﻿Homogeneous 
  Secondary 
  Hontgen 
  Radiations, 
  573 
  

  

  To 
  compare 
  the 
  intensity 
  of 
  this 
  scattered 
  radiation 
  from 
  

   silver 
  with 
  that 
  from 
  elements 
  in 
  the 
  H-S 
  group, 
  the 
  

   ionization 
  produced 
  by 
  the 
  secondary 
  radiation 
  from 
  a 
  thin 
  

   sheet 
  of 
  silver 
  '00064 
  cm. 
  thick 
  was 
  compared 
  with 
  that 
  

   produced 
  by 
  the 
  radiation 
  from 
  paper. 
  The 
  masses 
  of 
  silver 
  

   and 
  paper 
  emitting 
  the 
  secondary 
  rays 
  were 
  '2695 
  gr. 
  and 
  

   2*72 
  gr. 
  respectively. 
  The 
  relative 
  ionizations 
  produced 
  by 
  

   the 
  secondary 
  rays 
  from 
  these 
  were 
  148 
  and 
  280. 
  From 
  

   other 
  experiments 
  on 
  the 
  absorption 
  of 
  the 
  primary 
  beam 
  by 
  

   sheets 
  of 
  silver 
  and 
  paper 
  of 
  different 
  thicknesses, 
  it 
  was 
  

   estimated 
  that 
  about 
  60 
  per 
  cent, 
  of 
  the 
  silver 
  radiation 
  and 
  

   75 
  per 
  cent, 
  of 
  the 
  paper 
  radiation 
  was 
  transmitted 
  through 
  

   the 
  surface 
  layer. 
  The 
  intensities 
  of 
  radiation 
  from 
  these 
  

   masses 
  were, 
  therefore, 
  in 
  the 
  ratio 
  37 
  : 
  56 
  approximately. 
  

   From 
  equal 
  masses 
  this 
  was 
  37 
  : 
  5*6, 
  or 
  6*5 
  : 
  1 
  approximately. 
  

  

  As 
  the 
  primary 
  radiation 
  incident 
  on 
  silver 
  became 
  more 
  

   penetrating, 
  the 
  ionization 
  produced 
  by 
  the 
  secondary 
  rays 
  

   increased 
  enormously, 
  the 
  variation 
  of 
  intensity 
  in 
  the 
  two 
  

   principal 
  directions 
  at 
  right 
  angles 
  to 
  that 
  of 
  propagation 
  of 
  

   the 
  primary 
  rays 
  gradually 
  decreased 
  from 
  its 
  original 
  

   amount 
  — 
  about 
  14 
  per 
  cent. 
  — 
  until 
  it 
  was 
  inappreciable, 
  

   though 
  with 
  the 
  same 
  primary 
  the 
  variation 
  in 
  the 
  intensity 
  

   of 
  radiation 
  from 
  carbon 
  had 
  only 
  dropped 
  to 
  about 
  6'5 
  per 
  

   cent. 
  The 
  evidence 
  of 
  polarity 
  of 
  the 
  primary 
  given 
  by 
  the 
  

   secondary 
  rays 
  from 
  silver 
  thus 
  disappeared, 
  while 
  that 
  given 
  

   by 
  the 
  rays 
  from 
  carbon 
  simply 
  decreased 
  from 
  14 
  per 
  cent, 
  

   to 
  6*5 
  per 
  cent. 
  It 
  should, 
  however, 
  be 
  noticed 
  that 
  the 
  

   ionizing 
  effect 
  of 
  the 
  secondary 
  rays 
  from 
  silver 
  increased 
  

   considerably, 
  and 
  when 
  the 
  evidence 
  of 
  polarity 
  disappeared 
  

   the 
  total 
  secondary 
  ionization 
  had 
  increased 
  about 
  tenfold, 
  

   so 
  that 
  such 
  an 
  effect 
  would 
  have 
  been 
  produced 
  by 
  the 
  

   superposition 
  of 
  the 
  homogeneous 
  radiation, 
  like 
  that 
  emitted 
  

   by 
  Cu, 
  Fe, 
  Zn, 
  <fec; 
  for 
  such 
  a 
  radiation 
  gives 
  no 
  evidence 
  

   of 
  polarity 
  in 
  a 
  primary 
  beam, 
  being 
  uniformly 
  distributed 
  

   around 
  that 
  beam*. 
  

  

  * 
  An 
  early 
  experiment 
  by 
  one 
  of 
  us 
  on 
  the 
  radiation 
  from 
  tin 
  (e) 
  

   indicated 
  that 
  the 
  scattered 
  radiation 
  was 
  not 
  emitted 
  in 
  even 
  the 
  

   intensity 
  that 
  could 
  be 
  given 
  by 
  an 
  element 
  of 
  the 
  H-S 
  group. 
  The 
  

   experiment 
  was 
  performed 
  by 
  comparing 
  a 
  very 
  penetrating 
  portion 
  of 
  

   the 
  radiation 
  from 
  tin 
  with 
  that 
  from 
  paper. 
  There 
  are 
  possibilities 
  

   which 
  make 
  such 
  an 
  experiment 
  inconclusive, 
  and 
  we 
  feel 
  that 
  it 
  requires 
  

   verification. 
  If 
  the 
  numerical 
  values 
  for 
  the 
  polarization 
  given 
  in 
  

   Table 
  VIII. 
  could 
  be 
  taken 
  as 
  strictly 
  accurate 
  throughout, 
  we 
  should 
  be 
  

   led 
  to 
  conclude 
  that 
  the 
  evidence 
  of 
  polarity 
  disappeared 
  more 
  rapidly 
  

   than 
  could 
  be 
  accounted 
  for 
  by 
  mere 
  superposition 
  of 
  the 
  homogeneous 
  

   radiation, 
  but 
  the 
  measurements 
  in 
  the 
  final 
  stages 
  were 
  too 
  uncertain 
  

   for 
  such 
  a 
  conclusion 
  to 
  be 
  based 
  on 
  them. 
  We 
  have, 
  therefore, 
  no 
  

   conclusive 
  evidence 
  of 
  a 
  disappearance 
  of 
  the 
  scattered 
  radiation. 
  

  

  