Graveyard shifts and torpedo coffins

From Atul Gawande’s “Final Cut: Medical arrogance and the decline of the autopsy” (The New Yorker: 19 March 2001):

… in the nineteenth century … [some doctors] waited until burial and then robbed the graves, either personally or through accomplices, an activity that continued into the twentieth century. To deter such autopsies, some families would post nighttime guards at the grave site – hence the term “graveyard shift.” Others placed heavey stones on the coffins. In 1878, one company in Columbus, Ohio, even sold “torpedo cofins,” equipped with pipe bombs designed to blow up if they were tampered with.