water sprays and ammonium carbonate poultices. One of the figures which had lost its head and shoulders was replaced. The sculptures on the West front have been interpreted as representing "spiritual ascent through the virtue of humility and descent through the vice of pride" and Christ as the Man of Sorrow and the Antichrist. During the 1990s a major restoration and cleaning work were carried out on the exterior stonework, returning it to the yellow colour hidden under centuries of dirt. Windows The building has 52 windows, occupying about 80 per cent of the wall space. The east end has a square-framed window of seven lights. It includes a depiction of the nativity made by Clayton and Bell in 1872, and was presented to the church by the Bath Literary Club. The window of the Four Evangelists over the northwest door is a memorial to Charles Empson, who died in 1861. In 2010 a stained glass window was uncovered in the abbey vaults. The design around the window is by William Burges. Tower The two-stage central tower is not square but oblong in plan. It has two bell openings on each side and four polygonal turret pinnacles. The tower is high, and is accessed by a staircase of 212 steps. Bells In 1700 the old ring of six bells was replaced by a new ring of eight. All but the tenor still survive. In 1770 two lighter bells were added to create the first ring of ten bells in the diocese. The tenor was recast in 1870. The abbey's tower is now home to a ring of ten bells, which are hung unconventionally such that the order of the bells from highest to lowest runs anti-clockwise around the ringing chamber, rather than in the usual clockwise fashion. The tenor weighs 33 cwt (3,721 lb or 1,688 kg). Bath is a noted centre of change ringing in the West Country. Interior The interior fan vaulting ceiling, originally installed by Robert and William Vertue, was restored by Sir George Gilbert Scott between 1864 and 1874. The fan vaulting provides structural stability by distributing the weight of the roof down ribs that transfer the force into the supporting columns via the flying buttresses. Gilbert Scott's work in the 1870s included the installation of large gas chandeliers made by the Coventry metalworker Francis Skidmore. They were converted to electricity in 1979. Other new features