The history of glass is quite old, that of its scientific exploration very young. During formation of the earth, highly siliceous melts of rocks occasionally froze to natural glasses such as obsidian. Water, dissolved homogeneously under high pressure, evaporated rapidly if such melts penetrated the surface, e. g., in a volcanic eruption; and, when cooled quickly, the foaming melt became a solid natural glass foam, since high viscosity prevented the escape of bubbles. Modern industrial technologies may be considered variations of this basic process.
KeywordsOptical Glass Glass Type Glass Factory Lead Silicate Glass Prism
Unable to display preview. Download preview PDF.