Assertion: steam engine | /r/HasAspect | piston
Facets:
Source sentences:
text: Pioneered by Englishman Thomas Newcomen (1663/4–1729) in the early 18th century, they had a single cylinder and a piston attached to a large beam that rocked back and forth.
text: Today many steam engines are still at work, but they are almost all turbines which have no pistons but spin like a windmill pushed by jets of steam.