628 PHILOSOPHICAL TRANSACTIONS. [aNNO 1683. 



powerful a diversion at 1 or 3000 miles distance ? Yet I cannot deny that in 

 some places near the shore, or in shoal water, the needle may be irregularly di- 

 rected from the aforesaid causes, and that not a little, as Gassendus gives a 

 notable instance of the island Elba in the Mediterranean sea; but these differ- 

 ences from the general direction are always signs of the nearness of those mag- 

 netical substances, for the production whereof that island Elba has been famous 

 from all antiquity. Besides, against both Descartes and Gilbert, the change of 

 the variation, which has been within this 1 00 years last past more than 1 5° at 

 London, is an entire demonstration ; though Descartes does not stick to say, 

 that the transportation of iron from place to place, and the growth of new iron 

 within the earth, where there was none before, may be the cause thereof. The 

 same holds likewise against the hypothesis of magnetical fibres^ which Kircher 

 maintains. 



Now to propose something that may answer the several appearances, and in- 

 troduce nothing strange in philosophy, after a great many close thoughts I can 

 come to no other conclusion than that, the whole globe of the earth is one 

 great magnet, having 4 magnetical poles or points of attraction, near each pole 

 of the equator 2; and that, in those parts of the world which lie near adjacent 

 to any one of those magnetical poles, the needle is governed thereby, the 

 nearest pole being always predominant over the more remote. The parts of 

 the earth wherein these magnetical poles lie cannot as yet be exactly deter- 

 mined, for want of sufficient data to proceed geometrically ; but, as near as 

 conjecture can reach, I reckon that the pole which is at present nearest to us 

 lies in or near the meridian of the land's end of England, and not above 7° from 

 the north pole. By this pole the variations in all Europe and Tartary, and the 

 North Sea are principally governed ; though with regard to the other northern 

 pole, whose situation is in a meridian passing about the middle of California, 

 and about 15° from the north pole of the world; to this the needle has chiefly 

 respect in all the North America, and in the two oceans on either side thereof, 

 from the Azores westwards to Japan, and farther. The 2 southern poles are 

 rather farther distant from the south pole of the world. The one, about l6° 

 from it, is in a meridian about 20° to the westward of Magellan's Straits, or 

 95° west from London ; this commands the needle in all the South America, in 

 the Pacific Sea, and the greatest part of the Ethiopic Ocean. The fourth and 

 last pole seems to have the greatest power and largest dominions of all, as it is 

 the most remote from the pole of the world, being little less than 20° distant 

 from it, in the meridian which passes through Hollandia Nova and the island 

 Celebes, about 120° east from London; this pole is predominant in the 

 south part of Africa, in Arabia, and the Red Sea, in Persia, India and its 



