Now the cause of this variation was thought by _Gilbertus_ to be the inequality of the Earth, variously disposed, and indifferently intermixed with the Sea: withal the different disposure of its Magnetical vigor in the eminencies and stronger parts thereof. For the Needle naturally endeavours to conform unto the Meridian, but being distracted, driveth that way where the greater and powerfuller part of the Earth is placed. Which may be illustrated from what hath been delivered and may be conceived by any that understands the generalities of Geography. For whereas on this side the Meridian, or the Isles of _Azores_, where the first Meridian is placed, the Needle varieth Eastward; it may be occasioned by that vast Tract of Earth, that is, of _Europe_, _Asia_, and _Africa_, seated toward the East, and disposing the Needle that way. For arriving at some part of the _Azores_, or Islands of Saint _Michael_, which have a middle situation between these Continents, and that vast and almost answerable Tract of _America_, it seemeth equally distracted by both; and diverting unto neither, doth parallel and place it self upon the true Meridian. But sailing farther, it veers its Lilly to the West, and regardeth that quarter wherein the Land is nearer or greater; and in the same latitude as it approacheth the shore augmenteth its variation. And therefore as some observe, if _Columbus_ or whosoever first discovered _America_, had apprehended the cause of this variation, having passed more then half the way, he might have been confirmed in the discovery, and assuredly foretold there lay a vast and mighty continent toward the West. The reason I confess and inference is good, but the instance perhaps not so. For _Columbus_ knew not the variation of the compass, whereof _Sebastian Cabot_ first took notice, who after made discovery in the Northern part of that continent. And it happened indeed that part of _America_ was first discovered, which was on this side farthest distant, that is, _Jamaica_, _Cuba_, and the Isles in the Bay of _Mexico_. And from this variation do some new discoverers deduce a probability in the attempts of the Northern passage toward the _Indies_.