A saltpetre works or nitrary is a place of production of

potassium nitrate Potassium nitrate is a chemical compound with a sharp, salty, bitter taste and the chemical formula . It is a potassium salt of nitric acid. This salt consists of potassium cations and nitrate anions , and is therefore an alkali metal nit ...

saltpetre Potassium nitrate is a chemical compound with a sharp, salty, bitter taste and the chemical formula . It is a potassium salt of nitric acid. This salt consists of potassium cations and nitrate anions , and is therefore an alkali metal nitrate ...

used primarily for the manufacture of

gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...

. The saltpeter occurs naturally in certain places like the "Caves of Salnitre" (

Collbató Collbató () is a municipalities of Spain, municipality in the Comarques of Catalonia, ''comarca'' of the Baix Llobregat in Catalonia, Spain. It is situated on the southern slopes of Montserrat (mountain), Montserrat. The area has been inhabited ...

) known since the Neolithic. In the "Cova del Rat Penat",

guano Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a le ...

(in this case, bat excrements) deposited over thousands of years became saltpeter after being leached by the action of rainwater.

Manufacture

The process involved burial of excrements (human or animal) in the fields prepared for that purpose beside the nitraries, watering them and waiting until the leaching process did its job; after a certain time, operators gathered the saltpeter that "came out" to the ground surface by

efflorescence In chemistry, efflorescence (Derived from the Latin verb 'efflorescere' roughly meaning 'to flower') is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an i ...

. Then they transported it to be concentrated by

ebullition Boiling or ebullition is the rapid phase transition from liquid to gas or vapour; the reverse of boiling is condensation. Boiling occurs when a liquid is heated to its boiling point, so that the vapour pressure of the liquid is equal to the pre ...

in the boiler plant.

History

Besides " Montepellusanus", during the thirteenth century (and beyond) the only supply of

saltpeter Potassium nitrate is a chemical compound with a sharp, salty, bitter taste and the chemical formula . It is a potassium salt of nitric acid. This salt consists of potassium cations and nitrate anions , and is therefore an alkali metal nitrate ...

across Christian Europe (according to "De Alchimia" in 3 manuscripts of Michael Scot, 1180–1236) was "found in Spain in Aragonia in a certain mountain near the sea", (which can only be Catalonia): ''saraceni apellant ipsum borax et credunt quod sit alumen.'' ''Et in Hispania invenitur versus Argoniam in quodam monte juxta mare. et apellant ipsum hispani alumen acetum activum.'' In fact in 1561,

Elizabeth I of England Elizabeth I (7 September 153324 March 1603) was Queen of England and Ireland from 17 November 1558 until her death in 1603. She was the last and longest reigning monarch of the House of Tudor. Her eventful reign, and its effect on history ...

at war with

Philip II of Spain Philip II (21 May 152713 September 1598), sometimes known in Spain as Philip the Prudent (), was King of Spain from 1556, King of Portugal from 1580, and King of Naples and List of Sicilian monarchs, Sicily from 1554 until his death in 1598. He ...

, became unable to import the saltpeter (of which the

Kingdom of England The Kingdom of England was a sovereign state on the island of Great Britain from the late 9th century, when it was unified from various Heptarchy, Anglo-Saxon kingdoms, until 1 May 1707, when it united with Kingdom of Scotland, Scotland to f ...

had no home production), and had to pay "300 pounds gold" to the German captain Gerrard Honrik for the manual "Instructions for making salpeter to growe" (the secret of the "Feuerwerkbuch" -the nitraries-). In 1783,

Giuseppe Maria Giovene Giuseppe Maria Giovene (23 January 1753 – 2 January 1837) was an Italian archpriest, naturalist, agronomist, geologist, meteorologist, entomologist and ichthyologist. elogio-storico, pag. 9, note 8 He is best known for his studies on the "nitro ...

and

Alberto Fortis Alberto Fortis (9 or 11 November 1741 – 21 October 1803) was an Italian writer, naturalist and cartographer, citizen of Republic of Venice. Life His real name was Giovanni Battista Fortis (his religious name was ''Alberto'') and he was born i ...

together discovered a "natural nitrary" in a doline close to

Molfetta Molfetta (; Bari dialect, Molfettese: ) is a town located in the northern side of the Metropolitan City of Bari, Apulia, southern Italy. It has a well restored old city, and its own dialect. History The earliest local signs of permanent habit ...

, Italy, whose name is

Pulo di Molfetta Pulo di Molfetta is a doline located on the Murge plateau, in Apulia, southern Italy, around south-west of the city of Molfetta. It originated due to the collapse of the ceiling of one or more caves. It shares the local toponym ''pulo'' with ot ...

. The two scientists discovered that saltpeter formed inside the walls of the caves of the doline, under certain conditions of humidity and temperature. Prior to the discovery, nitraries were widespread all over the

Kingdom of Naples The Kingdom of Naples (; ; ), officially the Kingdom of Sicily, was a state that ruled the part of the Italian Peninsula south of the Papal States between 1282 and 1816. It was established by the War of the Sicilian Vespers (1282–1302). Until ...

. Manure was collected by the government and used to make

, which was a key ingredient for gunpowder. After the discovery, it was suggested that manure could be used for agriculture, in order to increase the production, rather than to make gunpowder. The discovery also generated issues; in particular, it was initially challenged by some scholars. Subsequently, chemist Giuseppe Vairo and his pupil Antonio Pitaro confirmed the discovery. This undoubtedly damaged producers of artificial saltpetre, and some scholars, most likely supported by the producers, tried to dismiss the discovery. Following the above discovery, naturalists sent by academies from all Europe came in large number to visit

, since the saltpeter was a fundamental ingredient in the production of

and these deposits were of considerable strategic interest. Soon, the government started to extract saltpetre from

and today the doline still contains the remains of the ancient plant used to extract saltpetre, making it a site of

industrial archaeology Industrial archaeology (IA) is the systematic study of material evidence associated with the Industry (manufacturing), industrial past. This evidence, collectively referred to as industrial heritage, includes buildings, machinery, artifacts, si ...

is currently not open to tourists. Shortly thereafter,

discovered that saltpetre also formed in other caves of

Apulia Apulia ( ), also known by its Italian language, Italian name Puglia (), is a Regions of Italy, region of Italy, located in the Southern Italy, southern peninsular section of the country, bordering the Adriatic Sea to the east, the Strait of Ot ...

. elogio-storico, pagg. 9-10 lettera-a-fortis-1784

References

Bibliography

* * * {{cite book , title=Lettera del Sig. canonico D. Giuseppe Maria Giovene, Vicario generale di Molfetta, al Sig. Abate Alberto Fortis, contenente varie osservazioni sulla nitrosità naturale della Puglia , author=Giuseppe Maria Giovene , date=7 August 1784 , location=

, url=https://books.google.com/books?id=hr3g4qMtHfsC&pg=PA309 , ref=lettera-a-fortis-1784 History of mining Nitrogen

Manufacture

History

See also

References

Bibliography