Patent for an Envelop-Lock, which "appertains to a sealing or locking device for envelops and other containers, and aims to provide a novel and improved means for locking or sealing the closure flap of an envelop, whereby the envelop cannot be opened without tearing or mutilating the same, so as to be apparent to the recipient of the envelop." (lines 8-14) including instructions and illustrations.