As the great gate to the Exposition, the Tower becomes historical in relation to the event celebrated beyond its archway. Its purpose, from this point of view, is to tell the entering visitor briefly of the milestones along the way of time up to the digging of the Canal. Its enrichment of sculpture, painting and inscription summarizes the story of Panama and of the Pacific shore northward from the Isthmus. The architect has expressed in its upper decorations something of the feeling of Aztec art. The four inscriptions on the south faces of the arches tell how Rodrigo de Bastides discovered Panama in 1501; how Balboa first saw the Pacific Ocean in 1513; how the United States began to dig the Canal in 1904, and opened it in 1915. The four on the north faces epitomize the history of California, thus honored as the state that commemorates the opening of the Canal. They speak of Cabrillo's discovery of California in 1542, of the founding of the Mission of San Francisco by Moraga, in 1776, of the acquisition of California by the United States, 1846, and its admission to the Union in 1850. The sculpture carries out the same idea. Pizarro and Cortez sit their horses before the Tower, splendid figures of the Spanish conquerors, the one by Charles C. Rumsey, the other by Charles Niehaus. (p. 48.) Above the entablature of the supporting columns are repeated around the outer wall of the arch, Adventurer and Priest, Philosopher and Soldier, types of the men who won the Americas, all done by John Flanagan. Above the cornice, the mounted figures by F. M. L. Tonetti are those of the Spanish cavaliers, with bannered cross. The eagles stand for the Nation that built the Canal. Excellent in spirit are Flanagan's figures of the four types, especially that of the strikingly ascetic Priest. (p. 44.) Besides their symbolism, the statues fulfill a useful architectural purpose in relieving what would otherwise be the blankness of the wall. But the same cannot be as truly said of the Armoured Horsemen above. Vigorous as they are, they are not in the right place. They clutter up the terrace on which they stand. The globe on the pinnacle, with its band, signifies that now a girdle has been put around the earth. On the side walls of the arch under the Tower, the murals by William de Leftwich Dodge tell the story of the triumphant achievement which the Exposition commemorates. On the east, the central panel pictures Neptune and his attendant mermaid leading the fleets of the world through the Gateway of All Nations. (p. 53.) On one side Labor, with its machines, draws back from the completed task, and, on the other, the Intelligence that conceived the work and the Science that made it possible, move upward and onward, while a victorious trumpeter announces the triumph. One figure, with covered face, flees from the appeal of the siren, but whom he represents, or why he flees, I cannot tell.