On the Magnet, by William Gilbert

Chap. xiiii. On the variation under the æquinoctial line, and near it.

I n the North the magnetick needle varies because of the Boreal eminences of the continent; in the South because of the Austral; at the æquator, if the regions on both sides were equal, there would be no variation. But because this rarely happens some variation is often observed under the æquator; and even at some distance from the æquator of three or 4 degrees toward the North, there may be a variation arising from the south, if those very wide and influential southern continents be somewhat near on one side.

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Last updated Tuesday, August 25, 2015 at 14:08