Afraid to move, fascinated, she stood still, staring at the rainbow.

Presently Tom disappeared.  When he returned Mamie could see him very plainly.  He had a stick of dynamite and a fuse.  Mamie saw him glance at his watch and measure the fuse.  Then, leaping from log to log, he approached the one in midstream which lay passive, blocking the advance of all the others.  With splendid skill and daring he adjusted the dynamite upon the small rock which held the log, and lit the fuse.  He returned as he had come, and Mamie could hear the cheers of the men upon the opposite bank.

“It’ll hev to go now,” she reflected.

At this moment Dennis, the dog, must have realised that his master had left something behind on the rock.  Mamie saw him spring from log to log, and then, holding the dynamite between his teeth, with the spluttering fuse still attached, follow his master.

“Tom!” she screamed.  “Look out!”

Tom turned and saw!  And the others—­Dennis Brown, Mamie, the river-drivers—­saw also and trembled.  Tom began to curse the dog, adjuring him to go back, to drop it, drop IT, DROP IT!

But the faithful creature, who had risked life to retrieve sticks thrown into fierce rapids, ran steadily on.  Mamie saw the face of her husband crumble into an expression of hideous terror and palsy.  His lips mouthed inarticulately, with his huge hands he tried to push back the monstrous fate that was overtaking him.

The dog laid the dynamite at his master’s feet at the moment when it exploded.

* * * * *

And the man whose name was Dennis knew that his turn had come at last.