﻿816 
  Mr. 
  J. 
  A. 
  Gray 
  on 
  the 
  Ultimate 
  Product 
  of 
  

  

  and 
  later 
  basaltic 
  flows, 
  but 
  the 
  one 
  from 
  sea- 
  level 
  at 
  Adams 
  

   Island 
  is 
  fine-grained 
  and 
  contains 
  hornblende, 
  while 
  the 
  

   other 
  is 
  very 
  coarse-grained 
  with 
  large 
  phenocrysts 
  of 
  olivine 
  

   and 
  augite. 
  

  

  The 
  Campbell 
  Island 
  limestone 
  is 
  of 
  Tertiary 
  age 
  and 
  

   markedly 
  foraminif 
  eral 
  ; 
  the 
  marble 
  is 
  derived 
  from 
  it 
  as 
  a 
  

   result 
  of 
  basic 
  intrusion. 
  

  

  A 
  general 
  conspectus 
  of 
  these 
  results 
  shows 
  that 
  the 
  radium 
  

   content 
  corresponds 
  roughly 
  with 
  the 
  basicity, 
  and 
  not 
  with 
  

   the 
  age 
  of 
  the 
  rocks. 
  

  

  Canterbury 
  College, 
  New 
  Zealand, 
  

   May 
  12, 
  1909. 
  

  

  LXXXVT. 
  The 
  Ultimate 
  Product 
  of 
  the 
  Uranium 
  

   Disintegratmi 
  Series. 
  By 
  J. 
  A. 
  Gkay, 
  B.Sc* 
  

  

  IN 
  Amer. 
  Journ. 
  Sc. 
  (vol. 
  xx. 
  p. 
  253, 
  1905, 
  and 
  vol. 
  xxii. 
  

   p. 
  77, 
  1907) 
  Boltwood 
  gives 
  considerable 
  evidence 
  which 
  

   goes 
  towards 
  proving 
  lead 
  the 
  ultimate 
  product 
  of 
  this 
  series. 
  

   He 
  finds, 
  e. 
  g., 
  that 
  in 
  primary 
  uranium 
  minerals 
  the 
  ratio 
  of 
  

   the 
  lead 
  to 
  the 
  uranium 
  is 
  practically 
  the 
  same 
  for 
  minerals 
  

   of 
  the 
  same 
  age, 
  and 
  greater 
  the 
  greater 
  the 
  age 
  of 
  the 
  

   mineral. 
  These 
  are 
  conditions 
  that 
  the 
  ultimate 
  or 
  any 
  

   inactive 
  product 
  must 
  fulfil, 
  and 
  lead 
  was 
  found 
  to 
  be 
  the 
  

   only 
  substance 
  fulfilling 
  them, 
  except 
  perhaps 
  helium, 
  which 
  

   has 
  been 
  definitely 
  proved 
  to 
  come 
  from 
  the 
  a 
  particles 
  

   (Rutherford 
  and 
  Royds, 
  Phil. 
  Mag. 
  vol. 
  xvii. 
  p. 
  281, 
  1909). 
  

   However, 
  in 
  all 
  the 
  minerals 
  of 
  which 
  analyses 
  were 
  obtained, 
  

   there 
  was 
  a 
  great 
  deal 
  of 
  contamination 
  from 
  other 
  sub- 
  

   stances; 
  so 
  that 
  it 
  is 
  not 
  unlikely 
  that 
  the 
  lead 
  was 
  deposited 
  

   in 
  some 
  other 
  way 
  than 
  as 
  a 
  product 
  of 
  the 
  uranium 
  series. 
  

   Certain 
  mineral 
  substances 
  exist 
  which 
  do 
  not 
  appear 
  to 
  be 
  

   open 
  to 
  this 
  objection. 
  These 
  are 
  the 
  hydrated 
  phosphates 
  of 
  

   uranium 
  with 
  (1) 
  calcium, 
  (2) 
  copper. 
  These 
  substances 
  

   exist 
  in 
  characteristic 
  crystals 
  having 
  somewhat 
  the 
  appear- 
  

   ance 
  of 
  artificially 
  purified 
  substances, 
  and 
  are 
  undoubtedly 
  

   derived 
  from 
  the 
  comparatively 
  recent 
  recrystallization 
  from 
  

   water 
  of 
  the 
  salts 
  derived 
  from 
  pitchblende 
  lodes. 
  A 
  spectro- 
  

   scopic 
  examination 
  was 
  made 
  of 
  these 
  salts, 
  to 
  see 
  what 
  light 
  

   they 
  would 
  throw 
  on 
  the 
  question. 
  

  

  A 
  spectroscopic 
  analysis 
  was 
  first 
  made 
  of 
  mineral 
  autunite, 
  

   {Ca(U02)2P208 
  + 
  8H20} 
  from 
  Portugal. 
  This 
  contains 
  ap- 
  

   proximately 
  50 
  per 
  cent, 
  of 
  uranium. 
  If 
  old 
  enough 
  the 
  mineral 
  

   would 
  contain 
  the 
  products 
  of 
  uranium 
  and 
  enough 
  of 
  the 
  

   'final 
  product 
  to 
  be 
  detectable 
  by 
  spectroscopic 
  analysis, 
  

  

  * 
  Communicated 
  by 
  Prof. 
  R. 
  J. 
  Strutt, 
  F.R.S. 
  

  

  