Ignition was electric via combination Bunsen cell and induction coil. The mold is positioned within the induction coil. The Cockcroft-Walton multiplier can be used to multiply the voltage produced by an induction coil. This AC power is then fed into the induction coil. This value is determined by what induction coil is used with the piece. The induction coil was the first type of electrical transformer. The induction coil was first designed by Nicholas Callan in 1836. The induction coil is usually made of copper tubing and fluid coolant. Callan's induction coil was named an IEEE Milestone in 2006. The necessary high voltage, typically 10,000 volts, is supplied by an induction coil or transformer. Nicholas Callan figure in the study of electromagnetism, inventing the induction coil and "Maynooth Battery". The welding apparatus contains an induction coil that is energised with a radio-frequency electric current.