TAILIEUCHUNG - An Encyclopedia of the History of Technology part 89

An Encyclopedia of the History of Technology part 89. This one of a kind encyclopedia presents the entire field of technology from rudimentary agricultural tools to communication satellites in this first of its kind reference source. Following an introduction that discusses basic tools, devices, and mechanisms, the chapters are grouped into five parts that provide detailed information on materials, power and engineering, transportation, communication and calculation, and technology and society, revealing how different technologies have together evolved to produce enormous changes in the course of history | PART FIVE TECHNOLOGY AND SOCIETY authorities believe it stemmed from the boat-building traditions of Scandinavia others that it has affinities with the pointed arch of Gothic design see p. 874 . More probably the form evolved from practical needs and limitation of knowledge as did the similarly-shaped early corbelled stone structures of areas as far apart as Mycenae in Greece or the Celtic oratories of western Ireland. In early cruck construction the basic timbers the crucks were massive whole or split tree trunks the lower edges of which were fixed into the ground in pairs at intervals in the long sides of a rectangular building the interval was generally some 12-16ft and the narrower tops were then bent over to be fastened together in the centre so forming an apex to the roof. A long horizontal timber the ridge piece was extended along this whole roof the crucks being affixed to it. Parallel to the ridge piece were other slenderer poles and these were crossed at right angles by more timbers. The interstices were filled with branches and mud and covered on the exterior by moss thatch or turf. The great drawback to the single-storeyed cruck building was its lack of headroom as it had no vertical walls so the design was further developed into two-storeyed buildings as the crucks were taken up higher. The next stage was to extend horizontal tie beams across the interior and beyond the crucks to attach to horizontal timbers at right angles to the tie beams which would carry the roof and act as the summit of the now vertical walls. Gradually cruck structures became more advanced and practical. The lower ends of the crucks were set into low stone walls or timber sills instead of directly into the ground. The crucks were shaped before use a pair forming a symmetrical arch. More complex roof designs followed see pp. 865-6 . Timber-framing In regions of northern Europe especially where hardwoods were available in quantity as in England a more sophisticated method .

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