Napoleon I beckoned Napoleon II to step forward.
Napoleon II obliged and moved closer to the table.
"My son had a brilliant idea about steam engines," Napoleon I said. "I am told the technology has many applications."
"That's correct, Sire," Antoine Lefèvre replied. He cleared his throat and turned slightly so both the Emperor and the boy could see the diagrams spread before him. "The Newcomen engine from Britain is the most well-known example at present."
He tapped the sketch with a fingertip.
"It was designed primarily for pumping water from mines. The principle is simple. Steam is introduced into a vertical cylinder, then rapidly condensed by cold water. This creates a vacuum. Atmospheric pressure then pushes the piston downward."
Napoleon raised an eyebrow. "So the power comes not from steam pressure, but from air?"
"Yes, Sire. The piston is connected to a beam, which drives a pump. It is slow, inefficient, and consumes a great deal of coal—but it works continuously. That alone makes it revolutionary."
Napoleon II listened closely, hands folded behind his back, and looked at Napoleon I.
"How's your design different from the Newcomen steam engine?"
Napoleon II cleared his throat as he prepared for an explanation.
Napoleon II stepped closer to the table and pulled one of his own drawings forward. The lines were rough, but deliberate.
"My design separates the processes," he continued. "You do not condense the steam inside the working cylinder. You keep the cylinder hot at all times."
Napoleon leaned in. "And how do you create the vacuum, then?"
"With a separate condenser," Napoleon II replied, tapping a smaller chamber drawn beside the cylinder. "Steam does its work by pushing the piston. Then it is routed away and condensed elsewhere. The cylinder never cools."
Antoine's eyes widened slightly. "That would drastically reduce heat loss."
"Yes," Napoleon II said. "Which means less coal. More cycles per minute. More power from the same size engine."
Napoleon straightened, interest sharpening. "So the steam itself does the pushing."
"Exactly," Napoleon II said. "Controlled pressure. Not atmospheric chance."
He traced the motion with his finger. Up. Down. Then to a wheel.
"And instead of a simple beam, we convert linear motion into rotation using a crank and flywheel. Once rotation is steady, the engine can drive anything."
Antoine leaned forward now, fully engaged. "Textile looms. Rolling mills. Lathes."
"Water pumps," Napoleon II added. "Canal locks. Grain mills. Even ships, eventually."
He traced the motion with his finger. Up. Down. Then to a wheel.
"And instead of a simple beam, we convert linear motion into rotation using a crank and flywheel. Once rotation is steady, the engine can drive anything."
Antoine leaned forward now, fully engaged. "Textile looms. Rolling mills. Lathes."
"Water pumps," Napoleon II added. "Canal locks. Grain mills. Even ships, eventually."
Napoleon's fingers tightened slightly on the edge of the table. "Ships?"
"Yes," Napoleon II said evenly.
"How do you know all of this?" Antoine inquired.
"I'm a genius," Napoleon II simply answered.
The room went quiet.
"Antoine, with a full state backing, how long can you build this steam engine?"
Antoine hesitated, eyes returning to the drawing. He studied the proportions, the condenser placement, the crank. His fingers hovered over the paper without touching it.
"With full state backing…" he began carefully, "…and assuming access to good iron, skilled machinists, and a workshop not interrupted by politics—"
Napoleon cut in. "You will have all of that."
Antoine nodded once. "Then a working prototype could be built within twelve to eighteen months."
The room remained silent.
"That long?" Napoleon asked, not displeased, but weighing the cost.
"Yes, Sire," Antoine said. "Not because the idea is flawed, but because our limitations are mechanical. The greatest obstacle is precision. Boring a cylinder perfectly round. Keeping tolerances tight enough so steam does not escape. Training men who can reproduce the parts consistently."
Napoleon II spoke again. "Which is why the first engines should be large and stationary."
Antoine looked at him sharply. "Exactly. Large tolerances are more forgiving. Mines. Pump houses. Mills near rivers."
Napoleon II nodded. "Once we master those, we shrink them. Refine them. Then mobility becomes possible."
Napoleon exhaled slowly through his nose. "And the cost?"
Antoine did not evade it. "High. Initially. But once the tooling exists, once we standardize components, the cost drops rapidly. The second engine is always cheaper than the first."
Napoleon turned away from the table, pacing once across the room.
"And coal consumption?" he asked without looking back.
Napoleon II answered before Antoine could. "Half of Newcomen's. Possibly less."
That made Napoleon stop.
Antoine confirmed it with a nod. "If the separate condenser works as described… yes. Possibly even better."
"That's good to hear. The state will invest in it," Napoleon I said and then added. "Now my son also said about mass-producing steel, I believe that's an expertise of Delaunay. I want to hear your opinion about this."