In hot haste six men with the machine-gun were sent off in a boat to the island with instructions to keep under cover and not to open fire until the approaching destroyer came within a hundred yards of the rock, which she must do by reason of the tortuous course of the deep-water channel.
The Alerte was swung athwart the river to enable her six-inch quick-firer to bear. With the exception of the captain, Mr. Marchant and the gun's crew, all the rest of the hands were ordered below to be ready to replace casualties amongst the men working the quick-firer.
Presently a signal came through from the island: "Destroyer holding on. Is flying Spanish colours."
"In that case we needn't worry much, my lads," exclaimed Cain. "She's probably going down the coast. If she isn't, then we're more than her match. There's not a single destroyer belonging to the Spanish Navy with a gun anything approaching our six-inch. We'll give it her in the neck if she tries conclusions with us."
After a brief interval, another message came through: "Destroyer turned eight point to port and is making for the bar."
"Good enough, my hearties!" declared Cain in his ringing, convincing voice. "Let her have it directly she pokes her nose round the bluff. What's the opening range, Mr. Marchant?"
"Two thousand yards, sir," replied the gunner.
Under the captain's orders one of the crew ran off with a bundle under his arm. Presently a flag was hoisted at the ensign staff. For the first time the Alerte was showing her true colours—the "Jolly Roger."
Alone on the bridge, Cain stood calm and confident. There was not the slightest tremor in his large, powerful hands as he grasped his binoculars ready to bring them to bear upon the as yet invisible enemy.
From his elevated position he gave a rapid glance at the gun's crew. The men had closed up round their weapon, the gunlayer bending as he peered through the sights. In the rear crouched the loading-party, each with his hands on a hundred-pound projectile, ready the moment the breech-block was opened to thrust the shell into the still smoking breech. And somehow Cain's thoughts flew back to a similar scene in the presence of an enemy. Then, he was fighting for a just cause under the glorious white ensign. Now, he was fighting for no cause but his own, his hand against every man's, and under the shadow of that emblem of dishonour—the skull and cross-bones.