The new moon shone in a clear sky and the tide was nearly full. Puffs of warm land-breeze shook the mangroves and drove small ripples against Columbine's side. She rode to the flood stream, ready for sea, and the clank of her windlass rolled across the swamps. The negro crew were shortening cable and sang as they hove at the levers.

Wyndham was talking to Peters, who had arrived in the afternoon, and Marston, standing near them, frowned. He was annoyed that Peters had come, because he had wanted to talk to Wyndham and after the other's arrival this was impossible. It was unlucky he had put it off, but he did not see why Harry had urged the fellow to stay and go back to the village with him when the schooner sailed. Marston felt rather hurt, since it almost looked as if Harry had kept Peters in order to prevent him trying to satisfy his curiosity.

Marston was curious. The old mulatto had told Harry something that had given him a bad jar; Bob could not forget his comrade's strained look when he entered the cabin, and he had found no clew to the puzzle. It was a relief to go to sea, but the satisfaction he had expected to get was dulled. He felt as if he were running away and leaving his partner when the latter needed him. Yet somebody must go and Harry would not."Short up, sah!" a Krooboy shouted when the windlass stopped. The pilot gave an order, and the foresail began to rise with a rattle of blocks. The canvas flapped and swelled, and Marston went forward.

"Break out the anchor," he said. "Hoist the inner jib."

Dark figures rose and fell with the windlass-bars; slowly at first, then faster, as with a harsh clank the chain ran through the pipe. Marston had generally found the noise inspiriting. It hinted at adventure on the open sea, but it did not move him now; he was not leaving the lagoon for good. Yet he was soothed when Columbine began to move. After lying on the mud, he liked to feel her lift as she met the gentle swell the tide brought in, and hear the ripple splash about her bows. The mangroves stole past, a gap opened in the trees, and a faintly-glittering track led out to sea.

"Hoist the mainsail," said the pilot, and the splash of ripples was louder when the dark canvas rose.

She drove out with the land-breeze and met the rollers on the bar. They were not high and hardly broke, only one here and there melting into foam. She lurched across with dry decks, and when the leadsman got deeper water the pilot brought her round and pulled up his canoe. Marston went to the gangway with Wyndham and Peters, and the latter laughed as he gave him his hand.

"I don't know if we'll meet again, but it's possible," he said. "You offered a good reward for some information not long since. I wonder whether you were rash.""The offer stands," Marston replied. "The man who tells me all about our agent's death will find me generous."

"Oh, well," said Peters. "I can't state that I expect to claim the reward, but after all I might. Then I hope we'll both be satisfied."

Marston let him go. He would have given much for ten minutes' frank talk with Wyndham, but this was impossible. The pilot was waiting and the yacht drifting near a dangerous shoal. He resigned himself and gave his comrade his hand.

"Run no risks and take care of yourself until I come back," he said.

"Good luck!" said Wyndham and jumped into the canoe.

Marston signed to the steersman, the sails filled, and the canoe dropped astern. Columbine gathered speed and listed down, throwing spray about while the water foamed below her lee rail. Small white waves rolled down the glittering track ahead and Marston's mood got lighter. After all, it was a relief to put to sea; the salt wind was tonic and blew morbid thoughts away. It was bracing to grapple with breaking waves and savage squalls.

He looked astern. The canoe had vanished and a misty line indicated the land. Marston was conscious of a strange repugnance as he watched it fade. Sickness lurked in the steamy forest, where the gloom was touched by mystery and something of horror. For a time, he had done with it, and he would come back strengthened and invigorated by the change.

He gave the helmsman the course, and going to the cabin, opened a tin box that held letters for England and manifests of cargo. He must copy these out on the bills of lading when he transshipped the goods and as he studied the lists he felt some surprise. Columbine did not carry much but her freight was valuable. Some had been put on board without his knowing and he thought it strange Wyndham had not talked about its cost. For example, there were small pearls. One found pearls at places on the Caribbean, but the fisheries were jealously guarded and none were near the lagoon. Then there was a packet of ambergris and Marston knew ambergris was worth much. Don Felix had said nothing about this curious stuff, which the cachalot whales throw up, and Marston wondered where Wyndham had got it.

The voyage was obviously going to pay, but the strange thing was, their cargo for the most part had come down after the agent died. To some extent this bore out Marston's conclusion that the old mulatto was the Bat and had power over Don Felix's uncivilized customers. Marston began to muse about the fellow. He had power; one felt it, although he was old and repulsive. Something indicated that he had inherited from his white ancestors qualities not often found in half-breeds. Marston began to see that this was partly why the fellow repelled him; one got a hint of intelligence put to a base use.

The matter was not important, and he pondered about his finding Wyndham and the other in the cabin. Harry was badly shaken, although Marston knew his pluck. Something very strange and startling was needed to drive the blood from his face and bring the sweat to his forehead. All the same, it was ridiculous to imagine the mulatto had frightened him. The old fellow was clever and no doubt claimed to be a magician in the bush, but Harry was not the man to be cheated by his tricks. After a time, Marston gave it up and went on deck.

Columbine leaned over to the steady breeze. The sea was flecked with white and a spray shower leaped about her bows. A foaming wake trailed behind her and Marston's heart got light as he heard the shrouds hum and felt her measured swing. He liked the sense of speed and buoyancy, the feeling that he had control of straining wood and sail. To fight the sudden wild Northers and keep her off reefs and shoals was a man's job, but it was a job he knew. He did not know the other that Mabel had given him, and often felt puzzled. Yet he had undertaken it and meant to make good. By-and-by he went down to the cabin and to bed.

After a quick run he reached port, transacted some business, shipped his cargo home by steamer, and then returned to the lagoon, where he found Wyndham had another load ready. On the night after his arrival they sat in the cabin, talking, and although Wyndham said nothing about the mulatto he was frank. Indeed, Marston smiled when he remembered the doubts with which he had left his comrade. All the same, he thought he noted something about Harry he had not known before.

"You will sail again as soon as we can load the cargo, but for another port," Wyndham said. "We have, so to speak, found a treasure house and want to keep it dark. If other folks get to know, the treasure will soon be picked up. Anybody can buy a pretty good chart of the coast for a few shillings, and we have been lucky so far, largely because the shoals keep steamers out."

"The thing will be known sometime," Marston remarked.

"Of course, but I hope to get the most part of the stuff that's worth getting before our rivals come in."

"After that you'll let this branch of the business go?"

"I think not," Wyndham replied. "If I can find a good agent, we ought to hold our ground in the regular trade, although the profits will not be large."

"But you, yourself, don't mean to stay very long?"

"No," said Wyndham. "When I get the best of the produce that seems to have been piling up and appoint our agent, I'll willingly clear out; but I don't expect to do so for three or four months. I've got my chance now and must seize it."

"Three months is a long time to stay at the lagoon. Besides, who will look after the business at home?"

"My manager is pretty capable, though he's young and recently promoted. Would you like to go?"

Marston laughed. "I'm not a business man. Would you trust me?"

"I don't think it would be rash. You're a careful fellow, Bob, and it begins to look as if you had talents you didn't know. You have transacted our business like a shipping clerk."

For a moment or two Marston hesitated. Wyndham looked amused and Bob admitted that the situation had a touch of humor. He meant to stay at a place for which he had a strange, superstitious dislike, in order to help his comrade, who would sooner be left alone.

"I may go by-and-by, but I won't go yet," he replied.

They let the matter drop and in the morning Wyndham went up the creek in the boat. He stated, rather vaguely, that he must arrange about some cargo and it was three or four days before he returned. Then Marston sailed with another load for a different port, and the French creole who shipped the goods to England was frankly surprised by their value. Indeed, his remarks indicated that the freight was worth much more than Marston had thought. The latter returned to the lagoon, satisfied in one way, but disturbed in another, and did not see much of his comrade.

Wyndham often left the vessel, and although he did not tell Marston where he went, the loaded canoes that came down the creek hinted that he was usefully engaged. It was plain that the business was remarkably profitable, but Marston imagined Wyndham was overdoing the thing. He began to look worn and was sometimes moody, for a white man cannot strain brain and body hard in the tropic swamps.

Marston got uneasy about him, but to some extent sympathized. They could not long enjoy their monopoly, rivals would soon be attracted to the lagoon, and Harry was justified in seizing his chance. He had not thought Harry greedy, but there was much at stake; Chisholm's approval, Harry's business standing, and his marriage to Flora. Marston could understand his comrade's running heavy risks for a girl like that.Still he was bothered because he did not know all the risks; it was possible that Harry was being driven far by his very natural ambition, but there were lengths to which one ought not to go.

Another thing puzzled Marston. Don Felix had known the negroes and had, moreover, negro blood in his veins, but the trade had not extended until he was dead. It was strange the efforts of a white man and a stranger had led to the sudden extension. Harry had obviously qualities and knowledge that had not marked the other. But what were the qualities, and what did he know? Although Marston sometimes brooded over this, he saw no light.

One evening he sat in the cabin and studied their trading accounts while Wyndham smoked. It was very hot and Marston's face and hands were wet with sweat and his eyes were dazzled. Flies hovered about the light and now and then a beetle struck the mosquito gauze in the skylight. Presently Marston put down his pen and frowned.

"My brain's dull to-night," he said. "I ought to be satisfied with the results of our venture, but there are things I don't see quite plain. For example, we have got a lot of stuff for which we don't seem to have paid."

"You are supercargo," Wyndham rejoined. "The accounts are yours and they're remarkably accurate. All we have got is properly charged against us."

"That is so; I have used your figures. All the same, we haven't handed over much money."

"The business is largely done by barter."

"Of course," said Marston, with a touch of impatience. "We haven't delivered much goods against the account."

"The goods will be delivered. Our customers haven't yet stated the articles they want."

"This means they trust us until we can bring the stuff from England or America? In fact, they're willing to trust us for some time?"

"It looks like that," said Wyndham and laughed. "Are you puzzled about it, Bob? After all, Wyndhams' has long traded here and the house's reputation is obviously pretty good."

"But I understand your agents never got such stuff as we have got."

"They were agents and we are principals; I expect that accounts for something," Wyndham replied with a twinkle. "Besides, Wyndhams' never had a supercargo like you."

Marston frowned and tried to think of some other matters that had excited his curiosity, but could not make the effort, and Wyndham put a bottle and glasses on the table.

"Shut the books and I'll mix a cocktail," he said. "You're working too hard and it's very hot."

They went to bed soon afterwards and when he awoke Marston's head ached and he did not get up. He thought he had a dose of fever and felt strangely annoyed. Somehow he had not expected to get fever; he had thought Harry might get it, and to be kept in his bunk was a complication he had not reckoned on. Although Wyndham dosed him as the medical book directed, the fever did not abate. For some days he tossed about in his narrow bunk with a throbbing head and pain in his limbs, and then lay half-conscious in limp exhaustion. He had strange dreams and long remembered ones; indeed, he sometimes doubted if it were all a dream.

He imagined he was back at the factory on the African river and Wyndham's uncle, the man who vanished, was in the big mildewed room. Marston saw him come out of his door and stand for a moment listening, with his face touched by the moonlight; and then run forward and stop by the body on the boards. The dream was horribly vivid and real, but the big room got hazy and melted, as it were, into Columbine's cabin.

Marston saw the lamp, turned low, hang at an angle to the beams, and the charts and cargo books in the net rack. He smelt the mud and heard the ripples splash against the schooner's side. Somebody sat in front of the table and when the man looked up he saw it was Rupert Wyndham. Marston knew him because he had seen his portrait, but his hair had gone white and his skin very dark. In fact, he did not look like a white man. He got up and his face and bent figure melted as the room at the factory had melted, but very slowly got distinct again and Marston thrilled with repulsion and horror. Rupert Wyndham had changed to the old mulatto.

His naked feet made no noise as he crossed the floor and Marston struggled to get up but could not. His lips refused to move when he tried to call for help; the old fellow had fixed his bloodshot eyes on him and he felt powerless. The mulatto stopped by his bunk, holding out a glass, and Marston knew he meant to poison him. He resolved he would not drink, but felt he must. There was something in the fellow's steady look that broke his resistance and for a few moments he fought a horrible battle against a strange conquering force. Then he took the glass and drained it, and the mulatto melted away. He did not vanish. This implied suddenness; he faded out of the cabin by imperceptible degrees.

Marston knew no more and awoke in daylight, haunted by the dream. He was surprised to feel he was not worse; indeed, his head did not ache and although he was very weak the pain in his limbs had gone. His throat was parched and there was a strange taste in his mouth, as if he had swallowed the draught he dreamed about. Wyndham sat on the locker and got up when he saw Marston was awake.

"You look different. I think you have seen the worst," he said. "I've been bothered about you, Bob."

Marston smiled. He did not want to talk and the relief he saw in his comrade's face was soothing. He went to sleep again and it was dark when he awoke. He did not dream that night and in a few days got, rather shakily, out of his bunk. Wyndham put some cushions for him on the locker and they began to talk.

"The boat's full to the hatches and we go to sea to-morrow," Wyndham said. "If the wind keeps fair, I expect to put you on board the Spanish liner for the Canaries in three or four days. You'll transfer to a homeward Cape boat when you arrive."

"But I don't want to go home yet," Marston objected.

"You are going all the same," Wyndham declared. "You have been very ill and a sick man hasn't much chance in this miasmatic air. There's no use in arguing; you have got to go."

Marston grumbled, but they sailed with the next high tide, and when they made the port where the Spanish steamer lay he let Wyndham help him on board.