The men of this island, in fact, are absorbed in such deep thought on astronomy and math that the women often take lovers from Balnibarbi, the island directly below.  
At its center is a chasm of fifty yards in diameter, connected to a dome known as the Flandona Gagnole, or astronomers' cave.  The rich employ servants known as climenoles, or flappers, who carry bladders full of small stones used as a stimulus to remind people to speak or listen to others.  The men of this island, in fact, are absorbed in such deep thought on astronomy and math that the women often take lovers from Balnibarbi, the island directly below.  For 10 points - name this floating island visited by Lemuel Gulliver.
At its center is a chasm of fifty yards in diameter, connected to a dome known as the Flandona Gagnole, or astronomers' cave.  
Laputa