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Benjamin Franklin Reference Libraries

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Lightning Rod
2010-10-21 17:15:50

A lightning rod is a metal conductor mounted on the top of a building and connected through a wire to the ground to protect the building from lightning. The rod should conduct the electricity from a lightning strike down through the wire instead of passing through the building. The rod is just a single component in the lightning protections system along with rooftop conductors and multiple...

Bifocals
2010-09-23 19:15:37

Bifocals are eyeglasses, commonly prescribed for presbyopia, with two distinct optical powers. Although there are arguments against him, Benjamin Franklin is generally credited with the invention of bifocals. After a correspondence between George Whatley and John Fenno it was thought that Franklin possibly invented the bifocals fifty years earlier than previously thought. Many inventions...

Word of the Day
sudarium
  • A handkerchief.
  • Specifically— The legendary sweat-cloth; the handkerchief of St. Veronica, according to tradition miraculously impressed with the mask of Christ; also, the napkin about Christ's head (Johu xx. 7).
  • In general, any miraculous portrait of Christ.
The word 'sudarium' comes from a Latin word meaning 'a handkerchief'.