publishing one of the earliest examples of counter-current condensers. In 1791 he improved a condenser design of his father's by using the "counter-current principle". By requiring water coolant to flow uphill, the effectiveness of the condenser was increased. This principle was later used by Justus Liebig, in what is today usually referred to as a Liebig condenser. Awards Gadolin was knighted and is registered under number 245 in the Finnish House of Nobility. He was also awarded the Order of Saint Vladimir and the Order of Saint Anna. His heraldic device was: Argent, on a bend Azure with two mullets Or between a rose Gules and crystals Proper. Later life Johan Gadolin married first, at age 35, Hedvig Tihleman, with whom he had nine children. After his wife's death he married, at age 59, Ebba Palander. Gadolin retired as professor emeritus in 1822 at age 62, a mandatory age of retirement. He moved to a country estate where he lived for another 30 years. He died in Mynämäki, Finland on 15 August 1852. The Great Fire of Turku of 1827 started in a bakery and damaged or destroyed much of the town of Åbo. Gadolin's laboratory and collection of minerals near the cathedral were destroyed. References 1760 births 1852 deaths 18th-century chemists 18th-century Finnish people 19th-century chemists 19th-century Finnish people Corresponding members of the Saint Petersburg Academy of Sciences Discoverers of chemical elements Finnish chemists Finnish geologists Finnish mineralogists Members of the Royal Swedish Academy of Sciences People from Turku Rare earth scientists Swedish-speaking Finns Uppsala University alumni