Who Discovered Electricity?
It may seem difficult to believe, that the tiny spark and weak snapping noise that are produced when a Leyden jar is discharged, are, in many respects, the same as lightning and thunder, but it is nevertheless true. This was proved by Benjamin Franklin, about the middle of the 18th century, in the following way. One afternoon, when a thunder shower was approaching, he sent up a kite, to the string of which he fastened a large metal key; and to the key, a ribbon of non-conducting silk, which he held in his hand. When the rain had been falling long enough to wet the string thoroughly, it become a good conductor of electricity, and Franklin found that the key had become charged with electricity transmitted from the clouds, along the wet kite string. The non-conducting silk ribbon, that formed the continuation of the kite string, from the key to his hand, was employed to prevent him from receiving shocks from the passage of the electricity, through his body, to the earth.
Up to this point, your attention has been directed in charges of electricity. You have been told how they may be produced, what some of their leading properties are, and what effects they produce, when they are discharged. The subject that will now be explained to you is that of electric currents.