﻿352 
  Intelligence 
  and 
  Miscellaneous 
  Articles. 
  

  

  bution 
  of 
  water-supplies 
  takes 
  the 
  place 
  of 
  a 
  few 
  paragraphs 
  in 
  

   the 
  Encyclopaedia 
  article 
  ; 
  and 
  the 
  discussion 
  of 
  the 
  flow 
  of 
  com- 
  

   pressible 
  fluids 
  is 
  considerably 
  extended. 
  There 
  is, 
  however, 
  in 
  

   the 
  book 
  no 
  chapter 
  corresponding 
  to 
  the 
  former 
  section 
  on 
  

   Hydraulic 
  Machinery 
  which 
  occupied 
  nearly 
  one 
  third 
  of 
  the 
  

   whole. 
  There 
  can 
  be 
  but 
  one 
  opinion 
  as 
  to 
  the 
  value 
  of 
  this 
  

   Treatise. 
  It 
  is 
  the 
  outcome 
  of 
  more 
  than 
  forty 
  years' 
  continued 
  

   study 
  of 
  the 
  subject 
  on 
  the 
  part 
  of 
  one 
  of 
  our 
  most 
  distinguished 
  

   teachers 
  of 
  engineering 
  science. 
  

  

  XXIX. 
  Intelligence 
  and 
  Miscellaneous 
  Articles. 
  

  

  REMARKS 
  ON 
  THE 
  PAPER 
  OF 
  HANS 
  GEIGER 
  : 
  " 
  THE 
  IRREGULA- 
  

   RITIES 
  IN 
  THE 
  RADIATION 
  FROM 
  RADIOACTIVE 
  BODIES." 
  BY 
  

   DR. 
  EDGAR 
  MEYER, 
  UNIVERSITY 
  OF 
  ZURICH, 
  AND 
  DR. 
  ERICH 
  

   REGENER, 
  UNIVERSITY 
  OF 
  BERLIN. 
  

  

  TN 
  the 
  Philosophical 
  Magazine 
  of 
  April 
  1908 
  Hans 
  G-eiger 
  has 
  

   published 
  a 
  paper 
  bearing 
  the 
  above 
  title. 
  At 
  the 
  end 
  of 
  

   his 
  communication 
  he 
  adds 
  a 
  note, 
  in 
  which 
  he 
  refers 
  to 
  a 
  paper 
  

   of 
  ours 
  entitled 
  " 
  Ueber 
  Schwankungender 
  radioaktiven 
  Strahlung 
  

   und 
  eine 
  Methode 
  zur 
  Bestimmung 
  des 
  elektrischen 
  Elementar- 
  

   quantums'"' 
  (paper 
  read 
  before 
  the 
  Deutsche 
  Physikalische 
  Gesell- 
  

   schaft, 
  December 
  13, 
  1907, 
  published 
  in 
  the 
  Verliandlungen 
  der 
  

   deutschen 
  physikaMschen 
  Gesellschaft, 
  x. 
  p. 
  1, 
  1908, 
  and 
  also 
  recently 
  

   in 
  the 
  Annalen 
  der 
  Physik, 
  xxv. 
  p. 
  757, 
  1908). 
  

  

  G-eiger 
  says 
  in 
  this 
  note 
  : 
  " 
  Further, 
  they 
  [the 
  authors] 
  state 
  

   that 
  b} 
  7 
  measuring 
  the 
  error 
  e 
  [the 
  average 
  oscillation 
  of 
  the 
  radiation 
  

   from 
  a 
  radioactive 
  body] 
  and 
  the 
  saturation 
  current 
  i, 
  the 
  charge 
  

   of 
  an 
  ion 
  may 
  be 
  determined. 
  But 
  the 
  calculation 
  involves 
  the 
  

   number 
  of 
  ions 
  produced 
  by 
  an 
  a 
  particle, 
  and 
  this 
  number 
  was 
  

   determined 
  by 
  Rutherford 
  under 
  the 
  assumption 
  that 
  the 
  charge 
  

   of 
  an 
  a 
  particle 
  is 
  identical 
  with 
  the 
  charge 
  of 
  an 
  ion. 
  This, 
  

   however, 
  is 
  still 
  an 
  unsettled 
  question." 
  

  

  In 
  relation 
  to 
  this 
  remark 
  we 
  have 
  to 
  say 
  that 
  we 
  were 
  fully 
  

   aware 
  of 
  the 
  fact, 
  that 
  in 
  our 
  calculation 
  we 
  assumed 
  the 
  charge 
  

   of 
  an 
  a 
  particle 
  to 
  be 
  identical 
  with 
  the 
  charge 
  of 
  an 
  ion. 
  This 
  

   follows 
  clearly 
  from 
  the 
  fact 
  that 
  in 
  our 
  paper 
  (§ 
  10 
  in 
  the 
  

   Verliandlungen, 
  § 
  14 
  in 
  the 
  Annalen) 
  we 
  have 
  also 
  given 
  a 
  new 
  

   method 
  of 
  determining 
  in 
  a 
  simple 
  manner, 
  whether 
  an 
  a 
  particle 
  

   carries 
  one 
  or 
  two 
  charges 
  of 
  an 
  ion 
  under 
  the 
  assumption 
  of 
  a 
  

   imown 
  value 
  of 
  the 
  charge 
  of 
  an 
  ion. 
  

  

  G-eiger 
  in 
  his 
  note 
  also 
  gives 
  a 
  method 
  of 
  determining 
  the 
  

   number 
  of 
  a 
  particles 
  emitted 
  per 
  second 
  by 
  a 
  given 
  radioactive 
  

   substance. 
  Perhaps 
  we 
  may 
  be 
  permitted 
  to 
  point 
  to 
  the 
  fact 
  

   that 
  the 
  same 
  method 
  has 
  been 
  already 
  applied 
  in 
  our 
  research. 
  

  

  Zurich 
  and 
  Berlin, 
  May 
  1908. 
  

  

  