Thirteenth. No merchant, storekeeper, or other person, shall keep for sale or sell pistols, bowie kniives, or dirk knives without first paying a license tax of one hundred dollars; Provided, said pistols, bowic knives or dirk knives, shall not be sold to minors. Every violation of this paragraph shall be punished by a fine of fifty dollars, or by imprisonment in the county jail not more than six months.