There was no fear of being surprised.

Uncle Prudent began by rubbing a small quantity of the powder very fine; and then, having slightly moistened it, he wrapped it up in a piece of rag in the shape of a match.

When it was lighted he calculated it would burn about an inch in five minutes, or a yard in three hours.

The match was tried and found to answer, and was then wound round with string and attached to the cap of the cartridge.

Uncle Prudent had all finished about ten o'clock in the evening without having excited the least suspicion.
During the day the work on the fore screw had been actively carried on, but it had had to be taken on board to adjust the twisted blades.
Of the piles and accumulators and the machinery that drove the ship nothing was damaged.
When night fell Robur and his men knocked off work.