Half way up the Black river, he encountered one of the rapids which was broken about the middle by a twelve-foot fall. Portaging past the fall, he attempted to "track" the canoe up the rest of the rapid. The two Indians were ashore tugging at the tow-line, while Thompson in the canoe tried to steer and at the same time direct their movements. Near the head of the rapid there was at the water's edge a tree which blocked their progress, and as the Indians stood hesitating which side of it they should pass, the canoe sheered off across the current. An upset was inevitable, had not Thompson waved to the Indians to let go the line and leave him to his fate. Springing to the bow, he cut the rope off short with the clasp knife which he kept in his waistcoat pocket, and got the head of the canoe around into the stream just in time to take the plunge over the cataract. For an instant, Thompson was buried beneath the boiling water at the foot of the fall. Striking his feet against the bottom, he pushed himself to the surface close to the upturned canoe. This he seized and dragged through shallow water to the beach. The Indians came rushing to his assistance, and, while he lay on the rocks, bruised, bleeding, and exhausted by his exertions, they searched the shore below the rapids for what could be recovered of their precious kit. The gun, the axe, and the tent had remained fastened in the canoe. In half an hour's time, the Indians brought back the cork-lined box containing Thompson's instruments and the maps of his survey, together with their three paddles and a pewter basin. Not one moment was to be lost. Thompson's body was naked except for his shirt and a thin linen vest, and his companions were in like condition. The small tent they tore into three pieces with which to wrap themselves as a defence against flies by day and chill by night. Worse still, Thompson found as he painfully raised himself from the rocks that the flesh of his foot had been torn away by the impact of the jagged stones of the river bed, and a part of his share of the tent had to be taken to bind the wound. The first duty was to repair the canoe, and the Indians were sent to the woods to procure gum from the pines. The question was then how to light a fire, for they had neither flint nor steel. Thompson pointed to his gun from which they took the flint, and with the steel blade of his pocket knife they struck a spark. When the gum was melted, they repaired the canoe and carried their kit above the fall and rapids. The Indians shouldered the canoe, while behind them the wounded leader hobbled painfully along under the burden of gun, axe, and sextant case.