Celsius that used this scale. In 1744, coincident with the death of Anders Celsius, the Swedish botanist Carl Linnaeus (1707–1778) reversed Celsius's scale. His custom-made "linnaeus-thermometer", for use in his greenhouses, was made by Daniel Ekström, Sweden's leading maker of scientific instruments at the time, whose workshop was located in the basement of the Stockholm observatory. As often happened in this age before modern communications, numerous physicists, scientists, and instrument makers are credited with having independently developed this same scale; among them were Pehr Elvius, the secretary of the Royal Swedish Academy of Sciences (which had an instrument workshop) and with
Christian Mayer (astronomer) of mathematics and physics at Heidelberg. By this age, however, he had developed a strong interest in astronomy. He was appointed Court Astronomer at Mannheim, and was tasked with selecting the instruments for the new observatories at Schwetzingen and Mannheim. With these completed, he was able to pursue his astronomical studies, and published numerous works. In 1769 he was invited to St. Petersburg to observe the transit of Venus, which he did together with Anders Johan Lexell. In 1773, the Jesuit order was dissolved by Pope Clement XIV, and consequently he was removed as Court Astronomer. However he was still