"The balls sent by this gun are not ordinary balls, but little cases of glass. These glass cases are covered with a case of steel, and weighted with a pellet of lead; they are real Leyden bottles"—18th-century devices used to store static electricity—"into which the electricity is forced to a very high tension. With the slightest shock they are discharged, and the animal, however strong it may be, falls dead."
Verne, Jules. Twenty Thousand Leagues Under the Sea. [book] 1870