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HISTORY OF GLASS
Glass was first made in the ancient world, but its earliest origins are obscure. Egyptian glass beads are the earliest glass objects known, dating from about 2500 BC. Later in Egyptian civilization, a type of glass characterized by feathery or zigzag patterns of coloured threads on the surface of the glass vessel was made.
The origins of modern glass were in Alexandria during the Ptolemaic period and, later, in ancient Rome. Alexandrian craftsmen perfected a technique known as mosaic glass in which slices of glass canes of different colours were cut crossways to make different decorative patterns. Millefiori glass, for which the canes are cut in such a way as to produce designs reminiscent of flower shapes, is a type of mosaic glass. Molded glass was also developed early, glass being pressed into a mold to form a particular shape. Various types of decoration involving engraving and colour were also possible. Glassblowing was invented by Syrian craftsmen in the area of Sidon, Aleppo, Hama, and Palmyra in the 1st century BC, where blown vessels for everyday and luxury use were produced commercially and exported to all parts of the Roman Empire. At first, glass was blown into decorative molds; vessels shaped as shells, clusters of grapes, and human heads were common early Syrian products, but later Syrian gaffers (blowers) executed natural, spherical forms, without the use of molds. The Romans perfected cameo glass, in which the design has been produced by cutting away a layer of glass to leave the design in relief. Portland Vase, Roman cameo glass, 1st century AD; in the British Museum By courtesy of the trustees of the British Museum The next major developments in the history of glass came during the 15th century in Venice. As early as the 13th century the Venetian island of Murano had become the centre for glassmaking. At first, Venetian glassmakers made use of many of the ancient and medieval decorative techniques to produce richly coloured and ornamental pieces having motifs characteristic of the Italian Renaissance. The technique has remained basically the same to the present day. The "metal" (molten glass having the consistency of molasses) is gathered on the end of a hollow pipe, inflated to a bubble, and formed into a vessel by blowing, swinging, or rolling on a smooth stone or iron surface (marver). Additions, such as stems, feet, or handles, are attached by welding. While still soft, the glass can be manipulated by hand tools or cut with shears. In the 17th century the gaffer's "chair," a bench with two extended arms on which the pipe is trundled to preserve the symmetry of the molten glass, came into use. The chair has been extended to include the glassmaking crew, the gaffer and two or three assistants.