The rock called Boinshly lies about 3³⁄₄ miles from Skerryvore, and is of considerable extent. The origin of the names of the different rocks in the vicinity of Tyree is by no means clear, and very little assistance or information is to be obtained in this matter from the natives. The name of Boinshly is probably derived from the Gaelic words _boun_, signifying _bottom_, and _slighe_, _deceitful_, as indicative of the dangers of the place; but other interpretations have been put on it, and that which has been now given is by no means certain. In the course of the survey, several soundings were at considerable risk obtained, both upon this Rock itself, and in its immediate vicinity. The sea in that exposed situation is seldom so tranquil as to warrant an attempt to approach very near this Rock. The swell, which, in a greater or less degree, almost constantly prevails, is apt to impel, or seemingly draw the boat as by a kind of suction, upon the rock; and sometimes such accidents cannot be prevented, even although the greatest caution is used. Sudden _lifts_ of the sea, during an apparent calm, are common in all the more exposed parts of the coast, more especially in the Orkney and Zetland Isles, and on the shores of the most western of the Hebrides; and any one much accustomed to the use of boats on these shores, must have experienced the hazard of encountering such unexpected risings of the sea, more especially near shelving rocks, or in rapid tide-ways. In some places the boatmen apply the name of _lumps_ to these sudden waves. This effect is not felt to the same extent in attempting to reach a rock which is partially uncovered at low water, as a landing can, in such a case, often be effected on one side, at a time when the same rock on the opposite side, or a sunk rock just topping with the water, would, on every side, be quite unapproachable. From the soundings marked on the plan, it will be seen that shoal water extends all round Boinshly to distances varying from a quarter to half a mile. The sea breaks on the rock with great violence, and its position can easily be discovered from the island of Tyree by the white foam with which it is almost constantly surrounded, and which, in the heavy swells which sometimes accompany a dead calm, before or after a heavy gale of wind, rises to a prodigious height in a column or jet, resembling, at a distance, the play of a gigantic fountain. So high, indeed, does the sea rise on this shoal after heavy gales, that it often quite obscures the larger and more distant object of the Rock and Tower of the Skerryvore, even when viewed from the top of Ben Hynish in Tyree. The wooden barrack erected on the Skerryvore for the use of the workmen during the progress of the operations, although about sixty feet in height, was often lost sight of at Tyree by the uprising of the sea on Boinshly, and could be seen only during the calm that intervenes between returning waves. * * * * *