SIR AUREL STEIN has recently completed a survey of the boundary line of the ancient frontier of the Roman Empire in Iraq and Transjordania. This is a part of a projected survey of the eastern frontier of the Empire, of which the Syrian section, with which Sir Aurel Stein's work connects, has been surveyed by Father Poidebard. Sir Aurel Stein's expedition was supported by the British Academy and the Society of Antiquaries of London and carried out with the co-operation of the Royal Air Force and the Iraq Petroleum Company. In a summary account of the survey (The Times, June 1) Sir Aurel states that he traced the line of forts along the south and north sides of the Jebel Sinjar. Between Nisibin and Mosul he found the old defences, which had commanded the road of invasion between Mesopotamia and northern Syria. Turning thence to Kirkuk, he visited and determined to his satisfaction the exact site of the battle of Arbela in Alexander's campaign, and along the middle Euphrates had made the remarkable discovery of a comparatively well-preserved castle, which was clearly Roman, and had at its side a barrage, which bore the stamp of Roman work. This affords evidence of the protection given to the trade route so far down as central Mesopotamia, possibly in the reign of Septimius Severus. The Roman track was traceable from the air and in places even on the ground. The last month of survey work covered the Via Nova, constructed in the reign of Trajan from the port of Aqaba on the Red Sea to Petra and the great centres of Syria, This route has now been determined and mapped for a distance of about 120 miles. Several old Roman milestones, from which the inscriptions had almost disappeared, were found in the Wadi Yitm. The distances between the milestones is remarkably accurate. Thence the road climbs to the top of the chain of mountains above the rift valley of the Wadi-el-Arabah, south of the Dead Sea, and follows the line of cleavage to Petra.