Elementary Treatise on Natural Philosophy, Volumen4

angle appears axis beam beats becomes body bright called centre colours common complete concave consists containing convex corresponding crystal curvature dark denote determined deviation direction directly distance double effect emergent employed equal example experiment face fact figure fixed focal length focus formed frequency fundamental give given glass greater Hence incident increase interval kind lens less light means measured medium mirror move nearly normal object observer obtained opposite ordinary parallel particles pass piece pipe pitch placed plane plate polarization portion position principal prism produced propagation ratio rays received reflected refraction regarded represented respectively resultant rotation screen seen shows side slit solid sound spectra spectrum string surface telescope tion tone travelling traversing tube turned usually velocity vibrations wave-length waves