Polo retrieved the red lacquer box emblazoned with the black dragon and I waved it away. “Not that one, the other one. Are you mad?” He handed me a black lacquer box, larger than the other, about the size of a large man’s foot. I worked the top off, and from a padded compartment, I pulled four round paper packets, each no bigger than a fingertip. I threw one at the floor at my feet, and jumped when it snapped in a small explosion and a puff of smoke. Another I threw at Drool’s feet, and he cowered at the noise and smoke. I did a backflip and snapped the last two to the floor as I landed, with a distinct and ear-ringing bang.

“They call it dragon powder,” said Marco Polo. He looked at me. “Although it has nothing to do with dragons.”

Othello watched, waited, said not a word. I brought the box to him and pulled up a pinch of the black powder from another compartment in the box. “Not impressive, I know. Just a few grains of this, in a packet with some fine gravel. When the gravel hammers the powder, it ignites with a snap. A magician’s trick, right? But imagine a larger amount, contained.”

I pulled from the box a small cylinder of paper, as big around as my thumb, Chinese characters drawn on the paper. From the cylinder protruded a waxed cord, impregnated with the black powder. “Now, just this amount, watch this.”

I spotted a Turkish vase as high as my chest, in the corner, and from the bowl on the table I grabbed a melon. Then spinning it on my finger as I went, I lit the wick of the paper cylinder, which hissed and threw out sparks as it burned. I scampered to the vase, dropped in the sizzling cylinder, then fit the melon in the mouth of the vase and hastily backed away.

“Don’t be alarmed,” said I. “It will be loud. I was startled when Polo showed us.”

“I weed meself,” said Drool.

In a second there was a deafening bang and the vase disintegrated into shards that peppered the room, including us. The melon calmly dropped to the spot where there had once been a vase, but now there was but a sunburst of porcelain dust and a dented melon.

Othello shook his head, trying to clear his ears, as each of us tried to make some adjustment to the high-pitched ringing we were all hearing. “So,” said I. “That is not, precisely, how I thought it would work, but you can see the potential. That was barely a spoonful of the powder, and compressed only in paper. If you were to pack it into a great steel or stone ball and fling it at your enemies with one of your war machines, I trust it might be days before the surprise was wiped from their faces.”