T. R. S. Tyndall, "Lessons in Electricity," Popular Science Monthly, June 1876

FIG. 14.

Instead of the chain you may interpose between the balls one hundred feet of wire supported by silk loops. This is done [at right], which shows the wire w supported by the silk strings S S S, and where, for the ball or turnip, the cylinder C, on a glass support G, is substituted. Every approach and withdrawal of the rubbed glass tube R is followed obediently by the corresponding motion of the index.

Or, substituting a carrot, a cucumber, or other elongated conductor for the ball T' ... you cause your rubbed glass tube to act upon a greater extent of surface. You thus decompose more electricity and produce a greater attraction.