Certainly a ship “going north about” is menaced every mile of her way between these two points unless she takes a very circuitous course. If the weather conditions are favourable and daylight prevails, the North of Britain may be rounded through the narrow strait washing the mainland and the Orkney Islands, but the Pentland Firth is not an attractive short-cut. The ships that run between Scandinavian ports and North America naturally follow this route, as it is several hundred miles shorter than that via the North Sea and English Channel; but they keep a sharp eye on the weather and are extremely cautious. When the Pentland Firth is uninviting, they may either choose the path between the Orkneys and the Shetlands, or, to eliminate every element of risk, may stand well out to sea, and round the most northern stretches of the Shetlands. These are lonely seas, comparatively speaking, and yet are well lighted. Although a wicked rock lies in the centre of the eastern entrance to the Pentland channel, it is indicated by the Pentland Skerries light. When the mariner in his wisdom pushes still farther north, he falls within the glare of the rays thrown from the beacon near Muckle Flugga. This is the northernmost point of the British Islands, and it is truly forbidding. The rock lies three-quarters of a mile off the Shetland Islands, and is a huge fang, sheering to a height of 196 feet above high-water. On the side facing north it rears up so abruptly that it appears to lean over, while on the opposite side it is almost as steep. The majority of lighthouses have been called into existence by the claims of commerce purely and simply. But it was not so with the North Unst lighthouse, as the beacon crowning this pinnacle is called. War was responsible for its creation, though probably sooner or later the requirements of peace would have brought about a similar result. While the armies of France and Britain were fighting the Russians in the Crimea, the British fleet was hovering about these waters, watching the mouth of the Baltic, so as to frustrate any attempts on the part of the Russian fleet to dash around the northern coast of Scotland. In those days these lonely seas were badly lighted, and the Admiralty realized only too well the many perils to which the warships were exposed while cruising about the pitiless coasts of the Orkneys and Shetlands. Accordingly, the department called upon the Commissioners of Northern Lighthouses to mark Muckle Flugga. Time was everything, and the engineers were urged to bring a temporary light into operation with the least delay.