 He was also the author of an ethnographical study of Southern Slavic peoples called "Slavus Venedus Illyricus".From 1774 to 1787, he was the secretary of the Carniolan Agricultural Society, members of which were also other prominent members of the Enlightenment, such as Sigmund Zois, Blaž Kumerdej, Gabriel Gruber, Peter Pavel Glavar, and Anton Tomaž Linhart.As a botanist Hacquet wrote a book on alpine flora from Carniola called "Plantae alpinae Carniolicae".