Blown glass; L. 30 1/2 in. (77.5 cm), Diam. 2 in. (5.1 cm)
Frankliniana Collection, The Franklin Institute, Inc. (Philadelphia, Pa.), 1492
The generation of static electricity through friction is now a commonplace experience, but Franklin's experiments with these glass tubes led him to the theory that electricity is transferred rather than created; and to the use of the terms "negative" and "positive," and "plus" and "minus" to describe the process.