Page "Roman candle (firework)" Paragraph 5

A Roman candle is a firework constructed with bentonite, lifting charge, pyrotechnic star, black powder, and delay charge.

The device is ignited from the top.

The delay powder is packed tightly in the tube, so that the flame cannot reach around the sides of the plug of delay composition.

It therefore burns slowly ; as it is consumed, the flame moves down through the tube.

When the flame reaches the topmost pyrotechnic star, the star is ignited.

Because the star fits loosely in the tube, the fire spreads around it and ignites the lift charge.

The lift charge burns quickly, propelling the star out of the tube, like a bullet from a gun.

In doing so it also ignites the layer of delay powder beneath it, and the process repeats.