Ireland's rich but often overlooked contribution to modern science is highlighted this Wednesday at NUI Maynooth with the unveiling by the Minister for Education of a plaque honoring Father Nicholas Callan.
Born in 1799 and ordained in 1823, Father Callan was a pioneer in the study of electricity. He built what was then the world's most powerful battery in 1848. He invented the induction coil, a step-up transformer which converts low voltages to high voltages and which is central to modern electricity use. He also conducted unorthodox experiments. Father Callan liked to test the power of his new battery designs and induction coils by asking his students to take shocks from the devices. He knew if the new design was worth pursuing on the basis of how the students reacted. He demonstrated the power of a radical new battery before a large audience in Maynooth. Aside from creating huge sparks and burning up a few carbon rods, Father Callan placed a large turkey in circuit. The bird was instantly electrocuted.
His improved batteries meant he could create powerful electro-magnets, a novel scientific device in the early 1800s. The College Museum at Maynooth displays a number of these magnets including the great horseshoe magnet, 1.8 metres high and weighing 95 kg. This magnet could lift a phenomenal 1,000 kg.
Electro-magnetism provides the basis for both electricity generation and modern motors. Father Callan was somewhat ahead of his time when he began work on a motor driven by electricity. He had hoped to electrify the railway from Dublin to Dun Laoghaire and believed that a magnetic engine as powerful as a steam engine could be built for £250.
He experimented on several designs and developed working motors but had difficulty translating laboratory devices into full-scale systems. Batteries were the only source of electricity at the time and these were large, heavy and would slosh out acid if moved. He eventually abandoned his efforts on electric locomotion.
The induction coil ranks as Father Callan's most important discovery, and over many years he reworked and refined initial designs. He had discovered that if a low voltage running through a small coil was interrupted, it could induce a much larger voltage in a second adjacent coil. This discovery is what today allows power from a 12 volt car battery to be converted to the several thousand volts needed to arc electricity across a petrol engine's spark plugs.
Father Callan used various wire types and coil cores in his experiments. The secondary winding in his "giant coil", built in 1837 and housed in the Maynooth museum, is wound with an estimated 46 km of fine iron wire. It produced a spark 38 cm long, a record not exceeded until after 1890, and generated up to 600,000 volts, the highest man-made voltage available at the time.
Father Callan, who became professor of mathematics and natural philosophy at Maynooth, died in January 1864. To mark his contribution the Institute of Physics has erected a plaque in his honour at Maynooth, to be unveiled next Wednesday by the Minister for Education and Science, Mr Martin. There will also be a talk on Father Callan and his work by Dr Michael Cawley of Maynooth.