Great photo of an unusual bike. The vertical fins on both the cylinder and head must be close to unique for a V twin, and that coupled with the loop frame (the frame tube cradles the engine) and the tank shape must be a real give-away to someone - but not to me! The date of the bike is probably 1905-6, give or take a year or two.
As for the tank badge, I originally thought Ariel, but although vaguely similar it is not the same as the early Ariel badge I know. Perhaps if you scan just the area of the badge at the highest possible resolution (1200 or 2400 dpi) you might get more detaill.
Leon
