hall between the two chapels, were alone left unwalled, for the admittance of Cardinals who might arrive after the commencement of business, or the ceremonial visits conceded as a privilege to royal persons who might happen to pass through Rome during a Conclave. But these doors, except on such occasions, were kept carefully closed with four locks, two on he outside, the keys of which were intrusted to the Marshal, as porter of this gate; two on the inner side, the key of one being in charge of the Camerlengo, and of the other in charge of the Master of Ceremonies. By the side of the door there were two wheels, or rather turning-boxes, for the admission of objects declared free from suspicion, after inspection by officers on guard against the introduction of correspondence, and in other parts of the building there were six other wheels of the same kind, similarly guarded, for the admission of the many articles without which it was physically impossible for so large a congregation of human beings to subsist. The shape of these wooden turning-wheels is the same as those used in the parlatories of nunneries, and their application is ascribed to the ingenuity of Paris de Grassis, who
