P. T. (Per Teodor) Cleve

Born in Stockholm in 1840, Per Teodor Cleve became one of Sweden’s best-known scientists of the late 19th century. He worked at Uppsala University, where he taught chemistry and built a reputation for careful research on the rare earth elements. He is especially remembered for helping distinguish substances that had previously been grouped together and for identifying the elements holmium and thulium.

Cleve’s interests went well beyond chemistry. He also studied geology and botany, and his scientific curiosity led him into marine research, where he examined plankton and the changing conditions of northern seas. That breadth makes his career stand out: he was not just a laboratory chemist, but a scientist interested in how the natural world fit together.

He died in 1905, but his name remains tied to both chemistry and earth science. Today he is remembered as a versatile researcher whose work helped deepen understanding of the elements while also contributing to the study of plants and the sea.