Things Electricity Can Do.--Exp. 191, To study the action of
a simple telegraph sounder.--Discussion.--Telegraph Line;
Connections.--Operation of Line.--Exp. 192, To study the action
of the "relay" on telegraph lines.--The Relay.--Exp. 193, To
study the action of a two-pole telegraph instrument.--Exp.
194, To study the action of a simple "single needle telegraph
instrument."--Exp. 195, To study the action of a simple
automatic contact breaker, or current interrupter.--Automatic
Current Interrupters.--Exp. 196, To study the action of a
simple electric bell, or a "buzzer."--Electric Bells and
Buzzers.--Exp. 197, To study the action of a simple telegraph
"recorder."--Exp. 198, To study the action of a simple
"annunciator."--Discussion.--Exp. 199, To study the shocking
effects of the "extra current." Induction Coils.--Action of
Induction Coils.--Transformers.--The Dynamo.--The Electric
Motor.--Exp. 200, To study the action of the telephone.--The
Telephone.--The Bell, or Magneto-transmitter.--The Receiver.--The
Carbon Transmitter.--Induction Coils in Telephone Work.--Electric
Lighting and Heating.--Arc Lamps.--The Incandescent Lamp.