On his return to Vienna in 1756 he became famous as teacher and composer, in 1759 he was appointed conductor to the private band of Count Morzin, for whom he wrote several orchestral works (including a symphony in D major erroneously called his first), and in 1760 he was promoted to the sub-directorship of Prince Paul Esterhazy's Kapelle, at that time the best in Austria.
Amongst the numerous scientific associations are the central statistical department, and the Budapest communal bureau of statistics, which under the directorship of Dr Joseph de KiirOsy has gained a European reputation.
On assuming the directorship of the Nautical Almanac he became very strongly impressed with the diversity existing in the values of the elements and constants of astronomy adopted by different astronomers, and the injurious effect which it exercised on the precision and symmetry of much astronomical work.
In 1813 he was appointed professor of chemistry at the Lycee Charlemagne, and subsequently undertook the directorship of the Gobelins tapestry works, where he carried out his researches on colour contrasts (De la loi du contraste simultane des couleurs, 1839).
He resigned the secretaryship of the Treasury in Dec. 1918 and the directorship of railways the following January.