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
Anaerobic digestion streams and lakes released flammable gas. In 1778, the Italian physicist Alessandro Volta (1745-1827), the father of Electrochemistry, scientifically identified that gas as methane. In 1808 Sir Humphry Davy proved the presence of methane in the gases produced by cattle manure. The first known anaerobic digester was built in 1859 at a leper colony in Bombay in India. In 1895, the technology was developed in Exeter, England, where a septic tank was used to generate gas for the sewer gas destructor lamp, a type of gas lighting. Also in England, in 1904, the first dual-purpose tank for both sedimentation and