The title, “The Effect of ‘Negative Gravity,’” refers to the idea that objects can be freed of the gravitational force pulling them earthward and consequently move skyward. The notion may have derived from a fictional story in the November 1884 issue of Century magazine, “A Tale of Negative Gravity,” by Francis “Frank” R. Stockton, a well-known American writer of humorous tales and fantasies in the late-nineteenth century. In it, the main character creates a machine that “could diminish, or entirely dissipate, the weight of an object of any kind.” Decades later, scientist Albert Einstein proposed the thesis of negative gravity by which an energy in the universe was forcing apart objects that would ordinarily be attracted together by gravity. Einstein later repudiated the theory, but it gained prominence in the 1990s as a way to explain why the universe was expanding at an increasing rate.