﻿102 
  Mr. 
  J. 
  Pose-Innes 
  on 
  the 
  Isothermals 
  of 
  Ether. 
  

  

  heating. 
  It 
  phosphoresced, 
  however, 
  on 
  heating 
  after 
  having 
  

   heen 
  electri 
  tied 
  by 
  the 
  brush-discharge. 
  The 
  phosphorescence 
  

   was 
  evidently 
  an 
  expression 
  of 
  the 
  electrical 
  energy 
  which 
  

   was 
  communicated 
  to 
  the 
  substance, 
  and 
  this 
  energy 
  was 
  

   suddenly 
  converted 
  into 
  light 
  by 
  the 
  action 
  of 
  the 
  heat 
  in 
  

   dispelling 
  the 
  electricity. 
  The 
  substance 
  was 
  next 
  subjected 
  

   to 
  the 
  action 
  of 
  the 
  A'-rays, 
  in 
  a 
  brass 
  box 
  closed 
  by 
  an 
  

   aluminium 
  window. 
  The 
  box 
  was 
  also 
  connected 
  to 
  the 
  ground. 
  

   When 
  the 
  substance 
  was 
  taken 
  from 
  the 
  metallic 
  box 
  it 
  

   showed 
  no 
  phosphorescence, 
  but 
  on 
  being 
  heated 
  it 
  exhibited 
  

   a 
  bright 
  phosphorescence 
  which 
  quickly 
  disappeared. 
  

  

  The 
  action 
  of 
  the 
  awavs 
  on 
  this 
  mineral 
  was 
  exactlv 
  

   similar 
  to 
  that 
  of 
  electrification 
  ; 
  and 
  we 
  cannot 
  but 
  regard 
  

   our 
  experiments 
  as 
  an 
  evidence 
  of 
  the 
  electrical 
  nature 
  of 
  

   the 
  action 
  of 
  the 
  «#-rays. 
  By 
  them 
  an 
  electrical 
  charge 
  is 
  

   communicated 
  to 
  fluorescent 
  and 
  phosphorescent 
  substances. 
  

   The 
  resulting 
  electrical 
  energy 
  in 
  being 
  dissipated 
  reduces 
  

   the 
  secretion 
  of 
  light. 
  By 
  heating 
  crystals 
  which 
  have 
  been 
  

   electrified 
  we 
  produce 
  a 
  sudden 
  dissipation 
  of 
  the 
  electrical 
  

   energy 
  which 
  has 
  been 
  communicated 
  to 
  the 
  particles 
  of 
  the 
  

   phosphorescent 
  substance, 
  either 
  by 
  direct 
  electrification 
  or 
  

   by 
  the 
  electrification 
  produced 
  by 
  the 
  A-rays. 
  

  

  Most 
  phosphorescent 
  substances, 
  after 
  having 
  been 
  sub- 
  

   mitted 
  to 
  sunlight 
  or 
  daylight, 
  glow 
  more 
  strongly 
  when 
  

   heated. 
  The 
  phosphorescence, 
  however, 
  dies 
  out 
  more 
  quickly 
  

   after 
  the 
  process 
  of 
  heating, 
  which 
  seems 
  to 
  cause 
  the 
  energy 
  

   communicated 
  to 
  the 
  substance 
  by 
  light 
  to 
  become, 
  dissipated 
  

   more 
  quickly. 
  The 
  same 
  thing 
  is 
  true 
  of 
  the 
  state 
  of 
  phos- 
  

   phorescence 
  communicated 
  by 
  the 
  A'-rays. 
  Can 
  we 
  therefore 
  

   conclude 
  that 
  the 
  phosphorescence 
  excited 
  by 
  sunlight 
  or 
  

   daylight 
  is 
  due 
  to 
  an 
  electrical 
  condition 
  which 
  is 
  dissipated 
  

   by 
  heat 
  ? 
  This 
  supposition 
  seems 
  to 
  us 
  not 
  inconsistent 
  with 
  

   the 
  electromagnetic 
  theory 
  of 
  light, 
  and 
  phosphorescence 
  may 
  

   be 
  an 
  evidence 
  of 
  the 
  electrical 
  stresses 
  which 
  produce 
  the 
  

   phenomena 
  of 
  ultra-violet 
  light. 
  

  

  Jefferson 
  Physical 
  Laboratory, 
  

   Harvard 
  University, 
  Cambridge, 
  U.S. 
  

  

  X. 
  On 
  the 
  Isothermals 
  of 
  Ether. 
  By 
  J. 
  Rose-Innes, 
  M.A., 
  

   B.Sc* 
  

  

  IN 
  a 
  paper 
  a 
  On 
  the 
  Isothermals 
  of 
  Isopentane/' 
  read 
  

   before 
  the 
  Physical 
  Society 
  last 
  May 
  "f* 
  I 
  gave 
  an 
  account 
  

   of 
  some 
  results 
  obtained 
  by 
  investigating 
  Prof. 
  Young's 
  

  

  * 
  Communicated 
  by 
  the 
  Physical 
  Society 
  : 
  read 
  Nov. 
  12, 
  1897. 
  

   t 
  Phil. 
  Mag-. 
  [5] 
  xliv. 
  p. 
  76. 
  

  

  