First steam engine. Drawing of the first-ever steam engine or Aeoliphile, designed by the Greek engineer Hero of Alexandria (flourished 1st century AD). The vessel in the lower frame was filled with water which was then heated. Steam from the vessel travelled up the two tubes supporting the hollow sphere at upper centre. Two jets of steam escaped from bent tubes in the side of the sphere, making it rotate because of the law of action and reaction. Although this was the first steam engine, it was very inefficient and remained a novelty. The first practical steam engines appeared in the early 18th century. Hero's engine was described in his Pneumatics.