Per Teodor Cleve (10 February 1840 – 18 June 1905) was a Swedish chemist, biologist, mineralogist, oceanographer, and professor. He discovered the chemical elements holmium and thulium and helped isolate helium from the uranium ore cleveite. Cleve was born in Stockholm and became an assistant professor at the Uppsala University in 1860. He died several months after contracting pleurisy in 1904.
In 1874 Swedish chemist Per Theodor Cleve showed that didymium, then considered an element, was actually comprised of two elements, neodymium and praseodymium. In 1879 he discovered two previously unknown elements, which he named holmium (from the Latin for his home town, Stockholm), and thulium (from Thule, an ancient name for Scandinavia). In the same year his research showed that the properties and position in the periodic table of the element scandium matched the hypothetical element “ekaboron” predicted by Dmitri Mendeleev.
The raven — Korpen pharmacy
The raven refers to Korpen (the raven) pharmacy, located in the old town of Stockholm. This pharmacy was founded in 1674 by Jurgen Brandt, a German immigrant to Sweden. Stortorget is a small public square in Gamla Stan, the old town in central Stockholm, Sweden. It is the oldest square in Stockholm, the historical center on which the medieval urban conglomeration gradually came into being.