After breakfast Hilliard disappeared. He went out ostensibly to post a letter, but it was not until nearly three o'clock that he turned up again.

“Sorry, old man,” he greeted Merriman, “but when I was going to the post office this morning an idea struck me, and it took me longer to follow up than I anticipated. I'll tell you. I suppose you realize that life in that barrel won't be very happy for the victim?”

“It'll be damnable,” Merriman agreed succinctly, “but we needn't worry about that; we're in for it.”

“Oh, quite,” Hilliard returned. “But just for that reason we don't want more of it than is necessary. We could easily bury ourselves twenty-four hours too soon.”

“Meaning?”

“Meaning that we mustn't go back to the wharf until the night before the Girondin arrives.”

“Don't see how we can be sure of that.”

“Nor did I till I posted my letter. Then I got my idea. It seemed worth following up, so I went round the shipping offices until I found a file of Lloyd's List. As you know it's a daily paper which gives the arrivals and departures of all ships at the world's ports. My notion was that if we could make a list of the Girondin's Ferriby arrivals and departures, say, during the last three months, and if we found she ran her trip regularly, we could forecast when she would be next due. Follow me?”

“Rather.”

“I had no trouble getting out my list, but I found it a bit disappointing. The trip took either ten, eleven, or twelve days, and for a long time I couldn't discover the ruling factor. Then I found it was Sunday. If you omit each Sunday the Girondin is in port, the round trip always takes the even ten days. I had the Lesque arrival and departure for that one trip when we were there, so I was able to make out the complete cycle. She takes two days in the Lesque to load, three to run to Hull, two at Ferriby to discharge, and three to return to France. Working from that and her last call here, she should be due back early on Friday morning.”

“Good!” Merriman exclaimed. “Jolly good! And today is Thursday. We've just time to get ready.”

They went out and bought a one-inch auger and a three-sixteenths bradawl, a thick footstool and a satchel. This latter they packed with a loaf, some cheese, a packet of figs, a few bottles of soda water and a flask of whisky. These, with their caps, rubber shoes, electric torches and the black cloth, they carried to their boat; then returning to the hotel, they spent the time resting there until eleven o'clock. Solemnly they drew lots for the first watch, recognizing that the matter was by no means a joke, as, if unloading were carried on by night, relief might be impossible during the ship's stay. But Merriman, to whom the fates were propitious, had no fear of his ability to hold out even for this period.

By eleven-thirty they were again sculling up the river. The weather was as perfect as that of the night before, except that on this occasion a faint westerly breeze had covered the surface of the water with myriads of tiny wavelets, which lapped and gurgled round the stem of their boat as they drove it gently through them. They did not hurry, and it was after one before they moored to the depot steps.

All was dark and silent above, as, carrying their purchases, they mounted to the wharf and crept stealthily to the barrel. Carefully they raised the lid, and Merriman, standing on the footstool, with some difficulty squeezed himself inside. Hilliard then lifted the footstool on to the rim and lowered the lid on to it, afterwards passing in through the opening thus left the satchel of food and the one-inch auger.

A means of observation now remained to be made. Two holes, they thought, should afford all the view necessary, one looking towards the front of the wharf, and the other at right angles, along the side of the shed. Slowly, from the inside, Merriman began to bore. He made a sound like the nibbling of a mouse, but worked at irregular speeds so as not to suggest human agency to anyone who might be awake and listening. Hilliard, with his hand on the outside of the barrel, stopped the work when he felt the point of the auger coming through, and he himself completed the hole from the outside with his bradawl. This gave an aperture imperceptible on the rough exterior, but large within, and enabled the watcher to see through a much wider angle than he could otherwise have done. Hilliard then once more raised the lid, allowing Merriman to lift the footstool within, where it was destined to act as a seat for the observer.

All was now complete, and with a whispered exchange of good wishes, Hilliard withdrew, having satisfied himself by a careful look round that no traces had been left. Regaining the boat, he loosed the painter and pulled gently away into the night.

Left to himself in the confined space and inky blackness of the cask, Merriman proceeded to take stock of his position. He was anxious if possible to sleep, not only to pass some of the time, which at the best would inevitably be terribly long, but also that he might be the more wakeful when his attention should be required. But his unusual surroundings stimulated his imagination, and he could not rest.

He was surprised that the air was so good. Fortunately, the hole through the lid which received the down spout was of large dimensions, so that even though he might not have plenty of air, he would be in no danger of asphyxiation.

The night was very still. Listening intently, he could not hear the slightest sound. The silence and utter darkness indeed soon became overpowering, and he took his watch from his pocket that he might have the companionship of its ticking and see the glimmering hands and ring of figures.

He gave himself up for the thousandth time to the consideration of the main problem. What were the syndicate people doing? Was Mr. Coburn liable to prosecution, to penal servitude? Was it possible that by some twist of the legal mind, some misleading circumstantial evidence, Miss Coburn—Madeleine—could be incriminated? Oh, if he but knew what was wrong, that he might be able to help! If he could but get her out of it, and for her sake Mr. Coburn! If they were once safe he could pass on his knowledge to the police and be quit of the whole business. But always there was this enveloping cloak of ignorance baffling him at every turn. He did not know what was wrong, and any step he attempted might just precipitate the calamity he most desired to avoid.

Suppose he went and asked her? This idea had occurred to him many times before, and he had always rejected it as impracticable. But suppose he did? The danger was that she might be alarmed or displeased, that she might refuse to admit there was anything wrong and forbid him to refer to the matter again or even send him away altogether. And he felt he was not strong enough to risk that. No, he must know where he stood first. He must understand his position, so as not to bungle the thing. Hilliard was right. They must find out what the syndicate was doing. There was no other way.

So the hours dragged slowly away, but at last after interminable ages had gone by, Merriman noticed two faint spots of light showing at his eyeholes. Seating himself on his footstool, he bent forward and put his eye first to one and then to the other.

It was still the cold, dead light of early dawn before the sun had come to awaken color and sharpen detail, but the main outlines of objects were already clear. As Merriman peered out he saw with relief that no mistake had been made as to his outlooks. From one hole or the other he could see the entire area of the wharf.

It was about five a.m., and he congratulated himself that what he hoped was the most irksome part of his vigil was over. Soon the place would awaken to life, and the time would then pass more quickly in observation of what took place.

But the three hours that elapsed before anything happened seemed even longer than those before dawn. Then, just as his watch showed eight o'clock, he heard a key grind in a lock, a door opened, and a man stepped out of the shed on the wharf.

He was a young fellow, slight in build, with an extremely alert and intelligent face, but a rather unpleasant expression. The sallowness of his complexion was emphasized by his almost jet black hair and dark eyes. He was dressed in a loose gray Norfolk jacket and knickerbockers, but wore no hat. He moved forward three or four feet and stood staring downstream towards Hull.

“I see her, Tom,” he called out suddenly to someone in the shed behind. “She's just coming round the point.”

There was another step and a second man appeared. He was older and looked like a foreman. His face was a contrast to that of the other. In it the expression was good—kindly, reliable, honest—but ability was not marked. He looked a decent, plodding, stupid man. He also stared eastward.

“Ay,” he said slowly. “She's early.”

“Two hours,” the first agreed. “Didn't expect her till between ten and eleven.”

The other murmured something about “getting things ready,” and disappeared back into the shed. Presently came the sounds of doors being opened, and some more empty Decauville trucks were pushed out on to the wharf. At intervals both men reappeared and looked down-stream, evidently watching the approach of the ship.

Some half an hour passed, and then an increase of movement seemed to announce her arrival. The manager walked once more down the wharf, followed by the foreman and four other men—apparently the whole staff—among whom was the bovine-looking fellow whom the friends had tried to pump on their first visit to the locality. Then came a long delay during which Merriman could catch the sound of a ship's telegraph and the churning of the screw, and at last the bow of the Girondin appeared, slowly coming in. Ropes were flung, caught, slipped over bollards, drawn taut, made fast—and she was berthed.

Captain Beamish was on the bridge, and as soon as he could, the manager jumped aboard and ran up the steps and joined him there. In a few seconds both men disappeared into the captain's cabin.

The foreman and his men followed on board and began in a leisurely way to get the hatches open, but for at least an hour no real activity was displayed. Then work began in earnest. The clearing of the hatches was completed, the ship's winches were started, and the unloading of the props began.

This was simply a reversal of the procedure they had observed at the clearing. The props were swung out in bundles by the Girondin's crew, lowered on to the Decauville trucks, and pushed by the depot men back through the shed, the empty trucks being returned by another road, and brought by means of the turn-tables to the starting point. The young manager watched the operations and took a tally of the props.

Merriman kept a close eye on the proceedings, and felt certain he was witnessing everything that was taking place. Every truckload of props passed within ten feet of his hiding place, and he was satisfied that if anything other than props were put ashore he would infallibly see it. But the close watching was a considerable strain, and he soon began to grow tired. He had some bread and fruit and a whisky and soda, and though he would have given a good deal for a smoke, he felt greatly refreshed.

The work kept on without intermission until one o'clock, when the men knocked off for dinner. At two they began again, and worked steadily all through the afternoon until past seven. During all that time only two incidents, both trifling, occurred to relieve the monotony of the proceedings. Early in the forenoon Bulla appeared, and under his instructions the end of the flexible hose from the crude oil tank was carried aboard and connected by a union to a pipe on the lower deck. A wheel valve at the tank was turned, and Merriman could see the hose move and stiffen as the oil began to flow through it. An hour later the valve was turned off, the hose relaxed, the union was uncoupled and the hose, dripping black oil, was carried back and left in its former place on the wharf. The second incident was that about three o'clock Captain Beamish and Bulla left the ship together and went out through the shed.

Merriman was now horribly tired, and his head ached intolerably from the strain and the air of the barrel, which had by this time become very impure. But he reflected that now when the men had left was the opportunity of the conspirators. The time for which he had waited was approaching, and he nerved himself to resist the drowsiness which was stealing over him and which threatened the success of his vigil.

But hour after hour slowly dragged past and nothing happened. Except for the occasional movement of one of the crew on the ship, the whole place seemed deserted. It was not till well after ten, when dusk had fallen, that he suddenly heard voices.

At first he could not distinguish the words, but the tone was Bulla's, and from the sounds it was clear the engineer and some others were approaching. Then Beamish spoke:

“You'd better keep your eyes open anyway,” he said. “Morton says they only stayed at work about a week. They're off somewhere now. Morton couldn't discover where, but he's trying to trace them.”

“I'm not afraid of them,” returned the manager's voice. “Even if they found this place, which of course they might, they couldn't find out anything else. We've got too good a site.”

“Well, don't make the mistake of underestimating their brains,” counseled Beamish, as the three men moved slowly down the wharf. Merriman, considerably thrilled, watched them go on board and disappear into the captain's cabin.

So it was clear, then, that he and Hilliard were seriously suspected by the syndicate and were being traced by their spy! What luck would the spy have? And if he succeeded in his endeavor, what would be their fortune? Merriman was no coward, but he shivered slightly as he went over in his mind the steps of their present quest, and realized how far they had failed to cover their traces, how at stage after stage they had given themselves away to anyone who cared to make a few inquiries. What fools, he thought, they were not to have disguised themselves! Simple disguises would have been quite enough. No doubt they would not have deceived personal friends, but they would have made all the difference to a stranger endeavoring to trace them from descriptions and those confounded photographs. Then they should not have travelled together to Hull, still less have gone to the same hotel. It was true they had had the sense to register under false names, but that would be but a slight hindrance to a skillful investigator. But their crowning folly, in Merriman's view, was the hiring of the boat and the starting off at night from the docks and arriving back there in the morning. What they should have done, he now thought bitterly, was to have taken a boat at Grimsby or some other distant town and kept it continuously, letting no one know when they set out on or returned from their excursions.

But there was no use in crying over spilt milk. Merriman repeated to himself the adage, though he did not find it at all comforting. Then his thoughts passed on to the immediate present, and he wondered whether he should not try to get out of the barrel and emulate Hilliard's exploit in boarding the Girondin and listening to the conversation in the captain's cabin. But he soon decided he must keep to the arranged plan, and make sure nothing was put ashore from the ship under cover of darkness.

Once again ensued a period of waiting, during which the time dragged terribly heavily. Everything without was perfectly still, until at about half past eleven the door of the captain's cabin opened and its three occupants came out into the night. The starboard deck light was on and by its light Merriman could see the manager take his leave, cross the gangway, pass up the wharf and enter the shed. Bulla went down towards his cabin door and Beamish, snapping off the deck light, returned to his. In about fifteen minutes his light also went out and complete darkness and silence reigned.

Some two hours later Merriman, who had kept awake and on guard only by the most determined effort, heard a gentle tap on the barrel and a faint “Hist!” The lid was slowly raised, and to his intense relief he was able to stand upright and greet Hilliard crouching without.

“Any news?” queried the latter in the faintest of whispers. “Absolutely none. Not a single thing came out of that boat but props. I had a splendid view all the time. Except this, Hilliard”—Merriman's whisper became more intense—“They suspect us and are trying to trace us.”

“Let them try,” breathed Hilliard. “Here, take this in.”

He handed over the satchel of fresh food and took out the old one. Then Merriman climbed out, held up the lid until Hilliard had taken his place, wished his friend good luck, and passing like a shadow along the wharf, noiselessly descended the steps and reached the boat. A few seconds later he had drifted out of sight of the depot, and was pulling with long, easy strokes down-stream.

The air and freedom felt incredibly good after his long confinement, and it was a delight to stretch his muscles at the oars. So hard did he row that it was barely three when he reached the boat slip in Hull. There he tied up the skiff and walked to the hotel. Before four he was sound asleep in his room.

That evening about seven as he strolled along the waterfront waiting until it should be time to take out his boat, he was delighted to observe the Girondin pass out to sea. He had dreaded having to take another twenty-four hours' trick in the cask, which would have been necessary had the ship not left that evening. Now all that was needed was a little care to get Hilliard out, and the immediate job would be done.

He took out the boat about eleven and duly reached the wharf. All was in darkness, and he crept to the barrel and softly raised the lid.

Hilliard was exhausted from the long strain, but with his friend's help he succeeded in clambering out, having first examined the floor of the barrel to see that nothing had been overlooked, as well as plugging the two holes with corks. They regained the boat in silence, and it was not until they were some distance from the wharf that either spoke.

“My goodness! Merriman,” Hilliard said at last, “but that was an awful experience! You left the air in that cursed barrel bad, and it got steadily worse until I thought I should have died or had to lift the lid and give the show away. It was just everything I could do to keep going till the ship left.”

“But did you see anything?” Merriman demanded eagerly.

“See anything? Not a blessed thing! We are barking up the wrong tree, Merriman. I'll stake my life nothing came out of that boat but props. No; what those people are up to I don't know, but there's one thing a dead cert, and that is that they're not smuggling.”

They rowed on in silence, Hilliard almost sick with weariness and disappointment, Merriman lost in thought over their problem. It was still early when they reached their hotel, and they followed Merriman's plan of the morning before and went straight to bed.

Next day they spent in the hotel lounge, gloomily smoking and at intervals discussing the affair. They had admitted themselves outwitted—up to the present at all events. And neither could suggest any further step. There seemed to be no line of investigation left which might bear better fruit. They agreed that the brandy smuggling theory must be abandoned, and they had nothing to take its place.

“We're fairly up against it as far as I can see,” Hilliard admitted despondently. “It's a nasty knock having to give up the only theory we were able to think of, but it's a hanged sight worse not knowing how we are going to carry on the inquiry.”

“That is true,” Merriman returned, Madeleine Coburn's face rising before his imagination, “but we can't give it up for all that. We must go on until we find something.”

“That's all very well. What are we to go on doing?”

Silence reigned for several minutes and then Hilliard spoke again.

“I'm afraid it means Scotland Yard after all.”

Merriman sat up quickly.

“Not that, not that!” he protested, as he had protested in similar terms on a previous occasion when the same SUGGESTION had been made. “We must keep away from the police at all costs.” He spoke earnestly.

“I know your views,” Hilliard answered, “and agree with them. But if neither of us can suggest an alternative, what else remains?”

This was what Merriman had feared and he determined to play the one poor trump in his hand.

“The number plates,” he suggested. “As I said before, that is the only point at which we have actually come up against this mystery. Why not let us start in on it? If we knew why those plates were changed, the chances are we should know enough to clear up the whole affair.”

Hilliard, who was suffering from the reaction of his night of stress, took a depressed view and did not welcome the SUGGESTION. He seemed to have lost heart in the inquiry, and again urged dropping it and passing on their knowledge to Scotland Yard. But this course Merriman strenuously opposed, pressing his view that the key to the mystery was to be found in the changing of the lorry numbers. Finally they decided to leave the question over until the following day, and to banish the affair from their minds for that evening by a visit to a music hall.