Chandelier Crystals and Prisms

Refraction:
When a ray of light passes through plane glass, like a window pane, it is shifted somewhat, but its direction does not change; that is, the emergent ray is parallel to the incident ray. But when a beam of light passes through a triangular glass prism, such as a chandelier crystal, its direction is greatly changed, and an object viewed through a prism is seen quite out of its true position.

Whenever light passes through a prism, it is bent toward the base of the prism, or toward the thick portion of the prism, and emerges from the prism in quite a different direction from that in which it entered. Hence, when an object is looked at through a prism, it is seen quite out of place. In Figure, the candle seems to be at S, while in reality it is at A.

FIG. - When looked at through the prism, A seems to be at S.