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lister’s travels in trante.

I do not relate thefe things as though they were new difcoveries; the world has longfince known them by the great industry of our mod learned countryman, Gilbert ofColchefter, to whom little has been added after near too years, though very manymen have written on this lubjecl, and formed divers hypothefes to folve thefe phceno-inena. A Dutchman, Mr. Hartfoeker, one of the Academie de Sciences, has publifh-ed a treatife of the principles of natural philofophy, and has accounted for thefe andmany more experiments of this nature, which he had (hewn him by Mr. Butterfield,whom he mentions very honorably.

And yet after all, the nature of thefe effluvia are little known, and what is faid byDes Cartes of fcrew-fafhioned particles, and the invifible channels and pores and pipesof the loadftone, are all mere fancies without any foundation in nature. It is wellcalled by fome a certain magnetic matter, but what properties it hath is little under-flood.

It is very ftrange to me that a little loadftone of that prodigious force, fhould have fofhort a fphere of a&ivity, and not fenfibly to affeft iron from above an inch or two •, andthe biggeft and ftrongeft not above a foot or two. We fee the vortices in water, howwide they work round about them, vaftly increafing the circles; and what little re.fiftance the air can make to a body of that fubtilty, as the effluvia of the loadftone,which can with eafe penetrate all bodies whatfoever, marie, flints, glafs, copper, gold,without any fenfible diminution of its virtue. Again, we fee the flame of a lamp inoil, or tallow, or wax, how fhort it is j and how long and tapering it is in fpirit of wine.If therefore the magnetic matter was darted out of infinite final 1 pipes, and was of thenature of a more fubtile and invifible flame, why does it not continue its courfe in adirect line to a great length, but return fo fuddenly ? We fee the perfpiration of ourfkins to rife into the air, and continue to mount, which yet has but a weak impulfefrom the heart, being interrupted and broke off when it comes out of the road of theblood into the dudlus excretorii. But the circle of the magnetic matter is without anyimpulfe, that we know of, from the ftone; and moves in a double circle, and with adouble and contrary dream in the fame pipes, contrary to the laws of the circulationof the blood in animals ; which has naturally but one current, and one road round;for the whole mafs of veffels in which the circulation of the blood is concerned, is butone continued pipe.

Until the nature of the effluvia is better known, no very fatisfa&ory account canbe given of the moft common phoenomena of the loadftone, ex. gr. why it does notdraw to it all bodies alike ? Why a great loadftone, though weak, extends its virtuemuch farther than a fmall one, though ftrong ? Why a loadftone communicates its vir-tue to iron, as foon as it touches it, nay even at fome diftance, and gives it the proper-ties of a loadftone.

The truth is, the earth’s being a great magnet feems to me a mere vifion and fable;for this reafon, becaufe it is not iron. It is true, iron mine is the moft common of allminerals, and found almoft in all places; but it holds not any proportion with the reftof the foffils of the earth ; and is not, at a guefs, as a million to other fofli'is. Thisfeems evident to any one, who has well confidered the chalky mountains and cliffs, thehigh rag-ftone mountains and lime-ftone cliffs, the feverai quarries and pits funk intothe bowels cf the earth for coal and lead, See. how little iron there is to be found incomparifon of other matters. Add to this, that very little of that very iron mine,which is to found any where, is magnetic, or capable of obedience to the magnet, tillit is calcined. Whence therefore lhould all thofe magnetic effluvia arife, which are

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