﻿410 
  Scientific 
  Intelligence. 
  

  

  determination 
  by 
  finding 
  the 
  relation 
  of 
  the 
  lead 
  chloride 
  to 
  the 
  

   silver 
  required 
  to 
  combine 
  with 
  the 
  chlorine, 
  according 
  to 
  the 
  

   highly 
  refined 
  methods 
  in 
  use 
  in 
  Professor 
  Richards' 
  laboratory. 
  

   Two 
  analyses 
  of 
  the 
  chloride 
  of 
  ordinary 
  lead 
  had 
  given 
  207*187 
  

   and 
  207*186 
  for 
  the 
  atomic 
  weight. 
  

  

  The 
  results 
  with 
  the 
  end 
  fractions 
  of 
  the 
  isotopic 
  lead 
  were 
  as 
  

   follows: 
  

  

  " 
  More 
  soluble 
  " 
  " 
  Less 
  soluble 
  " 
  

  

  206*426 
  206*406 
  

  

  206-409 
  206-422 
  

  

  206-431 
  206-399 
  

  

  Av. 
  206-422 
  206-409 
  

  

  These 
  atomic 
  weights 
  agree 
  so 
  closely 
  that 
  it 
  is 
  obvious 
  that 
  no 
  

   separation, 
  or 
  at 
  most 
  not 
  more 
  than 
  an 
  exceedingly 
  small 
  separa- 
  

   tion, 
  of 
  the 
  isotopes 
  was 
  effected 
  by 
  the 
  elaborate 
  fractional 
  crys- 
  

   tallization. 
  The 
  end-products 
  of 
  the 
  fractional 
  crystallization, 
  

   after 
  purification, 
  were 
  tested 
  as 
  to 
  their 
  radioactivity 
  in 
  order 
  to 
  

   find 
  if 
  there 
  had 
  been 
  any 
  separation 
  of 
  "radium 
  D" 
  which 
  is 
  

   supposed 
  to 
  have 
  an 
  atomic 
  weight 
  of 
  210, 
  and 
  is 
  supposed 
  to 
  be 
  

   present 
  in 
  this 
  lead 
  in 
  the 
  proportion 
  of 
  about 
  one 
  part 
  in 
  ten 
  

   million. 
  The 
  results 
  agreed 
  within 
  the 
  experimental 
  error 
  of 
  1 
  

   per 
  cent, 
  so 
  that 
  no 
  evidence 
  of 
  any 
  concentration 
  was 
  found. 
  — 
  

   Jour. 
  Amer. 
  Chem. 
  Soc, 
  xxxix, 
  531. 
  h. 
  l. 
  w. 
  

  

  2. 
  Manganese 
  in 
  Soils. 
  — 
  Maxwell 
  O. 
  Johnson 
  of 
  the 
  Hawaii 
  

   Agricultural 
  Experiment 
  Station 
  has 
  devised 
  a 
  remedy 
  for 
  a 
  

   serious 
  local 
  difficulty 
  in 
  the 
  culture 
  of 
  pineapples. 
  The 
  chief 
  

   pineapple 
  district 
  of 
  the 
  Islands 
  lies 
  on 
  the 
  island 
  of 
  Oahu 
  in 
  a 
  

   region 
  where 
  the 
  water 
  supply 
  is 
  insufficient 
  for 
  the 
  growth 
  of 
  

   sugar 
  cane. 
  In 
  this 
  district, 
  in 
  distinction 
  from 
  the 
  usual 
  red 
  

   soils, 
  there 
  occur 
  various 
  areas 
  of 
  dark 
  or 
  black 
  manganiferous 
  

   soils 
  where, 
  as 
  has 
  been 
  known 
  for 
  10 
  or 
  12 
  years, 
  pineapples 
  

   make 
  a 
  very 
  poor 
  growth. 
  The 
  leaves 
  of 
  the 
  plants 
  gradually 
  

   become 
  yellow, 
  and 
  the 
  plants 
  often 
  die 
  or 
  finally 
  produce 
  very 
  

   small 
  fruit 
  of 
  inferior 
  quality. 
  As 
  these 
  dark 
  soils, 
  where 
  the 
  

   yellowing 
  of 
  pineapples 
  occurs, 
  aggregate 
  from 
  6,000 
  to 
  10,000 
  

   acres 
  of 
  the 
  lowest 
  lying, 
  most 
  accessible 
  and 
  most 
  easily 
  culti- 
  

   vated 
  land 
  of 
  the 
  region, 
  the 
  matter 
  is 
  of 
  considerable 
  economic 
  

   importance. 
  Several 
  years 
  ago 
  this 
  trouble 
  was 
  attributed 
  by 
  

   Kelly, 
  of 
  the 
  same 
  experiment 
  station, 
  to 
  the 
  presence 
  of 
  an 
  

   abnormal 
  amount 
  of 
  manganese 
  in 
  the 
  black 
  soils. 
  He 
  found 
  

   that 
  one 
  of 
  the 
  black 
  soils 
  contained 
  about 
  6 
  per 
  cent 
  of 
  manga- 
  

   nese 
  oxide, 
  while 
  a 
  red 
  one 
  contained 
  only 
  about 
  0*3 
  per 
  cent 
  of 
  

   it. 
  He 
  analyzed 
  also 
  the 
  ashes 
  of 
  a 
  number 
  of 
  plants 
  grown 
  on 
  

   the 
  black 
  soil, 
  some 
  of 
  which 
  were 
  affected 
  by 
  the 
  presence 
  of 
  

   manganese 
  while 
  others 
  were 
  not 
  affected 
  by 
  it. 
  From 
  a 
  study 
  

   of 
  the 
  ash 
  analyses 
  Johnson 
  came 
  to 
  the 
  conclusion 
  that 
  the 
  

   affected 
  plants 
  were 
  abnormally 
  low 
  in 
  iron, 
  and 
  that 
  the 
  pres- 
  

   ence 
  of 
  manganese 
  causes 
  a 
  suppression 
  of 
  the 
  assimilation 
  of 
  iron 
  

  

  