After moving to Bologne he often visited the University physics laboratory and attended lectures, reinforcing his urge to experiment. At twenty, while on a summer holiday, he read a detailed description of Hertz’s experiments, inspiring his greatest work. He continued to improve upon others’ earlier designs of tubes between 1894 and 1895. His work was so original that on 7/07/1897 he was issued an Italian patent for "improvements in the transmission of impulses and of the relative apparatus." Marconi applied for patents in all the principal nations of the world.