They were discussing the escape-valve in a diver's helmet, and arguing whether it pays to stiffen the spring for very deep diving. Atkinson, who had worked eight fathoms deeper than either of them, said he left his spring alone; he used the same suit and the same valve action for any depth.
"But I look out for sand-banks," said he, "ever since that fellow—you know who I mean—had one cave in on him in the North River. He was tunneling under a vessel with a wall of sand beside him higher than his head, and the first thing he knew he was flat on his back, with sand jammed in his valve so it couldn't open. It wasn't a minute before he was shot up to the surface like a balloon. The reason of that," he explained for my benefit, "is because a diving-suit with its valve shut gets lighter and lighter as they drive down air from the air-pump, until all of a sudden it comes up, man and all, just as a plank would if you held it on the bottom and then let it go."
THE MAN WHO ATTENDS TO THE DIVER'S SIGNALS.
"Talking about planks coming up," said Timmans, who was seated under the picture of a prize-fighter, "I was down on the North German Lloyd steamer Main, the one that was burned and sunk, fixing a suction-pipe to pump grain out of her, when a big wooden hatch got loose and came up under me. I was working between decks, and the hatch swung me right up against the overhead beams and held me there, squeezing the life-line and hose so tight I couldn't signal. It's lucky the hose was wire wound, or that would have been the last of me. But I got my air all right, and after a while I worked free."
"Wire wound and all," observed Atkinson, "I've had my hose squeezed so the air was shut off. I was on a wreck off one of the Hoboken docks once, when an eight-inch suction-pipe caught the hose coming down through a hatch, and the next second I felt my air stop, though I could hear the pump beating. I jerked 'slack away' on the life-line, and that loosed the hose and saved me, but I got a blast of compressed air as the jam eased that jumped me up a yard."
"Suppose your life-line had been jammed, too," I asked, "so that you couldn't jerk 'slack away'?"
Atkinson paused to think. "There's a difference of opinion about how long a man can live on the air that's in his helmet. Some say three or four minutes. I don't believe it. I think two minutes would do the business."
"There was George Seaman—" began Timmans.
"Yes," said Atkinson, taking up the story, as was a senior's right, "there was George Seaman, who put trust in the argument of Tom Scott and Low and some of those old-timers, that a man can cut his hose and press his thumb quick against the hole and live long enough on what air's in the helmet to reach the top. Years ago they used to give that talk to us youngsters, but I notice none of 'em ever tried it. Well, Seaman, he did try it; he was down on a wreck somewhere along Sixtieth Street, and his hose got caught in the timbers. The life-line was all right, and he was getting air enough, only when they tried to haul him up he stuck on account of the hose. They tried three times to lift him, and each time he'd come up a few feet and stick, and then they'd have to let him fall back. You can see that's awful discouraging for a man, especially when he's tired and cold. If Seaman had kept his nerve and waited they'd prob'bly have sent another diver down to get him untangled, but he didn't keep his nerve. All he saw was that the hose was caught and he couldn't free it, and they couldn't get him up. It's a lot easier to get rattled at the bottom of a river than up in the air, and Seaman called to mind what he'd heard about stopping the hole with your thumb, and he got out his knife. All divers carry a knife fast to the suit. See, like this." He drew a two-edged knife, a wicked-looking weapon, out of its leathern sheath, and moved his thumb along the edge.