﻿Directive 
  System 
  of 
  Wireless 
  Telegraphy. 
  

  

  641 
  

  

  the 
  intersection 
  of 
  the 
  planes 
  of 
  the 
  two 
  fixed 
  windings. 
  

   This 
  winding 
  s 
  is 
  included 
  in 
  the 
  oscillatory 
  exciting 
  circuit, 
  

   by 
  means 
  of 
  contact 
  brushes. 
  S 
  is 
  the 
  secondary 
  of 
  the 
  

   spark 
  coil 
  or 
  transformer. 
  

  

  It 
  is 
  evident 
  that 
  on 
  placing 
  the 
  movable 
  winding 
  in 
  

   different 
  positions 
  the 
  magnetic 
  flux 
  which 
  passes 
  through 
  

   the 
  two 
  fixed 
  windings 
  will 
  vary, 
  as 
  also 
  will 
  the 
  oscillatory 
  

   currents 
  in 
  the 
  aerials. 
  The 
  electromagnetic 
  field 
  in 
  space 
  

   will 
  be 
  produced 
  by 
  the 
  superposition 
  of 
  the 
  partial 
  fields 
  

   created 
  by 
  the 
  two 
  aerial 
  circuits. 
  Its 
  intensity 
  will 
  be 
  

   independent 
  of 
  its 
  direction, 
  and 
  this 
  latter 
  will 
  coincide 
  

   with 
  the 
  direction 
  of 
  the 
  central 
  plane 
  of 
  the 
  movable 
  

   winding. 
  The 
  law 
  of 
  angular 
  variation 
  of 
  the 
  energy 
  

   and 
  of 
  the 
  magnetic 
  field 
  is 
  the 
  same 
  as 
  for 
  a 
  single 
  

   circuit. 
  

  

  Fig. 
  C. 
  

  

  Af 
  

  

  The 
  apparatus 
  is 
  provided 
  with 
  a 
  fixed 
  dial 
  over 
  which 
  

   moves 
  a 
  pointer 
  rigidly 
  attached 
  to 
  the 
  movable 
  winding. 
  

   On 
  setting 
  the 
  pointer 
  in 
  the 
  direction 
  of 
  the 
  station 
  to 
  which 
  

   the 
  signals 
  are 
  to 
  be 
  sent, 
  the 
  emission 
  will 
  be 
  a 
  maximum 
  

   in 
  the 
  vertical 
  plane 
  which 
  contains 
  the 
  transmitting 
  and 
  

   receiving 
  stations 
  — 
  that 
  is 
  to 
  say, 
  both 
  towards 
  the 
  receiving 
  

  

  Phil. 
  Mag. 
  S. 
  6. 
  Vol. 
  16. 
  No. 
  94. 
  Oct. 
  1908. 
  2 
  U 
  

  

  