Up to this moment, the narrator doesn't identify the sound. It's described first as "a ringing," and then as "a low, dull, quick sound – much such a sound as a watch makes when enveloped in cotton" (9). Only in the very last line does the narrator conclude that the sound was "the beating of [the man's] hideous heart!" (10).You was known that when people making a bad thing and try concealed or hidden. In someday the truth must reveal. It is unavoidable circumstances and be reluctant in things act.