The most probable hypothesis about the invention of glass is that of pottery-kiln, having its walls somewhat melted on the surface after exposing them to high temperature of fire. But why did it occur just in Eastern Mediteranean, while pottery was being made all over the world. The mystery lies in the ground composition of this area. The clay used to build the kiln contained considerable amount of sand and chiefly soda, which is a very easily melted material. This is a raw material very easily to be found in Northern Africa as there are thousands of small salt and soda containing lakes such as Vadi Natrum (soda consists Natrium). From such place the material for building this kiln should come and this is a condition not repeated in other places in the world.

The oldest products were beads made by winding of glass thread on the clay-rod and blue coloured glazings. Such a blue glaze, colored with a copper compound, was probably discovered by accident and used tu fabricate beads in imitation of greatly prized blue and green stones.

The earliest glass vessels, again Egyptian and dating from about 15th century B.C., were made by an adaptation of this bead covering technique; threads of hot ductile glass were wound upon a core of clay and sand which was afterwards removed. Small vessels and decorative objects continued to be made by moulding and modelling, until just before the beginning of the Christian era, when a revolutionary change in practise was brought by the invention, apparently in Syria, of the glass-blowing tube. No technical change of comparable importance took place thenceforward until the present time, with the exception of machinery for bottle making, pressing of glass in moulds and the large-scale manufacture of glass in sheets.