de esos Polos Magnéticos, la Aguja se rige principalmente por él, siendo siempre el polo más cercano predominante sobre el más remoto.* Y allí me he esmerado en establecer y acotar la Posición actual de dichos Polos en la Superficie de nuestro Globo, lo cual, si el Lector tiene a bien consultarlo, nos ahorrará la pena de
But after all, tho' that Discourse was favourably receiv'd both at home and abroad, as seeming to render a tolerable account of the observ'd Variations, yet I found two Difficulties not easie to surmount; * the one was, that no Magnet I had ever seen or heard of, had more than two opposite Poles, whereas the Earth had visibly four, and perhaps more. * And secondly, it was plain that these Poles were not, at least all of them, fixt in the Earth, but shifted from place to place, as appear'd by the great Changes in the Needles Direction