As those metals earliest known, viz. copper, iron, gold, silver, lead, quicksilver and tin, received the same names as the nearest heavenly bodies, which appear to us largest, and have been distinguished by the like characters, two questions arise: Whether these names and characters were given first to the planets or to the metals? When, where, and on what account were they made choice of; and why were the metals named after the planets, or the planets after the metals? The latter of these questions, in my opinion, cannot be answered with any degree of certainty; but something may be said on the subject, which will not, perhaps, be disagreeable to those fond of such researches, and who have not had an opportunity of examining it.
That the present usual names were first given to the heavenly bodies, and at a later period to the metals, is beyond all doubt; and it is equally certain that they came from the Greeks to the Romans, and from the Romans to us. It can be proved also that older nations gave other names to these heavenly bodies at much earlier periods. The oldest appellations, if we may judge from some examples still preserved, seem to have originated from certain emotions which these bodies excited in the minds of men; and it is not improbable that the planets were by the ancient Egyptians and Persians named after their gods, and that the Greeks only adopted or translated into their own language the names which those nations had given them62. The idea that each planet was the residence of a god, or that they were gods themselves, has arisen, according to the most probable conjecture, from rude nations worshiping the sun, which, on account of his beneficent and necessary influence over all terrestrial bodies, they considered either as the deity himself, or his abode, or, at any rate, as a symbol of him. In the course of time, when heroes and persons who by extraordinary services had rendered their names respected and immortal, received divine honours, particular heavenly bodies, of which the sun, moon and planets seemed the fittest, were also assigned to these divinities63. By what laws this distribution was made, and why one planet was dedicated to Saturn and not to another, Pluche did not venture to determine: and on this point the ancients themselves are not all agreed64. When the planets were once dedicated to the gods, folly, which never stops where it begins, proceeded still further, and ascribed to them the attributes and powers for which the deities, after whom they were named, had been celebrated in the fictions of their mythologists. This in time laid the foundation of astrology; and hence the planet Mars, like the deity of that name, was said to cause and to be fond of war; and Venus to preside over love and its pleasures.
The next question is, Why were the metals divided in the like manner among the gods, and named after them? Of all the conjectures that can be formed in answer to this question, the following appears to me the most probable. The number of the deified planets made the number seven so sacred to the Egyptians, Persians and other nations, that all those things which amounted to the same number, or which could be divided by it without a remainder, were supposed to have an affinity or a likeness to and connexion with each other65. The seven metals, therefore, were considered as having some relationship to the planets, and with them to the gods, and were accordingly named after them. To each god was assigned a metal, the origin and use of which was under his particular providence and government; and to each metal were ascribed the powers and properties of the planet and divinity of the like name; from which arose, in the course of time, many of the ridiculous conceits of the alchemists.
The oldest trace of the division of the metals among the gods is to be found, as far as I know, in the religious worship of the Persians. Origen, in his Refutation of Celsus, who asserted that the seven heavens of the Christians, as well as the ladder which Jacob saw in his dream, had been borrowed from the mysteries of Mithras, says, “Among the Persians the revolutions of the heavenly bodies were represented by seven stairs, which conducted to the same number of gates. The first gate was of lead; the second of tin; the third of copper; the fourth of iron; the fifth of a mixed metal; the sixth of silver, and the seventh of gold. The leaden gate had the slow tedious motion of Saturn; the tin gate the lustre and gentleness of Venus; the third was dedicated to Jupiter; the fourth to Mercury, on account of his strength and fitness for trade; the fifth to Mars; the sixth to the Moon, and the last to the Sun66.” Here then is an evident trace of metallurgic astronomy, as Borrichius calls it, or of the astronomical or mythological nomination of metals, though it differs from that used at present. According to this arrangement, tin belonged to Jupiter, copper to Venus, iron to Mars, and the mixed metal to Mercury. The conjecture of Borrichius, that the transcribers of Origen have, either through ignorance or design, transposed the names of the gods, is highly probable: for if we reflect that in this nomination men at first differed as much as in the nomination of the planets, and that the names given them were only confirmed in the course of time, of which I shall soon produce proofs, it must be allowed that the causes assigned by Origen for his nomination do not well agree with the present reading, and that they appear much juster when the names are disposed in the same manner as that in which we now use them67.
This astrological nomination of metals appears to have been conveyed to the Brahmans in India; for we are informed that a Brahman sent to Apollonius seven rings, distinguished by the names of the seven stars or planets, one of which he was to wear daily on his finger, according to the day of the week68. This can be no otherwise explained than by supposing that he was to wear the gold ring on Sunday; the silver one on Monday; the iron one on Tuesday, and so of the rest. Allusion to this nomination of the metals after the gods occurs here and there in the ancients. Didymus, in his Explanation of the Iliad, calls the planet Mars the iron star. Those who dream of having had anything to do with Mars are by Artemidorus threatened with a chirurgical operation, for this reason, he adds, because Mars signifies iron69. Heraclides says also in his allegories, that Mars was very properly considered as iron; and we are told by Pindar that gold is dedicated to the sun70.
Plato likewise, who studied in Egypt, seems to have admitted this nomination and meaning of the metals. We are at least assured so by Marsilius Ficinus71; but I have been able to find no proof of it, except where he says of the island Atlantis, that the exterior walls were covered with copper and the interior with tin, and that the walls of the citadel were of gold. It is not improbable that Plato adopted this Persian or Egyptian representation, as he assigned the planets to the demons; but perhaps it was first introduced into his system only by his disciples72. They seem, however, to have varied from the nomination used at present; as they dedicated to Venus copper, or brass, the principal component part of which is indeed copper; to Mercury tin; and to Jupiter electrum. The last-mentioned metal was a mixture of gold and silver; and on this account was probably considered to be a distinct metal, because in early periods mankind were unacquainted with the art of separating these noble metals73.
The characters by which the planets and metals are generally expressed when one does not choose to write their names, afford a striking example how readily the mind may be induced to suppose a connexion between things which in reality have no affinity or relation to each other. Antiquaries and astrologers, according to whose opinion the planets were first distinguished by these characters, consider them as the attributes of the deities of the same name. The circle in the earliest periods among the Egyptians was the symbol of divinity and perfection; and seems with great propriety to have been chosen by them as the character of the sun, especially as, when surrounded by small strokes projecting from its circumference, it may form some representation of the emission of rays. The semicircle is in like manner the image of the moon, the only one of the heavenly bodies that appears under that form to the naked eye. The character ♄ is supposed to represent the sythe of Saturn; ♃ the thunderbolts of Jupiter; ♂ the lance of Mars, together with his shield; ♀ the looking-glass of Venus; and ☿ the caduceus or wand of Mercury.
The expression by characters adopted among the older chemists agrees with