A new chemical etching technique was used to study minute flaw patterns in g;ass. The etched structure disclosed that the minute defects react to the chemical treatment in a different manner from ordinary fissures. Flaw patterns formed at the tips of slow-moving internal cracks were analogues to dislocation phenomena in crystals. Oriented and repeating flaw groupings were observed in various types of glass. These patterns are produced above the "strain point" and were shown to be influenced permanently induced stresses and internal homogeneity. Fracturing by localised stresses created flaw patterns radiating from the point or origin with shapes simlar in appearance to shock wave phenomena. The impact breaking strength of glass containers was directly influenced by the number of flaws. The flaw distribution decreased rapidly with decreasing diameter of glass fibres.
