How do you use the explosive barrel on Poptropica?

On Time Tangled island, the gunpowder can blast open the rock cave at the Viking time (831 AD, 2 o'clock on the time device). The golden vase is at the bottom left inside the cave.

(You will have to take the long way, and hurry before the torch burns out. Go down, up, up, up, across to the right, then down and left and jump the water puddles at the end.)

At the Pirate Outpost on Skullduggery Island, get the Cannon Starter (fuses) at the top left, then push the small barrel of explosives off the mast (you can climb up past the Cannonry at right). Once it is in the water, paddle it out to the water beneath the golden tooth of the stone skull. Swim to the cannon at bottom left and fire it to hit the barrel, blasting loose the Golden Tooth and revealing the map piece.