Now the stringers of the ship are long iron girders, so to speak, that run lengthways from stern to bow. They keep the iron frames (what are called ribs in a wooden ship) in place, and also help to hold the ends of the deck-beams, which go from side to side of the ship. Stringers always consider themselves most important, because they are so long. "You will take steps--will you?" This was a long echoing rumble. It came from the frames--scores and scores of them, each one about eighteen inches distant from the next, and each riveted to the stringers in four places. "We think you will have a certain amount of trouble in _that_;" and thousands and thousands of the little rivets that held everything together whispered: "You will. You will! Stop quivering and be quiet. Hold on, brethren! Hold on! Hot Punches! What's that?" Rivets have no teeth, so they cannot chatter with fright; but they did their best as a fluttering jar swept along the ship from stern to bow, and she shook like a rat in a terrier's mouth. An unusually severe pitch, for the sea was rising, had lifted the big throbbing screw nearly to the surface, and it was spinning round in a kind of soda-water--half sea and half air--going much faster than was proper, because there was no deep water for it to work in. As it sank again, the engines--and they were triple expansion, three cylinders in a row--snorted through all their three pistons, "Was that a joke, you fellow outside? It's an uncommonly poor one. How are we to do our work if you fly off the handle that way?" "I did n't fly off the handle," said the screw, twirling huskily at the end of the screw-shaft. "If I had, you'd have been scrap-iron by this time. The sea dropped away from under me, and I had nothing to catch on to. That's all." "That's all, d'you call it?" said the thrust-block whose business it is to take the push of the screw; for if a screw had nothing to hold it back it would crawl right into the engine-room. (It is the holding back of the screwing action that gives the drive to a ship.) "I know I do my work deep down and out of sight, but I warn you I expect justice. All I ask for is bare justice. Why can't you push steadily and evenly instead of whizzing like a whirligig, and making me hot under all my collars." The thrust-block had six collars, each faced with brass, and he did not wish to get them heated. All the bearings that supported the fifty feet of screw-shaft as it ran to the stern whispered: "Justice--give us justice." "I can only give you what I can get," the screw answered. "Look out! It's coming again!" He rose with a roar as the _Dimbula_ plunged, and "whack--flack--whack--whack" went the engines, furiously, for they had little to check them.