Reckon'I might stand corrected according to Wikipedia and the use of "fer" for a canon barrel. However "Pot de feux" is a term I used to speak of a pot of fire a/k/a early fire grenade. The term "petard" , a form of pot de feux refers to another earlier form of thrown munitions, in which a fuse was added to provide an explosion on arrival. The unreliability of early fuses often caused an explosion whilst being heaved,, killing the "grenadier". This gave rise to the expression of "t'was hoist by his own petard." "Doc" :hmm: