Ordinances [of Jeffersonville], § 3, pt. 10. It shall also be a nuisance and unlawful: . . . To keep in any one building more than twenty five pounds of gun powder, except in a powder house or Magazine, or to keep any quantity of gun powder for sale except in some metallic vessel and having the words “gun powder” in letters at least three inches long always affixed in some conspicuous place on the house in which it is kept.