It shall be unlawful to transport, carry or convey, or cause to be transported, carried or conveyed, any dynamite, gunpowder or other explosive, between any points or places within the State of Alabama, on any vessel, car or vehicle of any description, operated by any common carrier, which vessel, car or vehicle is carrying passengers for hire. It shall be lawful to transport on any such vessel, car or vehicle small arms ammunition in any quantity and such fusees, torpedoes, rockets or other signal devices as may be essential to promote safety in operation, and properly packaged and marked samples for laboratory examination, not exceeding a net weight of one-half pound each, and not exceeding 20 samples at one time in a single vessel, car or vehicle; but such samples shall not be carried in that part of a vessel, car or vehicle which is intended for the transportation of passengers for hire. Nothing in this section shall be construed to prevent transportation of military or naval forces with their accompanying munitions of war on passenger equipment vessels, cars or vehicles.