ClipArt ETC

The Lenses and Refraction ClipArt gallery offers 75 illustrations of light changing direction as it passes through media with different refractive indices.

"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 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…

"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…

"Plane mirrors M revolve on an endless chain placed outside of the apparatus and alter the direction of the flashes after they pass into the dark arc on the landward side so as to cause the lenses L, L to repeat their flashes over the seaward are which requires strengthening. The condensing spherical mirror and mirror of unequal areas will also be found applicable in cases where the flashes do not require to sweep over the whole horizon." —The Encyclopedia Britannica, 1910

Repeating Light

"Plane mirrors M revolve on an endless chain placed outside of the apparatus and alter the direction…

"In order to produce, on the catoptric system, a fixed light showing all round the circle, a number of reflectors are fixed round the outside of a stationary chandelier n. As the ordinary paraboloid has about 14 degrees of divergence, twenty-five reflectors were needed to light up continuously (though not equally) the whole horizon." —The Encyclopedia Britannica, 1910

Revolving Light

"In order to produce, on the catoptric system, a fixed light showing all round the circle, a number…

"If again the light was to revolve, then a revolving chandelier was employed having a certain number of flat faces, on each of which was fixed a number separate lamps and reflectors with their axes parallel to each other. When the chandelier revolved, and one of the flat sides was turned towards the sailor, he would, when at some distance from the shore, receive a flash at once form each of the mirrors which were on that face, but when the face was turned away from him a dark period would intervene until the next face came round again." —The Encyclopedia Britannica, 1910

Revolving Light

"If again the light was to revolve, then a revolving chandelier was employed having a certain number…

A rose cut is a cut of gemstone. In this cut, the upper surface is shaped into triangular facets of nearly equal size throughout.

Rose Cut

A rose cut is a cut of gemstone. In this cut, the upper surface is shaped into triangular facets of…

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.

"An instrument used chiefly to measure the angular deviation of light rays in passing through a prism, and hence to determine the refractive indices of the substance of which the prism is formed." &mdashWhitney;, 1889

Spectrometer

"An instrument used chiefly to measure the angular deviation of light rays in passing through a prism,…

A split cut is a cut of gemstone. It is similar to a trap cut.

Split Cut

A split cut is a cut of gemstone. It is similar to a trap cut.

"In 1835 Mr. Stevenson, in a report to the Northern Lighthouse Board, proposed to add fixed reflecting prisms p below the lenses of Fresnel's revolving light, and he communicated this proposal to M. L. Fresnel, who approved of his suggestion, and assisted in carrying out the design in 1843. This combination added, however, but little to the power of the flash, and produced both a periodically flashing and constantly fixed light; but it must be remembered that the prism for fixed lights was the only kind of reflecting prism then known." —The Encyclopedia Britannica, 1910

Stevensons Revolving Light

"In 1835 Mr. Stevenson, in a report to the Northern Lighthouse Board, proposed to add fixed reflecting…

"Professor Swan's Designs.—Among several ingenious arrangements and new forms of agents proposed by Professor Swan is the mode of sending rays from prisms through interstices left between other prisms placed in front, and also a form of agent which he termed the triesoptric prism, in which the rays would undergo two refractions and three reflexions. a are the front and b the triesoptric prisms. The two upper and lower prisms a are constructed of flint glass of high refractive power. It will be observed from the drawing that this ingenious arrangement is nevertheless open to objection, for cones of light of 30 degrees in front and of 65 degrees at the back are lost through the interstices." —The Encyclopedia Britannica, 1910

Swans Designs

"Professor Swan's Designs.—Among several ingenious arrangements and new forms of agents proposed by…

A Trap Cut is a cut of gemstone. Emeralds are commonly cut this way.

Trap Cut

A Trap Cut is a cut of gemstone. Emeralds are commonly cut this way.