"When the object is at a long distance from the lens, the image formed is smaller than the object, and inverted." -Foster, 1921

Convex Lens

"When the object is at a long distance from the lens, the image formed is smaller than the object, and…

A triangular prism.

Prism

A triangular prism.

A triangular prism on a stand.

Prism

A triangular prism on a stand.

"A prism is a piece of glass, having for its sides three plane surfaces and for its ends two equal and parallel triangles." —Quackenbos 1859

Prism

"A prism is a piece of glass, having for its sides three plane surfaces and for its ends two equal and…

"Cross-section of prismatic reflector, showing how light rays are refracted and dispersed." —Croft 1917

Prismatic Reflector

"Cross-section of prismatic reflector, showing how light rays are refracted and dispersed." —Croft…

"Since air is a rarer medium and water is denser, as ray A passes into the water, it is refracted to C. Also note that as ray B leaves the water, it is refracted to D as it enters the air." —Quackenbos 1859

Refraction Between Mediums

"Since air is a rarer medium and water is denser, as ray A passes into the water, it is refracted to…

"Although a ray of light will pass in a straight line, when not interrupted, yet when it passes obliquely from one transparent body into another, of a different density, it leaves its linear direction, and is bent, or refracted more or less, out of its former course." -Comstock 1850

Refraction of Light

"Although a ray of light will pass in a straight line, when not interrupted, yet when it passes obliquely…

"When radiant energy passes through a medium bounded by parallel planes, the refractions at the two surfaces are equal and contrary in direction. The direction after passing through the plate is parallel to the direction before entereing the plate; the rays merely suffer lateral aberration." -Avery 1895

Refraction by Plates

"When radiant energy passes through a medium bounded by parallel planes, the refractions at the two…

"The prism will deflect the red and orange, and form a reddish colored image at n. The violet, indigo, blue, green and yellow light, not caught by the prism, will unite at f to form a greenish image. When the prism is removed, the reddish light that fell at n, and the greenish light that fell at f, unite to form white light." -Avery 1895

Refraction of Complimentary Colors

"The prism will deflect the red and orange, and form a reddish colored image at n. The violet, indigo,…

"Let the medium b be glass, and the medium c, water. The ray a, as it falls upon the medium b, is refracted towards the perpendicular line e d; but when it enters the water, whose refractive power is less than that of glass, it is not bent so near the perpendicular as before, and hence it is refracted from, instead of towards the perpendicular line, and approaches the originial direction of the ray a g, when passing through the air." -Comstock 1850

Refraction, glass and water

"Let the medium b be glass, and the medium c, water. The ray a, as it falls upon the medium b, is refracted…

"LA represents a ray of light propagated in air, falling obliquely upon the surface of the water at A, and deviated by the water from AE to AK." -Avery 1895

Refraction of Light Between Air and Water

"LA represents a ray of light propagated in air, falling obliquely upon the surface of the water at…

"If the coin were to be observed in an empty pan and then watched as the pan was filled with water, the image of the coin would be refracted to position N." —Quackenbos 1859

Refraction as seen by the Human Eye

"If the coin were to be observed in an empty pan and then watched as the pan was filled with water,…

"Suppose the rod a, to be set with one half of its length below the surface of the water and the other half above it. The eye being placed in an oblique direction will see the lower end apparently at the point o, while the real termination of the rod would be at n; the refraction will therefore make the rod appear shorter by the distance from o to n, or one-fourth shorter than the part below the water really is." -Comstock 1850

Refraction, water

"Suppose the rod a, to be set with one half of its length below the surface of the water and the other…

Ruler and with a lens and screen, used for demonstrating refraction.

Ruler and lens

Ruler and with a lens and screen, used for demonstrating refraction.