From Manx Soc vol IV,VII & IX

Boethius

Opposite to Scotland, in the Irish Sea, are 43 islands, some of which are 30 miles long, others not more than 12, while some are more and others less. These isles are called by some authors Ebonie, and by others Hebredes. Of these, the first and principal is Mona, called in the vernacular tongue, Man, lying opposite to Galloway and the end of England. It was formerly celebrated as being the principal seat of the Druids, as Julius Caesar, Cornelius Tacitus, and other Roman writers, ancient and modern, testify. North from the Isle of Man is Arran, which is otherwise called Both. This second name was given to it by St. Brandan, for he built there a chapel, which is called Both, and resided there some time. Next to this is Helaw and Rothsay, called after the first Scot who came out of Ireland into Albion. Not far from this is situated Ailsa, which, as we have heard said, abounds in such quantities of Solan geese. Besides these are many other isles abounding in metals. The largest and chief of these is Isla, which lies beyond the peninsula of Lorne, in sight of Lochquebar, 30 miles in length, abounding in corn, and rich in ores, if there were enterprising and industrious persons to work them. Not far from Ida is Cumbria and Mulla, but smaller than Isla. In Mulla is a very limpid fountain, two miles distant from the sea, from which descends a rivulet, abounding in pearl oysters, to the sea, end which, in the space of 12 hours after they reach the sea, become a great size. Near to this isle is lona, full of religious men. It was the common place of sepulture of the Scotch kings from Fergus II., until the time of King Malcolm Camore, who built the Abbey of Dumferline, where most of our kings lie since the foundation thereof. Beyond this, in the north-west sea, opposite to Ross, is an isle called Lewis, 60 miles in length, and 30 in breadth. In it is a river, of which it is said that if any woman throw this water (at the spring of the year) that no salmon shall be seen in it for that year, but that at other times it will abound in great plenty. Beyond this is Sky and Rona. In this last isle are marine animals, in great numbers, astonishing to behold. The last and most remote isle is called Hirtha, having the polar elevation of 63°, and which at the Isle of Man does not exceed an altitude of 57°—if we are to believe the astronomy of Ptolemy—corresponding to 62½ terrestrial miles, from which I conclude that from the Isle of Man, the first isle of Albion, to Hirtha, the last, there are 377 miles. Hirtha was the ancient name of this island, for in it. were formerly a large number of goats of great size, with thick horns like an ox, and tails hanging down to the ground. This island is surrounded on every side by rocks of great height, so that no boats can land, except at one place, where there is a narrow entrance. Formerly it could only be entered, with great caution, in summer, and when the sea was calm. In the month of June a priest comes out of the Isle of Lewis in a boat to this isle, and baptizes all the children born in it the year before, remaining there for some days administering the sacrament, and then returns home. In the Isle of Lewis are two chapels,—one dedicated to St. Peter, and the other to St. Clements. It is celebrated for the following —As soon as a fire breaks forth in this isle, the man who possessed the most upright life lays a wisp of straw on the altar, and when the people are going most devoutly to their prayers, the straw kindles into a blaze. Beyond this isle is another, but it is not inhabited. In it are certain animals, which are not much different in form from sheep, but so wild that they cannot be taken unless by great searching ; the hair is long, and neither like the hair of the sheep or goat. Between these isles are numerous passages, dangerous to navigate, and often over-whelming boats, from the constant flux and reflux of the tide. The most dangerous vortex is called Corbrek : it flows with such impetuosity as to attract and absorb ships.