Electromagnetic radiation — these interactions include the Faraday effect and the Kerr effect. In refraction, a wave crossing from one medium to another of different density alters its speed and direction upon entering the new medium. The ratio of the refractive indices of the media determines the degree of refraction, and is summarized by Snell's law. Light of composite wavelengths (natural sunlight) disperses into a visible spectrum passing through a prism, because of the wavelength-dependent refractive index of the prism material (dispersion); that is, each component wave within the composite light is bent a different amount. EM radiation exhibits both wave properties
A Tale of a Tub in the reception of Swift's work is that the narrator of the work is an extremist in every direction. Consequently, he can no more construct a sound allegory than he can finish his digressions without losing control (eventually confessing that he is insane). For a Church of England reader, the allegory of the brothers provides small comfort. Martin has a corrupted faith, one full of holes and still with ornaments on it. His only virtue is that he avoids the excesses of his brothers, but the original faith is lost to him. Readers of the "Tale" have picked up on