I doubt I have tir'd your Patience with too much Prolixity upon familiar Spirits, therefore, to make you amends, I will be but short in my Dissertation upon the Loadstone; which in the first place, is, a very ponderous Fossile, found in different Climates, and seems in its Nature and Qualities to be nearly related to Iron Oar, from whence it is endow'd with a peculiar property of drawing Iron to its self by the Power of Sympathy, or the natural Disposition it has to Embrace that particular Metal. In _Ægypt_ there are large Mines of it, some few Magnets have been found in _Æthiopia_, which have attracted Iron very forcibly; but two sorts are dug up at the foot of the _Sardinian_ Mountains, of such different Natures, that as one draws Iron, the other will repel it; as you will find it reported by _Johannes Jonstonus_, in his History of _Nature_, also by _Pliny_, in his Second Book, who, for the aforesaid Reason, calls this Stone _Theamedes_: As to the singular Virtues hitherto discover'd in the common Loadstone, the most admirable of all are the strict Correspondence it maintains with the two Poles, and the wonderful Property it communicates, by a touch, to the Needle, for the Benefit of Mariners. The Power of its Attraction, is thought by some Virtuosos to be owing to a clammy bituminous Substance, by which the Contexture of the more solid Parts are closely semented and confirm'd; to prove this, work a Loadstone in the Fire and it shall cast forth a blewish Flame, like that of lighted Brimstone, and so continue, till it spends its Life and loses the Power of Attraction. There is a great deal of Sulphur in Iron as well as in the Loadstone, which is the principal Cause of their Sympathising with each other, and if you destroy the first in either, the last will fail in course, which is the Reason, why the Loadstone will not attract the Rust of Iron, tho' it will the Filings, because in the former, the bituminous Matter is quite spent and nothing left but a kind of _Caput mortuum_. The Loadstone hath also two Poles, which answer those in the Heavens, if you touch the Needle with the North Pole of the Stone, it will point to the Artick, if with the South part thereof, as it stood posited in the Mine, it will point to the Antartick, but not with the utmost exactness, except it stands in the Meridian: But to be further satisfy'd in these Mysteries, have recourse to _Libavius_, _Cardanus_, _Pliny_, _Bodin_, _Porta_, our own _Philosophical Transactions_, and such Authors as have treated more largely upon this Subject: for, I suppose, all that you want to know of me is, if ever I have heard from others, or discover'd by my own Experience, any such Physical Virtue in the Loadstone, as may tend to the Cure of any Chronical or other Disease incident to humane Bodies, that may strengthen the Opinion you seem to entertain of it in such Cases, from the Benefit your self has lately receiv'd in so extraordinary a manner.