Heron's Aeolipile: Why Was Steam Power Kept as a Demonstration?
Around the first century CE, in Alexandria in Roman Egypt, the engineer Heron described a device called an aeolipile. A boiler sent steam into a hollow sphere. Steam escaped through bent tubes on its sides and made the sphere rotate. The device showed that steam could create rotary motion. It was not yet a piston engine for driving a pump or a loom, although many histories call it a precursor of the steam engine.