Lodestones, fragments of magnetite (Fe_{3}O_{4}), are said to have been first discovered at Magnesia, in Asia Minor,—hence the word _magnetism_. Some of the earliest references to the lodestone relate to its property of lying in a north-and-south direction when an elongate stone is freely suspended, one particular end always pointing northward, just as the great magnet the earth, or the mariner’s compass-needle, has two opposite magnetic poles. The location of the poles of a disk-shaped stone is readily found by turning it round in the presence of a compass-needle.[6] Iron and steel are more strongly magnetic than any other metals. While only one kind of iron ore is naturally magnetic—forming magnets—the property of magnetism may always be given to any kind of iron or steel. One need only strike an iron bar while it is lying in a north-south position, or rub the iron with a magnet, and it becomes a magnet. If it is desired to make a _permanent_ magnet, steel must be employed. A compass-needle is therefore made of magnetized steel. If balanced upon a pivot, the positive pole of the needle will point (roughly) towards the earth’s north geographical pole.[7] A compass-needle is also a “dipping needle”, unless the suspended magnetized needle lies about half way between the earth’s magnetic poles. The north magnetic pole lies below the earth’s surface—at an unknown depth—at the extreme northeastern corner of the continent of North America; and the corresponding south magnetic pole on the edge of the Antarctic continent—King George’s Land—about 2,300 miles south of Australia. These magnetic poles do not correspond even roughly with the geographic poles, nor does the magnetic equator by any means correspond with the geographic equator. Only a small section of the magnetic equator runs north of the true (geographic) equator—e. g., from the coast of Brazil to the coast of Kamerun (Africa). According to Prof. T. J. J. See, “the whole magnetic system has been pushed southward 200 miles by bodily displacement of both poles towards the ocean hemisphere.” This eminent physicist-astronomer also stated (in 1922) that his researches led him to the discovery that the two magnetic poles are at unequal depths in the earth, the North Pole being much deeper than the South Pole, “with the result that the total magnetic forces in the southern hemisphere are considerably stronger than in the northern hemisphere.”[8]