The pendent ceiling is one of the most striking features of the cathedral, and is worth careful study. Ferguson considers this work to be the most satisfactory attempt ever made to surmount the great difficulty presented in all fan-tracery by the awkward, flat, central space which is left in each bay by the four cones of the vault. At Gloucester, King's College Chapel, Cambridge, Henry VII.'s Chapel, Westminster, and other places, various attempts were made to deceive the eye, and hide the unmanageable space; in Henry VII.'s Chapel the well-known pendants were boldly introduced with this object. None were wholly satisfactory, but, says Fergusson:-- "Strange as it may appear from its date, the most satisfactory roof of this class is that erected by Cardinal Wolsey in the beginning of the sixteenth century [this is a mistake, the roof having been built some time before] over the choir of Oxford Cathedral. In this instance the pendants are thrust so far forward, and made so important, that the central part of the roof is practically quadripartite. The remaining difficulty was obviated by abandoning the circular, horizontal outline of true fan-tracery, and adopting a polygonal form instead. As the whole is done in a constructive manner and with appropriate detail, this roof, except in size, is one of the best and most remarkable ever executed." Fan-tracery is a peculiarly English feature, and was invented, according to Fergusson, in order to get rid of the endless repetition of inverted pyramids which earlier vaulting produced. He therefore considers it an improvement on the vaulting of the early English and Decorated periods; and, as he thinks the ceiling of Christ Church Cathedral to be the best example of fan-tracery, he comes near to pronouncing it the finest in the world. It certainly must strike every observer as possessing exceptional beauty. At once rich and light, it yet accords wonderfully with the homely Norman work that it crowns, and gives a happy finish to the most important part of the cathedral. Even the lantern pendants seem more graceful than is usually the case with those strange architectural solecisms. Mr. Ruskin calls the ceiling "true Tudor grotesque, inventively constructive, delicately carved, summing the builder's skill in the fifteenth century." [Illustration: TRACERY OF THE CHOIR CEILING, SHOWING TRANSEPT CLERESTORY BEFORE THE RESTORATION.]