## Archive for February 11, 2011

### Edison’s Birthday

Today’s date is kind of cool — 2/11/2011. It also happens to mark the 174th anniversary of the birth of inventor Thomas Alva Edison.

To honor his birthday, Google posted the following image this morning:

As it turns out, Edison was not particularly fond of mathy folks.

Edison once hired a math graduate to assist him. One day, he gave the assistant a light bulb and asked him to calculate its volume. The assistant determined the equation of a curve approximating the cross section of the bulb, then used calculus and his slide rule to find the volume of revolution. After many hours of calculating and checking his work, he presented his results to Edison.

“You’re off by at least 30%,” said Edison. “I just calculated the volume myself by taking the top off and filling the bulb with water.”

Edison’s thirst for knowledge was never quenched. He once visited a science institution and was asked to sign a guest book. The first column asked for the visitor’s name, under which he wrote, “Thomas A. Edison.” Another column asked, “Interested in?” under which he wrote, “Everything.”

Edison had a sense of humor. In honor of telegraphy, he bestowed the nicknames Dot and Dash on his first two children, Marion and Thomas Jr.

He was also an incredibly efficient man. At his summer residence, there was a heavy turnstile through which visitors had to pass to reach the main path to the house. A guest once asked Edison why, with all his clever inventions, he couldn’t have installed a less laborious turnstile. Edison explained that everyone who operated the turnstile helped to pump eight gallons of water into the tank on his roof.