STEPLING, Joseph

S.’s father, originating from Westphalia, performed a service of Secretary at Emperor's embassy in Regensburg. He died shortly after the birth of his son. His mother returned with him to her native city in Prague. S. attended the Jesuit Latin School in Mala Strana near Prague, but due to his weak constitution could not join the Jesuit order. After that he studied philosophy and at the age of 17 with great precision documented the lunar eclipse on 28 March 1733. The same year he managed to join the Jesuit order in Brno. From 1735 to 1738 he studied at the Jesuit College in Olomouc and continued his studies in Graz. He got acquainted with Leibnitz mathematics in Christian von Wolff‘s book and began to explore it. Before S. began to study theology in 1743 in Prague, he taught mathematics and physics at various Jesuit schools. There are contemporary records of that time about his attempt to install electricity through a 800 m long chain in 1745 in Klementinum. After completion of theology study in 1747 he also began – in addition to teaching mathematics and physics his Jesuit brothers – dealing with the astronomical, meteorological and geophysical observations. He changed the Klementinski tower, built in 1721 into an observatory, instruments and fittings of which he brought up to the latest scientific standard. Since 1752 he began collecting systematic and regular records of air pressure, temperature and precipitation, which were published later. Thus he established the tradition of continuous climate observations in Prague. After the Gerard van Swietens university reform in 1752, S. assumed the post of Director of philosophical studies. At that time S. was in contact with a large number of international scholars. Protestants Christian von Wolff and Leonhard Euler, living in Halle were also among his correspondents. Although the Jesuits supported Aristotelian scholastic tradition, S. and Wolff discussed the principles of the planets moving according to Newton’s principles. As a supporter of the Aristotelian philosophy S. also rejected Ruđer → Bošković philosophy. He expressed support to Newton's principles book, issued by his pupil Jan Tesánek (1728-1788). The book contained a commentary on Newton's physics and evidence of a differential and integral calculus (1785). S. laid the foundation for it in his classes and by issuing the textbook on infinitesimal calculus in 1765. S. was also the first strong supporter of the introduction of lightning conductor, as he knew the benefits of grounding lightning conductor, produced by Prokop →Diviš in 1754. In 1770 the patriotic-economic association in the Kingdom of Poland asked him for an assessment of Johann Albert Heinrich Reimarus' works on the description of the lightning conductors construction in Hamburg. In his comment S. singled out the ball lightning and the risk of secondary effects of the induced voltage.