An Encyclopedia of the History of Technology part 9. 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 ONE MATERIALS Although many arsenical copper artefacts of the Early Bronze Age appear to have been roughly cast to shape in open stone moulds and then forged to size this practice died out soon after the 8 per cent tin bronze alloy came into general use. Most artefacts were cast almost directly to the finished size in fairly advanced closed moulds similar to that shown diagrammatically in Figure . Many of these moulds were made from clay into which internal cavities were precisely moulded before firing. During the early years of the third millennium foundry processes in the Land of Sumer appear to have developed rapidly. Before 3000 BC most of the copper artefacts from Ur were simply fabricated from sheet metal. By 2700 BC however very refined cast copper articles were being produced probably by a version of shell moulding using a prefired mould of thin clay. Long thin sections such as the blades of swords and daggers were also cast into thin shell moulds which appear to have been heated to redness before the molten metal was introduced. By 2500 BC the Egyptians had developed considerable expertise in the production of hollow copper and bronze statuary. Many large Egyptian statues were cast with an internal sand core which is still present in some of the figures which have been found. Smaller components such as the spouts of copper water vessels were undoubtedly made by the cire perdue lost wax technique which had obviously been mastered by Egyptian craftsmen before 2200 BC. Grecian bronze Daggers with bronze blades inlaid longitudinally with niello a black compound of sulphur with copper or other metals which formed a background for lively and naturalistic pictures in gold and silver figured very prominently in the grave goods found by Schliemann in 1876 when he opened the Royal Bronze Age tombs of Mycenae. Such weapons and most of the other metalwork which was found are now believed to be of Cretan origin. The shaft graves date from the sixteenth century
