The Drum and the Bugle
At six o'clock in the morning during winter and five o'clock for the rest of the year, somebody would beat the drum or blow the bugle. This would also be repeated at nine o'clock at night through the whole year. The drum would only be used if it was dry, and the bugle would be used if it were wet.
The drum and the bugle were used well into the 19th century, but then they were not used so often because clocks started to become more popular.