> It would have been easy to attach a camera to a small hydrogen balloon, with a clockwork device to puncture the balloon to bring it down in a reasonable dista

> It would have been easy to attach a camera to a small hydrogen balloon, with a clockwork device to puncture the balloon to bring it down in a reasonable distance. Maybe, but homing pigeons have a few advantages. They return to their home "automatically" and they are not as conspicuous flying through the air.