A Rocket In His Pocket

We've all heard the declaration, "I know it when I see it".  Most of us have probably used it, or some expression that means more or less the same thing.  Nobody knows who first uttered it, but it's most often attributed to Supreme Court Justice Potter Stewart in an obscenity case.  He admitted he couldn't define pornography, but he knew it when he saw it. I'd love to know how he, or anyone else knows!;-)

(By the way:  He decided that the work in question wasn't pornography.)

I think most people would respond in the same way as Justice Stewart if asked to define a "bicycle".  Just about everybody agrees that it has two wheels.  (That, after all, is the literal definition of the word.)  I think most would also say that it has pedals, or is powered by human energy in some way or another.

Very few people, I believe, would define anything with a motor on it as a bicycle.  Even fewer, I think, would say that a bicycle is powered by a rocket.

 

That makes the record held by Francois Gissy questionable, to say the least.  His 263KPH (163MPH) ride is listed as the land speed record for a bicycle.  At least one rider has reached 260 KPH with his own feet:  He was paced by a racing car, but pedaled to his record nonetheless.