Stars and Stripes in Peril by Harry Harrison Page A

out from it and what appeared to be a rotating shaft projecting from one side. At last he could control his curiosity no longer. He tried to interrupt, but Ericsson was in full spate.
    "These turrets will be far smaller than those I have built before because there will be no need to pull the gun back into the turret after firing to reload through the muzzle. Being smaller the turret will be lighter, and that much easier to rotate. And without the need of pulling the guns in and out after each shot the rate of fire will be faster."
    He laughed as he clapped the small man on the back, sent him staggering. "There will be two turrets, four guns. And I shall design the fastest armored ship in the world to carry these guns into battle. No ship now afloat will stand against her!"
    He stepped back, smiling down at his design, and Parrott finally had a chance to speak. "Excellent, excellent indeed. When I return I shall begin work on the other three guns at once. But pardon me, if you don't mind—could you tell me what this machine is?"
    He tapped the black metal surface of the machine and Ericsson turned his way.
    "That is a prototype, still under development." He pointed back at the drawings of his iron ship. "This new ship will be big—and with size comes problems. Here look at this."
    He picked up a half-model of Monitor and pointed out the steam boiler. "A single source of steam here, that is more than enough in a ship this size. The turret you will notice is almost directly above the boiler. So it was simple enough to run a steam line to it to power the small steam engine that rotates the turret. But here, look at the drawing of Virginia. Her engine is on the lowest deck. While the turrets are far above, fore and aft. This means that I will need insulated steam lines going right through the ship. Even when they are insulated they get very hot. And there is the danger of ruptures, natural or caused by enemy fire. Live steam is not a nice thing to be near. Should I have a separate boiler under each turret? Not very practical. I have considered this matter deeply, and in the end I have decided to do it this way."
    "You have considered electric motors?"
    "I have. But none are large enough to move my turrets. And the generators are large, clumsy and inefficient. So I am considering a mechanical answer." He looked over at the engineer. "You have heard of the Carnot cycle?"
    "Of course. It is the application of the second law of thermodynamics."
    "It is indeed. The ideal cycle of four reversible changes in the physical condition of a substance. A steam engine works in a Carnot cycle, though since the source of energy is external it is not a perfect cycle. In my Carnot engine I am attempting to combine the complete cycle in a single unit. I first used coal dust as a fuel, fed into the cylinder fast enough so that isothermal expansion would take place when it burned."
    "And the results?" Parrott asked enthusiastically.
    "Alas, dubious at best. It was hard to keep the cylinder temperature high enough to assure combustion. Then there is the nature of the fuel itself. Unless it is ground exceedingly fine, a weary and expensive process at best, it tended to lump and clog the feed tube. To get around that problem I am now working with coal oil and other combustible liquids with improved results."
    "How wonderful! You will have a self-contained engine under each turret then. You will keep me informed of your progress?"
    "Of course."
    Parrott thought of the patent of the land battery that had been hanging on his office wall for many years. A most practical idea. Lacking only an engine sufficiently small to move it.
    Was Ericsson's machine going to fulfill that role?
    Gustavus Fox was signing papers at his desk when the two Irish officers came in. He waved them to the waiting chairs, then finished his task and put his pen aside.
    "General Meagher—do I have your permission to ask Lieutenant Riley a few questions?"
    "Ask away, your