When we were outside the little town I found the starlight was quite sufficient for my purpose. The white roadway, the low walls, and objects about us, could easily be distinguished. "Now," said I to Mr. Gilbert, "I want to put this knapsack on you, and let you see how it feels, and how it will help you to walk." To this he assented with some eagerness, and I strapped it firmly on him. "I will now turn this screw," said I, "until you shall become lighter and lighter." "Be very careful not to turn it too much," said my wife, earnestly. "Oh, you may depend on me for that," said I, turning the screw very gradually. Mr. Gilbert was a stout man, and I was obliged to give the screw a good many turns. "There seems to be considerable hoist in it," he said, directly. And then I put my arms around him, and found that I could raise him from the ground. "Are you lifting me?" he exclaimed, in surprise. "Yes; I did it with ease," I answered. "Upon--my--word!" ejaculated Mr. Gilbert. I then gave the screw a half-turn more, and told him to walk and run. He started off, at first slowly, then he made long strides, then he began to run, and then to skip and jump. It had been many years since Mr. Gilbert had skipped and jumped. No one was in sight, and he was free to gambol as much as he pleased. "Could you give it another turn?" said he, bounding up to me. "I want to try that wall." I put on a little more negative gravity, and he vaulted over a five-foot wall with great ease. In an instant he had leaped back into the road, and in two bounds was at my side. "I came down as light as a cat," he said. "There was never anything like it." And away he went up the road, taking steps at least eight feet long, leaving my wife and me laughing heartily at the preternatural agility of our stout friend. In a few minutes he was with us again. "Take it off," he said. "If I wear it any longer I shall want one myself, and then I shall be taken for a crazy man, and perhaps clapped into an asylum." "Now," said I, as I turned back the screw before unstrapping the knapsack, "do you understand how I took long walks, and leaped and jumped; how I ran uphill and downhill, and how the little donkey drew the loaded wagon?" "I understand it all," cried he. "I take back all I ever said or thought about you, my friend." "And Herbert may marry Janet?" cried my wife. "_May_ marry her!" cried Mr. Gilbert. "Indeed, he _shall_ marry her, if I have anything to say about it! My poor girl has been drooping ever since I told her it could not be." My wife rushed at him, but whether she embraced him or only shook his hands I cannot say; for I had the knapsack in one hand and was rubbing my eyes with the other. "But, my dear fellow," said Mr. Gilbert, directly, "if you still consider it to your interest to keep your invention a secret, I wish you had never made it. No one having a machine like that can help using it, and it is often quite as bad to be considered a maniac as to be one."