their soft high boots up to their knees and secured them there; and, moreover, they smeared an abomination of grease and eucalyptus oil over their hands.  The mosquitoes set up a shrill trumpeting that could be heard ten paces away, and held a mass meeting to protest; whereupon the father of all the dragon-flies, a magnificent warrior in a steel-blue armour, saw that a conspiracy was afoot, and swept into the midst with a whirr and a snap, a turn here and a flash there, that scattered the host in a twinkling of a gnat’s eye.

The islands shimmered in the glare as if they were afloat; the hippos took to the water, and a deep and drowsy silence fell upon the great river.  But man, ever restless, was astir, and through the stillness there was borne to the three a soft continuous humming, that merged quietly into the short, clamorous throbs of an engine at work under pressure.

The launch was afloat again!  Mr. Hume caught the trail of the smoke first, and Compton next.  They marked the course under the north bank right up to a bend about six miles off, and they judged that the launch had stopped there, as the smoke went up in a straight thin column.  Then Venning saw a canoe dart out from the south bank, followed by two others from different points.  The sun struck like fire on gun-barrel and spear-head, and gleamed on the wet paddles.  He moistened his parched lips with a taste of water from his filter-bottle, and gave the call.  The answer came, and he drew his friends to him with a low whistling.  As they came crouching, he pointed upriver.

“Three canoes put out.  Two are hidden behind that outside island, and there is the other creeping round the end.”

“Oh ay,” said Mr. Hume.  “If they’re after us, they will have placed outlooks in the tallest trees;” and with his glass he swept the forest.

“They could not see us at that distance.”

“But they could see our boat as soon as we appeared in open water.  We’ll stay where we are.”

“Then we shall need our guns.”

“It is not our guns that will save us, my lad, but strategy.  Any one could fire off a rifle, but it takes nerve to keep cool in readiness to do the right thing at the right time.”

“But,” said Compton, obstinately, “we don’t want to be caught undefended.”

“Leave this matter with me,” said the hunter, sternly.  “See that crocodile asleep on that stretch of sand?  He’s our best protector.  Why?  Because he is asleep.  The natives, seeing him, would think we were not near.  We will, however, keep watch together.”

They returned to the boat, made all ready for an instant departure, in case they were discovered, then settled down to wait and watch once more.  Gradually the strain wore off, the old silence fell upon the scene, and their eyes grew heavy from sheer monotony.  The night had seemed long, bat the day was worse.

Then the boys rubbed their eyes and lifted their heads.  Where there had been a bare stretch of water white under the sun between two islands a quarter of a mile off, there appeared a long canoe, with a tall spearman standing in the bows, and a full crew behind.