﻿Chemistry 
  and 
  Physics. 
  565 
  

  

  radiation 
  from 
  rubidium 
  consists 
  of 
  /3-rays. 
  Further 
  experimenta- 
  

   tion 
  enabled 
  the 
  author 
  to 
  estimate 
  the 
  speed 
  of 
  these 
  rays 
  as 
  

   1-85 
  X10 
  10 
  cm 
  / 
  sec— 
  Physih 
  Zeitschr., 
  No. 
  14, 
  July 
  1913, 
  p. 
  655. 
  

  

  H. 
  S. 
  U. 
  

  

  9. 
  Researches 
  in 
  Magneto- 
  Optics 
  ; 
  by 
  P. 
  Zeeman. 
  Pp. 
  xv, 
  

   219, 
  with 
  74 
  figures 
  and 
  8 
  plates. 
  London, 
  1913 
  (Macmillan 
  and 
  

   Co.). 
  — 
  Since 
  this 
  volume 
  is 
  a 
  member 
  of 
  the 
  series 
  entitled 
  " 
  Mac- 
  

   miliarias 
  /Science 
  Monographs 
  " 
  it 
  is 
  unique 
  and 
  authoritative, 
  

   inasmuch 
  as 
  the 
  author 
  describes 
  chiefly 
  his 
  own 
  contributions 
  to 
  

   the 
  subject 
  with 
  special 
  reference 
  to 
  the 
  magnetic 
  resolution 
  of 
  

   spectrum 
  lines. 
  The 
  material 
  in 
  the 
  different 
  chapters 
  has 
  been 
  

   arranged 
  in 
  the 
  main 
  historically. 
  The 
  author's 
  style 
  is 
  remark- 
  

   ably 
  simple 
  and 
  lucid, 
  the 
  photographs 
  reproduced 
  in 
  the 
  plates 
  

   are 
  very 
  clear, 
  and 
  the 
  typographical 
  work 
  is 
  a 
  model 
  of 
  accuracy 
  

   and 
  neatness. 
  The 
  index 
  is 
  immediately 
  preceded 
  by 
  two 
  com- 
  

   plete 
  bibliographical 
  lists 
  of 
  which 
  the 
  first 
  refers 
  to 
  Zeeman's 
  

   original 
  papers 
  only, 
  while 
  the 
  second 
  gives 
  all 
  the 
  pertinent 
  pub- 
  

   lications 
  starting 
  with 
  the 
  year 
  1896 
  and 
  including 
  1912. 
  Con- 
  

   sequently 
  this 
  monograph 
  is 
  a 
  very 
  valuable 
  contribution 
  to 
  the 
  

   subject 
  of 
  magneto-optics. 
  h. 
  s. 
  it. 
  

  

  JO. 
  A 
  New 
  Element, 
  Uranium 
  JT 
  a 
  . 
  — 
  The 
  following 
  important 
  

   conclusions 
  have 
  been 
  drawn 
  by 
  K. 
  Fajans 
  and 
  O. 
  Gohring 
  

   from 
  their 
  latest 
  investigations, 
  (a) 
  Uranium 
  X 
  is 
  complex 
  and 
  

   consists 
  of 
  two 
  elements 
  symbolized 
  by 
  UX, 
  and 
  UX 
  2 
  . 
  The 
  

   half-value 
  period 
  of 
  24*6 
  days, 
  formally 
  ascribed 
  to 
  uranium 
  X, 
  

   belongs 
  to 
  uranium 
  X 
  2 
  . 
  (b) 
  The 
  half-value 
  time 
  for 
  the 
  new 
  ele- 
  

   ment, 
  UX 
  2 
  , 
  is 
  1*15 
  minutes 
  and 
  its 
  constant 
  of 
  disintegration 
  

   equals 
  0-0100 
  sec" 
  1 
  , 
  (c) 
  Uranium 
  X 
  2 
  emits 
  hard 
  /3-rays 
  only 
  and 
  

   these 
  are 
  identical 
  with 
  the 
  hard 
  /3-rays 
  of 
  uranium 
  X. 
  The 
  soft 
  

   yS-rays 
  of 
  uranium 
  X 
  pertain 
  to 
  uranium 
  X 
  1# 
  The 
  coefficients 
  of 
  

   absorption 
  in 
  aluminium 
  are 
  given 
  as 
  500 
  cm 
  -1 
  and 
  15 
  cm 
  -1 
  for 
  

   the 
  soft 
  and 
  hard 
  /3-rays 
  respectively. 
  In 
  the 
  case 
  of 
  uranium 
  X 
  x 
  

   hard 
  /?-rays 
  could 
  not 
  be 
  detected. 
  These 
  facts 
  constitute 
  a 
  new 
  

   verification 
  of 
  the 
  rule 
  that 
  very 
  hard 
  and 
  very 
  soft 
  /3-rays 
  are 
  

   emitted 
  by 
  short- 
  and 
  long-lived 
  elements, 
  in 
  the 
  order 
  named. 
  

   (d) 
  Uranium 
  X 
  5 
  is 
  electrochemically 
  "nobler" 
  than 
  uranium 
  

   X,. 
  (e) 
  The 
  chemical 
  properties 
  of 
  uranium 
  X 
  2 
  are 
  in 
  full 
  

   accord 
  with 
  the 
  assumption 
  that 
  it 
  belongs 
  in 
  the 
  fifth 
  group 
  

   of 
  the 
  tenth 
  series 
  of 
  the 
  periodic 
  table 
  and 
  has 
  tantalum 
  as 
  its 
  

   closest 
  analogue. 
  (/') 
  The 
  beginning 
  of 
  the 
  family 
  tree 
  of 
  the 
  

   uranium 
  series 
  should 
  read 
  : 
  

  

  — 
  -> 
  UX 
  2 
  > 
  UII 
  > 
  Io 
  > 
  Ra. 
  

  

  5 
  6 
  4 
  2 
  

  

  — 
  Physik. 
  Zeitschr., 
  No. 
  18, 
  Sept., 
  1913, 
  p. 
  877. 
  h. 
  s. 
  it. 
  

  

  11. 
  Mechanics 
  and 
  Heat 
  ; 
  bv 
  J. 
  Duncan. 
  Pp. 
  xiii, 
  381, 
  with 
  

   314 
  figures. 
  London, 
  1913 
  (Macmillan 
  and 
  Co.). 
  — 
  This 
  volume 
  

   contains 
  the 
  subject-matter 
  of 
  an 
  elementary 
  course 
  in 
  applied 
  

   physics, 
  and 
  is 
  especially 
  designed 
  for 
  use 
  in 
  the 
  upper 
  forms 
  of 
  

   certain 
  secondary 
  schools 
  and 
  for 
  candidates 
  preparing 
  to 
  take 
  

  

  