The uncertainty which still surrounds much of the topography of Jerusalem, owing to its very foundations having been turned over by the ploughshare of the invader, while some of its sacred sites have been buried under huge mounds of rubbish, renders it impossible to trace Nehemiah's night ride in all its details. If we are to accept the latest theory, according to which the gorge hitherto regarded as the _Tyropœon_ is really the ancient Valley of Hinnom, some other sites will need considerable readjustment. The "Gate of the Valley" seems to be one near the head of the Valley of Hinnom; we know nothing of the "Dragon Well"; the "Dung Port" would be a gateway through which the city offal was flung out to the fires in the Valley of Hinnom; the "King's Pool" is very likely that afterwards known as the "Pool of Siloam." The main direction of Nehemiah's tour of inspection is fairly definite to us. He started at the western exit from the city and passed down to the left, to where the Valley of Hinnom joins the Valley of the Kidron; ascending this valley, he found the masses of stones and heaps of rubbish in such confusion that he was compelled to leave the animal he had been riding hitherto and to clamber over the ruins on foot. Reaching the north-eastern corner of the Valley of the Kidron, he would turn round by the northern side of the city, where most of the gates had been situated, because there the city, which was difficult of access to the south and the east on account of the encircling ravines, could be easily approached. And what did he gain by his journey? He gained knowledge. The reformation that is planned by the student at his desk, without any reference to the actual state of affairs, will be, at best, a Utopian dream. But if the dreamer is also a man of resources and opportunities, his impracticable schemes may issue in incalculable mischief. "Nothing is more terrible," says Goethe, "than _active ignorance_." We can smile at a knight-errant Don Quixote; but a Don Quixote in power would be as dangerous as a Nero. Most schemes of socialism, though they spring from the brains of amiable enthusiasts, break up like empty bubbles on the first contact with the real world. It is especially necessary, too, to know the worst. Optimism is very cheering in idea, but when it is indulged in to the neglect of truth, with an impatient disregard for the shady side of life, it simply leads its devotees into a fools' paradise. The highest idealist must have something of the realist in him if he would ever have his ideas transformed into facts.