Note 24: In Denmark, sound films had been experimented with since 1908, but it was not until around 1923 that the engineers Axel Petersen and Arnold Poulsen tried their hand at sound film systems, and they succeeded in finding a workable method. It was demonstrated at a screening at Palads Teatret in Copenhagen on October 12, 1923. For the occasion, Petersen and Poulsen had recorded seven short films, and among these was a nonsense dialogue between Storm-og-Stille, alias Storm P. and Christian Arhoff. The comedian couple performed at that time with the number in "Cabaret Bonbonnieren" in Copenhagen. Petersen and Poulsen continued to improve their sound film system between 1924-27. Source: Filmen i Danmark, pp. 35-39, 38. - Filmens Hvem - Hvad - Hvor, 1967, pp. 182-184. - American inventors and engineers also tried to develop and improve Edison's sound film system, and various methods were patented and applied. Within the American cartoon industry, some of the animators at Pat Sullivan Studios had already in 1926 experimented with adding speech and sound to Felix the Cat film, but Sullivan rejected the attempts that it would increase production. Walt Disney therefore became the first to introduce the soundtrack to cartoons, namely with the Mickey Mouse film Steamboat Willie (1928). This technical and in a way also artistic achievement and innovation undoubtedly helped to ensure Walt Disney a leading position in both the domestic and foreign markets.