"I wish we could guard against the risk," he said to Barney. "We don't want to be continuously on the fidget in case the blockhouses are fired. Yet we can't make 'em fireproof."
"That's true, sorr; still, something might be done to rejuce the inflammation."
"What's that?" said Jack without a smile. To call in question Barney's English was to wound him in the tenderest part.
"Why, sorr, why not drop down some uv them boulders we keep for repairing the wall? If we let them down wid care to the foot uv the blockhouses, close up against the woodwork, 'twould prevent any wan from setting a match to 'm."
"A good idea! we'll try it. Get the men to carry the stones up to the wall. We won't do anything more till it is dark."
When the sun had set, Jack had the stones hauled up to the roof of the blockhouse at the north-west corner, and then dropped down outside, as close to the woodwork as possible. The task was carried on in almost total darkness, only a few rushlights inside the camp preventing the workers from colliding with one another. But it was impossible to contrive that the heavy stones should fall silently, and a shot from up the slope soon told that the enemy had discovered what was going on. Active sniping for a time gave Jack a good deal of annoyance, and one or two of his men were hit; but he persevered in his work, and had partially accomplished it, when another danger suddenly threatened.
Up the slope, near the position occupied by the enemy in the morning, there appeared small points of light, which moved apparently at random for a few moments, and then came all in one direction, down the hill. They all started fairly close together, and Jack counted twelve in a line; but soon some diverged from the rest and went off at an angle. The others came on more and more rapidly towards the fort, jumping occasionally, but keeping on the whole a surprisingly straight course.
"Barrels again!" said Jack to Barney.
Only a few seconds after he had first observed them, they came with a quick succession of thuds against the wall and the half-finished rampart at the foot of the blockhouse, and the points of light spread out into fierce tongues of flame. Lighted matches had been attached to the barrels, and with the bursting of these by the stonework the resin they contained had taken fire. Of the dozen barrels that started, only four had reached their goal, the rest having rolled over the gully on the western slope as had happened during the day.
Jack hoped that his new stonework was sufficient to protect the logs at the base of the blockhouse. But one of the barrels, under the impetus gained in its passage down the hill, had jumped the boulders, and breaking as it crashed over, burst into flame within an inch or two of the woodwork. Another line of barrels was starting down the slope. Jack had called up his best marksmen at the first alarm, and ordered them to take pot-shots at the twinkling points of light, or the figures above, dimly lit up by the matches attached to the barrels. Whether any of the shots got home he could not tell; another set of barrels was trundling down towards the fort.