_Third._ The expression "lowest passenger deck" means the deck next below the water line; and the expression "passenger deck" includes every deck or portion of a deck which is above the lowest passenger deck, and is appropriated for passengers. _Fourth._ A vessel shall not carry passengers, whether cabin or steerage passengers, on more than one deck below the water line. _Fifth._ The height between that part of any deck on which steerage passengers are carried and the deck immediately above it shall not be less than six feet. _Sixth._ No steerage passengers shall be carried on the lowest passenger deck unless it is efficiently lighted by side scuttles and otherwise to the satisfaction of the inspector. _Seventh._ No greater number of steerage passengers shall be carried on the lowest passenger deck than in the proportion of one steerage passenger to every twenty-one clear superficial feet allotted to their use. If, however, the height between the lowest passenger deck and the deck immediately above it is less than seven feet, and the apertures, exclusive of side scuttles, through which light and air are admitted are less in size than in the proportion of three square feet to every one hundred superficial feet of that deck, no greater number of steerage passengers shall be carried on that deck than in the proportion of one steerage passenger to every thirty clear superficial feet thereof, subject to the allowance for measurement of public rooms, lavatories, and bath rooms, if any, provided for by paragraph ten. _Eighth._ No greater number of steerage passengers may be carried on a passenger deck than in the proportion of one steerage passenger to every eighteen clear superficial feet of deck allotted to their use, subject to the allowance for measurement of public rooms, lavatories, and bath rooms, if any, provided for by paragraph ten. If, however, the height between any passenger deck and the deck immediately above it be less than seven feet, no greater number of steerage passengers may be carried on that deck than in the proportion of one steerage passenger to every twenty-one clear superficial feet thereof, subject to the allowance for measurement of public rooms, lavatories, and bath rooms, if any, provided for by paragraph ten. _Ninth._ A vessel, whatever be the superficial space of the passenger decks and of the lowest passenger deck, shall not carry a greater number of steerage passengers on the whole than in the proportion of one steerage passenger to every five superficial feet of air or promenade space provided on a deck so open as not to be included in the tonnage and approved by the inspector, and this space shall not be counted or included in the area available for any other passengers, or in other areas for steerage passengers prescribed by this section.