The plan was carried out as arranged, and soon after seven o’clock Rupert Holliday and Gerald Dillon, leaving the camp, strolled down to the river, on whose bank Hugh was already sitting.  The day had been extremely hot, and numbers of soldiers were bathing in the river.  It was known that the assault was to take place that night, but as the cavalry would take no part in it, the soldiers, with their accustomed carelessness, paid little heed to the matter.  As it grew dusk, the bathers one by one dressed and left, until only the three watchers remained.  Then Rupert called Hugh, who had been sitting at a short distance, to his side; they then stripped, and carefully concealed their clothes.  The petards were taken out from beneath a heap of stones, where Hugh had hid them, and were fixed on the piece of timber, one end of which was just afloat in the stream.  By their side was placed some lengths of fuse, a brace of pistols, a long gimlet, some hooks, and cord.  Then just as it was fairly dark the log was silently pushed into the water, and swimming beside it, with one hand upon it, the little party started upon their adventurous expedition.

The log was not very large, although of considerable length, and with the petards upon it, it showed but little above water.  The point where they had embarked was fully two miles above the town, and it was more than an hour before the stream took them abreast of it.  Although it was very dark, they now floated on their backs by the piece of timber, so as to show as little as possible to any who might be on the lookout, for of all objects the round outline of a human head is one of the most easily recognized.

Presently they came, as they had expected, to a floating boom, composed of logs of timber chained together.  Here the piece of timber came to a standstill.  No talk was necessary, as the course under these circumstances had been already agreed to.  The petards and other objects were placed on the boom, upon which Rupert, as the lightest of the party, crept, holding in his hand a cord fastened round the log.  Hugh and Gerald Dillon now climbed upon one end of the log, which at once sank into the water below the level of the bottom of the boom, and the current taking it, swept it beneath the obstacle.  Rupert’s rope directed its downward course, and it was soon alongside the boom, but on the lower side.

The petards were replaced, and the party again proceeded; but now Hugh swam on his back, holding a short rope attached to one end, so as to keep the log straight, and prevent its getting across the mooring chains of the boats forming the bridge; while Rupert and Gerald, each with a rope also attached to the log, floated down some ten or twelve yards on either side of the log, but a little behind it.  The plan answered admirably; the stream carried the log end-foremost between two of the boats, which were moored twelve feet apart, while Gerald and Rupert each floated on the other side of the mooring chains of the boats; round these chains they twisted the ropes, and by them the log lay anchored as it were under the bridge, and between two of the boats forming it.  If there were any sentries on the bridge, these neither saw nor heard them, their attention being absorbed by the expectation of an attack upon the breaches of Fort Saint Michael.