He argued from what he saw, or what he thought he saw, that the line of no variation marked the beginning of a protuberance of the earth, up which he ascended as he sailed westerly, and that this was the reason of the cooler weather which he experienced. He never got over some notions of this kind, and he believed he found confirmation of them in his later voyages. Even as early as the reign of Edward III. of England, Nicholas of Lynn, a voyager to the northern seas, is thought to have definitely fixed the magnetic pole in the Arctic regions, transmitting his views to Cnoyen, the master of the later Mercator, in respect to the four circumpolar islands, which in the sixteenth century made so constant a surrounding of the north pole. The next day (September 14), after these magnetic observations, a water wagtail was seen from the _Nina_,--a bird which Columbus thought unaccustomed to fly over twenty-five leagues from land, and the ships were now, according to their reckoning, not far from two hundred leagues from the Canaries. On Saturday they saw a distant bolt of fire fall into the sea. On Sunday, they had a drizzling rain, followed by pleasant weather, which reminded Columbus of the nightingales, gladdening the climate of Andalusia in April. They found around the ships much green floatage of weeds, which led them to think some islands must be near. Navarrete thinks there was some truth in this, inasmuch as the charts of the early part of this century represent breakers as having been seen in 1802, near the spot where Columbus can be computed to have been at this time. Columbus was in fact within that extensive _prairie_ of floating seaweed which is known as the Sargasso Sea, whose principal longitudinal axis is found in modern times to lie along the parallel of 41 deg. 30', and the best calculations which can be made from the rather uncertain data of Columbus's journal seem to point to about the same position. There is nothing in all these accounts, as we have them abridged by La Casas, to indicate any great surprise, and certainly nothing of the overwhelming fear which, the _Historie_ tells us, the sailors experienced when they found their ships among these floating masses of weeds, raising apprehension of a perpetual entanglement in their swashing folds.