Jumping back over Lacost's prostrate body, he reached the stern, switched on the boat's engine and flung the gear into reverse. His thoughts were now miles from the Boa Viagem, away up in the Royal bure, with Manon and the Witch; so he was aware only subconsciously that the firing above had ceased.
As the boat backed away, James appeared at the stern rail of the yacht, with Olinda beside him. `What the devil are you doing?' he called to Gregory. `Why have you cast off?'
Gregory made no reply, switched the gear into neutral and gave the wheel a sharp twist that brought the boat round broadside on.
James, thinking that he was about to nose in again, cried in excited triumph, `It's all over! One dead and the others prisoners. Bring her under the stern and I'll lower Olinda to you:
To his astonishment, instead of complying, Gregory pushed the gear lever into full speed ahead and again gave a twist to the wheel. The boat leapt forward, churning up great sheets of spray on either side of the bow and curving round in a wide half circle until she was heading for the port.
In vain James shouted after him. Gregory had forgotten the very existence of the yacht. His mind was in a turmoil. The White Witch had been heavily drugged. He had been convinced that Roboumo would not have given her a dose that was likely to kill her or deliberately have poisoned her. He would never have done that as long as he had the faintest hope of keeping her as his prisoner, so that, through the natives' fear of her, he could continue to exercise his evil power. But people had often been known to die of an overdose of a normally harmless drug. If Manon also recalled the Macumba priest's prediction, and decided to poison the Witch, she could get away with it. Everyone would believe that the Witch had died as a result of Roboumo's drug.
And Manon had the means to poison at hand. The sweat broke out on Gregory's forehead as he remembered the ring she always wore the so called Borgia ring the secret of which she had revealed to him in Rio. In his mind's eye he could see her again now, sitting on the side of his bed and showing how, if pressed, a hidden spring caused the big amethyst to slide back, revealing a hollow in which there lay a cyanide of potassium pellet. _
The first grey light preceding dawn had begun to lighten the scene while the fracas on the yacht was in progress. By the time Gregory was halfway to the harbour the light had increased perceptibly. Suddenly he noticed a movement in the fore part of the boat. Peering forward, he saw Lacost struggle up into a sitting position. Evidently his thick yellow hair had prevented his being put out for more than ten or twelve minutes after the blow on the head James had. given him with his pistol. He was now coming round.
Gregory gave vent to the unprintable Italian oath which he used only on very rare occasions. This was hell's own luck. At the speed the boat was going he dared not leave the wheel, even for a minute, in order to knock Lacost out again. He could only pray to all his gods that the big Frenchman would not be sufficiently recovered to attack him before they reached harbour.
While the boat roared on, bumping abruptly as it lifted over small waves, Gregory kept a wary eye on his dangerous passenger. Another five minutes passed, and he had good reason to believe that his worst fears were to be realised. Lacost lurched to his feet and, swaying slightly, stood staring at him across the cabin roof.
His anxiety on account of the Witch was now replaced by a more immediate one. What was he to do if Lacost did rush him? The automatic he had brought, anticipating that he would take part in the capture of the yacht, was in the cabin with his clothes. A swift glance round had shown him that no weapon, such as an iron bar or a marlin spike, with which he could defend himself, was in sight. Worst handicap of all for any man in a fight, he was still stark naked.
Lacost took a shuffling step towards him. Gregory knew now that he stood no chance of rounding the mole and bringing the boat alongside the wharf, where he could have shouted for help, before the murderous Colon would be upon him. Again his thoughts flashed for a second to what might be taking place up at the Royal bure, and the urgency of getting there. But he knew that his best chance of overcoming Lacost lay in tackling him before he had recovered the full use of his wits. With agonised reluctance he pulled the boat's gear lever over, bringing her down to half speed.
At that moment Lacost stopped to pick up something from the deck. Gregory's heart missed a beat, for he felt certain that his enemy had found a weapon; but as Lacost came upright again he was holding two sheets of paper. He had stumbled on the licence to salvage the treasure and its transfer to himself which James had signed while Gregory was fouling the propellers of the yacht.
Gregory swore beneath his breath. Should Lacost succeed in overcoming him that would now mean a double defeat. Not only would the Frenchman be able to get away in the motor cruiser to some other island, but, if he was ever caught, the possession of those documents could enable him to plead justification for having fired on the gendarmes.
Lacost pushed the papers into his jacket pocket and moved a step nearer. `It is now or never,' Gregory decided. `He is just near enough for me to jump him.' Stretching out a hand, he switched off the engine.
Guessing his intention, Lacost stepped quickly back, at the same time thrusting a hand into his trouser docket. Next moment he had withdrawn it, holding a jack knife. With a swift movement he flicked it open. By now there was light enough for Gregory to see his face clearly. Under his long moustache his slightly protruding teeth showed in a sardonic smile.
Although Gregory had been tensed to spring, his enemy's quick retreat had given him pause. The flash of the knife had deterred him altogether. Naked as he was, he knew that it would now be suicidal to attack Lacost unarmed.
For the first time the Frenchman spoke. `Fate has favoured me, after all, Monsieur Sallust. It is you who have been the ruin of my enterprise. Temporarily at least I have lost the treasure; although later, now that I have the necessary documents, I may yet appoint nominees to put in for me a legal claim to it. But at least I'll have thee satisfaction of settling with you. When we met in Guatemala I recall you said that, should occasion arise, you would take pleasure in throwing me to the sharks. Now it is I who will throw you to the sharks. The smell of the blood that will flow after I've stuck my knife in your stomach will bring them racing to you.'
As he ceased speaking he made a sudden rush at Gregory. Abandoning the wheel of the now slowly rocking boat, Gregory dodged to the port side of the cabin roof. Lacost followed, hurling blasphemies at him. Three times they sped round the roof. The tall Frenchman had the longer stride, but Gregory the greater agility and, being barefooted, a firmer purchase on the deck. The chase ended with them on either side of the low roof, panting for breath and glaring at each other.
Suddenly Lacost sprung on to the roof. A wave caused the boat to tilt a little. He staggered, but regained his balance.
For a moment he stood there, huge and menacing, a towering bulky figure outlined against the pale light of the predawn sky. Then, his boots thudding on the cabin roof, in three strides he was across it.
The movement was so sudden that Gregory had no chance to jump aside and, had he turned, Lacost would have knifed him in the back. Lowering his head, he threw himself forward and butted the Frenchman in the stomach. Lacost gave a choking gasp and somersaulted over Gregory's shoulders, but the impact of his heavy body brought them both crashing to the deck.