IN his description of his experiences in the Soudan, Rev. R. E. Colston gives the following account of how the Arabs subsist in the desert:— "In the 'Waterless Land,' water is the paramount question. If it be asked how a large body of Bedouins, like the 10,000 who nearly destroyed the British squares at Tamai, manage to subsist, the reason is plain. In the first place, they do not need the enormous trains required for a European army. They are the most abstemious of men. Each man carries a skin of water and a small bag of grain, procured by purchase or barter from caravans. Their camels and goats move with them, supplying them with milk and meat, and subsisting upon the scanty herbage and foliage of the thorny mimosa, growing in secluded wadies. These people could live upon the increase of their flocks alone, which they exchange readily for other commodities; but being the exclusive carriers and guides for all the travel and commerce that cross their desert, they realize yearly large amounts of money. As to water, they know every nook and hollow in the mountains, away from the trails, where a few barrels of water collect in some shaded ravine, and they can scatter, every man for himself, to fill their water-skins. On my first expedition, near the close of the three years' drought, I reached some wells on which I was depending, and found them entirely dry. It was several days to the next wells. But my Bedouin guide knew some natural reservoirs in the hills about six miles off. So they took the water-camels at nightfall, and came back before daylight with the water-skins filled. An invading army would find it hard to obtain guides, and even if they did, they must keep together, and could not leave the line of march to look for water. Besides, the Bedouins, accustomed from infancy to regard water as most precious and rare, use it with wonderful economy. Neither men nor animals drink more than once in forty-eight hours. As to washing, they never indulge in such wasteful nonsense. When Bedouins came to my camp, water was always offered them. Their answer would frequently be, 'No, thanks; I drank yesterday.' They knew too well the importance of keeping up the habit of abstemiousness. No wonder they can subsist where invaders would quickly perish."