The Governor's Balls is a Misnomer

I always thought the phrase "driving balls out" was a crude reference to speed and not much caring what anyone thought.

Oh how wrong I was.

Turns out that engines have a linkage from an RPM monitor to the engine. Point being that the power source could create more power than the engine can handle. So at maximum levels, the monitor would slow or stop supplying power so as not to damage the engine. Seems reasonable.

Back in 1860 or so, the monitor was this set of spinning balls, called the Governor Balls. It governed the cessation of excess power to preserve the engine.

So these balls would spin above the engine. Two of them on chains or whatever. They'd spin opposite of each other. As power increased, the balls would spin faster and higher. At maximum power, the balls would swing at their apex - straight out at 90 degrees.

How fast we going? Balls out, sir.

Good fact.