Twenty slow, deliberate, and powerful strokes did Denbigh take, then, treading water, he turned his head to see how his companion was progressing.
In that short distance the outlines of the Myra looked vague and distorted in the eddying vapour. Already the swimmers were practically safe from observation, since O'Hara, who was barely three yards away, looked indistinct in his cork-blackened disguise.
A dozen strokes more and the two officers were in the midst of a sluggish, turgid stream, their horizon bounded by banks of mist. Were it not for the moon, that shone dully through the haze, all sense of direction would have been lost. The water was warm and sickly-smelling. An odour like that of decaying flowers in an ill-ventilated room assailed their nostrils.
Once O'Hara gave vent to a partly smothered yell as his naked foot came in contact with a slimy water-logged tree. It was easy to imagine unpleasant things in that modern Styx.
At the sound Denbigh turned.
"What's wrong?" he asked in a whisper.
"Nothing," replied the Irishman. "Carry on."
He was swimming rapidly. His quick strokes betrayed his acute anxiety to traverse the stretch of water in as short a time as possible.
"Steady; don't splash," cautioned Denbigh.
A reply to his admonition came from another quarter, for almost in front of the swimmers rose a huge black object, quickly followed by another. In the semi-light the two men could see that these were enormous hippopotami, distinguish even their thick lips and wire-like bristles, and hear the business-like snap of their formidable teeth, capable of biting the side of a boat and shaking the craft like a terrier does a rat.