Chapter Iii. the Electric Light.--Causes of Heat and Light in

the conductor of a current.--The first Electric Light.--The Arc Light, and how constructed.--The Incandescent.--The Dynamo.--Date of the invention.--Successive steps.--Faraday the discoverer of its principle.--Pixü's machine.--Pacinatti.--Wilde.--Siemens' and Wheatstone.--The Motor.--How the Dynamo and Motor came to be coupled.--Review of first attempts.--Kidder's battery.--Page's machine.--Electric Railroads.--Electrolysis.--General facts.--Electrical Measurements.--"Death Current."--Instruments of Measurement.--Electricity as an Industry.--Medical Electricity.--Incomplete possibilities.--What the "Storage Battery" is.