"He made darkness his secret place: his pavilion round about him were dark waters and thick clouds of the skies."
565. Why does the rubbing of a stick of sealing-wax cause it to attract small particles of matter?
Because it excites in the sealing wax that force which was first observed in the amber. Sealing-wax, therefore, is called an electric (amber-like) body.
566. Why do we hear of the electric fluid?
Simply because the term fluid is the most convenient that can be found to express our ideas when speaking of the phenomena of electric force. But of the nature of electricity, except through its observed effects, nothing is known.
567. What substances are electric?
All substances in nature, from the metals to the gases. But they differ very widely in their electrical qualities.