“This contrivance externally resembles a watch in size and shape. Within the case is a bell and spring hammer, the latter connected with a fob chain. The supposition is, that the thief will pull the chain in order to obtain the prize. But instead of getting the watch, the watch gets him. The pull sounds the alarm bell, the owner of the watch grabs the rogue, and the policeman conducts him to limbo.”

Scientific American, August 1856

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