8

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 Calcagninus, 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, than 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 Phoenician navigators, and also Ulysses, 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 philosopher's stone, yet sent unto Ophir for gold. It is not to be denied, that, besides his political wisdom, his knowledge in philosophy was very large; and perhaps from his works therein, the ancient philosophers, especially Aristotle, who had the assistance of Alexander's 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 Eziongeber in the Red Sea unto Ophir, which is supposed to be Taprobana or Malacca in the Indies, not many months' sail; and since, in the same or lesser time, Drake and Cavendish performed their voyage about the earth.

from

Turnebus.] Otherwise Turnbull, whose father was a Scotchman. -Jef.

9

improbable.] Ross reads probable, and so indulges in a long discourse to refute the position.

a three years' voyage, &c.] That the voyage from Eziongeber to

And, as the knowledge of its verticity is not so old as some conceive, so is it more ancient than 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,2 left a tract of the magnet, and a perOphir occupied three years is by no means to be inferred from the expressions used by the sacred historian: see 1 Kings x. 22; 2 Chron. ix. 21.

If, in his identification of the ancient Taprobane with Malacca, Sir Thomas may be supposed to have included the adjacent islands of Sumatra, Borneos, and Java, which is extremely probable, his opinion is supported by the high authority of Sir T. Stamford Raffles; though other modern geographers have considered it to be Ceylon.

The true situation of Ophir, however, has been the subject of very many conflicting hypotheses. One of the most recent, and perhaps most probable, is that of Mr. C. T. Beke, who supposes it to have been situated at the northern extremity of the Persian gulph. See his Origines Biblicæ, vol. i. p. 114.

2 two hundred years since.] The knowledge of the directive power or polarity of the magnet, is now known to be of a date considerably earlier than this. Sir John F. W. Herschel, in his Preliminary Discourse on the Study of Natural Philosophy, p. 326, thus concisely states the present amount of our information on the subject: "It does not appear that the ancients had any knowledge of this property of the magnet, though its attraction of iron was well known to them. The first mention of it in modern times cannot be traced earlier than 1180, though it was probably known to the Chinese before that time." The following passage from the late Professor Sir John Leslie's Dissertation on the Progress of Mathematical and Physical Science, prefixed to the seventh edition of the Encyclopædia Britannica, gives a more circumstantial view of the history of the compass, which is further interesting, when contrasted with the previous passage of the text, as showing that the notions respecting the antiquity of the knowledge of magnetic polarity, which are therein contemned by Browne, have been revived and supported by high modern authority. "The magnetic compass, with the art of distillation, which was never practised by the ancient Greeks or Romans, seems to have been discovered in Upper Asia, and thence communicated by their Tartarian conquerors, to the Chinese. From them again, the knowledge of the invention spread gradually over the East. The Crusaders, during the occupation of their bloody conquests in those regions, had leisure to admire the arts acquired by their more civilized rivals. Having their curiosity thus awakened, they appear, about the latter part of the twelfth century, to have imported into Europe the compass, along with the substance which, mistaking it for natron, they called saltpetre, and of which they had learned the deflagrating property. That invaluable instrument was at first very rudely formed, consisting merely of a piece of the native mineral fixed to a broad cork, and set to float

petual 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 Arabic 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 lie therein like sand.3 This is to be undertood 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 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.

in a dish of water. An artist, of the opulent town of Amalphi, the great emporium of the East, and seated on the shore of Calabria, in the direct route of the Crusaders, improved the construction, and marked the north point by a fleur-de-lis, the armorial bearing of the kingdom of Naples. From its directive property, it was now called, in English, the loadstone, or leadingstone.-Br.

3 but lie therein like sand.] Some explanatory remarks are requisite in this place. The crocus martis described by the author, is the peroxide of iron of modern chemists, that is, iron combined with the greatest proportion of oxygen with which it is capable of uniting, in which state of combination the metal ceases to obey the magnetic influence. But the "common chalybs præparatus," which he afterwards mentions, consists merely of steel, in which the metal retains, in great measure, its metallic form, but is mixed and disguised with variable proportions of its oxides, and chiefly of the black oxide, and this, containing less oxygen than the peroxide, is like the unoxidated metal attracted by the magnet; which explains why this preparation is attracted by "the loadstone,"

"like ordinary filings of iron." While the "flakes of iron that are rusty," &c. adverted to at the conclusion of the paragraph, are only in the state of black oxide, they also obey the magnet; but when they have acquired their full dose of oxygen, and thus become peroxide, "their cognation then expireth, and the loadstone will not regard them."-Br.

And therefore, this may serve as a trial of good steel,4 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 blue copperas; for the loadstone will not attract it. Although it may be questioned, whether, in this operation, the iron or copperas be transmuted,5 as may be doubted from the cognation of copperas with copper, and the quantity of iron remaining after the conversion. And the same may be useful

4 as a trial of good steel.] This statement is no further true than that the magnet, if caused to act upon filings of iron or steel in which the metal fully retained its metallic form, free from oxidation, and also upon similar filings which had become partially oxidated, would attract a greater quantity of the former than of the latter. As a trial of the purity or goodness of iron or steel in the mass, the proposed test is quite nugatory.—Br.

5 whether in this operation the iron or copperas be transmuted.] This alleged conversion of iron into copper is an experiment of the alchymists and of the old chemists their successors; the true nature of which has been explained by modern chemists, and appears, from the passage before us, to have been suspected also by Browne. The metallic salt, here termed "blue copperas" (or blue vitriol, as it is also called), is properly a hydrated persulphate of copper, a combination of the peroxide of that metal with the sulphuric acid and with water. But iron, having a stronger chemical attraction for oxygen than copper has, when immersed in a solution of this salt, attracts and unites with the oxygen of a part of the peroxide of copper, thus separating an equivalent quantity of the copper itself, which being precipitated, in its pure metallic state, upon the iron, imparts to it externally the appearance of copper, just as gilding would impart that of gold. It was formerly imagined, however (and the experiment was cited as demonstrating the transmutability of metals into one another), that part of the iron was actually converted into copper. But our author, knowing the "cognation of [blue] copperas with copper," and considering "the quantity of iron remaining after the conversion," justly questions whether the iron or the "copperas ""be transmuted." It is evident from this, that he entertained as correct a notion upon the subject as it was possible to arrive at in the existing state of chemical knowledge; for, although in reality a particle of iron becomes dissolved in the solution for every particle of copper which is precipitated from it, yet, in the manner in which the experiment is commonly made, and as it was always made formerly, the iron is not sensibly diminished in substance, and continues unaltered in form, so that the obvious essential change takes place with the metallic salt only. The last sentence of the first period alluding to this subject would be more readily intelligible, were it read "for the loadstone will not attract the copperas."-Br.

to some discovery concerning vitriol or copperas 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 odour of steel, is not without good question.7

CHAPTER III.

Concerning the Loadstone; a rejection of sundry common opinions and relations thereof; natural, medical, historical, magical.

AND 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 trahit ferrum, sive potiùs magnes et ferrum ad invicem acce

6 some discovery concerning vitriol or copperas of Mars.] The salt here alluded to, commonly termed green vitriol, is the hydrated protosulphate of iron, a combination of the protoxide of iron with the sulphuric acid and with water, bearing nearly the same relation to metallic iron which blue vitriol bears to metallic copper. The manner in which Browne adverts to these substances, evinces that he entertained approximately correct ideas respecting the nature of the several salts termed copperas. But when he supposes that "those shooting salts" (meaning thereby the hydrated protosulphate of iron), "partake but little" of the metal from which they are formed, he is entirely mistaken. He appears to have been led into this error by the application of his own proposed magnetic test: finding that the "corroded powder of steel," the nature of which is explained in our preceding note, was readily attracted by the magnet, but that the "copperas of Mars not, he seems to have inferred that that salt could not be materially related to the metal from which it is formed; not knowing that those substances which obey the magnet in their metallic state, and in some instances in their oxidated form also, cease to be amenable to its influence when united with acids into salts.-Br.

1 And therefore, &c.] Added in 2nd edition.

was