7. Electrographic Vote recorder
Edison was 22 years old and working as a telegrapher when he filed his first patent for the Electrographic Vote Recorder. The device was made with the goal of helping legislators in the US Congress record their votes in a quicker fashion than the voice vote system.
To work, a voting device was connected to a clerk’s desk where the names of the legislators were embedded. The legislators would move a switch to either yes or no, sending electric current to the device at the clerks desk. Yes and No wheels kept track of the votes and tabulated the final results. This invention is still with us in the form of electronic voting machines which are widely used these days in modern political systems.
The phonograph was the first of its kind. It was a device that recorded sounds and that might not seem much today but try doing that in those times. The phonograph recorded and reproduced audible sounds first using paraffin paper and then metallic foil on a cylinder. Edison created multiple versions over the years, improving on each model. The sound vibration waveforms are recorded as corresponding physical deviations of a groove engraved or impressed into the surface of a rotating cylinder or disc.
To recreate the sound, the surface is similarly rotated while a playback stylus traces the groove and is therefore vibrated by it, very faintly reproducing the recorded sound. The first recorded sound recorded onto this first ever recorder was Edison saying “Mary had a little lamb”, which amused the inventor and his staff.
The kinetoscope is to the eye as the phonograph is to the ear. The Kinetoscope was not a movie projector but introduced the basic approach that would become the standard for all cinematic projection before the advent of video by creating the illusion of movement by conveying a strip of perforated film bearing sequential images over a light source with a high-speed shutter.
In Edison’s movie studio, technically known as a Kinetographic Theater, but nicknamed “The Black Maria” (1893), Edison and his staff filmed short movies for later viewing with his peep hole Kinetoscopes (1894). One-person at a time could view the movies via the Kinetoscope.
Each Kinetoscope was about 4 feet tall, 20 inches square, and had a peep hole magnifier that allowed the person to view 50 feet of film in about 20 seconds. A battery-operated lamp allowed the film to be illuminated. And that was the start of the ever growing movie industries around the world.
4. Alkaline batteries
Alkaline batteries are a type of primary batteries dependent upon the reaction between zinc and manganese dioxide. A rechargeable alkaline battery allows reuse of specially designed cells. Edison started his work on the battery in the 1890s, just after the automobile had been introduced. At that time, the gasoline automobile was still unreliable, and steam and electric cars sold in larger numbers.
One problem with electric cars, however, was that the lead-acid batteries that they used (similar to the batteries used to start gasoline-powered cars today) were extremely heavy. Another was that the acid corroded the lead inside the battery, shortening the useful life of the battery. Edison began looking for a way to make batteries lighter, more reliable, and at least three times more powerful so that they could become the basis of a successful electric car. The tests for the best material numbered in the thousands and lasted until 1903, when he finally declared his battery finished.
The battery used potassium hydroxide, which reacted with the battery’s iron and nickel electrodes to create a battery with a strong output that was reliable and rechargeable.