Firesetting has been widely used for hard-rock breakage purposes form the 5th millennium B.C up to the 19th century.
Pliny the Elder during the first century A.C., in The Natural History (XXXIII, 21): "In mining either by shaft or by gallery, barriers of silex [flint?] are met with, which have to be driven asunder by the aid of fire and vinegar"
From Punic Wars to Mining Extraction
Pliny the Elder, in The Natural History (XXIII, 27): "Poured upon rocks in considerable quantities, it has the effect of splitting them, when the action of fire alone has been unable to produce any effect thereon. As a seasoning, too, there is no kind that is more agreeable than vinegar, or that has a greater tendency to heighten the flavour of food".
In the 16th century, Georgius Agricola wrote "Applying this principle [editor’s note: firesetting], Hannibal, the Carthaginian General, imitating the Spanish miners, overcame the hardness of the Alps by the use of vinegar and fire".
Authors first thought this story was invented by the Romans to account for their defeat by Hannibal.
Hannibal crossed the Alps in 218 B.C. Livy (59 B.C. – A.D. 17), the famous Roman historian who wrote a monumental History of Rome and the Roman People seems to be the first to talk about this. In connection with Hannibal's crossing of the Alps, he wrote: "They set fire to it (the timber) when a wind had arisen suitable to excite the fire, then when the rock was hot it was crumbled by pouring on vinegar (infuso aceto). In this manner the cliff heated by the fire was broken by iron tools, and the declivities eased by turnings, so that not only the beasts of burden but also the elephants could be led down." (The History of Rome, XXI, 37)
By Pliny's time (23-79 A.D.) it had become an established fact. It has to be reminded that myths were part of the Roman life and picturing.
The Debate Around The Vinegar’s Breaking Potential
In their commentaries about Agricola’s masterpiece, De re Metallica, Herbert Clark and Lou Henry Hoover wrote: "by Pliny's time the vinegar was generally accepted, and has been ceaselessly debated ever since. Nor has the myth ceased to grow, despite the remarks of Gibbon, Lavalette, and others." (Georgius Agricola, De re Metallica, Book V, Herbert Clark Hoover and Lou Henry Hoover’s traduction, note 14 page 118, Dover Publication Inc., New York, 1950).
Several authors argued that vinegar was part of the current supply of the armies in Antiquity. Its presence should then not be surprising. Spreading vinegar on heated rock would have aimed at triggering a fragmentation process by thermal shock. Diodorus Siculus wrote about such a method applied to mining in its description of firesetting in use in Nubian gold mines. Moreover, for Pliny the Elder vinegar was deemed to be a "cold liquid".
Other authors claimed the rock to be pure limestone, or even snow, while Eugene Hennebert (1826-1896), in Histoire d'Annibal (II, p. 253) gave its own analysis as a soldier and as an engineer specialized in the explosive devices. After having set that the action of regular vinegar cannot break rock, he put forth a hypothesis: Hannibal must have possessed some mysterious high explosive coming from the Phoenicians. Hennebert’s hypothesis was taken up by William O’Connor Morris in Hannibal: Soldier, Stateman, Patriot (New-York: GP Putman’s Sons, 1903).
The Long-Lasting Story Of Two Corrupted Words?
My personal favorite explanation is… that an error was made when copying Livy’s original text, before Pliny wrote the Natural History, 20 years later. Remember that books were copied by hand."Although there are grammatical objections" (Hoover, 1950), it is conceivable that "infuso aceto" (vinegar) was originally "infosso acuto". This would make some sense considering both words belong to the earth and rock-related lexical field:
- "Infosso" as the past participle form of "infodio": "digging" (Junius Moderatus Columella, 3,13,5), "bury" (Procius Cato, in De Agricultura 37,3), "insert something" (Pliny the Elder 12,2)
- "Acuto" (acutare) a transitive verb meaning "to sharpen" (Flavius Vegetius Renatus, in Ars veterinaria sive mulomedicina, 1,22,4)
A small mistake that make vinegar producers’ fortune as spreading vinegar on heated rocks became a common practice in the mines for centuries!