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varieth but five or six. And so likewise, because the CHAP. Cape de las Agullas hath Sea on both sides near it, and other Land remote, and as it were æquidistant from it, therefore at that point the Needle conforms unto the true Meridian, and is not distracted by the vicinity of Adjacencies. This is the general and great cause of variation. But if in certain Creeks and Vallies the Needle prove irregular, and vary beyond expectation, it may be imputed unto some vigorous part of the Earth, or Magnetical eminence not far distant. And this was the invention of D. Gilbert, not many years past, a Physician in London. And therefore although some assume the invention of its direction, and other have had the glory of the Card; yet in the experiments, grounds, and causes thereof, England produced the Father Philosopher, and discovered more in it then Columbus or Americus did ever by it.

Unto this in great part true the reason of Kircherus may be added: That this variation proceedeth not only from terrestrious eminencies, and magnetical veins of the Earth, laterally respecting the Needle, but the different coagmentation of the Earth disposed unto the Poles, lying under the Sea and Waters, which affect the Needle with great or lesser variation, according to the vigour or imbecility of these subterraneous lines, or the entire or broken compagination of the magnetical fabrick under it. As is observable from several Loadstones placed at the bottom of any water, for a Loadstone or Needle upon the surface, will variously conform it self, according to the vigour or faintness of the Loadstones under it.

Thus also a reason may be alledged for the variation of the variation, and why, according to observation, the variation of the Needle hath after some years been

CHAP. found to vary in some places. For this may proceed II from mutations of the earth, by subterraneous fires, fumes, mineral spirits, or otherwise; which altering the constitution of the magnetical parts, in process of time, doth vary the variation over the place.

It is also probable what is conceived of its Antiquity, that the knowledge of its polary power and direction unto the North was unknown unto the Ancients; and though Levinus Lemnius, and Cælius Colcagninus, are of another belief, is justly placed with new inventions by Pancirollus. For their Achilles and strongest argument is an expression in Plautus, a very Ancient author, and contemporary unto Ennius. Hic ventus jam secundus est, cape modo versoriam. Now this versoriam they construe to be the compass, which notwithstanding according unto Pineda, who hath discussed the point, Turnebus, Cabeus, and divers others, is better interpreted the rope that helps to turn the Ship, or as we say, doth make it tack about; the Compass declaring rather the Ship is turned, then conferring unto its conversion. As for the long expeditions and sundry voyages of elder times, which might confirm the Antiquity of this invention, it is not improbable they were performed by the help of Stars; and so might the Phoenicean navigators, and also Ulisses sail about the Mediterranean, by the flight of Birds, or keeping near the shore; and so might Hanno coast about Africa; or by the help of Oars, as is expressed in the voyage of Jonah. And whereas it is contended that this verticity was not unknown unto Solomon, in whom is presumed an universality of knowledge; it will as forcibly follow, he knew the Art of Typography, Powder and Guns, or had the Philosophers Stone, yet sent unto Ophir for Gold. It is not to be denied, that

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beside his Political wisdom, his knowledge in Philosophy CHAP. was very large; and perhaps from his works therein, the ancient Philosophers, especially Aristotle, who had the assistance of Alexanders acquirements, collected great observables. Yet if he knew the use of the Compass, his Ships were surely very slow, that made a three years voyage from Eziongeber in the red Sea unto Ophir; which is supposed to be Taprobana or Malaca in the Indies, not many moneths sail; and since in the same or lesser time, Drake and Candish performed their voyage about the Earth.

And as the knowledge of its verticity is not so old as some conceive, so it is more ancient then most believe; nor had its discovery with Guns, Printing, or as many think, some years before the discovery of America. For it was not unknown unto Petrus Peregrinus a Frenchman, who two hundred years since left a Tract of the Magnet, and a perpetual motion to be made thereby, preserved by Gasserus. Paulus Venetus, and about five hundred years past Albertus Magnus make mention hereof, and quote for it a Book of Aristotle, De Lapide; which Book although we find in the Catalogue of Laertius, yet with Cabeus we may rather judge it to be the work of some Arabick Writer, not many years before the days of Albertus.

Lastly, It is likewise true what some have delivered of Crocus Martis, that is, Steel corroded with Vinegar, Sulphur, or otherwise, and after reverberated by fire. For the Loadstone will not at all attract it, nor will it adhere, but lye therein like Sand. This to be understood of Crocus Martis well reverberated, and into a violet colour: for common chalybs præparatus, or corroded and powdered Steel, the Loadstone attracts like ordinary filings of Iron; and many times most of

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CHAP. that which passeth for Crocus Martis. So that this way may serve as a test of its preparation; after which it becometh a very good medicine in fluxes. The like may be affirmed of flakes of Iron that are rusty and begin to tend unto Earth; for their cognation then expireth, and the Loadstone will not regard them.

And therefore this may serve as a trial of good Steel. The Loadstone taking up a greater mass of that which is most pure, it may also decide the conversion of Wood into Iron, as is pretended from some Waters: and the common conversion of Iron into Copper by the mediation of blew Coperose, for the Loadstone will not attract it. Although it may be questioned, whether in this operation, the Iron or Coperose be transmuted, as may be doubted from the cognation of Coperose with Copper; and the quantity of Iron remaining after the conversion. And the same may be useful to some discovery concerning Vitriol or Coperose of Mars, by some called Salt of Steel, made by the spirits of Vitriol or Sulphur. For the corroded powder of Steel will after ablution be actively attracted by the Loadstone, and also remaineth in little diminished quantity. And therefore whether those shooting Salts partake but little of Steel, and be not rather the vitriolous spirits fixed into Salt by the effluvium or odor of Steel, is not without good question.

CHAP.

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CHAPTER III

Concerning the Loadstone, therein of sundry common Opinions, and received several relations: Natural, Historical, Medical, Magical.

AND

ND first not only a simple Heterodox, but a very hard Paradox, it will seem, and of great absurdity unto obstinate ears, if we say, attraction is unjustly appropriated unto the Loadstone, and that perhaps we speak not properly, when we say vulgarly and appropriately the Loadstone draweth Iron; and yet herein we should not want experiment and great authority. The words of Renatus des Cartes in his Principles of Philosophy are very plain. Præterea magnes trahet ferrum, sive potius magnes & ferrum ad invicem accedunt, neque enim ulla ibi tractio est. The same is solemnly determined by Cabeus. Nec magnes trahit proprie ferrum, nec ferrum ad se magnetem provocat, sed ambo pari conatu ad invicem confluunt. Concordant hereto is the assertion of Doctor Ridley, Physitian unto the Emperour of Russia, in his Tract of Magnetical Bodies, defining Magnetical attraction to be a natural incitation and disposition conforming unto contiguity, an union of one Magnetical Body with another, and no violent haling of the weak unto the stronger. And this is also the doctrine of Gilbertus, by whom this motion is termed Coition, and that not made by any faculty attractive of one, but a Syndrome and concourse of each; a Coition alway of their vigours, and also of their bodies, if bulk or impediment prevent not. And