Recent research in Mesopotamia has centred around the site of Babylon, where results of a most interesting and encouraging description have been achieved. The German Oriental Society commenced work upon the site in the spring of 1899, and after twelve years of incessant labour under the direction of Dr Robert Koldewey, published the report of their labours in 1911. The Babylon of Nebuchadrezzar II The portion of the city laid bare in these twelve years of digging was contemporary with the reigns of Nebuchadrezzar II and Nabonidus, the last native King of Babylon, but certain parts of the ruins unearthed had been built in the much more ancient era of Khammurabi, the great law-maker, and even during the First Dynasty. The later Babylon is known to us from the pages of Herodotus and Ctesias, and the explorers speedily found that the accounts of these writers in nowise squared with the actual topographical conditions of the ruins unearthed and surveyed. Herodotus speaks of a Babylon 53 miles in circumference, and Ctesias is not much more modest in his estimate of over 40 miles. The city wall to the north-east side may still be traced in its entirety, and remains to prove that the city on this side measured not more than 2 3/4 miles, and judging from this, we obtain an approximate circumference of 11 miles--a figure far short of the estimate of the 'Father of History.' The Outer Wall The walls themselves are of considerable interest. The outer wall was nearly twenty feet in thickness, and was built of burnt bricks impressed with the royal stamp of Nebuchadrezzar. Here and there its length was broken by towers for outlook or defensive purposes. Herodotus states that so broad was the top of the wall that a four-horse chariot could easily turn upon its surface, and that two of these vehicles had a sufficiency of room to pass one another without risk to horses or driver. Companies of men could be moved along this mural highway in time of siege, so that a supply of defenders could be brought with dispatch to guard any portion of the defences that was imminently threatened. Bâbil as a Citadel The mound of Bâbil, to which we have frequently referred in this account of Babylonian excavation, was recognized by the German expedition as a citadel built for defensive purposes by Nebuchadrezzar--a place of refuge to which the King and court could repair in case of the capture of the city itself. It contained the royal stores and treasury, a large armoury and arsenal, and there is reason to believe that the monarch resided there even in times of peace. It was, indeed, a miniature city, a lesser Babylon, containing everything necessary for the royal support and pleasure. Babylon's Water-Supply