Anders Celsius magnitude (a measure of brightness) of certain stars. This was the first attempt to measure the intensity of starlight with a tool other than the human eye. He made observations of eclipses and various astronomical objects and published catalogues of carefully determined magnitudes for some 300 stars using his own photometric system (mean error=0.4 mag). Celsius was the first to perform and publish careful experiments aiming at the definition of an international temperature scale on scientific grounds. In his Swedish paper "Observations of two persistent degrees on a thermometer" he reports on experiments to check that the freezing point is
Uppsala University as leader of the ecumenical movement. The university became prominent in the sciences in the 18th century with names such as the physician and botanist Carl Linnaeus (1707–1778), the father of biological and mineralogical taxonomy, and his numerous important pupils, the physicist and astronomer Anders Celsius (1701–1744), inventor of the Celsius scale the predecessor of the Celsius scale, and the chemist Torbern Bergman (1735–1784). Another scientist from this era is Emanuel Swedenborg (1688–1772), better remembered today as a religious mystic. Several of the elements were discovered by Uppsala scientists during this period or later. Jöns Jakob Berzelius, one of the