between the gap in a nearby metal loop antenna, between 1886 and 1888 Hertz would conduct a series of scientific experiments that would validate Maxwell's theory. Hertz published his results in a series of papers between 1887 and 1890, and again in complete book form in 1893. The first of the papers published, "On Very Rapid Electric Oscillations", gives an account of the chronological course of his investigation, as far as it was carried out up to the end of the year 1886 and the beginning of 1887. For the first time, electromagnetic radio waves ("Hertzian waves") were intentionally and unequivocally proven to have been transmitted through free space by a spark-gap device, and detected over a short distance. Hertz was able to have some control over the frequencies of his radiated waves by altering the inductance and capacitance of his transmitting and receiving antennas. He focused the electromagnetic waves using a corner reflector and a parabolic reflector, to demonstrate that radio behaved the same as light, as Maxwell's electromagnetic theory had predicted more than 20 years earlier. Hertz did not devise a system for practical utilization of electromagnetic waves, nor did he describe any potential applications of the technology. Hertz was asked by his students at the University of Bonn what use there might be for these waves. He replied, "It's of no use whatsoever. This is just an experiment that proves Maestro Maxwell was right, we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there." Hertz died in 1894, and the art of radio wave communication was left to others to implement into a practical form. After Hertz's experiments, Sir William Crookes published an article in February 1892 in The Fortnightly Review on 'Some possibilities of electricity' with his thoughts on possibility of wireless communication based on the research of Lodge and Hertz, and the American physicist Amos Emerson Dolbear brought similar attention to the idea. Pre-Hertz radio wave detection During 1789–91, Luigi Galvani noticed that a spark generated nearby caused a convulsion in a frog's leg being touched by a scalpel. In different experiments, he noticed contractions in frogs' legs caused by lightning and a luminous discharge from a charged Leyden jar that disappeared over time and was renewed whenever a spark occurred nearby. Joseph Henry observed magnetised needles from lightning in the early 1840s. In 1852 Samuel