At that time a deluded gentleman, who called himself "Parallax," was obsessed with the notion that the globe was a flat disc, and used to go lecturing with great vigour on the subject. After these lectures he invited questions, none of which were able to shake his belief. When asked, for example, "Why does the hull of a ship disappear below the horizon while the masts remain visible?" he would answer, "Because the lowest stratum of air is the densest, and, therefore, soonest conceals objects seen through it." In view of the present Polar exploration, it may interest our readers to know that one of his points was the absolute non-existence of the South Pole. "Explorers say they cannot get near it, because of an icy barrier. Of course. That barrier is the raised rim of our world plate, and they can but sail round and round inside it." Finally he showed his wholehearted belief in his absurd views by laying a heavy wager that no one would disprove them. The stakes were deposited in the hands of judges, and the trial, under agreed conditions, took place upon the New River. Three boats were moored three miles apart, each provided with a cross-tree of equal height. If the earth was spherical the central cross would appear above the other to an observer looking through a telescope levelled from the cross-tree of the boat at either end; if it was flat he would see both the other cross-trees as one. "Parallax" declared that he did so (!), but the judges decided against him, and the poor man lost his money. CHAPTER XIII Island of Ely.--Haddenham.--Aldreth, Conqueror's Causeway, Belsars Hill.--Wilburton.--Sutton.--Wentworth.--Via Devana.--Girton, College.--Oakington, Holdsworth.--Elsworth.--Conington, Ancient Bells.--Long Stanton, Queen Elizabeth.--Willingham, Stone Chamber.--Over, Gurgoyles.--Swavesey, Finials.--Ely Road.--Chesterton.--Fen Ditton.--Milton, Altar Rails.--Horningsea.--Bait's Bite, Start of Race.--Clayhithe.--Waterbeach.--Car Dyke.--Denny.--Stretham.--Upware.--Wicken Fen.