Mr. Jackson followed the direction of his companion's outstretched hand. He could see the uncovered shoal known as the Shingles, over which a ground swell was breaking heavily. Farther away, and more on the port quarter, he could discern the cliffs of Totland Bay. There the view of the Isle of Wight ended. Alum Bay and the detached chalk masses known as the Needles were blotted out in a thick but invisible mist that blended with the grey sky.
"It's stopped, sir," exclaimed Hepburn.
"What's stopped?" inquired Mr. Armitage.
"The fog-horn, sir," replied Alan, who, like the rest of the Sea Scouts, knew the character of the Needles "fog reed-horn" well, since Milford is within six miles of the lighthouse. "It's a blast of five seconds every fifteen seconds. I haven't heard it for more than a couple of minutes."
"The fog's lifted out there, perhaps," suggested Roche.
"It certainly doesn't look like it," observed Mr. Armitage. "Most likely we have struck a zone of silence. You remember how we saw an inverted phantom image of Dungeness Lighthouse? That was caused by irregular layers of air. Sound is similarly affected. The volume of noise leaps, as it were, and although we might not hear it fairly close to, vessels much farther away might hear it distinctly. There it is again, Alan. We have passed through the zone of silence."
Attention was then turned in a new direction. The Rosalie, having "made her numbers" to Hurst Signalling Station, was passing within a quarter of a mile of Milford. The Sea Scouts could discern their hut, perched half-way up the low, gravelly cliff, and, what was more, every lad was able to distinguish, by the aid of the glasses, the features of some relative, for parents and other kith and kin had gone down to the beach to watch the Rosalie pass.
"Give Christchurch Head a wide berth, Peter," cautioned the Scoutmaster. "Although there's plenty of water for us over the ledge, there'll be a nasty sea after the recent gale. Can you see the Ledge buoy?"
"Yes, sir," replied Stratton, after a brief survey. "A point on our port bow."
"Then starboard a point. Note the compass bearing in case it comes on thick. I rather fancy it will before long."