• drag up and down on the sliding beam to take control of the engine
• drag in the 'correct' direction, and to the end of each movement
• drag off the beam to stop the engine, click the beam to start it up again
to show an indicator graph, this idea was developed much later by James Watt but it will help you to understand the physics underlying the Newcomen engine
• you can now drag on the beam in both directions
• up for 'forwards' and down for 'backwards'
drag the beam to a position where you think that there would be a vacuum in the cylinder, and check to see if you are right