How is the Becke line useful for analyzing glass?

The Becke line is useful for determining the refractive index of glass, which can help identify the type of glass and its composition. By observing how the Becke line moves when the glass is immersed in different liquids with known refractive indexes, valuable information about the glass's optical properties can be obtained. This can aid in distinguishing between different types of glass or in detecting impurities within the glass.