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Tuesday, 5 February 2013

Muriatic acid, up against the wall

Before there were chemists, there were alchemists, and in the absence of a proper science of chemistry, the early alchemists made do with the equally proper mysteries of alchemy. And as with chemists who later emerged from the guff of alchemy, the commencing alchemist had a large vocabulary to learn.

It was unsystematic, but it was romantic, and while the names of the stock-in-trade of the alchemist gave you no clues about what something contained, they gave clear indications of how a substance was made — or sometimes, what it did, or was used for.

Instead of our methanoic acid, the alchemists spoke of formic acid, made from the destructive distillation of crushed ants (ants are formices in Latin, giving us the word 'formicate', meaning to rush around like ants), while a silver diammine solution was ammoniacal moon silver, and marsh gas was the name given to methane, though their combination has the same alarming result, no matter what you called them.  It goes BANG!

In the same way, the substance that we now call hydrochloric acid was referred to as muriatic acid, and this name is still common among metal workers who use the acid in priming metal surfaces for soldering, and brick layers use muriatic acid to clean up stray cement on brick walls.

In fact, to generations of chemists and building workers, this use on walls has been the well-known derivation, with the word well-known to be derived from the Latin murus, a wall, along with 'mural', a painting on a wall, the 'murenger', who was an obscure city officer charged with keeping the walls of a town or city in good order, and the word 'immure' meaning to wall-in, or surround with walls.

Shakespeare speaks once or twice of a 'mure' when he means a wall, and even once, in Troilus and Cressida, of the "strong immures" of Troy, wherein Helen may be found. He speaks more often, though, of those who are 'demure', a word which comes from the Old French meur, meaning calm or still. Somehow the word acquired the de- prefix, but it is just another of the mure words which has nothing at all to do with walls.

Sadly for generations of chemists, who have learned the derivation of 'muriatic' and passed it on, the word has even less to do with walls, and far more to do with the Latin muria, which is brine, or with muriaticus, which means pickled in brine. Hydrochloric acid was prepared from brine, and so could have been called briney acid, but in the arcane language of the alchemists, this had to be muriatic acid.

The expression also lives on as 'muriate', which can either be a lay term for 'chloride', or a verb, meaning to pickle in brine, but these days, 'muriated' only means a compound containing chlorine, or treated with chlorine, which is also derived from brine.

There are a couple of other names given to muriatic acid, like acidum salis, a Latin term meaning 'salt acid', but none of them has anything whatsoever to do with walls. Still, the generations of deceived chemists are no worse off than earlier generations who were deceived about antimony by Dr Johnson, often referred to as the Grand Cham of literature by his admirers.
(As a side issue, the original Grand Cham was the emperor of the Tartars, and there is a mild acid called tartaric acid, but that has nothing to do with this tale—and the acid has nothing to do with the Tartars, either: the name comes from Greek and nobody knows where they got it from.  Tartaric acid has a lot to do withe stereochemistry and Louis Pasteur, but that's another story.)
Now, where were we?  Ah, yes, with Lichfield's other famous son, the one who wasn't Charles Darwin's grandfather.  (You can see why I have to work hard to stay on course!)

According to our first lexicographer, an abbot added antimony to the feed of pigs, and they thrived on it. Then, according to the worthy dictionary maker, the abbot fed the same mix to his monks, who promptly sickened and died, causing the mix to be called antimonachus, bad for monks.

Like the theory of muriatic acid getting its name from the walls it cleaned, the antimony tale is untrue.

If you want to pull somebody's leg, though, think of the way formic acid is produced by the destructive distillation of crushed ants: while 'muriform' is a specialist word for botanists, 'murine' means having to do with mice, so with a bit of effort, if you want to persuade somebody that muriatic acid is prepared by the distillation of crushed mice, then why not?

In any case, they will be no worse off than the generations imposed upon by Dr Johnson, or the succession of chemists and artisans who thought muriatic acid was a product just made for walls.

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