arsenical sulfosalt minerals, and selenous acid, extending the work of Berzelius. Elements In 1874 Nilson became professor of general and agricultural chemistry at Uppsala. From then on he could devote more time to research. He began working on rare earths such as euxenite and gadolinite, using methods of successive fractionation introduced by Nils Johan Berlin. One of his goals was to better understand the relationship of the newly discovered elements to the proposed periodic system. In 1879 Nilson separated out the oxide scandia. By doing so he discovered a new element, scandium, which he named for Scandinavia. The discovery was of particular importance because the existence of an element with such properties, "ekaboron", had been predicted by Mendeleev, based on his organization of the periodic system. Nilson's spectral analysis indicated a previously unreported pattern of lines. Per Theodor Cleve demonstrated the equivalence of Nilson's scandium and Mendeleev's hypothetical ekaboron. Nilson and Sven Otto Pettersson were the first to isolate titanium metal in a relatively pure form, extracting a 95% pure sample in 1887. Jöns Jacob Berzelius had extracted titanium metal in 1825, but only in a very impure form. In 1910 Matthew Hunter was finally able to produce 99.9% pure titanium metal, through his new Hunter process. Nilson also studied the gas density of metals which made it possible to determine the valence of various metals. Agriculture Nilson was professor of analytical chemistry at Uppsala from 1878 until 1883, when he became professor of chemistry of the Royal Swedish Academy of Agriculture and Forestry in Stockholm. As an agricultural chemist and Director of the Agricultural Chemical Experiment Station, he published nearly sixty papers concerning topics such as soils and manures. As a result of his inquiries many of the swamps of Gothland were drained and cultivated. The sugar beet was introduced and became a major crop, as chalky moors were treated with potash fertilizers. He also conducted studies of cow's milk and various plants for cattle fodder. Nilson was elected a foreign member of the Chemical Society of Great Britain on February 2, 1888. Nilson was a member of several other academies as well. He received several awards, including the Order of the Polar Star. References Further reading English excerpt English excerpt Swedish chemists Uppsala University alumni 1840 births 1899 deaths Discoverers of chemical elements 19th-century Swedish scientists 19th-century chemists Scandium Order of the Polar Star Rare earth scientists Members