﻿454 
  Mr. 
  Wilson 
  on 
  the 
  Influence 
  of 
  Dissolved 
  Substances 
  

  

  certain 
  capacity 
  giving 
  a 
  maximum 
  spark-length 
  for 
  a 
  given 
  

   primary 
  current, 
  just 
  as 
  my 
  experiments 
  prove. 
  

  

  But 
  he 
  did 
  not 
  examine 
  the 
  relation 
  of 
  capacities 
  with 
  several 
  

   primary 
  currents, 
  as 
  I 
  have 
  done. 
  From 
  theoretical 
  consi- 
  

   deration 
  he 
  drew 
  the 
  conclusion 
  that 
  a 
  maximum 
  secondary 
  

   potential-difference 
  E 
  2 
  is 
  equal 
  to 
  J^v^/C^, 
  where 
  J 
  : 
  is 
  the 
  

   primary 
  current, 
  Z 
  2 
  the 
  coefficient 
  of 
  self-induction 
  of 
  the 
  

   secondary 
  circuit, 
  and 
  C^ 
  the 
  capacity 
  of 
  the 
  condenser 
  in 
  the 
  

   primary. 
  This 
  conclusion, 
  however, 
  does 
  not 
  appear 
  to 
  me 
  

   to 
  be 
  valid. 
  

  

  For 
  a 
  comparison 
  of 
  the 
  above 
  formula 
  with 
  experimentally 
  

   observed 
  facts 
  brings 
  out 
  a 
  rather 
  wide 
  discrepancy 
  as 
  to 
  the 
  

   capacity 
  effect. 
  In 
  my 
  view 
  the 
  existing 
  theories 
  of 
  the 
  

   induction-coil 
  as 
  they 
  stand 
  are 
  yet 
  insufficient 
  to 
  account 
  

   for 
  all 
  the 
  observed 
  phenomena, 
  especially 
  the 
  effect 
  of 
  capacity 
  

   on 
  secondary 
  spark-lengths. 
  

  

  This 
  might 
  perhaps 
  arise 
  from 
  the 
  incompleteness 
  of 
  the 
  

   data 
  in 
  establishing 
  the 
  theories, 
  that 
  is 
  to 
  say, 
  mathematically 
  

   writing 
  down 
  the 
  differential 
  equations 
  for 
  the 
  primary 
  and 
  

   secondary 
  circuits. 
  For 
  according 
  to 
  the 
  existing 
  theories 
  

   the 
  coefficients 
  of 
  self-induction 
  and 
  mutual 
  induction 
  are 
  

   both 
  regarded 
  as 
  constant, 
  and 
  almost 
  no 
  account 
  is 
  taken 
  of 
  

   the 
  relation 
  which 
  they 
  bear 
  to 
  the 
  effect 
  of 
  capacity, 
  and 
  also 
  

   the 
  variable 
  magnetization 
  of 
  iron 
  bundles 
  in 
  the 
  primary 
  

   circuit. 
  

  

  To 
  sum 
  up, 
  in 
  order 
  to 
  elaborate 
  the 
  theory 
  of 
  the 
  induction- 
  

   coil 
  to 
  a 
  greater 
  perfection, 
  I 
  believe 
  a 
  considerable 
  number 
  

   of 
  further 
  experiments 
  on 
  the 
  mutual 
  relations 
  of 
  capacity, 
  

   self-induction, 
  and 
  the 
  magnetization 
  of 
  iron 
  bundles 
  in 
  the 
  

   coil 
  must 
  be 
  made. 
  

  

  The 
  Physical 
  Laboratory, 
  

   Daiichi 
  Koto 
  Pakko, 
  Tokyo, 
  Japan, 
  

   January 
  1898. 
  

  

  XLVT. 
  On 
  the 
  Influence 
  of 
  Dissolved 
  Substances 
  and 
  of 
  Elec- 
  

   trification 
  on 
  the 
  Re-formation 
  of 
  Clouds. 
  By 
  Harold 
  A. 
  

   Wilson, 
  B.Sc. 
  Lond. 
  § 
  Vict., 
  Trinity 
  College, 
  Cambridge, 
  

   1851 
  Exhibition 
  Scholar*. 
  

  

  THE 
  object 
  of 
  the 
  experiments 
  described 
  below 
  was 
  to 
  see 
  

   whether 
  clouds 
  consisting 
  of 
  dilute 
  solutions 
  of 
  various 
  sub- 
  

   stances 
  after 
  being 
  destroyed 
  by 
  bubbling 
  through 
  sulphuric 
  

   acid 
  would 
  reappear 
  on 
  passing 
  into 
  air 
  saturated 
  with 
  

   moisture, 
  and 
  also 
  to 
  see 
  whether 
  electrifying 
  the 
  cloud 
  had 
  

   any 
  effect 
  on 
  its 
  power 
  of 
  reappearing. 
  

  

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

  

  