Aran Mor is about nine miles long and two at its greatest breadth; it is separated by Gregory Sound[158] from the Middle Island, which is rudely elliptical, and about eight miles in circumference. This latter island is separated from Inishere by a narrower passage, about one mile wide, called the "Foul Sound,"[159] which deserves the name, for it is a rather dangerous passage, containing a hidden shoal with only six feet of water over it. Gregory Sound is wider and deeper, being quite navigable from shore to shore. The tides blocked by the island barriers rush with great force through these narrow channels, rendering the navigation very difficult and dangerous. The passage between the north-western extremity of Aran Mor and Golam Head in Connemara is called the North Sound--in Irish _Bealach Locha Lurgain_. It is about eight miles across. The passage between Inishere and the co. Clare--the more usual one for sea-going ships--is called the South Sound, and is about five miles broad at its narrowest point. There is a lighthouse near a place called Finnis Rock[160] at the south-eastern extremity of Inishere, which marks the limit of a very dangerous shoal, that stretches out from the island into the Sound. This rock, says O'Flaherty, was remarkable for 'ship-wracks.' Aran Mor contains 7,635 acres, with a population of nearly 2,000, the greater part of whom, in 1901, could neither read nor write. It has three considerable villages--Killeany on the east; Kilmurry in the middle; and Oonagh towards the north-western extremity of the island. On the northern slopes of the island there is a sweet, juicy herbage, on which sheep and cattle thrive very well. The grasses are intermingled with various medicinal herbs, such as the wild garlic, which is said to give a delicate flavour to butter, and the _rineen_, or fairy flax, which is believed to have wonderful curative properties. R. O'Flaherty declares that in his own time "beef, veal, and mutton are better and earlier in season here than anywhere else." He could hardly say so now with truth; but there is no doubt that the veal and mutton are well flavoured. On the shore, in his time, "were samphire in plenty, ring root, and sea-holly, or sea cabbage." The samphire is there still--the _crithmum maritimum_, or cranagh. It is said to have been used for preserves, and when boiled is frequently eaten by the poorer classes. The crops consist of patches of oats, rye, and potatoes--the latter is an uncertain crop, whose failure causes great hardships to the islanders. Kelp-making and fishing are the two staple industries of the place. The kelp, or burned sea-weed, is used in the manufacture of iodine, and pays very fairly in dry seasons.