numbers are located on the south side of the building, and higher room numbers on the north side. Many spaces contain quarry-tile floors; walls with shelves or wood paneling; and molded plaster ceilings. The interior contains ornate detail from Carrère and Hastings, such as motifs of lions, and the decorative scheme extended to such minute details as doorknobs and wastebaskets. There is a pair of public stairways on the north side of the building, which lead between the ground and third floors. The stairs share landings in the middle of each flight, allowing visitors to switch between staircases. The stairways contain vaulted ceilings made of Vermont marble; they are separated by solid marble floors, except at the landings, where there are square archways. These stairways may have been influenced by the design of the Louvre's Henry II Wing. The cellar, which is not open to the public, was initially used as a mechanical plant and contains remnants of the original Croton Reservoir. The western side of the building, from the cellar to the second floor, contains part of the Main Branch's storage stacks. Supplementing the Main Reading Room on the third floor, there are 21 other reading rooms in the Main Branch, including a ground-floor room with a cast-iron ceiling. There were originally 1,760 seats in all of the reading rooms combined, of which 768 were located in the Main Reading Room. Ground floor The ground floor contains the entrance to 42nd Street. Originally it contained a coat-check, circulating library, newspaper room, and children's-book room. There were also spaces for telephones, a "library-school office", and a "travelling-library office". The former newspaper room in room 78 became the children's-book room, and the former children's-book room in room 81 is not open to the public. Room 80 operated as the circulating library from 1911 to 1981. It measures across. The room is placed at the center of the building, but its ground-floor location indicates that the library's trustees did not see the circulating library as an important part of the building's plan. The glass ceiling measures tall and is supported by four iron arches; it was covered by a dropped ceiling for much of the mid-20th century. Since 1987, room 80 has been the Bartos Forum, a 400-seat lecture room. Most of the Bartos Forum's original design remains in place, but the floors have been covered with carpets and the perimeter skylights