A graduation tower (occasionally referred to as a thorn house) is a structure used in the production of

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quanti ...

which removes

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...

from a saline solution by evaporation, increasing its concentration of mineral salts. The tower consists of a wooden wall-like frame stuffed with bundles of brushwood (typically

blackthorn ''Prunus spinosa'', called blackthorn or sloe, is a species of flowering plant in the rose family Rosaceae. The species is native to Europe, western Asia, and regionally in northwest Africa. It is locally naturalized in New Zealand, Tasmania ...

) which have to be changed about every 5 to 10 years as they become encrusted with mineral deposits over time. The salt water runs down the tower and partly evaporates; at the same time some minerals from the solution are left behind on the brushwood twigs. Graduation towers can be found in a number of spa towns, primarily in

Germany Germany, officially the Federal Republic of Germany (FRG),, is a country in Central Europe. It is the most populous member state of the European Union. Germany lies between the Baltic and North Sea to the north and the Alps to the sou ...

but also

Poland Poland, officially the Republic of Poland, , is a country in Central Europe. Poland is divided into Voivodeships of Poland, sixteen voivodeships and is the fifth most populous member state of the European Union (EU), with over 38 mill ...

and Austria. The mineral-rich water droplets in the air are regarded as having beneficial health effects similar to that of breathing in

sea air Sea air has traditionally been thought to offer health benefits associated with its unique odor, which Victorians attributed to ozone. More recently, it has been determined that the chemical responsible for much of the odor in air along certain se ...

. A large complex of graduation towers is located in Ciechocinek and

Inowrocław Inowrocław (; german: Hohensalza; before 1904: Inowrazlaw; archaic: Jungleslau) is a city in central Poland with a total population of 70,713 in December 2021. It is situated in the Kuyavian-Pomeranian Voivodeship since 1999, previously in the B ...

.Affelt, Waldemar:
Wooden masterwork of saline in Ciechocinek, Poland
'', in: Santiago Huerta (ed.): ''Proceedings of the First International Congress on Construction History: Madrid, 20th–24th January 2003'', Instituto Juan de Herrera, Madrid 2003, This entirely wooden construction in Ciechocinek was erected in the 19th century by

Stanisław Staszic Stanisław Wawrzyniec Staszic (baptised 6 November 1755 – 20 January 1826) was a leading figure in the Polish Enlightenment: a Catholic priest, philosopher, geologist, writer, poet, translator and statesman. A physiocrat, monist, pan-Slav ...

. The complex consists of three graduation towers with a total length of over 2 km. Many tourists visit it for health reasons.

Gallery

File:Bad_Duerrenberg_Gradierwerk_S.jpg, Graduation tower in Bad Dürrenberg File:Gradierwerk.JPG, 18th-century schematic File:Aerozol pod teznia.JPG,

Aerosol An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of ant ...

at Ciechocinek facility File:Gradierwerk Bad Kreuznach 07.jpg, Graduation towers in

Bad Kreuznach Bad Kreuznach () is a town in the Bad Kreuznach district in Rhineland-Palatinate, Germany. It is a spa town, most well known for its medieval bridge dating from around 1300, the Alte Nahebrücke, which is one of the few remaining bridges in the ...

Partial list of towns and cities with graduation towers

With years of initial construction where available. Does not include modern indoor facilities found in some spas. ;France * Saulnot (16th century) * Arc-et-Senans (1775) ;Germany *

Bad Dürkheim Bad Dürkheim () is a spa town in the Rhine-Neckar urban agglomeration, and is the seat of the Bad Dürkheim district in Rhineland-Palatinate, Germany. Geography Location Bad Dürkheim lies at the edge of Palatinate Forest on the German W ...

(1736) * Bad Dürrenberg * Bad Essen *

Bad Karlshafen Bad Karlshafen () is a baroque, thermal salt spa town in the district of Kassel, in Hesse, Germany. It has 2300 inhabitants in the main ward of Bad Karlshafen, and a further 1900 in the medieval village of Helmarshausen. It is situated at the co ...

(1986) *

Bad Kissingen Bad Kissingen is a German spa town in the Bavarian region of Lower Franconia and seat of the district Bad Kissingen. Situated to the south of the Rhön Mountains on the Franconian Saale river, it is one of the health resorts, which bec ...

(16th century) *

(1732) *

Bad Kösen Bad Kösen () is a spa town on the Saale river in the small wine-growing region of Saale-Unstrut, Germany. It is a former municipality in the Burgenlandkreis district, in Saxony-Anhalt. Bad Kösen has a population of around 5,300. Since 1 Janua ...

* Bad Münster am Stein (1729) *

Bad Nauheim Bad Nauheim is a town in the Wetteraukreis district of Hesse state of Germany. As of 2020, Bad Nauheim has a population of 32,493. The town is approximately north of Frankfurt am Main, on the east edge of the Taunus mountain range. It is a worl ...

Bad Oeynhausen Bad Oeynhausen () is a spa town on the southern edge of the Wiehengebirge in the district of Minden-Lübbecke in the East-Westphalia-Lippe region of North Rhine-Westphalia, Germany. The closest larger towns are Bielefeld (39 kilometres southwest ...

Bad Orb Bad Orb (; " Thermae on the Orb River") is a spa town in the Main-Kinzig-Kreis district of Hesse, Germany. It is situated east of Hanau between the forested hills of the Spessart. Bad Orb has a population of over 10,000. Its economy is dom ...

(1806) *

Bad Rappenau Bad Rappenau (; South Franconian: ''Rappene'') is a city municipality in the district of Heilbronn in Baden-Württemberg in southern Germany. It is situated about northwest of Heilbronn. Geography Bad Rappenau is situated in the northeastern ...

(2008) *

Bad Reichenhall Bad Reichenhall ( Central Bavarian: ''Reichahoi'') is a spa town, and administrative center of the Berchtesgadener Land district in Upper Bavaria, Germany. It is located near Salzburg in a basin encircled by the Chiemgau Alps (including Mount Sta ...

(1911) * Bad Rothenfelde (1777) *Bad Salzelmen (part of

Schönebeck Schönebeck (), officially Schönebeck (Elbe), is a town in the district of Salzlandkreis, in Saxony-Anhalt, Germany. It is situated on the left bank of the Elbe, approx. southeast of Magdeburg. For much of the twentieth century it was noted ...

, 1756) *Bad Salzhausen (around 1600) *

Bad Salzuflen Bad Salzuflen is a town and thermal spa resort in the Lippe district of North Rhine-Westphalia, Germany. At the end of 2013, it had 52,121 inhabitants. Geography Bad Salzuflen lies on the eastern edge of the Ravensberg Basin, at the confluence ...

(18th century) *

Bad Salzungen Bad Salzungen () is a town in Thuringia, Germany. It is the capital of the Wartburgkreis district. Geography Location Bad Salzungen is situated on the river Werra, east of Tiefenort and south of Eisenach. Divisions In July 2018 the former ...

Bad Sassendorf Bad Sassendorf is a municipality in the district of Soest, in North Rhine-Westphalia, Germany. History From the 8th century, the area around the Soester plain was under the Merovingian dynasty. The name “Sassendorf” indicates that it was a ...

*Bad Soden (part of

Bad Soden-Salmünster Bad Soden-Salmünster () is a town in the Main-Kinzig district, in Hesse, Germany. It is situated on the river Kinzig, between Fulda and Hanau. It has a population of around 13,000. Geography Location The municipality is located on both sides o ...

, 2006) *

Bad Sooden-Allendorf Bad Sooden-Allendorf is a spa town in the Werra-Meißner-Kreis in Hesse, Germany. Geography Location The spa town of Bad Sooden-Allendorf lies in the Werra valley near the Hoher Meißner, right on the boundary with Thuringia, almost at Germany's ...

* Bad Staffelstein *Eibach (part of

Dillenburg Dillenburg, officially Oranienstadt Dillenburg, is a town in Hesse's Gießen region in Germany. The town was formerly the seat of the old Dillkreis district, which is now part of the Lahn-Dill-Kreis. The town lies on the German-Dutch holiday road ...

, 2004) *

Hamm Hamm (, Latin: ''Hammona'') is a city in North Rhine-Westphalia, Germany. It is located in the northeastern part of the Ruhr area. As of 2016 its population was 179,397. The city is situated between the A1 motorway and A2 motorway. Hamm railwa ...

(2008) *

Lüneburg Lüneburg (officially the ''Hanseatic City of Lüneburg'', German: ''Hansestadt Lüneburg'', , Low German ''Lümborg'', Latin ''Luneburgum'' or ''Lunaburgum'', Old High German ''Luneburc'', Old Saxon ''Hliuni'', Polabian ''Glain''), also calle ...

(1907) *

Rheine Rheine () is a city in the district of Steinfurt (district), Steinfurt in Westphalia, Germany. It is the largest city in the district and the location of Rheine Air Base. Geography Rheine is on the river Ems (river), Ems, approx. north of Münst ...

(''Saline Gottesgabe'') *

Salzgitter-Bad With a population of about 20,000, Salzgitter-Bad is the second biggest quarter of the Germany, German city Salzgitter in Lower Saxony. Salzgitter's name derives from it; the quarter is regarded as the historical and cultural centre of Salzgitter. ...

(2009) *

Salzkotten Salzkotten is a town in the district of Paderborn, in North Rhine-Westphalia, Germany. The name Salzkotten (in English, "Salt cottages") is based in the former salt production, which gave Salzkotten its raison d'être. Salt was found in the salt ...

;Poland * Ciechocinek (three towers: 1824 to 1859) *

Chorzów Chorzów ( ; ; german: link=no, Königshütte ; szl, Chorzōw) is a city in the Silesia region of southern Poland, near Katowice. Chorzów is one of the central cities of the Upper Silesian Metropolitan Union – a metropolis with a population ...

Gliwice Gliwice (; german: Gleiwitz) is a city in Upper Silesia, in southern Poland. The city is located in the Silesian Highlands, on the Kłodnica river (a tributary of the Oder). It lies approximately 25 km west from Katowice, the regional cap ...

Gołdap Gołdap ( or variant ''Goldapp''; lt, Geldupė, Geldapė, Galdapė) is a town in northeastern Poland, in the region of Masuria, seat of Gołdap County in the Warmian-Masurian Voivodeship. It is located on the Gołdapa River, between the Szeskie ...

(since 2014) *

Grudziądz Grudziądz ( la, Graudentum, Graudentium, german: Graudenz) is a city in northern Poland, with 92,552 inhabitants (2021). Located on the Vistula River, it lies within the Kuyavian-Pomeranian Voivodeship and is the fourth-largest city in its pro ...

(since 2006) *

(since 2001) *

Katowice Katowice ( , , ; szl, Katowicy; german: Kattowitz, yi, קאַטעוויץ, Kattevitz) is the capital city of the Silesian Voivodeship in southern Poland and the central city of the Upper Silesian metropolitan area. It is the 11th most populo ...

(since 2018) *

Konstancin-Jeziorna Konstancin-Jeziorna is a town in Piaseczno County, Masovian Voivodeship, Poland, with 17,566 inhabitants (as of March 2011, according to GUS). It is located about south of downtown Warsaw and is a part of the metropolitan area of that city. ...

(since 1978) *

Kraków Kraków (), or Cracow, is the second-largest and one of the oldest cities in Poland. Situated on the Vistula River in Lesser Poland Voivodeship, the city dates back to the seventh century. Kraków was the official capital of Poland until 159 ...

(two towers: in Nowa Huta and Bagry districts, since 2021) *

Latoszyn Latoszyn is a village in the administrative district of Gmina Dębica, within Dębica County, Subcarpathian Voivodeship, in south-eastern Poland. It lies approximately south-west of Dębica Dębica (; yi, דעמביץ ''Dembitz'') is a town ...

* Radlin (since 2014) * Rabka-Zdrój *

Rymanów-Zdrój Rymanów-Zdrój (; uk, Риманів-Здрій) is a village and a spa in southern Poland, in Subcarpathian Voivodeship, in Krosno County. Location Rymanów-Zdrój lies south of the town of Rymanów, in the valley of the river Tabor surroun ...

Ustka Ustka (pronounced ; csb, Ùskô; german: Stolpmünde) is a spa town in the Middle Pomerania region of northern Poland with 17,100 inhabitants (2001). It is part of Słupsk County in Pomeranian Voivodeship. It is located on the Slovincian Coast on ...

(since July 2020) *

Wieliczka Wieliczka (German: ''Groß Salze'', Latin: ''Magnum Sal'') is a historic town in southern Poland, situated within the Kraków metropolitan area in Lesser Poland Voivodeship since 1999. The town was initially founded in 1290 by Premislaus II of ...

(since 2014) ;Romania *

Baile Figa Baile ("dance" in Spanish) may refer to: * Baile (Spanish play), a Spanish dramatic form * Baile funk, a type of dance music from Rio de Janeiro * Baile, the Irish Gaelic word for a town, usually anglicized as "bally" or "balla" * Baile, the Scot ...

(2020)

References

External links

__NOTOC__ {{authority control Mining equipment Salt production