Balloon mail

Balloon mail is the transport of mail (usually for weight reasons in the form of a postcard) carrying the name of the sender by means of an unguided hydrogen or helium filled balloon. Since the balloon is not controllable, the delivery of a balloon mail is left to good fortune; often the balloon and postcard are lost. A found balloon should be returned to the sender (by conventional post) with an indication of the discovery site, so that the sender can determine how far their balloon flew. Frequently balloon mail is sent as part of a balloon competition.