XX. Moonlight--and a Clue
 

"Are you satisfied? Have you got what you wanted?" asked Sweetwater, when they were well away from the shore and the voice they had heard calling at intervals from the chasm they had left.

"Yes. You're a good fellow. It could not have been better managed." Then, after a pause too prolonged and thoughtful to please Sweetwater, who was burning with curiosity if not with some deeper feeling: "What was that light you burned? A match?"

Sweetwater did not answer. He dared not. How speak of the electric torch he as a detective carried in his pocket? That would be to give himself away. He therefore let this question slip by and put in one of his own.

"Are you ready to go back now, sir? Are we all done here?" This with his ear turned and his eye bent forward; for the adventure they had interrupted was not at an end, whether their part in it was or not.

Mr. Grey hesitated, his glances following those of Sweetwater.

"Let us wait," said he, in a tone which surprised Sweetwater. "If he is meditating an escape, I must speak to him before he reaches the launch. At all hazards," he added after another moment's thought.

"All right, sir--How do you propose--"

His words were interrupted by a shrill whistle from the direction of the bank. Promptly, and as if awaiting this signal, the two men in the rowboat before them dipped their oars and pulled for the shore, taking the direction of the manufactory.

Sweetwater said nothing, but held himself in readiness.

Mr. Grey was equally silent, but the lines of his face seemed to deepen in the moonlight as the boat, gliding rapidly through the water, passed them within a dozen boat-lengths and slipped into the opening under the manufactory building.

"Now row!" he cried. "Make for the launch. We'll intercept them on their return."

Sweetwater, glowing with anticipation, bent to his work. The boat beneath them gave a bound and in a few minutes they were far out on the waters of the bay.

"They're coming!" he whispered eagerly, as he saw Mr. Grey looking anxiously back. "How much farther shall I go?"

"Just within hailing distance of the launch," was Mr. Grey's reply.

Sweetwater, gaging the distance with a glance, stopped at the proper point and rested on his oars. But his thoughts did not rest. He realized that he was about to witness an interview whose importance he easily recognized. How much of it would he hear? What would be the upshot and what was his full duty in the case? He knew that this man Wellgood was wanted by the New York police, but he was possessed with no authority to arrest him, even if he had the power.

"Something more than I bargained for," he inwardly commented. "But I wanted excitement, and now I have got it. If only I can keep my head level, I may get something out of this, if not all I could wish."

Meantime the second boat was very nearly on them. He could mark the three figures and pick out Wellgood's head from among the rest. It had a resolute air; the face on which, to his evident discomfiture, the moon shone, wore a look which convinced the detective that this was no patent-medicine manufacturer, nor even a caterer's assistant, but a man of nerve and resources, the same, indeed, whom he had encountered in Mr. Fairbrother's house, with such disastrous, almost fatal, results to himself.

The discovery, though an unexpected one, did not lessen his sense of the extreme helplessness of his own position. He could witness, but he could not act; follow Mr. Grey's orders, but indulge in none of his own. The detective must continue to be lost in the valet, though it came hard and woke a sense of shame in his ambitious breast.

Meanwhile Wellgood had seen them and ordered his men to cease rowing.

"Give way, there," he shouted. "We're for the launch and in a hurry."

"There's some one here who wants to speak to you, Mr. Wellgood," Sweetwater called out, as respectfully as he could. "Shall I mention your name?" he asked of Mr. Grey.

"No, I will do that myself." And raising his voice, he accosted the other with these words: "I am the man, Percival Grey, of Darlington Manor, England. I should like to say a word to you before you embark."

A change, quick as lightning and almost as dangerous, passed over the face Sweetwater was watching with such painful anxiety; but as the other added nothing to his words and seemed to be merely waiting, he shrugged his shoulders and muttered an order to his rowers to proceed.

In another moment the sterns of the two small craft swung together, but in such a way that, by dint of a little skilful manipulation on the part of Wellgood's men, the latter's back was toward the moon.

Mr. Grey leaned toward Wellgood, and his face fell into shadow also.

"Bah!" thought the detective, "I should have managed that myself. But if I can not see I shall at least hear."

But he deceived himself in this. The two men spoke in such low whispers that only their intensity was manifest. Not a word came to Sweetwater's ears.

"Bah!" he thought again, "this is bad."

But he had to swallow his disappointment, and more. For presently the two men, so different in culture, station and appearance, came, as it seemed, to an understanding, and Wellgood, taking his hand from his breast, fumbled in one of his pockets and drew out something which he handed to Mr. Grey.

This made Sweetwater start and peer with still greater anxiety at every movement, when to his surprise both bent forward, each over his own knee, doing something so mysterious he could get no clue to its nature till they again stretched forth their hands to each other and he caught the gleam of paper and realized that they were exchanging memoranda or notes.

These must have been important, for each made an immediate endeavor to read his slip by turning it toward the moon's rays. That both were satisfied was shown by their after movements. Wellgood put his slip into his pocket, and without further word to Mr. Grey motioned his men to row away. They did so with a will, leaving a line of silver in their wake. Mr. Grey, on the contrary, gave no orders. He still held his slip and seemed to be dreaming. But his eye was on the shore, and he did not even turn when sounds from the launch denoted that she was under way.

Sweetwater; looking at this morsel of paper with greedy eyes, dipped his oars and began pulling softly toward that portion of the beach where a small and twinkling light defined the boat-house. He hoped Mr. Grey would speak, hoped that in some way, by some means, he might obtain a clue to his patron's thoughts. But the English gentleman sat like an image and did not move till a slight but sudden breeze, blowing in-shore, seized the paper in his hand and carried it away, past Sweetwater, who vainly sought to catch it as it went fluttering by, into the water ahead, where it shone for a moment, then softly disappeared.

Sweetwater uttered a cry, so did Mr. Grey.

"Is it anything you wanted?" called out the former, leaning over the bow of the boat and making a dive at the paper with his oar.

"Yes; but if it's gone, it's gone," returned the other with some feeling. "Careless of me, very careless,--but I was thinking of-- "

He stopped; he was greatly agitated, but he did not encourage Sweetwater in any further attempts to recover the lost memorandum. Indeed, such an effort would have been fruitless; the paper was gone, and there was nothing left for them but to continue their way. As they did so it would have been hard to tell in which breast chagrin mounted higher. Sweetwater had lost a clue in a thousand, and Mr. Greywell, no one knew what he had lost. He said nothing and plainly showed by his changed manner that he was in haste to land now and be done with this doubtful adventure.

When they reached the boat-house Mr. Grey left Sweetwater to pay for the boat and started at once for the hotel.

The man in charge had the bow of the boat in hand, preparatory to pulling it up on the boards. As Sweetwater turned toward him he caught sight of the side of the boat, shining brightly in the moonlight. He gave a start and, with a muttered ejaculation, darted forward and picked off a small piece of paper from the dripping keel. It separated in his hand and a part of it escaped him, but the rest he managed to keep by secreting it in his palm, where it still clung, wet and possibly illegible, when he came upon Mr. Grey again in the hotel office.

"Here's your pay," said that gentleman, giving him a bill. "I am very glad I met you. You have served me remarkably well."

There was an anxiety in his face and a hurry in his movements which struck Sweetwater.

"Does this mean that you are through with me?" asked Sweetwater. "That you have no further call for my services?"

"Quite so," said the gentleman. "I'm going to take the train to-night. I find that I still have time."

Sweetwater began to look alive.

Uttering hasty thanks, he rushed away to his own room and, turning on the gas, peeled off the morsel of paper which had begun to dry on his hand. If it should prove to be the blank end! If the written part were the one which had floated off! Such disappointments had fallen to his lot! He was not unused to them.

But he was destined to better luck this time. The written end had indeed disappeared, but there was one word left, which he had no sooner read than he gave a low cry and prepared to leave for New York on the same train as Mr. Grey.

The word was--diamond.