“Ha!  Who calls?” answered the deep voice of Mr. Mortimer after two seconds’ interval.

“Hucks.  And I want a word with you.”

The door opened a little way . . . and with that someone within the van uttered a cry, as a dark object sprang out over the flap, hurtled past Mr. Hucks, and hurled itself across the court towards the gate.

“’Dolph!  ’Dolph!” called an agonised voice—­a child’s voice.

“The dog’s daft!” chimed in Mr. Mortimer.

“’E’ll kill ’im!”

As Mr. Hucks recovered his balance and stared in at the caravan doorway, now wide open, from the darkness beyond the gate came a cry and a fierce guttural bark—­the two blent together.  Silence followed.  Then on the silence there broke the sound of a heavy splash.

CHAPTER VIII.

FLIGHT.

“So all night long and through the dawn the ship cleft her way.”  —­ODYSSEY, ii.

Mr. Hucks ran.  Mr. Mortimer ran.  As they reached the gate they heard the voice of Doctor Glasson uplifted, gurgling for help.

They spied him at once, for by a lucky chance his lantern—­one of the common stable kind, with panes of horn—­had fallen from his grasp as he pitched over the edge of the basin.  It floated, bobbing on the waves cast up by his struggles and splashings, and by the light of it they quickly reached the spot.  But unluckily, though they could see him well enough, they could not reach Doctor Glasson.  He clung to the head-rope of a barge moored some nine feet from shore, and it appeared that he was hurt, for his efforts to lift himself up and over the stem of the boat, though persistent, were feeble, and at every effort he groaned.  The dog—­cause of the mischief—­craned forward at him over the water, and barked in indecent triumph.

Mr. Mortimer, who had gone through the form of tearing off his coat, paused as he unbuttoned his waistcoat also, and glanced at Mr. Hucks.

“Can you swim?” he asked.  “I—­I regret to say it is not one of my accomplishments.”

“I ain’t goin’ to try just yet,” Mr. Hucks answered with creditable composure.  “They ’re bound to fetch help between ’em with the row they ’re making.  Just hark to the d—­d dog.”

Sure enough the alarm had been given.  A voice at that moment hailed from one of the boats across the water to know what was the matter, and half a dozen porters, canal-men, night watchmen from the warehouses, came running around the head of the basin; but before they could arrive, a man dashed out of the darkness behind the two watchers, tore past them, and sprang for the boat.  They heard the thud of his feet as he alit on her short fore-deck, and an instant later, as he leaned over the stem and gripped Dr. Glasson’s coat-collar, the light of the bobbing lantern showed them his face.  It was Sam Bossom.

He had lifted the Doctor waist-high from the water before the other helpers sprang on board and completed the rescue.  The poor man was hauled over the bows and stretched on the fore-deck, where he lay groaning while they brought the boat alongside the quay’s edge.  By this time a small crowd had gathered, and was being pressed back from the brink and exhorted by a belated policeman.