CHAPTER I.

THE PHYSICAL AND CHEMICAL PROPERTIES OF GLASS.

Definition of the term “Glass”--Amorphous structure the common feature of all vitreous bodies--Glass a congealed fluid--Glasses not definite chemical compounds but complex solutions--Range of chemical composition available for glass-making--Considerations governing chemical composition--Influence of composition on physical properties--Chemical stability of glass-- Permanence of glass surfaces--Action of water, acids, and alkalies on glass--Action of light on glass _p._ 1