Before the steam engine there was no general-purpose way to move water uphill. There were specific ways — each one a different bargain between how high you needed the water, how much of it you needed, and what you had to pull with. These three machines sit at three corners of that bargain, and all three were still in daily use within living memory. Pick one and take it apart.
Every point on these curves is the most water the machine can move at
that lift, found by optimising each sim's own parameters — slope, pot spacing, lever
ratio, prime mover — against its own physics. No curve here is copied from a table: each
falls out of Q = ηP / ρgH
and the losses that machine actually suffers, and each sim checks itself against a
measured historical range once you are inside it.
Lift axis is the shared 0–30 m scale used in all three sims; the saqiyah runs off the top of it, and a deep well is the one thing only it can do. The curves reach past the typical spans on the cards because the sliders do: a dragon bone with a twelve-metre trough at forty-five degrees really will lift 8.5 m — it is just not what anyone built. Inside each sim the small corner plot shows the other thing, a typical machine of each kind rather than the best one.
What each machine spends, and what it will not do.
| Dragon bone | Saqiyah | Shaduf | |
|---|---|---|---|
| Prime mover | men, ox or stream | one draft animal | one man |
| Typical lift | 0.3–4 m | 3–30 m | 0.5–3 m/stage |
| Best flow | 123 m³/h | 42 m³/h | 19 m³/h |
| Efficiency as it starts |
50% | 53% | 66% |
| Loses work to | leakage past the pallet clearance, and drag on the trough floor | a wooden gear train, and pots carried past the discharge | hauling its own bucket and pole back down again |
| Duty | continuous | continuous, all day | one man's cycle, then rest |
| Wears out at | the pallets and the trough | the gear teeth and the pot ropes | the operator |
| Cannot | reach a deep well — the trough would be absurdly long | be built or repaired without a carpenter | run unattended, or reach past a man's arms without stacking |