“The amphibian burns wood alcohol to generate steam,” Sam said. “Let’s go inside, through this hatch in the side here. You’ll notice that the boiler takes up about a third of the interior. There’s a good reason for that, as you’ll see.”
They climbed up a ladder into the interior of the center turret, which was lit by a single light bulb. Firebrass exclaimed at this. It was the only electric light bulb he had ever seen on The River. Sam explained that it was powered by a fuel cell.
“And here is the Superdooper Steam Machine Cannon,” he said. He pointed at the cylinder sticking out of the gray bulkhead of the turret. Underneath it were a pistollike butt and a trigger. Firebrass got behind it, put his finger on the trigger and looked out through the opening above the barrel. He raised and lowered the weapon.
“There’ll be a chair for the operator to sit in,” Sam said. “He’ll be able to rotate the turret any way he wants by pushing pedals. He can depress the gun about twenty degrees up or down. The steam from the boiler is the motive power for the eighty-caliber plastic bullets. The gun is fired from an open breech—that is, there’s no bullet in the barrel when the trigger is pulled. Pulling the trigger releases a catch which permits the breech block to move forward, impelled by a spring. During its forward travel, the breech block picks up a plastic bullet from the clip and pushes it into the breech. Just before the block reaches the breech, the camming lugs on either side engage in their slots and turn the breech block a quarter turn to the right, thus locking the breech. You follow me?” Firebrass nodded.
“Good. As soon as the quarter turn is completed, the inlet channel in the breech block comes into line with the feed channel from the high-pressure steam line. This allows hot, say approximately four-hundred-degree F., steam to enter the chamber in the breech block. The plastic cartridge is forced through the barrel by the expansion of steam. At the same time the steam pressure, acting against the rear of the chamber, begins to force the breech block back. Because of the greater weight of the block, however, the block doesn’t begin to move until the bullet has already cleared the muzzle of the rifle.
“As the block begins to move backward, the camming lugs move in the camming slots and turn the bolt a quarter turn to the left, thus shutting off the steam. Then the breech block returns to its original position. If the trigger is still held back, the operation is repeated indefinitely.”
Firebrass said, “I’m impressed, but won’t the gun operate most efficiently if its temperature is the same as the incoming high-pressure steam? That way, less of the steam’s energy would be used to heat the gun and this means more steam to propel the bullet. Ah, I see! You do have a hollow jacket around the barrel. The steam travels through that before it enters the weapon itself, right?”
“Yes. There’s an insulating jacket of plaster encased in wood. Note that bleeder valve. It permits the gun to be heated up before use—a few seconds before it’s fired. If that isn’t done, the gun might jam. And since the gun’s maximum temperature is the same as the steam in the boiler, there’s no danger of burning up the barrel. You can use the gun like a fire hose. In fact, that’ll be about the only way it’ll be effective. The accuracy of a light plastic bullet with such comparatively low muzzle velocity isn’t high.”
Firebrass was far from being depressed because of the military superiority the amphibian would give Parolando. This probably was because he was planning on building one for Soul City. Or, if Parolando had one, then perhaps he might build two. In which case, Parolando would have to build three.
Soul City could not outbuild Parolando. But Parolando could not cut the supplies off, because then Soul City would cut off the bauxite, cryolite, platinum and indium.
The exhilaration from showing off his deadly invention whistled out almost audibly from Sam. The only solution to the problem, if Soul City did start a weapons race, would be to smash Soul City and take direct control of the minerals. This meant putting off the building of the Riverboat. And it also meant offending the two states, Publiujo and Tifonujo, that lay between Parolando and Soul City. And if those two states got together, they would be formidable, what with the weapons that Parolando had to give them in exchange for their wood.