Little Johnny walked into his classroom with a fried egg on his head. The teacher asked, "Why do you have a fried egg on your head?" Little Johnny responded, "Because a hard boiled egg rolls off."
In 1850, the first U.S. patent for magic lantern slides made of glass plate was issued to their inventor Frederick Langenheim of Philadelphia, Pa. (No. 7,784) as an "improvement in photographic pictures on glass."
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