A fuse made from a 'tube' of gunpowder surrounded by a waterproofed varnished jute rope, with a timed burn time?

A fuse made from a 'tube' of gunpowder surrounded by a waterproofed varnished jute rope, with a timed burn time?

• A. Safety Fuse (Visco Fuse)
• B. No Fire Current
• C. Portfire
• D. Lance

Answer: (A)

Recognizing a fuse designed to provide a timed delay. The description—a tube of gunpowder inside a waterproof varnished jute rope—fits how a safety fuse (visco fuse) is built. The waterproof outer wrapper keeps moisture out, while the slow, consistent burn gives a reliable delay between lighting and ignition of the main charge. Portfire, by contrast, is used to light fuses or charges but does not itself provide a timed delay. The other terms don’t describe a fuse with this slow, timed-burning, waterproof construction.

Recognizing a fuse designed to provide a timed delay. The description—a tube of gunpowder inside a waterproof varnished jute rope—fits how a safety fuse (visco fuse) is built. The waterproof outer wrapper keeps moisture out, while the slow, consistent burn gives a reliable delay between lighting and ignition of the main charge. Portfire, by contrast, is used to light fuses or charges but does not itself provide a timed delay. The other terms don’t describe a fuse with this slow, timed-burning, waterproof construction.