He went back up the slip, hoping he might be able to see the tug's deck. Now he was on higher ground, he noted a faint and rather puzzling illumination behind her bulwarks. Its position indicated that it came from the engine-room and he imagined the skylight was open but somebody had thrown a tarpaulin across the frames. The hinged lights opened from the bottom, and perhaps the engineer wanted to dry his paint and yet keep the heavy dew off the machinery. Anyhow, since there was a light in the engine-room, one could see below. Marston hesitated at the bottom of the ladder. It would be very awkward if he were caught on board the tug; but he must find out if she were ready for sea and he wore light, rubber-soled deck shoes. The ladder was not fastened, for the top began to slip along the plates when he climbed, and he was forced to reach up and seize the rail. Next moment he stepped cautiously down on deck. Nobody seemed to have heard him and all was dark but for the glow from the skylight, which only shone for a few feet on the damp planks. As Marston made for the engine-room his foot struck an iron drum and he stopped. It was a paint-drum, but he must discover if it were empty and what paint the crew had used. He tilted the drum and its lightness indicated that there was not much inside. Then he turned it round carefully until he could see the brass label on the top. The letters were obscured by paint, but he distinguished JES--and was satisfied. He knew the famous anti-fouling composition; the crew had put on the last coat and, so far as her being painted went, the tug was ready for sea. Now he must look at her engines, and he put back the drum. Its rim jarred on the deck and Marston thought he heard a movement below. Stooping down, he looked under the tarpaulin and got something of a shock. A man stood on the floor plates in the engine-room, with his face turned up towards the skylight as if he had been disturbed. Marston could not see him well, because the bars of the top platform were in the way, but the fellow carried a small, bright piece of steel and a ball of waste. It looked as if he had been cleaning a valve-spindle, and his working at night was significant. Marston's heart beat, but after a few moments the other seemed to be satisfied and sitting down on a locker picked up a file. When the fellow bent his head over his work Marston glanced carefully about the engine-room. He saw the condenser; the cover was on, which indicated that the repairs were finished. A chain tackle hung from the beams above the cylinders and some nuts lay about their heads. The pistons had obviously been lifted in order to put on new rings. Other things Marston noted implied that the engines had been given a thorough overhaul. He thought the work was nearly completed, but when one examined a vessel's engines the boiler was generally opened and he crept cautiously to the stokehold.