The fact that for more than a century one family has held the exacting position of chief engineer to the Northern Commissioners, and has been responsible for the lights around Scotland’s troublous coasts, is unique in the annals of engineering. Each generation has been identified with some notable enterprise in this field. Thomas Smith, the father-in-law of Robert Stevenson, founded the service, and was the first engineer to the Commissioners. Robert Stevenson assumed his mantle and produced the “Bell Rock.” His son, Alan Stevenson, was the creator of the “Skerryvore.” The next in the chain, David Stevenson, built the “North Unst.” David and Thomas Stevenson, who followed, contributed the “Dhu-Heartach” and the “Chicken Rock” lights; while the present generation, David and Charles, have erected such works as “Rattray Briggs,” “Sule Skerry,” and the Flannen Islands lighthouses. In addition, the latter have developed lighthouse engineering in many novel directions, such as the unattended Otter Rock lightship, the unattended Guernsey lighthouse, and the automatic, acetylene, fog-signal gun, which are described elsewhere in this volume. Some forty years ago the Stevensons also drew up the scheme and designed the first lighthouses for guarding the coasts of Japan. The essential optical apparatus and other fittings were built and temporarily erected in England, then dismantled and shipped to the East, to be set up in their designed places. The Japanese did not fail to manifest their characteristic trait in connection with lighthouses as with other branches of engineering. The structures produced by the Scottish engineers fulfilled the requirements so perfectly, and were such excellent models, as to be considered a first-class foundation for the Japanese lighthouse service. The native engineers took these lights as their pattern, and, unaided, extended their coast lighting system upon the lines laid down by the Stevensons. Since that date Japan has never gone outside her own borders for assistance in lighthouse engineering. CHAPTER II BUILDING A LIGHTHOUSE