placed 
  in 
  simultaneous 
  communication 
  with 
  the 
  

   air-pump. 
  

  

  In 
  the 
  first 
  bulb, 
  however, 
  the 
  reflector 
  was 
  a 
  sheet 
  of 
  

   platinum 
  of 
  the 
  thickness 
  of 
  ^ 
  of 
  a 
  millimetre, 
  and 
  in 
  the 
  

   second 
  bulb 
  a 
  sheet 
  of 
  aluminium 
  of 
  the 
  same 
  thickness. 
  

  

  The 
  electrical 
  discharge 
  was 
  sent 
  alternately 
  in 
  the 
  two 
  

   bulbs 
  minute 
  after 
  minute. 
  

  

  On 
  the 
  two 
  films 
  which 
  faced 
  respectively 
  the 
  two 
  re- 
  

   flectors, 
  strong 
  impressions 
  were 
  always 
  received 
  and 
  of 
  the 
  

   same 
  intensity. 
  To 
  a 
  feeble 
  impression 
  obtained 
  at 
  the 
  back 
  of 
  

   the 
  sheet 
  of 
  aluminium, 
  no 
  impression 
  whatever 
  corresponded 
  

   on 
  the 
  film 
  placed 
  at 
  the 
  back 
  of 
  the 
  sheet 
  of 
  platinum. 
  But 
  

   to 
  a 
  sufficiently 
  marked 
  impression 
  on 
  the 
  first, 
  a 
  very 
  feeble 
  

   impression 
  showed 
  on 
  the 
  second. 
  

  

  hth 
  Experiment. 
  — 
  The 
  same 
  arrangement 
  was 
  maintained 
  

   as 
  in 
  the 
  preceding 
  experiment 
  ; 
  but 
  in 
  the 
  first 
  bulb 
  the 
  

   reflector 
  w 
  r 
  as 
  now 
  of 
  aluminium 
  of 
  the 
  thickness 
  of 
  ^ 
  of 
  a 
  

   millimetre, 
  and 
  in 
  the 
  second 
  the 
  reflector 
  was 
  also 
  of 
  

   aluminium, 
  but 
  of 
  the 
  thickness 
  of 
  but 
  j 
  1 
  ^ 
  of 
  a 
  millimetre. 
  . 
  

  

  The 
  impressions 
  on 
  the 
  films 
  in 
  front 
  w 
  T 
  ere, 
  as 
  usual, 
  of 
  the 
  

   same 
  intensity. 
  And 
  as 
  for 
  the 
  posterior 
  films, 
  a 
  stronger 
  

   impression 
  was 
  obtained 
  on 
  the 
  one 
  situated 
  behind 
  the 
  thinner 
  

   sheet. 
  

  

  1th 
  Experiment. 
  — 
  The 
  same 
  disposition 
  as 
  in 
  the 
  preceding 
  

   experiment. 
  The 
  reflector 
  of 
  one 
  of 
  the 
  bulbs 
  was 
  of 
  black 
  

   paper 
  of 
  the 
  thickness 
  of 
  T 
  §j 
  of 
  a 
  millimetre, 
  and 
  that 
  of 
  the 
  

   other 
  was 
  a 
  sheet 
  of 
  aluminium 
  of 
  the 
  same 
  thickness. 
  

  

  