Father Nicholas Joseph Callan (22 December 1799 – 10 January 1864) was an Irish priest and scientist from Darver, County Louth, Ireland. He was Professor of Natural Philosophy in Maynooth College in County Kildare from 1834, and is best known for his work on the induction coil. Early life and education He attended school at an academy in Dundalk. His local parish priest, Father Andrew Levins, then took him in hand as an altar boy and Mass server, and saw him start the priesthood at Navan seminary. He entered Maynooth College in 1816. In his third year at Maynooth, Callan studied natural 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 bioelectricity 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 (now called physics), where he also began working with electricity in his basement laboratory at the college. Induction coil Influenced by William Sturgeon and Michael Faraday, Callan began work on the idea of the induction coil in 1834. He invented the first induction coil in 1836. An induction coil produces an intermittent high-voltage alternating current from a low-voltage direct current supply. It has a primary coil consisting of a few turns of thick wire wound around an iron core and subjected to a low voltage (usually from a battery). Wound on top of this is a secondary coil made up of many turns of thin wire. An iron armature and make-and-break mechanism repeatedly interrupts the current to the primary coil, producing a high-voltage, rapidly alternating current in the secondary circuit. Callan invented the induction coil because he needed to generate a higher level of electricity than currently available. He took a bar of soft iron, about long, and wrapped it around with two lengths of copper wire, each about long. Callan connected the beginning of the first coil to the beginning of the second. Finally, he connected a battery, much smaller than the enormous contrivance just described, to the