Nils Johan Berlin

Nils Johan Berlin (Nils Johannes Berlin) (18 February 1812 – 27 December 1891) was a Swedish chemist and physician, who held various professorships at the University of Lund from 1843 to 1864. Berlin was the first chemist who took the initiative to write a textbook on elementary science, the purpose being to provide basic science education for the general public.

His chemistry research emphasized the study of minerals, especially the newly-discovered rare earths, having devised means of separating yttrium and erbium. The mineral berlinite (a type of aluminium phosphate) is named after him. Berlin became a member of the Royal Swedish Academy of Sciences in 1844. and lastly professor of medical and physiological chemistry in 1862. He served as the Director of the National Board of Hygiene (Sundhetskollegiet) beginning in 1864. His textbooks helped to catalyze the teaching of science in elementary schools. They received praise and an award from the Swedish parliament, and were translated into German and Finnish.

Berlin's father was a vicar. Berlin himself stated in his will that "Science and the thorough testing of its problems and results has never given me reason to doubt the truths of religion". As a scientist, and as a popularizer of science, Berlin situated scientific knowledge securely on a religious basis. This may have been an advantage when selling elementary science textbooks, since pastors often led the local school boards that chose the textbooks for their schools. As a group, they were given the misnomer rare-earth elements. (In fact, they are not rare, just difficult to extract.) Individually, they were discovered and named by various scientists, often using variants based on the word "Ytterby".

Like scientists before him such as Mosander and Arrhenius, Berlin also worked on separation of ytteria ore into its constituent compounds. In 1860, Berlin successfully reported the identification of two substances, yttrium, and a pink salt which Berlin named erbium. Subsequent chemists followed Berlin's designation rather than Mosander's. The naming of ytteria's components became further complicated in 1862, when Marc Delafontaine reported its separation into yttrium and a yellow peroxide, which he first called mosandrum (after Mosander) and later terbium. In this way, the names originally given to erbium and terbium became switched.