“The Light-room at the Point of Ayre is glazed all round, but the light is hid from the mariner by the high land of Maughold Head towards the south, and by Rue Point towards the west. Being elevated 106 feet above the medium level of the sea, its most luminous side may be seen, like a star of the first magnitude, at the distance of five leagues; but the side tinged red, being somewhat obscured by the coloured shades, cannot be seen at so great a distance.” _Calf of Man._ [Sidenote: Description of Calf of Man Light.] “There are two leading lights on the _Calf of Man_, situate on the western side of the small island called the Calf, in north Lat. 54° 5´, and Long. 4° 46´ west of London. These two light-houses are distant from each other 560 feet. The higher light bears by compass from the Mull of Galloway, S. SW. distant 37 miles; Peelhead, in the Isle of Man, SW. distant 11 miles; Langness Point, W. by N. ½ N. distant 6 miles; and from the sunken rocks, called the Chickens, NE. ⅓ E. distant about 1¼ mile. “These lights are from oil, each light-room being furnished with a distinct reflecting and revolving apparatus, by which they are distinguished from the other lights on the coast, and rendered useful as leading lights for passing the dangerous rocks called the Chickens. The light-house towers, as before noticed, are built at the distance of 560 feet apart, bearing from each other NE. ⅓ E. and SW. ¼ W. Consequently, to an observer, in the direction of the Chickens, both lights will appear in one, or be seen in the same line of direction, and be known to mariners as “Double-revolving and Leading-lights without colour.” These lights will respectively attain their most luminous effect at the end of every two minutes; but, in the course of each periodic revolution of the reflector frames, they alternately become fainter and more obscure, and, to a distant observer, are totally eclipsed for a short time. The two light-rooms at the Calf of Man are glazed all round, but are hid from the mariner by the high land of Peel Head towards the NE. and by Spanish Head in an eastern direction; both lights, however, will be visible at about ¼ of a mile from Langness Point. The lower light is elevated 305 feet above the medium level of the sea, and the high light 396 feet, and they will be seen like two stars of the first magnitude, at the distance of six or seven leagues, in a favourable state of the atmosphere.” [Sidenote: Extension of the Northern Lights to the Irish Sea.]