An Irishwoman's Diary
The small priest must have seemed like an Irish Frankenstein - experimenting with electricity in his basement laboratory at Maynooth college, dishing out almighty electric shocks to unsuspecting volunteers, and electrocuting turkeys. Yet Rev Nicholas Callan (1799-1864) was one of Ireland's great inventors. He invented the induction coil, built the most powerful batteries and electromagnets of his time, and earned an entry in the Encyclopaedia Britannica. Now a new museum at Maynooth college celebrates his achievements.
Callan was born in Dromiskin, Co Louth, and studied for the priesthood in Rome. There he learned about Alessandro Volta's battery, a chemical device that could store electricity. Back in Maynooth in 1826, and with funding from friends and family, Callan began designing better batteries. Electricity was still something of a toy, but he realised that with powerful batteries it could be put to practical and commercial use.
His most successful battery design sold commercially in London as the Maynooth Battery. The Duracell of its time, it was long-lasting and powerful, hard-wearing and cheap. Where other batteries used costly platinum, Callan found a way of using cheap cast-iron: his positive plate was a small cast-iron box filled with strong acid; in it sat a porous pot, also filled with acid, and containing a zinc sheet as the negative plate.
Callan would connect large numbers of these battery cells, and once joined 577 together, using 30 gallons of acid, to make what was then the world's largest battery.
Since there were no instruments yet to measure current or voltage, Callan assessed his batteries by the weight they could lift when connected to an electromagnet. His best effort lifted two tons and was noted in the Encyclopaedia Britannica (8th edition). When Callan reported it in the Annals of Electricity, a London professor came over to witness the spectacle, and was said to be incredulous.
In 1836 Callan made his most important discovery: the induction coil. He wound two long wires around a large electromagnet and connected one wire to a battery. But when he interrupted the current from the battery, he got spectacular sparks between the ends of the second, unconnected coil.
It was the world's first transformer. He had induced a high voltage in the second wire, starting with a low voltage in the adjacent first wire. And the faster he interrupted the current, the bigger the spark. In 1837 he produced his giant induction machine: using a mechanism from a clock to interrupt the current 20 times a second, it generated 15-inch sparks, an estimated 600,000 volts and the largest artificial bolt of electricity then seen.
The coils were made from miles of hand-drawn metal wire which Callan himself laboriously insulated by hand, using tape and wax. A model was sent to London for demonstrations and similar machines soon appeared in Europe and North America.
Shock for bishop
The voltmeter had not been invented, so to measure the power of his induction coils, Callan improvised. Something of a showman, he would electrocute large birds, or use chains of volunteers holding hands. One almighty shock rendered Michael Walsh, a future archbishop of Dublin, unconscious, after which the college asked Callan to limit his experiments.
Callan's induction coil is used today in car ignitions, for example, to generate powerful voltages from a low-voltage battery and produce sparks to cross the gap in the spark plugs.
In 1838 this intrepid priest stumbled on the principle of the self-exciting dynamo. Simply by moving his electromagnet in Earth's magnetic field, he found he could produce electricity without a battery. The effect was feeble so he never pursued it, and the discovery is generally credited to Werner Siemens in 1866.
The Maynooth professor probably also had one of the world's first electric vehicles, because in 1837 he was using a primitive electric motor to drive a small trolley around his lab. With great foresight he also predicted electric lighting, at a time when oil was still widely used and gas was the next new thing.
He even proposed using batteries instead of steam locomotives on the new-fangled railways. Callan later realised his batteries were not powerful enough, and indeed, it took another hundred years before battery-powered trains invented by another Irishman, James Drumm, were used on Dublin railways.
Callan's ingenuity knew no bounds and in 1853 he patented an early form of galvanisation using a lead-tin mix to protect iron from rusting, something he discovered when he was experimenting with various battery designs.
His 1853 patent document, complete with an enormous royal seal from Queen Victoria, is displayed at Maynooth's new museum, along with many of his induction coils and batteries, and a recreation of his laboratory.
There is a wonderfully varied collection of other scientific instruments, including equipment which Marconi used in 1898 to relay the results of Dun Laoghaire's yacht race - the world's first sports radio broadcast! - as well as surveying instruments, magic lantern slides and many beautiful, Irish-made scientific instruments.
The museum, which also has an ecclesiastical section, is open on Tuesdays, Thursdays and Sundays from 2 p.m. to 4 p.m. More information about Callan and the museum can be found on the college website: www.may.ie/museum.