The ebony clock symbolizes in "The Masque of the Red Death" a powerful symbol of mortality and the inevitability of death. The ebony clock is described as striking each hour with a "deep and solemn tone," which serves as a constant reminder to the revelers that their time is running out. The clock also stands in stark contrast to the colorful and luxurious setting of Prince Prospero's masquerade ball, emphasizing the stark reality of death in the midst of revelry and excess. The clock's black and eerie appearance suggests the presence of death itself, as does its location in the "black chamber" of the abbey.
Throughout the story, the clock remains a constant reminder of the impermanence of life and the inevitability of death. As the story progresses, the clock's chimes become increasingly ominous, with each strike signaling the approach of death. The clock's presence also suggests that no amount of wealth, power, or luxury can protect one from death, as even Prince Prospero and his guests are ultimately unable to escape the Red Death.
Furthermore, the clock's striking of each hour suggests that time is an ever-present force, steadily marching forward and bringing us all closer to our eventual demise. In this way, the clock serves as a reminder to the reader of the importance of making the most of the time we have and living life to the fullest. Overall, the clock is a powerful and haunting symbol in "The Masque of the Red Death," representing the inescapable nature of death and the fleeting nature of life.