Good morning.
In Whitewater, we’ll have a mostly cloudy day with a high of forty-four. Sunrise today is 7:16 AM and sunset will be 6:03 PM. The moon is in a waning gibbous phase with 92% of its visible disk illuminated.
On this day in 1879, Thomas Edison invents the incandescent bulb. The New York Times later reported on Edison’s achievement, after a visit to Edison’s laboratory:
There was no lack of enthusiasm or of confidence about Mr. Edison as he greeted the Times reporter who entered his laboratory at Menlo Park, N. J., yesterday. The inventor, a short, thick-set man, with grimy hands, led the way through his workshop, and willingly explained the distinctive features of what he and many others look upon as an apparatus which will soon cause gas-light to be a thing of the past.
The lamp which Mr. Edison regards as a crowning triumph is a model of simplicity and economy.
In the lamp the light is emitted by a horseshoe of carbonized paper about two and a half inches long and the width of a thread. This horseshoe is in a glass globe, from which the air has been as thoroughly exhausted as science is able to do. So good a vacuum is produced that it is estimated that at the utmost no more than a one-millionth part of the air remains. The operation of pumping lasts one hour and a quarter.
At the ends of the carbon horseshoe are two platinum clamps, from which platinum wires run outwardly through a small glass tube contained within a larger one leading out of the glass globe. The small tube contains air. Within it the platinum wires are met by two copper wires connecting with the conductors of the electricity. The air is left in the small tube, because otherwise the copper wires would be fused by the electric current. The carbonized paper is capable of being made incandescent by a current of electricity, and while it allows the current to pass over it, its resistance to the heat is strong enough to prevent it from fusing.
On this day in Wisconsin history, a dedication:
1897 – Yerkes Observatory Dedicated
On this date the Yerkes Observatory was dedicated. Founded by astronomer George Hale and located in Williams Bay, the Yerkes Observatory houses the world’s largest refracting optical telescope, with a lens of diameter 102 cm/40 inches. It was built through the largess of the tycoon Charles Tyson Yerkes, who rebuilt important parts of the Chicago transportation system after the fire. Situated in a 77-acre park on the shore of Lake Geneva, this observatory was the center for world astronomy in the early 20th century and invited a number of astronomers from around the world, including Japan, for scientific exchange. [Source: Yerkes Observatory Virtual Museum]
Scientific American‘s daily trivia question asks about tourism. (Clicking on the question leads to its answer.)