The opening or outlet of the valley of Tyropœon, or the Cheesemongers, still remains, and is very distinct. The ground begins to decline into it as soon as we leave the court of the mosque of Omar, advancing southward; and at the distance of about 400 feet we come to its lowest part, and the spot where it is lost in the valley of Kedron. This opening is opposite a mountain, called now the Mount of Offence, but styled by Josephus “that other hill,” and described by him as just south of the Mount of Olives. A short distance up this valley we come to an oblong pool sunk partly in the ground, and walled on three sides, the fourth being broken down; it is called the Pool of Siloam, and very probably occupies the site of the ancient pool of that name noticed in the Scriptures. A few hundred feet above this pool the valley enters the modern city, and I believe cannot be traced any further. There can be no doubt that it is the ancient Tyropœon, and we thus get a portion of the northern boundary of Mount _Zion_.[26] Mount Zion had on the east the valley of Kedron, and on the south and west the valley of Hinnom,[27] or Gehenna, and these boundaries are now just as described by Josephus, except that the sides of the valleys towards the city are now rendered sloping by the vast quantities of debris or loose stuff from the ancient city, instead of being perpendicular as they were in ancient times. That of Hinnom, on its southern and western sides, still presents that appearance, a bold perpendicular precipice, which it would be impossible to scale. This valley is described by Strabo (lib. xvi.) as having a depth of 60 feet and a width of 250, which are pretty nearly its present dimensions. The wall of the ancient city was built on the edge of the precipice, and, according to Tacitus, was, in the parts thus guarded by nature, 60 feet in height; on the northern side of Jerusalem, where the ground offered fewer advantages, it had the prodigious elevation of 120 feet.[28] It was built in a crooked or zigzag line, “so that they might flank the besiegers and cast darts on them sideways.”[29] We have thus far had what sailors call plain sailing, for no one can easily be at a loss as regards the eastern, southern, and a portion of the western boundaries of the ancient Jerusalem. The northern limits offer a subject of greater difficulty, and it is one also of greater importance, for on this depends the question whether the spot pointed out as Mount Calvary be really the place of the crucifixion or not. The objectors, including almost all Protestant visitors, say it is not and cannot be, since this spot was evidently within the ancient city; and both from the Scriptures, and from the well-known custom of the Jews on such occasions, we know that this event occurred without the walls. This subject we will now examine.