James Watt is usually credited with inventing the steam engine.
In fact this isn’t true.
Watt didn’t invent the steam engine – he reinvented the steam engine.
The same way Steve Jobs didn’t invent the computer – he reinvented the computer.
Just like Jobs, Watt was a marketing genius.
Thomas Newcomen actually invented the first practical steam engine in 1712.
It was slow and inefficient, but nobody knew any better.
Steam would be forced into a piston, which would raise a beam.
Cold water would then be sprayed on to the cylinder, which would dissipate the steam, which would lower the piston and lower the beam.
In this way, water could be slowly pumped up from 25 feet down a mineshaft.
The problem was, after each stroke the cylinder lost its heat and had to be warmed again.
So it was slow and inefficient.
What Watt invented, in 1775, was a separate cylinder to spray cold water on to the steam.
This meant the main cylinder always stayed hot, so it moved much faster.
Then Watt added a flywheel, which translated the up-and-down motion into rotary motion.
So the entire engine was non-stop and much more efficient, pumping water from 150 feet down the mineshaft.
In fact, the engine was so efficient it used 75% less coal.
So getting market share was easy for Watt.
He would agree to take a third of the savings Newcomen engine users would make on coal.
They’d still keep two-thirds of the savings.
They couldn’t lose, and Watt made a fortune.
That took care of market share, but the real opportunity was market growth.
Most people still used horses.
How could Watt persuade people to switch from horses to his steam engine?
He needed to create a comparison they could understand.
He started with the fact that the average horse pushed a beam attached to a mill wheel: the average mill wheel was 12-foot radius, which made the circumference 75 feet.
The average horse could walk 144 circuits per hour, lifting 180 pounds, which equalled 550 foot-pounds per second.
So everyone could agree that was the work rate of one horse.
And that is how Watt invented the unit called a "horse power".
Now he could talk to people about how many horses his steam engine could replace.
Each horse worked an eight-hour shift, but a steam engine worked non-stop.
So a "one horse power" steam engine could replace three horses.
In fact, Watt’s early steam engines replaced 500 horses at a single colliery.
"Horse power" was a comparison everyone could understand.
Suddenly Watt had put the steam engine into a language that made sense to the layman.
Which is exactly what Jobs did when he launched the iPod.
He didn’t compare it to other MP3 players for speed and fidelity.
That would have been a market share comparison.
Jobs had a much bigger opportunity in mind – market growth.
That’s why he compared the iPod to something ordinary people could understand.
He simply held it up and said: "It’s a thousand songs in your pocket."
Because 200 years later, the rules for creative communication hadn’t changed.
You talk to your audience in their language, not yours.
That’s the only route into their minds.
Technology may change, but people don’t.
Dave Trott is the author of Creative Mischief, Predatory Thinking and One Plus One Equals Three.