This building was known, in monastic terminology, as the "Lavabo." A fountain of water issued in jets from a central column, and fell into a basin, in which the monks washed their hands, before entering the Refectory for their meals. It is quite easy, from the construction of the roof, to imagine a number of branches springing from the capital of the column, and meeting the ribs of the groined roof, in the same manner, as the "Marble Tree," in the Chapter-house of Graignamanagh. Drains in connection with this building were discovered when the excavations were made, and Sir Thomas Deane is of opinion, that it was surrounded on the outside by a wooden verandah, or shed. Certainly, in the plan of Clairvaux, a low building is shown, adjoining the Lavabo, at its east and west ends; but no use is assigned it. Very probably it was the Lavatory. Petrie thinks the Lavabo may have been built as far back as 1165, but that can hardly be held; for Clairvaux had not been remodelled till 1175, and it had no such ornamental structure in the time of St. Bernard. He remarks, too, that fragments of bricks were discovered in the building, and says they were never employed earlier in any other building in Ireland. It is now certain, that it was the monks of Mellifont who first manufactured bricks in this country. This Lavabo was not isolated or detached from the Cloister, but, as at Clairvaux, a door led from one into the other, opposite the entrance into the Refectory; and, since the excavations, portions of the door-way are visible. Some small shafts and their bases remain. Even at the present day, in one of the most recently constructed monasteries of the Order (near Tilburg, Holland), what might be termed a semi-octagonal Lavabo, having its fountain and basin, has been built. It answers the same purpose as those in ancient times. By keeping the Lavabo before one's mind, one can form an idea of the Cloister itself; which, consisting of arcades, closely resembled this in every detail, except that these were glazed, and in all probability its walks had a lean-to roof. The site of the east walk of the Cloister is easily traced, and the places occupied by the piers being now concreted, mark their positions. This eastern walk was 21 feet 6 inches wide. The opposite, or western one, was some 19 feet 6 inches; that on the south, 14 feet; and the north one, adjoining the church, and which was usually the Reading-Cloister, may also have been 14 feet. Thus, we would have an enclosed space or Garth, 100 feet square.