Once the corner of the building was supported by the concrete sawhorse, the problem was only half-solved, for water covered the altar up to the top of the outside steps. Pumping was labor in vain; it would only have weakened the substructure of the palace and adjoining buildings. What were needed were dikes, to keep the water out while the area inside them was emptied. But a cement dike was impossible, because of the maze of water, gas, and sewer mains, heat, power, and light conduits which, at all levels and in all directions, crisscrossed the subsoil of this busy part of modern Rome. A trench about five feet wide was dug, with a 230-foot perimeter. From a horizontal pipe laid in it, fifty-five three-inch pipes ran down vertically at equal intervals to a depth of twenty-four feet. Into these pipes was pumped carbon dioxide under a pressure of eighty atmospheres. Radiation from the refrigerant in the vertical pipes froze the surrounding muddy earth, and the impenetrable dike was a reality. The water inside covering the altar was then pumped out, and all the architectural blocks and fragments could be removed. Thus succeeded one of the most difficult and delicate excavations ever made. All was finished to meet a deadline, the bimillennary of Augustus’ birth, September 23, 1938. What Moretti now had to work with in his reconstruction was not only the slabs and fragments he had just extracted, but also the finds from previous excavations going back to 1568 (Fig. 6.7). Over the intervening years these had been scattered. Most of the 1568 finds had been sawn into three lengthwise (for the slabs were over two feet thick, too heavy for easy transport) and shipped to Florence to the Grand Duke of Tuscany, who then owned the Palazzo Fiano site in Rome. One slab was in the Vatican Museum, another in the Villa Medici (seat of the French Academy in Rome), still another in the Louvre. The finds from the 1859 dig had also been kept unrestored in the palace, and then transferred to Rome’s Terme Museum. One slab was found in re-use face down as a cover for a tomb in Rome’s Church of the Gesù. [Illustration: FIG. 6.7 Rome, Altar of Peace. Plan showing fragments discovered up to 1935. (G. Lugli, _Mon. Ant._, p. 185)] [Illustration: FIG. 6.8 Rome, Altar of Peace. Plan showing results of Moretti’s excavation, still _in situ_ under the Palazzo Fiano. (Moretti, _op. cit._, Pl. 5)]