That's one of my favorite stories by Ambrose Bierce! I think the time elapsed was about 30-45 seconds, the time it took the Southern plantation owner to die and suffocate of a snapped neck. The last pictures on his brain were those of his life passing before his very eyes. His home, his graceful wife, his loyal retainers, etc. A wonderfully-written short example of the the classic "flash-back" story, wherein the end and the beginning are pretty much the same, with explanation of the circumstances in between.