It hath been remarked that the magnetick Poles must be, from the direction of the Magnetick Needle some where about the Poles of the Earth, to find the situation thereof hath been not of the desiderata of Navigators; also to ascertain if there was any particular spot in the Earth to which the Needle uniformly pointed, when uninfluenced by accidental causes, such as Iron Ores, in any Magnetic Bodies interposed or adjacent thereto: and likewise to ascertain the Laws of motion by which they were governed. This was a favourite Scheme of the celebrated Doctor Haller, but notwithstanding the many accurate observations made by him, at the public charge for want of them being universal, and for want of laying them down in a Globe in a proper manner he seams to have fallen something short of finding the exact situation of the magnetick Poles, and thereby lost the satisfaction which modern times afford, by the abundant Blessings of the great Creator of the Universe, of finding the Longitude in a simple easy and certain way. Having bestowed some time in the examination of various antient and modern observations particularly of Captain Cooks last Voyage round the World, to whom I hold myself under many obligations, I have compared with a System which to me had appeared the only reasonable one that the circumstances observed to attend the variation would warrant. I have ventured to make the following conclusions which I am encouraged tho with the greatest diffidence to lay before the president of the American Philosophical Society in hopes they prove of some utility and are as follows 1st. That the Magnetick Needle hath a direction to two points at certain distances from each Pole of the Earth. 2nd. That these points to which it hath a direction are called the Magnetick Poles. 3rd. That one of these Poles is found by laying down many observations of the Variation of the Magnetick Needle in the Northern Hemisphere to be at a certain distance from the North Pole of the Earth which for distinction may be called the North Magnetick Pole. 4th. That in the Southern Hemisphere the South Point of the Needle hath a direction to a shot or point at a certain distance from the South Pole of the Earth altho not diametrically opposite to the other which may be called the South Magnetick Pole. 5th. That a Great Circle crossing the Meridians of the Earth at equal distances between the two Magnetick Poles we call the magnetick Equator. 6th. That a Magnetick Meridian for any part of the Globe is a Circle drawn through the two magnetick Poles and the Place of observation. 7th. That the Angle between the Magnetick Meridian and the Earths Meridian (which is universally more or less in proportion to the situation of the place of observation from the meridian of the Magnetick Pole) is the variation of the Compass. 8th. That the Globe on which they are laid may be called the Variation Globe. 9th. Haveing all these observations of the variation laid down which have been made with a sufficient degree of accuracy they will intersect each other in the Magnetick Poles which appear to describe Circles of this Globe at unequal distance from the North and South Poles of the Earth. 10th. That these Poles have an uniform motion and perform revolutions in given times, from West to East the Northern one in the Year 1779 was distant from the North Pole of the Earth 13°. 56 its Longitude from Greenwich 85°. 12 West its period 463 Years and 344 days. The period of the Southern one for want of sufficient observations cannot yet be so accurately determined, but its distance from the South Pole of the Earth about 18°. in the Year 1777 and its Longitude from Greenwich about 140 East. Hence after knowing the exact distance of the Magnetick Poles from the Poles of the Earth and their Longitude for any given time we are enabled to ascertain the Longitude of a place; from an observation of the Latitude and Variation of the Magnetick Needle. I remain with the greatest sentiments of respect &ca. &ca.