﻿438 
  Mr. 
  C. 
  A. 
  Chant: 
  An 
  Experimental 
  Investigation 
  

  

  to 
  pass 
  as 
  nearly 
  alike 
  as 
  possible, 
  these 
  ends 
  were 
  faced 
  with 
  

   sheet 
  platinnm 
  of 
  a 
  thickness 
  0'003 
  cm. 
  By 
  means 
  of 
  a 
  die 
  

   disks 
  of 
  1 
  cm. 
  diameter 
  were 
  punched 
  from 
  the 
  sheet. 
  In 
  

   the 
  case 
  of 
  cylinders 
  No. 
  I 
  to 
  No. 
  4, 
  these 
  disks, 
  after 
  being- 
  

   given 
  the 
  proper 
  spherical 
  curvature,, 
  were 
  soldered 
  directly 
  

   on 
  the 
  cylinder, 
  after 
  which 
  the 
  surplus 
  solder 
  was 
  removed 
  

   and 
  the 
  platinum 
  polished 
  by 
  a 
  buffing-wheel. 
  

  

  In 
  the 
  case 
  of 
  ^lo. 
  5, 
  copper 
  was 
  first 
  deposited 
  on 
  the 
  end, 
  

   and 
  a 
  cap 
  with 
  curvature 
  rather 
  greater 
  than 
  that 
  of 
  the 
  end 
  

   face 
  was 
  cemented 
  on 
  with 
  shellac. 
  To 
  do 
  this, 
  a 
  small 
  piece 
  

   of 
  shellac 
  was 
  placed 
  on 
  the 
  end, 
  and 
  the 
  cap 
  placed 
  in 
  position 
  

   over 
  it. 
  The 
  shellac 
  was 
  melted 
  by 
  holding 
  a 
  hot 
  wire 
  on 
  the 
  

   cap, 
  which 
  was 
  then 
  pressed 
  by 
  the 
  finger 
  firmly 
  against 
  the 
  

   end 
  until 
  the 
  shellac 
  hardened. 
  In 
  this 
  way 
  excellent 
  contact 
  

   was 
  made 
  all 
  about 
  the 
  circumference 
  of 
  the 
  cap. 
  

  

  No. 
  6 
  had 
  excellent 
  platinum 
  faces 
  already, 
  and 
  No. 
  7 
  was 
  

   left 
  without 
  them. 
  On 
  all 
  the 
  rest 
  caps 
  were 
  fastened 
  as 
  on 
  

   No. 
  5, 
  i. 
  e., 
  directly 
  cemented 
  with 
  shellac. 
  

  

  Later 
  on, 
  some 
  of 
  the 
  caps 
  were 
  secured 
  in 
  place 
  by 
  holding 
  

   them 
  firmly 
  against 
  the 
  end 
  of 
  the 
  cylinder 
  and 
  then 
  depositing 
  

   copper 
  on 
  the 
  edge 
  of 
  the 
  cap 
  and 
  on 
  the 
  cylinder 
  where 
  it 
  

   rested. 
  This 
  certainly 
  insured 
  perfect 
  electrical 
  connexion, 
  

   and 
  is 
  superior 
  to 
  the 
  cementing 
  method, 
  being 
  more 
  durable, 
  

   but 
  the 
  results 
  obtained 
  were 
  not 
  noticeably 
  better. 
  

  

  By 
  referring 
  to 
  Table 
  I. 
  it 
  will 
  be 
  seen 
  that 
  for 
  every 
  

   frequency 
  mentioned 
  there, 
  gold 
  and 
  silver 
  leaf 
  are 
  decidedly 
  

   thinner 
  than 
  the 
  i 
  skin 
  ' 
  as 
  there 
  given 
  ; 
  while 
  in 
  the 
  case 
  of 
  the 
  

   lowest 
  frequency 
  (that 
  of 
  the 
  cylinders), 
  beside 
  the 
  gold 
  and 
  

   the 
  silver 
  leaf, 
  the 
  metallic 
  portion 
  of 
  cylinders 
  numbered 
  11, 
  

   12, 
  13, 
  14, 
  and 
  16 
  was 
  thinner 
  than 
  the 
  calculated 
  'skin/ 
  

   One 
  would 
  expect, 
  therefore, 
  that 
  if 
  the 
  efficiency 
  of 
  the 
  

   oscillator 
  depends 
  on 
  the 
  thickness 
  of 
  the 
  metal 
  constituting 
  

   it, 
  that 
  dependence 
  would 
  manifest 
  itself 
  in 
  the 
  use 
  of 
  these 
  

   cylinders 
  ; 
  but 
  extended 
  and 
  careful 
  observation 
  failed 
  to 
  

   detect 
  any 
  evidence 
  whatsoever 
  of 
  such 
  an 
  effect. 
  

  

  The 
  manner 
  of 
  experimenting 
  was 
  as 
  follows. 
  The 
  cylinders 
  

   were 
  placed 
  in 
  position 
  in 
  the 
  zinc 
  reflector, 
  and 
  the 
  connexions 
  

   and 
  sparking-distance 
  carefully 
  adjusted. 
  Then 
  the 
  magnetized 
  

   detector 
  was 
  hung 
  in 
  the 
  other 
  reflector, 
  which 
  was 
  placed 
  

   directly 
  before 
  the 
  first 
  reflector 
  with 
  a 
  certain 
  distance 
  (usually 
  

   30 
  cms. 
  at 
  first) 
  between 
  the 
  focal 
  lines 
  of 
  the 
  two. 
  The 
  

   key 
  was 
  then 
  depressed 
  while 
  the 
  pendulum 
  made 
  10 
  swings, 
  

   after 
  which 
  the 
  detector 
  was 
  placed 
  in 
  its 
  pocket 
  behind 
  the 
  

   magnetometer 
  and 
  the 
  change 
  noted 
  in 
  the 
  scale-reading. 
  

   The 
  detector 
  was 
  then 
  magnetized 
  again, 
  and 
  the 
  same 
  work 
  

   performed 
  with 
  the 
  mirrors 
  at 
  a 
  greater 
  distance 
  apart. 
  This 
  

  

  