"The angle, ABD, included between the direction of the moving body before it strikes the reflecting surface, and a perpendicular to that surface drawn from the point of contact, is called the angle of incidence. The angle between the perpendicular and the direction of the moving body after striking is called the angle of reflection." -Avery 1895

Law of Reflected Motion

"The angle, ABD, included between the direction of the moving body before it strikes the reflecting…

"Angle of incidence equals angle of reflection." —Croft 1917

Reflection of Light

"Angle of incidence equals angle of reflection." —Croft 1917

"Irregular reflection or diffusion results from the incidence of radiant energy upon an irregular surface, as is illustrated. Bodies are made visible to the eye mainly by the light that they thus diffuse." -Avery 1895

Irregular Reflection or Diffusion

"Irregular reflection or diffusion results from the incidence of radiant energy upon an irregular surface,…

"The ray a, c, is the ray of incidence, and that from c, to d, is the ray or reflection. The angles which a, c, make with the perpendicular line, and with the plane of the mirror, is exactly equal to those made by c, d, with the same perpendicular, and the same plane surface." -Comstock 1850

Reflection of Light

"The ray a, c, is the ray of incidence, and that from c, to d, is the ray or reflection. The angles…

"Regular reflection results from the incidence of radiant energy upon a polished surface. When a beam of light falls upon a mirror, the greater part of it is reflected in a definite direction as is illustrated, and forms an image of the object from which it came. A perfect mirror would be invisible." -Avery 1895

Regular Reflection

"Regular reflection results from the incidence of radiant energy upon a polished surface. When a beam…

"If the ray passes in the opposite direction, i.e., from water into air, the process is the reverse of that just indicated. Let KA represent the incident ray." -Avery 1895

Refraction of Light Between Water and Air

"If the ray passes in the opposite direction, i.e., from water into air, the process is the reverse…