The Irish ecclesiastics did not scruple to deviate from the established plans of their sacred buildings, when the necessities of individual cases required it. In the Firth of Forth west winds are the most prevalent of all; and sometimes the western blast is still as fierce and long continued as when of old it drove King Alexander on the shores of Inchcolm. The hermit's cell or oratory is placed on perhaps the most protected spot on the island; and yet it would have been scarcely habitable with an open window exposing its interior to the east, and with a door placed directly opposite it in the western gable. It has been rendered, however, much more fit for a human abode by the door being situated in the south wall; and the more so, because the ledge of rock against which the south-west corner of the building abuts, protects in a great degree this south door from the direct effects of the western storm. The building itself is narrower than the generality of the Irish oratories, but this was perhaps necessitated by another circumstance, for its breadth was probably determined by the immovable basaltic blocks lying on either side of it. The head of the doorway in the Inchcolm oratory is, as pointed out in a preceding page, peculiar in this respect, that externally it is constructed on the principle of the radiating arch, whilst internally it is built on the principle of the horizontal arch. But in other early Irish ecclesiastical buildings in Scotland, as well as in Ireland, the external and internal aspect of the doorway is sometimes thus constructed on opposite principles. In the round tower, for example, of Abernethy, the head of the doorway externally is formed of a large single stone laid horizontally, and having a semicircular opening cut out of the lower side of the horizontal block; while the head of the doorway internally is constructed of separate stones on the plan of the radiating arch.