Answer:
The symbol of the ebony clock appears used by Edgar Allan Poe in his short gothic story "The Masque of the Red Death", which was pubished in 1842.
"The Masque of the Red Death" narrates the story of Prince Prospero and a group of his closest noble friends, who, in an attempt to save themselves from a plague known as the Red Death, which has been decimating the people of Prospero´s land, close themselves in in Prospero´s luxurios abbey. A party ensues as these people wait for the plague to end, and they fluctuate between seven rooms, each with a specific color to it. However, none dare enter the seventh room, which is coincidentaly colored black, and which has an ebony clock. Every hour, this clock chimes the time and as it does, the people in the abbey stop their revelry. In the end, a strange figure wearing a blood-splattered cloack and with a face that resembles someone who has died from the Red Death. Prospero persues the figure, enters the seventh room and as the two confront each other, Prospero falls dead.
The message, therefore, that Poe wanted to convey to his readers through the clock and its chiming every hour is that time continues passing, for all, and since black represents death, this means that all mortal lives are limited to time, and inevitably tied to death.