§ 300. Size of rooms; air space per person. No greater number of persons shall be employed in any room of a factory between six o'clock in the morning and six o'clock in the evening than will allow each person so employed two hundred and fifty cubic feet of air space nor, unless by written permit of the commissioner, than will allow four hundred cubic feet of air space for each person employed between six o'clock in the evening and six o'clock in the morning. Such rooms shall be lighted by electricity whenever persons are employed therein between six o'clock in the evening and six o'clock in the morning.