﻿102 
  Prof. 
  A. 
  S. 
  Eve 
  on 
  the 
  Amount 
  of 
  

  

  of 
  aggregation 
  and 
  deny 
  the 
  possibility 
  of 
  any 
  chemical 
  com- 
  

   bination 
  of 
  the 
  metnl 
  with 
  a 
  gas. 
  The 
  writer, 
  on 
  the 
  other 
  

   hand, 
  has 
  assumed 
  in 
  common 
  with 
  Houllevigne, 
  that 
  such 
  

   films 
  are 
  the 
  result 
  of 
  partial 
  oxidation. 
  This 
  view 
  seemed 
  

   to 
  be 
  supported 
  by 
  the 
  fact, 
  already 
  mentioned, 
  that 
  films 
  

   deposited 
  in 
  oxygen 
  (air) 
  showed 
  the 
  same 
  decrease 
  of 
  rotation 
  

   with 
  increasing 
  wave-length 
  after 
  about 
  X 
  = 
  Ifjb, 
  To 
  throw 
  

   more 
  light 
  on 
  this 
  point, 
  a 
  thick 
  film, 
  giving 
  a 
  rotation 
  

   (Na 
  light) 
  of 
  +2°- 
  5 
  before 
  oxidation, 
  was 
  oxidized 
  by 
  moist 
  

   air 
  and 
  ozone 
  and 
  its 
  rotation 
  then 
  measured 
  bolometrically. 
  

   When 
  corrected 
  for 
  the 
  glass, 
  the 
  results 
  gave 
  H- 
  014:° 
  for 
  

   X=l-08/A, 
  and 
  4-*006° 
  for 
  A 
  = 
  l-75/x. 
  the 
  successive 
  measure- 
  

   ments 
  differing 
  by 
  only 
  a 
  few 
  thousandths 
  of 
  a 
  degree. 
  It 
  

   will 
  be 
  noted 
  that 
  the 
  rotation 
  is 
  still 
  in 
  the 
  same 
  sense 
  but 
  

   many 
  times 
  smaller 
  than 
  before, 
  and 
  that 
  it 
  shows 
  this 
  decrease 
  

   with 
  increasing 
  wave-length 
  after 
  \ 
  = 
  Ifx. 
  These 
  same 
  

   characteristics 
  are 
  exhibited, 
  in 
  a 
  smaller 
  degree, 
  by 
  the 
  

   yellow-broAvn 
  films. 
  

  

  In 
  conclusion, 
  it 
  seems 
  to 
  the 
  writer 
  that 
  it 
  is 
  unnecessary 
  

   at 
  present 
  to 
  explain 
  either 
  of 
  the 
  types 
  of 
  films 
  obtained 
  by 
  

   the 
  cathode 
  deposit 
  as 
  an 
  especially 
  anomalous 
  state 
  of 
  the 
  

   metal. 
  For 
  the 
  "metallic^' 
  ^}V^-> 
  ^^ 
  shown 
  by 
  Skinner 
  and 
  

   Tool, 
  in 
  general 
  resembles, 
  more 
  or 
  less, 
  electrolyticall}'' 
  

   deposited 
  films 
  ; 
  and 
  in 
  the 
  case 
  of 
  the 
  " 
  dark 
  " 
  films, 
  while 
  

   it 
  is 
  admittedly 
  difficult 
  to 
  account 
  for 
  the 
  presence 
  of 
  oxygen 
  

   in 
  the 
  depositing 
  chamber 
  when 
  one 
  notes 
  the 
  care 
  taken 
  by 
  

   these 
  experimenters, 
  these 
  films 
  shov 
  at 
  least 
  some 
  of 
  the 
  

   characteristics 
  of 
  oxides. 
  

  

  X. 
  On 
  the 
  Amount 
  of 
  Radium 
  present 
  in 
  Sea-Water. 
  

   By 
  A. 
  8. 
  Eve, 
  M,A., 
  I),Sc., 
  McGill 
  University, 
  Montreal^. 
  

  

  IN 
  this 
  paper 
  measurements 
  will 
  be 
  expressed 
  in 
  terms 
  of 
  

   billionths 
  (10 
  ~^^) 
  gram 
  of 
  radium 
  per 
  kilogram 
  of 
  water 
  

   tested. 
  

  

  Three 
  observers 
  have 
  made 
  determinations 
  of 
  the 
  amount 
  

   of 
  radium 
  in 
  sea-salt 
  or 
  sea-water. 
  

  

  Struttt 
  found 
  7*5 
  x 
  10"^^ 
  gram 
  of 
  radium 
  per 
  gram 
  of 
  

   sea-salt, 
  and 
  this 
  is 
  equivalent 
  to 
  2'3 
  x 
  10"^^ 
  gram 
  radium 
  

   per 
  kilogram 
  of 
  sea-water. 
  This, 
  the 
  first 
  determination, 
  

   was 
  stated 
  to 
  be 
  approximate 
  only. 
  

  

  The 
  writer 
  | 
  examined 
  Inagua 
  sea-salt, 
  and 
  a 
  sample 
  of 
  

  

  * 
  Communicated 
  by 
  the 
  Author. 
  

  

  t 
  Proc. 
  Roy. 
  Soc. 
  A. 
  vol. 
  Ixxxviii. 
  p. 
  151. 
  

  

  I 
  Phil. 
  Mag. 
  Feb. 
  1007. 
  

  

  