I don't have your answer David but I watched a show yesterday (History Channel?) about the siege of Troy. They were using what can only be called hand grenades even back then. Some were filled from incendiary substances and possibly even explosive chemicals. In an instance from Iran they found "hand grenades" composed of thin pottery that were filled with scorpions. It looked like a simple clay jar, filled with those little devils with a cloth tied around the lid. Who know what devices the ancients had that have been lost.

As for a "Thunder-Barrell"... Isn't that what they old folks kept their shine in? LOL!

Joking aside, were these not explosive filled barrells that were rolled down the hills toward the advancing siege lines? Especially toward any attempts to dig trenches toward the Confederate lines?