Knowingly sending, etc., dangerous or offensive matter

Every person who knowingly posts, sends, tenders or delivers, in order to be sent by post, any postal packet, parcel or other postal matter which either, (a) encloses any explosive or other dangerous material or substance, or any glass or glass bottle which may be likely to injure the contents of the mail, or any article which may be likely to injure the contents of the mail or any property of the Post Office or the Government or the person of any officer of the Post Office; or (b) has, on such a postal packet, parcel or other postal matter, or on the cover thereof, any words, marks or designs of an indecent, 27 obscene, libellous or grossly offensive character, commits an offence and shall be liable on conviction therefor to a fine not exceeding five hundred dollars, or to a term of imprisonment not exceeding six months, or to both such fine and term of imprisonment.