Packing of transmitters
Permeability
Pitch
  Doppler’s principle
  vibration of diaphragms
Polarity method of selective signaling
Polarization of cells
Polarized ringer
  brazed bell
  Kellogg
  Western Electric
Poole lock-out system
Primary cells
  conventional symbol
  series and multiple connections
  simple voltaic
  types of
    closed-circuit
      Fuller
      gravity
      Lalande
      prevention of creeping
      setting up
    open-circuit
      Le Clanche
    standard
      chloride of silver
Propagation of sound
Protective means
  against high potentials
    air-gap arrester
      advantages of carbon
      commercial types
      continuous arcs
      discharge across gaps
      dust between carbons
      introduction of impedance
      metallic electrodes
      vacuum arresters
    against sneak currents
      heat coil
      sneak-current arresters
    against strong currents
      fuses
        enclosed
        mica
        proper functions
    central-office protectors
        self-soldering heat coils
        sneak-current and air-gap arrester
    city exchange requirements
    complete line protection
    electrolysis
    subscribers’ station protectors
      ribbon fuses
Pulsating-current commutator

R

Receivers
  Dean
  direct-current
  early
  Kellogg
  modern
  Monarch
  operator’s
  single-pole
  symbols
  Western Electric
Reluctance
Repeating coil
Ribbon fuses
Ringer symbols
Ringing and listening key
Robert’s latching relay
Robert’s self-cleansing arrester
Rolled condenser

S

Saw-tooth arrester
Selective party-line systems
  broken-line method
  classification
    broken-line systems
    harmonic systems
    polarity systems
    step-by-step systems
  harmonic method
  polarity method
  step-by-step method
Self-induction
Signal code
Signaling, method of
Silk and cotton insulation
Single electrode
Single-pole receiver
Sneak-current arresters
Solid-back transmitter
Sound
  characteristics of
    loudness
    pitch
    timbre
Standard cell
Step-by-step lock-out system
Step-by-step method of selective signaling
Subscribers’ station protectors
Switchboard cords
Switchboard plugs
Switchboard transmitter
Symbols
  battery
  condenser
  generator
  hook switch
  impedance coil
  induction coil
  receiver
  repeating coil
  ringer
  ringing and listening key
  transmitter

T