Odds are good you've never seen this bike, because as far as we know it's the only one ever made.
It's a Spiral, supposedly made in 1896 by one Hermann Gehle, who taught at a vocational school in New York City. It gets its name from the construction of the cylinder barrel, which was made from a solid piece of steel that was chucked in a lathe and turned with a screw feed, which gave it spiraled fins, hence the name "Spiral." The crankcase is made of bronze.
I bumped into this intriguing machine at last year's Antique Motorcycle Club meet in Davenport, Iowa, and had a chance to speak with its owner, Harry Buck. Harry says he's comfortable with the 1896 date, at least for the engine, which features a magneto he says dates to 1900 at the latest. But he can't swear to when the whole machine was put together, and my sense is it had to be later. Perhaps Hermann played around with various frames, but as it looks today I'd guess it was constructed sometime between 1905 and 1910, looking as it does like a Harley Davidson from that period. — Richard Backus, Editor in chief