A LIQUID for packaging and architecture, engineering and art! Essential to automobiles, radio, television and satellites, it is indispensable in hospitals, factories and homes. It can be as strong as steel, hard as gems, heavy as iron; or fragile as eggshells, soft as silk, light as cork. Supplied in abundance surpassed by few other materials, it is the liquid of antiquity​—glass.

“Glass​—a liquid?” you may ask in disbelief. Yes, when glass is formed from a white-hot mixture of molten ingredients its atoms and molecules retain the random pattern of a liquid even though it becomes as rigid as ordinary solids. A liquid that looks, feels and behaves like a solid seems fantastic, but the peculiar properties of its unique state make glass one of your most versatile and valuable servants.

Continuous Production

The basic ingredients of glass have remained unchanged for thousands of years. Silica sand, lime and soda still make about 90 percent of the world’s glass, but the production scale has been considerably increased to meet modern demands. Today’s glassmakers scrupulously select tons of pure raw materials, weigh them to the ounce, thoroughly mix them and then feed the mixture, or batch, to gigantic tank furnaces that can hold more than 1,000 tons of molten glass. Although added cullet, or scrap glass of the same formula to be manufactured, speeds the melting process, the furnace must be heated to about 2,800 degrees Fahrenheit!