a flying-spot scanner to scan slides and film. Philo Farnsworth gave the world's first public demonstration of an all-electronic television system, using a live camera, at the Franklin Institute of Philadelphia on August 25, 1934, and for ten days afterwards. In Britain the EMI engineering team led by Isaac Shoenberg applied in 1932 for a patent for a new device they dubbed "the Emitron", which formed the heart of the cameras they designed for the BBC. In November 1936, a 405-line broadcasting service employing the Emitron began at studios in Alexandra Palace and transmitted from a specially built mast atop one of the Victorian building's towers. It alternated for a short time with Baird's mechanical system in adjoining studios but was more reliable and visibly superior. This was the world's first regular high-definition television service. The original American iconoscope was noisy, had a high ratio of interference to signal, and ultimately gave disappointing results, especially when compared to the high definition mechanical scanning systems then becoming available. The EMI team under the supervision of Isaac Shoenberg analyzed how the iconoscope (or Emitron) produces an electronic signal and concluded that its real efficiency was only about 5% of the theoretical maximum. They solved this problem by developing and patenting in 1934 two new camera tubes dubbed super-Emitron and CPS Emitron. The super-Emitron was between ten and fifteen times more sensitive than the original Emitron and iconoscope tubes and, in some cases, this ratio was considerably greater. It was used for an outside broadcasting by the BBC, for the first time, on Armistice Day 1937, when the general public could watch on a television set how the King laid a wreath at the Cenotaph. This was the first time that anyone could broadcast a live street scene from cameras installed on the roof of neighbouring buildings, because neither Farnsworth nor RCA could do the same before the 1939 New York World's Fair. On the other hand, in 1934, Zworykin shared some patent rights with the German licensee company Telefunken. The "image iconoscope" ("Superikonoskop" in Germany) was produced as a result of the collaboration. This tube is essentially identical to the super-Emitron. The production and commercialization of the super-Emitron and image iconoscope in Europe were not affected by the patent war between Zworykin and Farnsworth, because Dieckmann and Hell had priority in Germany for the invention of the image dissector, having submitted a