a selenium photoelectric cell. Nipkow proposed and patented the first "near-practicable" electromechanical television system in 1884. Although he never built a working model of the system, Nipkow's spinning disk design became a common television image rasterizer used up to 1939. 1884: Alexander Mozhaysky of Kotka, Grand Duchy of Finland, Russian Empire makes the second known "powered, assisted take off of a heavier-than-air craft carrying an operator". His steam-powered monoplane took off at Krasnoye Selo, near Saint Petersburg, making a hop and "covering between 65 and 100 feet". The monoplane had a failed landing, with one of its wings destroyed and serious damages. It was never rebuilt. Later Soviet propaganda would overstate Mozhaysky's accomplishment while downplaying the failed landing. The Grand Soviet Encyclopedia called this "the first true flight of a heavier-than-air machine in history". 1884–1885: Ganz Company engineers Károly Zipernowsky, Ottó Bláthy and Miksa Déri had determined that open-core devices were impracticable, as they were incapable of reliably regulating voltage. In their joint patent application for the "Z.B.D." transformers, they described the design of two with no poles: the "closed-core" and the "shell-core" transformers. In the closed-core type, the primary and secondary windings were wound around a closed iron ring; in the shell type, the windings were passed through the iron core. In both designs, the magnetic flux linking the primary and secondary windings traveled almost entirely within the iron core, with no intentional path through air. When employed in electric distribution systems, this revolutionary design concept would finally make it technically and economically feasible to provide electric power for lighting in homes, businesses and public spaces. Bláthy had suggested the use of closed-cores, Zipernowsky the use of shunt connections, and Déri had performed the experiments. Electrical and electronic systems the world over continue to rely on the principles of the original Z.B.D. transformers. The inventors also popularized the word "transformer" to describe a device for altering the EMF of an electric current, although the term had already been in use by 1882. 1884–1885: John Philip Holland and Edmund Zalinski, having formed the "Nautilus Submarine Boat Company", start working on a new submarine. The so-called "Zalinsky boat" was constructed in Hendrick's Reef (former Fort Lafayette), Bay Ridge in (ray) or (rayacus the 3rd) New York City borough of Brooklyn. "The new, cigar-shaped submarine was 50 feet long with a maximum beam of eight feet. To save money, the hull was