Hi Jim,
These items are mentioned in W.W.Greeners book The Gun and its Development Ninth Edition 1910. They were made for all sorts of "alarm" purposes, right thru the various ignition systems--Flint, Percussion, Pinfire and Centrefire and some were made to fire flares. Probably a forerunner of more modern versions used in recent wars to fire parachute flares.
Use was not limited to graveyards. They were also used to protect stately homes, warn of poachers etc, and during the Boer War, to warn garrisons of native, and enemy activity.
Maybe they need to be reinvented to keep undesirables away from our collections!
Regards Stu