Every carriage used for conveying gunpowder or gun cotton within the city of Philadelphia, in accordance with the provisions of the acts now in force relative thereto, shall, in addition to the requirements therein contained, have painted on each side thereof, in letters distinctly legible to all passers-by, the word "gunpowder," and any failure so to do shall subject the offender or offenders to the penalties herein contained for violations of this act.
53 P.S. § 16565