Nicholas Callan and experimental philosophy under Dr. Cornelius Denvir. He introduced the experimental method into his teaching, and had an interest in electricity and magnetism. Callan was ordained a priest in 1823 and went to Rome to study at Sapienza University, obtaining a doctorate in divinity in 1826. While in Rome he became acquainted with the work of the pioneers in electricity such as Luigi Galvani (1737–1798) who was a pioneer in modern obstetrics and Alessandro Volta (1745–1827) who is known especially for the development of the electric battery. In 1826, Callan returned to Maynooth as the new Professor of Natural Philosophy
University of Pavia that immediately preceded the Unification (1859–66). During the following centuries, through periods of both adversity and prosperity, the fame of the University of Pavia grew over the last years due to the large number of applicants. Throughout its history, the university has benefited from the presence of many learned men and distinguished scientists who wrote celebrated works and made important discoveries: mathematician Girolamo Cardano (born in Pavia, 1501–76), physicist Alessandro Volta (Pavia chair of natural philosophy 1769-1804), poet Ugo Foscolo (chair of Italian eloquence 1809-10). Three Nobel Prize winners also taught in Pavia: physician Camillo Golgi (at Pavia from 1861),