midday
It recorded the fact that Peter Hardcastle was dead , and that examination had revealed no cause for his end . The news reached Sir Walter at once , and if ever he rejoiced in the death of a fellow-creature , it was upon this occasion . It meant unspeakable relief both for him and his daughter . The detectives began their operations after a midday meal , and having first carefully studied the Grey Room in every visible particular , they emptied it of its contents , and placed the pictures , furniture , and statuette outside in the corridor . They asked for no assistance , and desired that none should visit the scene of their labors . The apartment , empty to the walls , they examined minutely ; with the help of ladders , they investigated the outer walls on the east and south side ; and they probed the chimney from above and below . They searched the adjoining room -- Mary 's old nursery -- to satisfy themselves that no communication existed , and they drove an iron rod through the walls in various directions , only to prove they were of solid stone , eighteen inches thick within and two feet thick without .