Hornblower climbed up into the cart with Bracegirdle, and two seamen led the plodding horse along the causeway to the bridge. There they halted and looked down at the muddy water — running swiftly with the ebb — craning their heads over the parapet to look at the solid stone construction.
'It is the keystone of the arch which we should blow out,' said Bracegirdle.
That was the proverbial recipe for the destruction of a bridge, but as Hornblower looked from the bridge to Bracegirdle and back again the idea did not seem easy to execute. Gunpowder exploded upwards and had to be held in on all sidles — how was that to be done under the arch of the bridge?
'What about the pier?' he asked tentatively.
'We can but look and see,' said Bracegirdle, and turned to the seaman by the cart. 'Hannay, bring a rope.'
They fastened the rope to the parapet and slid down it to a precarious foothold on the slippery ledge round the base of the pier, the river gurgling at their feet.
'That seems to be the solution,' said Bracegirdle, crouching almost double under the arch.
Time slipped by fast as they made their preparations; a working party had to be brought from the guard of the bridge, picks and crowbars had to be found or extemporized and some of the huge blocks with which the pier was built had to be picked out at the shoulder of the arch. Two kegs of gunpowder, lowered gingerly from above, had to be thrust into the holes so formed, a length of slow match put in at each bunghole and led to the exterior, while the kegs were tamped into their caves with all the stones and earth that could be crammed into them. It was almost twilight under the arch when the work was finished, the working party made laboriously to climb the rope up to the bridge and Bracegirdle and Hornblower left to look at each other again.
'I'll fire the fuses,' said Bracegirdle. 'You go next, sir.'
It was not a matter for much argument. Bracegirdle was under orders to destroy the bridge, and Hornblower addressed himself to climbing up the rope while Bracegirdle took his tinderbox from his pocket. Once on the roadway of the bridge Hornblower sent away the cart and waited. It was only two or three minutes before Bracegirdle appeared, frantically climbing the rope and hurling himself over the parapet.