It's one on those thingies you see at amusement parks. You get into a small gondola, the machine starts whirling about, and centrifugal force lifts the gondolas up in the air. Me, I prefer bumper cars.
Sir Hiram Maxim was an American who moved to Great Britain, where he invented the Maxim gun, curling irons and a coffee substitute, as well as other gizmos outside that narrow range. He was probably responsible for the British in general, and Agatha Christie in particular, thinking that 'Hiram' was a common American name.
There's no sign of Sir Hiram in this short. He was probably off somewhere, inventing a mousetrap. He died in 1916, aged 76.