He's best known for his role in the so-called Altamuran Revolution (1799), advocating peace[2] and helping the refugees, who had fled Altamura after the battle with the Sanfedisti, to be allowed in Terlizzi.

[3] He was also appointed as rector of the University of Altamura, established in 1748 by his predecessor Marcello Papiniano Cusano, with the purpose of promoting, together with the teachings of his friend Antonio Genovesi, the study of natural sciences with a special focus on agriculture.

The university included courses ranging from economics and law to scientific subjects, with the help of the vicar Vitangelo Bisceglia, who promoted in particular the study of botany thanks to research conducted with Vincenzo Petagna and Michele Tenore.

The reform of the University of Altamura promoted by de Gemmis was intended to stimulate economic development by teaching young people the new science applied to production systems.

Many students from neighboring cities attended the new courses of botany, of mineralogy, of chemistry and physics, with the help of academic and mathematician Luca de Samuele Cagnazzi.