Might have been:
Light fuse
Drop cannonball in cannon
Light cannon fuse
I could be wrong though.
The fuse was a pewter disk with numbers that gave you the delay. Under the disk was a powder train going to the main charge, wether black powder or lead balls held in place by pine pitch. Sectioned some, and the black powder was still good after all these years.
Not sure about cannon but with mortars they tried it that way at first and had some terrifying results. Someone then thought to load the shell with the fuse facing in toward the lifting charge so the fuse would light on firing. It was soon noticed that method caused the shell to explode immediately as the shell left the muzzle! After a bit of experimentation it was observed that the mortar shell fuse would reliably light from the muzzle blast of the propelling charge if the shell was loaded with the fuse facing out the muzzle.
Regards,
GtG