frequent manifestation of the proverbial symptom of a puzzled Scotchman than from these early brothers of the craft--the crannog-builders. This is how they worked:-- (1.) Immediately over the chosen site a circular raft of trunks of trees, laid above branches and brushwood, was formed, and above it additional layers of logs, together with stones, gravel, etc., were heaped up till the whole mass grounded. (2.) As this process went on, upright piles, made of oak, and of the required length, were inserted into prepared holes in the structure, and probably also a few were inserted into the bed of the lake. (3.) The rough logs forming the horizontal layers were made of various kinds of wood, generally birch, it being the most abundant. These were occasionally pinned together by thick oak pegs, and here and there at various levels oak-beams mortised into one another stretched across the substance of the island, and joined the surrounding piles. (4.) When a sufficient height above the water-line was attained, a prepared pavement of oak-beams was constructed, and mortised beams were laid over the tops of the encircling piles which bound them firmly together as already described. The margin of the island was also slantingly shaped by an intricate arrangement of beams and stones, constituting in some cases, according to Dr. Stuart, a well-formed breakwater. (5.) When the skeleton of the island was thus finished, probably turf would be laid over its margin where the pointed piles protruded, and a superficial barrier of hurdles, or some such fence, erected close to the edge of the water. (6.) Frequently a wooden gangway, probably submerged, stretched to the shore, by means of which secret access to the crannog could be obtained without the use of a canoe. (For the mode of structure of gangway, see page 101.) Bearing in mind that all these structures were solidly put together without nails or bolts, and that the gangways, which have remained permanently fixed to the present time, had neither joint nor mortise, we may fearlessly challenge modern science to produce better results under these, or indeed any, circumstances. That future discoveries may show slight deviations from the exactness of these details I am quite prepared to believe, as the mechanical knowledge of the age was too thorough not to be readily adapted to varied circumstances. What I do however maintain is, that the general principles of structure here laid down, being the outcome of a sound knowledge of mechanics, varied during the whole period of their practical application as little as the essential laws of architecture do in the structure of different styles of our modern houses.