﻿278 
  Notices 
  respecting 
  New 
  Boohs, 
  

  

  when 
  the 
  pairs 
  of 
  quadrants 
  were 
  insulated 
  from 
  one 
  another. 
  

   With 
  the 
  uranium 
  opposite 
  the 
  insulated 
  polished 
  aluminium 
  

   a 
  deviation 
  of 
  — 
  84 
  scale-divisions 
  from 
  the 
  metallic 
  zero 
  was 
  

   found 
  in 
  about 
  half 
  a 
  minute. 
  [Sensibility 
  of 
  electrometer 
  

   140 
  scale-divisions 
  per 
  volt.] 
  After 
  that 
  the 
  electrometer- 
  

   reading 
  remained 
  steady 
  at 
  this 
  point, 
  which 
  we 
  may 
  call 
  the 
  

   uranium 
  rays-zero 
  for 
  the 
  two 
  metals 
  separated 
  by 
  air 
  which 
  

   was 
  traversed 
  by 
  uranium 
  rays. 
  If 
  instead 
  of 
  having 
  the 
  

   uranium 
  opposite 
  to 
  the 
  aluminium, 
  with 
  only 
  air 
  between 
  

   them, 
  the 
  uranium 
  was 
  wrapped 
  in 
  a 
  piece 
  taken 
  from 
  the 
  

   same 
  aluminium 
  sheet, 
  and 
  then 
  placed 
  opposite 
  to 
  the 
  insu- 
  

   lated 
  polished 
  aluminium 
  disk, 
  no 
  deviation 
  was 
  produced. 
  

   Thus 
  in 
  this 
  case 
  the 
  rays-zero 
  agreed 
  with 
  the 
  metallic 
  zero. 
  

  

  With 
  polished 
  copper 
  as 
  the 
  insulated 
  metal, 
  and 
  the 
  

   uranium 
  separated 
  only 
  by 
  air 
  from 
  this 
  copper, 
  there 
  was 
  a 
  

   deviation 
  of 
  about 
  +10 
  scale-divisions. 
  With 
  the 
  uranium 
  

   wrapped 
  in 
  thin 
  sheet 
  aluminium 
  and 
  placed 
  in 
  position 
  

   opposite 
  the 
  insulated 
  copper 
  disk 
  a 
  deviation 
  from 
  the 
  

   metallic 
  zero 
  of 
  +43 
  scale-divisions 
  was 
  produced 
  in 
  two 
  

   minutes, 
  and 
  at 
  the 
  end 
  of 
  that 
  time 
  a 
  steady 
  state 
  had 
  not 
  

   been 
  reached. 
  

  

  With 
  oxidized 
  copper 
  as 
  the 
  insulated 
  metal, 
  opposed 
  to 
  

   the 
  uranium 
  with 
  only 
  air 
  between 
  them, 
  a 
  deviation 
  from 
  the 
  

   metallic 
  zero 
  of 
  about 
  + 
  25 
  scale-divisions 
  was 
  produced. 
  

  

  When 
  the 
  uranium, 
  instead 
  of 
  being 
  placed 
  at 
  a 
  distance 
  of 
  

   1 
  centim. 
  from 
  the 
  insulated 
  metal 
  disk, 
  was 
  placed 
  at 
  a 
  

   distance 
  of 
  2 
  or 
  3 
  millim., 
  the 
  deviation 
  from 
  the 
  metallic 
  zero 
  

   was 
  the 
  same. 
  

  

  These 
  experiments 
  show 
  that 
  two 
  polished 
  metallic 
  surfaces 
  

   connected 
  to 
  the 
  sheath 
  and 
  the 
  insulated 
  electrode 
  of 
  an 
  

   electrometer, 
  when 
  the 
  air 
  between 
  them 
  is 
  influenced 
  by 
  the 
  

   uranium 
  rays, 
  give 
  a 
  deflexion 
  from 
  the 
  metallic 
  zero, 
  the 
  

   same 
  in 
  direction, 
  and 
  of 
  about 
  the 
  same 
  amount, 
  as 
  when 
  the 
  

   two 
  metals 
  are 
  connected 
  by 
  a 
  drop 
  of 
  water. 
  

  

  XXXII. 
  Notices 
  respecting 
  New 
  Books. 
  

  

  Hecherches 
  Experimentales 
  sur 
  quelques 
  Actinometres 
  Electro- 
  

   chimlques. 
  Par 
  H. 
  Rigollot, 
  Chef 
  des 
  travaux 
  de 
  Physique 
  a 
  

   V 
  Univer 
  site 
  de 
  Lyon. 
  Paris: 
  Masson, 
  1897. 
  

  

  ""PHIS 
  volume, 
  published 
  as 
  one 
  of 
  the 
  series 
  of 
  annals 
  of 
  the 
  

   University 
  of 
  Lyons, 
  contains 
  a 
  full 
  account 
  of 
  Dr. 
  Rigollot's 
  

   work 
  on 
  the 
  electromotive 
  force 
  between 
  two 
  plates, 
  one 
  of 
  which 
  

   is 
  illuminated 
  and 
  the 
  other 
  kept 
  in 
  the 
  dark. 
  Two 
  metallic 
  plates 
  

   are 
  taken, 
  and 
  one 
  side 
  of 
  each 
  is 
  coated 
  with 
  the 
  substance 
  to 
  

   be 
  examined 
  ; 
  the 
  other 
  side 
  of 
  each 
  plate 
  is 
  then 
  varnished 
  or 
  

   paraffined, 
  and 
  the 
  plates 
  are 
  placed 
  in 
  an 
  electrolyte 
  in 
  the 
  dark 
  

  

  