magnesium

Magnesium is a chemical element with atomic number 12 and the symbol Mg. It is a shiny, gray metal with low density, low melting point, and high reactivity. It has a wide variety of uses and is commonly used in aluminum alloys for aircraft, automobiles, and other applications demanding a strong but light metal. Magnesium easily ignites and burns with a bright, white light, making it useful for various illumination and pyrotechnic applications.

The element was not isolated until the early nineteenth century, but the name dates to antiquity. It comes from the ancient Greek Μαγνῆτις λίθος (Magnetis lithos) or Magnesian stone, referring to a lodestone or magnet. The mineral is named after the region of Magnesia in Thessaly where the ore was found. In Hellenistic/Byzantine Greek starting in the second century CE, μαγνησία (magnesia) referred to several different ores. The word was borrowed into post-classical Latin and from there into English by the fourteenth century.

Medieval alchemists considered various types of magnesia to be constituents of the philosopher’s stone, and Geoffrey Chaucer records this idea in the Canon Yeoman’s Tale from c.1387:

Also ther was a disciple of Plato,
That on a tyme seyde his maister to,
As his book Senior wol bere witnesse,
And this was his demande in soothfastnesse:
"Telle me the name of the privee stoon."
And Plato answerde unto hym anoon,
"Take the stoon that men name Titanos."
"Which is that?" quod he. "Magnasia is the same,"
Seyde Plato. "Ye, sire, and is it thus?
This is ignotum per ignocius.
What is Magnasia, good sire, I yow preye?"
"It is a water that is maad, I seye,
Of elementes foure," quod Plato.
"Telle me the roote, good sire," quod he tho,
"Of that water, if it be youre wil."
"Nay, nay," quod Plato, "certein, that I nyl.
The philosophres sworn were everychoon
That they sholden discovere it unto noon,
Ne in no book it write in no manere.

(Also, there was a disciple of Plato,
That one time said to his master,
As his book Senior will bear witness,
And this was his question in truth:
“Tell me the name of the secret stone.”
And Plato answered him at once,
“Take the stone that men name Titanos.”
Which is that?” said he. “Magnesia is the same,”
Said Plato. “Yes, sir, and is it thus?
This is explaining the unknown with more unknowns.
What is Magnesia, good sir, I pray you?”
“It is a liquid that is made, I say,
Of the four elements,” said Plato.
“Telle me the basic constituent, good sir,” he then said,
“Of that liquid, if it be your will.”
“Nay, nay,” said Plato, “certainly I won’t.
The philosophers were sworn every single one
That they should reveal it to no one,
Nor in any book write it in any manner.”)

But by the seventeenth century magnesia had become a name for the element we now call manganese. In his 1677 Natural History of Oxford-shire, Robert Plot records this usage:

There is also near Thame on Cuttlebrook-side, another Iron-colour'd stone, but more spungy than the former, and including within it a blackish kind of Cinder; the most like, of any thing I yet have seen, to Magnesia (in the Glass-houses, called Manganese) only it wants of its closeness of texture and weight.

And by the late eighteenth century the form magnesium is being used to refer to manganese. From a 23 April 1781 letter by chemist Joseph Black to James Watt:

I have lately made some on Manganeze [sic] and find the purest I can get contains some lead and I suspect that the Metal you got from it was mostly Lead—The Swedish Chemists also have got a Metal from it \they call it Magnesium/ which they say is hard and brittle and more difficult to melt than Iron.

But this nomenclature created problems, with manganese being confused with other magnesia minerals. In his 1784 Travels into Poland, Russia, Sweden, and Denmark, William Coxe records this confusion:

manganesium* salitum, or manganese united to the muriatick acid

The note reads:

* In the original it is magnesium; but Mr. Withering informs us, that it is now changed by the concurrence of professor Bergman, to manganesium, in order to prevent confusion from its similarity to magnesia.

Finally, in 1808 chemist Humphry Davy isolated what we now know as the element magnesium, but he originally dubbed it magnium:

These new substances will demand names; and on the same principles as I have named the bases of the fixed alkalies, potassium and sodium, I shall venture to denominate the metals from the alkaline earths barium, strontium, calcium, and magnium; the last of these words is undoubtedly objectionable, but magnesium has been already applied to metallic manganese, and would consequently have been an equivocal term.

But Davy recanted this decision, and by the 1812 publication of his Elements of Chemical Philosophy, he had changed the name to magnesium:

In my first paper on the decomposition of the earths, published in 1808, I called the metal from magnesia, magnium, fearing lest, if called magnesium, it should be confounded with the name formerly applied to manganese. The candid criticisms of some philosophical friends have induced me to apply the termination in the usual manner.

Now, over two hundred years later, the confusion over exactly what magnesium is has ended, and students of chemistry, unlike their predecessor, the Canon’s Yeoman, are no longer learning ignotum per ignocius.

Sources:

Black, Joseph. Letter to James Watt, 23 April 1781. Partners in Science: Letters of James Watt and Joseph Black. Eric Robinson and Douglas McKie, eds. London: Constable, 1970, 111.

Chaucer, Geoffrey. “The Canon Yeoman’s Tale.” The Canterbury Tales, 8.1448–66. Harvard’s Geoffrey Chaucer Website.

Coxe, William. Travels into Poland, Russia, Sweden, and Denmark, vol. 3 of 3. Dublin: S. Price, et al., 1784, 262. Eighteenth Century Collections Online.

Davy, Humphry. “Electro-Chemical Researches, on the Decomposition of the Earths; with Observations on the Metals Obtained from the Alkaline Earths, and on the Amalgam Procured from Ammonia.” Philosophical Transactions of the Royal Society, 98, 30 June 1808, 333–70 at 346.

———. Elements of Chemical Philosophy. Philadelphia: Bradford and Inskeep, 1812, 198. HathiTrust Digital Archive.

Miśkowiec, Pawel. “Name Game: The Naming History of the Chemical Elements—Part 1—from Antiquity till the End of 18th Century.” Foundations of Chemistry, 1 November 2022. DOI: 10.1007/s10698-022-09448-5.

Oxford English Dictionary, third edition, March 2000, s.v. magnesium, n., magnesia, n., magnium, n., magnes, n.

Plot, Robert. The Natural History of Oxford-shire. Oxford: Theater, 1677, 79. Early English Books Online.

Photo credit: Hiroaki Nakamura, 2007. Wikimedia Commons. Used under a Creative Commons Attribution-Share Alike 3.0 Unported license.