chunk: Later that night Robur kidnaps the Weldon Institute's secretary, president, and the president's valet. He takes them on board his ship, a huge, battery-powered, multirotor gyrodyne called the Albatross, which has many vertical airscrews to provide lift, and two horizontal airscrews in a push-pull configuration to drive the vessel forward. It bears the same black flag with golden sun that has been sighted on so many landmarks, and the music in the sky is explained to be one of the crewmen playing a trumpet. To demonstrate the vessel's superiority, Robur takes his captives around the world in the course of three weeks. The president and secretary are angry at Robur for kidnapping them and unwilling to admit that the Albatross is a fantastic vessel, or that their notions of "lighter than air" superiority are wrong. They demand that Robur release them, but he is aloof and always says that they shall remain as long as he desires it. Fearing they will be held captive forever, the two