faction. At first Mr. Swift thought that the visit of Mr. Berg would have unpleasant results, for he feared that the agent would talk about the craft, of which he had so unexpectedly gotten a sight. But nothing seemed to follow from his chance inspection, and it was forgotten.
It was one evening, about a week later, that Tom was alone in the shop. The two mechanics that had been hired to help out in the rush had been let go, and the ship needed but a few adjustments to make it ready for the sea.
"I think I'll just take another look at the water tank valves," said Tom to himself as he prepared to enter the big compartments which received the water ballast. "I want to be sure they work properly and quickly. We've got to depend on them to make us sink when we want to, and, that's more important, to rise to the surface in a hurry. I've got time enough to look them over before dad and Mr. Sharp get back."
Tom entered the starboard tank by means of an emergency sliding door between the big compartments and the main part of the ship. This was closed by a worm and screw gear, and once the ship was in the water would seldom be used.
The young inventor proceeded with his task, carefully inspecting the valves by the light of a lantern he carried. The apparatus seemed to be
