When was sound introduced?
Sound was introduced at the end of the 1920s.
Did films in the early days have sound?
No, they did not.
What form of films appeared as the old silent films were being replaced by spoken ones?
As the old silent films were being replaced by spoken ones, the musical cinema appeared.
What did scientists discover at the time?
At that time, scientists discovered that when a sequence of still pictures were set in motion, they could give the feeling of movement.
When were audiences able to see long films?
The audiences were able to see long films in the early 1910s.
When did the history of cinema begin?
The history of cinema began in the early 19th century.