OBJECT HISTORY: Yerkes Telescope

The 40-inch refracting telescope at Yerkes Observatory in Williams Bay, Wisconsin, contains the world’s largest refracting lenses. Built in 1895, the telescope contains two lenses, one made of crown glass, and one made of flint glass. The lenses are each 40 inches in diameter, weigh 500 pounds, and have a 62-foot focal length. The telescope and observatory…

OBJECT HISTORY: Le Maire Sundial

The Le Maire Sundial is a rare example of a mid-18th century French sundial (cadran solaire) compass (boussole). It was found near Green Bay in 1902 by a local antiquities collector, Frank Duchateau. The sundial is broken, missing its glass compass cover as well as the back of its gnomon holder. Located on the front surface,…

OBJECT HISTORY: Employers Mutual Audiometer

This Maico Audiometer was one of many devices used by health and safety consultants of the Employers Mutual Liability Insurance Company of Wisconsin throughout the mid-to-late 1960s. Employers Mutual was the very first workers compensation insurance company in the United States. The company was founded in Wausau, Wisconsin, in 1911 shortly after the nation’s first workers compensation law was…