All about stretches the vast humming city of low-built houses covering the short steep hills and filling all the hollow between. Northeastward lies the seething Suburra; the yellow river runs beyond the Velabrum and the cattle market to the west; southward rise the enchanted palaces of Caesar; due east is the Esquiline of evil fame, redeemed and made lovely with trees and fountains by Maecenas, but haunted even today, say modern Romans, by the spectres of murderers and thieves who there died bloody deaths of quivering torture. All around, as the sun sinks and the cool shadows quench the hot light on the white pavements, the ever-increasing crowds of men--always more men than women--move inward, half unconsciously, out of inborn instinct, to the Forum, the centre of the Empire, the middle of the world, the boiling-point of the whole earth's riches and strength and life. Then as the traveller muses out his short space of rest, the vision grows confused, and Rome's huge ghosts go stalking, galloping, clanging, raving through the surging dream-throng,--Caesar, Brutus, Pompey, Catiline, Cicero, Caligula, Vitellius, Hadrian,--and close upon them Gauls and Goths and Huns, and all barbarians, till the dream is a medley of school-learned names, that have suddenly taken shadows of great faces out of Rome's shadow storehouse, and gorgeous arms and streaming draperies, and all at once the sight-seer shivers as the sun goes down, and passes his hand over his eyes, and shakes himself, and goes away rather hastily, lest he should fall sick of a fever and himself be gathered to the ghosts he has seen. It matters very little whether the day-dream much resembles the reality of ages long ago, whether boys played with lupins or with hazel-nuts then, or old women roasted chestnuts in the streets, or whether such unloving spirits should be supposed to visit one man in one vision. The traveller has had an impression which has not been far removed from emotion, and his day has not been lost, if it be true that emotion is the soul's only measure of time. There, if anywhere, lies Rome's secret. The place, the people, the air, the crystal brightness of winter, the passion-stirring scirocco of autumn, the loveliness of the long spring, the deep, still heat of summer, the city, the humanity, the memories of both, are all distillers of emotion in one way or another.