regard for other people's convictions. Most Arabian expeditions fail through lack of time spent in preliminary steps. I have tripped up in that way myself, but it was owing to the restrictions of a paternal Government, and not through lack of patience. Before I started serious exploration in the Aden hinterland I spent a year on the littoral plain getting in touch with the people and mastering the dialect. Any success I may have had up-country was due to the foundation I laid in those early days, and it was not until the Aden authorities closed their sphere of influence against exploration in general and myself in particular that my expeditions began to miss fire, as I had to land at remote places along the coast and hasten up-country before their fostering care could set the tribes on me. He who would explore Asir should take a Khedivial mail steamer from Suez to Jeddah, and there show his credentials and explain his purpose to his consul and the local authorities. The Idrisi has an agent there, and it should not be difficult to pick up an Asiri dhow returning down the coast to Gîzân, which is the port for Sabbia. He would have to stay there until he got the Idrisi's permit and an escort, without which he would be held up to a certainty. In any case, no such enterprise need be contemplated until Asiri affairs have settled down a good deal. In Yamen proper it should be feasible to travel again within certain limits as soon as the Imam can come to an understanding with the tribal chiefs. There is not much left for the explorer or naturalist to do, unless he goes very far inland toward the great central desert, which project is not likely to be encouraged by the local authorities. There is, however, a possible field for the mineralogist and prospector east and south-east of Sanaa, which area also contains Sabæan ruins and inscriptions of interest to the archæologist. The northern boundary of Yamen may be said nowadays to trend north-east from Loheia inland through highland country to the desert borders of Nejran (once a Christian diocese). Its eastern border is very vague, but may be said to coincide approximately with the 45th parallel of longitude. Southward the limit has been clearly defined by the Anglo-Turkish Boundary Commission of 1902-5 inland from the Bana valley, about a hundred map-miles north of Aden, to the straits of Bab-el-Mandeb.