American rocket pioneer Robert Goddard (1882-1945) and his graduate students used this object between 1924 and 1928 in their experiments to determine the feasibility of ion propulsion for space travel. Ion engines, in which electrically charged particles of atoms are discharged, produce extremely high exhaust velocities. But the first U.S. experiments in space with ion propulsion took place in 1964.
This device may have been made by one of Goddard's graduate students, Louis M. Sleeper. According to 1964 observations by Russell B. Hastings, a former graduate student who helped Goddard in his ion experiments, "a large tube[,] this was probably used to produce 'clouds' of ions rather than directed beams of ions." Mrs. Goddard gave this artifact to the Smithsonian in 1965 as part of a set of laboratory glassware from her husband's pioneering ion-propulsion experiments.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.