﻿Ckemisti^y 
  and 
  Physics. 
  159 
  

  

  SCIENTIFIC 
  INTELLIGENCE. 
  

  

  I. 
  Chemistry 
  and 
  Physics. 
  

  

  1. 
  On 
  the 
  tico 
  new 
  Madio-actino 
  Elements, 
  Polonium 
  and 
  

   Radium. 
  — 
  Early 
  in 
  1898* 
  Mme. 
  Sklodowska 
  Curie 
  pointed 
  out 
  

   the 
  fact 
  that 
  certain 
  uranium 
  and 
  thorium 
  minerals, 
  pitchblende, 
  

   torbernite 
  and 
  autunite, 
  emitted 
  Becquerel 
  rays 
  more 
  actively 
  than 
  

   even 
  uranium 
  or 
  thorium, 
  and 
  suggested 
  the 
  presence 
  in 
  these 
  

   minerals 
  of 
  a 
  new 
  substance. 
  Later, 
  in 
  conjunction 
  with 
  her 
  hus- 
  

   band, 
  P. 
  CuEiE, 
  she 
  published 
  the 
  method 
  followed 
  in 
  the 
  chem- 
  

   ical 
  examination 
  of 
  pitchblende, 
  which 
  resulted 
  in 
  the 
  isolation 
  

   of 
  the 
  new 
  active 
  substance. 
  The 
  mineral 
  was 
  dissolved 
  in 
  acid 
  

   and 
  the 
  solution 
  treated 
  with 
  hydrogen 
  sulphide. 
  The 
  uranium 
  

   and 
  thorium 
  remained 
  in 
  solution 
  and 
  the 
  precipitate 
  contained, 
  

   besides 
  lead, 
  bismuth, 
  copper, 
  arsenic 
  and 
  antimony, 
  the 
  sulphide 
  

   of 
  the 
  new 
  material, 
  which 
  being 
  insoluble 
  in 
  ammonium 
  sulphide, 
  

   was 
  thus 
  separated 
  from 
  arsenic 
  and 
  antimony. 
  The 
  insoluble 
  

   sulphides 
  were 
  treated 
  with 
  nitric 
  acid, 
  and 
  a 
  partial 
  beparation 
  

   from 
  lead 
  effected 
  by 
  sulphuric 
  acid. 
  On 
  exhausting 
  the 
  lead 
  

   sulphate 
  with 
  dilute 
  sulphuric 
  acid, 
  the 
  active 
  substance 
  together 
  

   with 
  copper 
  and 
  bismuth 
  were 
  obtained 
  in 
  solution. 
  On 
  adding 
  

   ammonia, 
  the 
  new 
  body 
  and 
  the 
  bismuth 
  were 
  thrown 
  down, 
  thus 
  

   separating 
  them 
  from 
  copper. 
  Complete 
  separation 
  from 
  bismuth 
  

   was 
  not 
  obtained 
  ; 
  though 
  by 
  heating 
  the 
  mixed 
  sulphides 
  to 
  

   700°, 
  the 
  greater 
  volatility 
  of 
  the 
  new 
  sulphide 
  enabled 
  them 
  to 
  

   get 
  a 
  product 
  which 
  was 
  400 
  times 
  more 
  active 
  than 
  uranium. 
  

   Believing 
  this 
  new 
  substance, 
  resembling 
  bismuth 
  so 
  closely, 
  to 
  

   contain 
  a 
  new 
  element, 
  the 
  authors 
  gave 
  it 
  the 
  name 
  polonium 
  

   from 
  Poland, 
  Mme. 
  Curie's 
  native 
  country. 
  For 
  this 
  discovery 
  

   the 
  Academy 
  of 
  Sciences 
  awarded 
  the 
  Gegner 
  prize 
  to 
  Mme. 
  

   Curie. 
  

  

  In 
  continuing 
  their 
  observations 
  upon 
  pitchblende, 
  M. 
  and 
  

   Mme. 
  Curie, 
  in 
  association 
  with 
  Bemont, 
  detected 
  a 
  second 
  radio- 
  

   active 
  substance 
  in 
  this 
  mineral, 
  having 
  entirely 
  different 
  chem- 
  

   ical 
  properties. 
  It 
  resembles 
  barium 
  closely, 
  not 
  being 
  precipi- 
  

   tated 
  either 
  by 
  hydrogen 
  sulphide, 
  by 
  ammonium 
  sulphide 
  or 
  by 
  

   ammonia. 
  Its 
  sulphate 
  is 
  insoluble 
  in 
  water 
  and 
  in 
  acids, 
  its 
  car- 
  

   bonate 
  is 
  insoluble 
  in 
  water 
  and 
  its 
  chloride, 
  while 
  very 
  soluble 
  in 
  

   water, 
  is 
  insoluble 
  in 
  concentrated 
  hydrogen 
  chloride 
  and 
  in 
  alco- 
  

   hol. 
  The 
  product 
  obtained 
  gave 
  the 
  barium 
  spectrum, 
  showing 
  

   that 
  the 
  body 
  consisted 
  mainly 
  of 
  this 
  substance. 
  But 
  barium 
  is 
  

   not 
  radio-active 
  ; 
  and 
  since 
  radio-activity 
  seems 
  to 
  be 
  an 
  atomic 
  

   property, 
  the 
  authors 
  attribute 
  it 
  to 
  a 
  new 
  element 
  associated 
  

   with 
  the 
  barium. 
  The 
  first 
  portions 
  obtained 
  were 
  60 
  times 
  more 
  

   active 
  than 
  uranium. 
  By 
  a 
  series 
  of 
  fractional 
  precipitations 
  of 
  

   the 
  chloride 
  with 
  alcohol 
  a 
  final 
  product 
  was 
  obtained 
  900 
  times 
  

  

  *C. 
  R., 
  cxxvi, 
  1101-1103. 
  

  

  