This short film from the Edison Manufacturing Company shows, as the title pretty much sums up, some trained cavalry horses. We see them lying down, stay there for a short while, before standing up again. During this action men from the cavalry stay on the back of the horse.
From its first film the Edison Manufacturing Company has produced over a thousand of short films. The most famous is probably 'The Great Train Robbery', considered to be the first western, even though it was shot in New Jersey. The Brothers Lumière and Georges Méliès did their part in developing the cinema in France, Edison and later D.W. Griffith were their American counterparts.
As for the single shot films from the Edison Manufacturing Company, they are all historically interesting. For some reason those from Lumière have a higher entertainment value, if that's what you should call it, but that does not mean they are more important. The Edison Manufacturing Company's short films existing out of multiple scenes belong to the highpoint of American cinema.