A Tale of Negative Gravity by Frank R. Stockton

A retired middle-aged gentleman and his wife take a long walk, arm-in-arm, many miles, up hills, across fields, with a laden knapsack and a heavy picnic basket, and yet they are completely at ease because of the gentleman's invention, a negative gravity device, which they carry to lighten their weight. He uses the device to help with farm work. The gentleman later uses the device on a mountain climb and amazes an unknowing Alpine-club member with his speed and agility on a difficult mountain climb in spite of his carrying a heavy load and not looking particularly strong. He realizes the invention has tremendous financial potential. However, this invention gets him into a humorous predicament and causes a problem for his family, which he resolves in an unexpected way.

This light-hearted short story was first published in a collection by Frank R. Stockton entitled The Christmas Wreck and Other Stories (New York, 1886), an imaged copy of which is available at The Internet Archive.