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"Two-light lancet." —D'Anvers, 1895

Two-light lancet

"Two-light lancet." —D'Anvers, 1895

A parabolic reflection lantern.

Lantern

A parabolic reflection lantern.

A lantern is a portable lighting device used to illuminate broad areas. Lanterns may be used for signaling, or as general light sources for camping.

Lantern Holder

A lantern is a portable lighting device used to illuminate broad areas. Lanterns may be used for signaling,…

The earliest bicycle and car lights were powered by acetylene, generated in a carbide lamp, now almost unused except by cavers. They were dim and temperamental, and the arrival of battery lamps was welcomed.

Bicycle Lantern Illumination

The earliest bicycle and car lights were powered by acetylene, generated in a carbide lamp, now almost…

Principle of light and shade from light to dark.

Light and Shade

Principle of light and shade from light to dark.

A lamp is a replaceable component such as an incandescent light bulb, which is designed to produce light from electricity. These components usually have a base of ceramic, metal, glass or plastic, which makes an electrical connection in the socket of a light fixture. This connection may be made with a screw-thread base, two metal pins, 2 metal caps or a bayonet cap.

Light Fixture

A lamp is a replaceable component such as an incandescent light bulb, which is designed to produce light…

"The radiation of light, or the intensity of light is inversely proportional to the square of the distance from the light source." —Croft 1917

Light Intensity

"The radiation of light, or the intensity of light is inversely proportional to the square of the distance…

"Another illustration of how luminous density varies inversely as the square of the distance." —Croft 1917

Light Intensity Versus Distance

"Another illustration of how luminous density varies inversely as the square of the distance." —Croft…

"A card placed at point A receives normal light. At point B the card receives four times as much light, but only at 1/4 intensity. At point C nine times the area covered, but only 1/9 the intensity." —Quackenbos 1859

Light Intensity at Different Distances

"A card placed at point A receives normal light. At point B the card receives four times as much light,…

"The intensity of light from a candle decreases proportionally with an increase in distance from the candle." -Comstock 1850

Dispersion of Light

"The intensity of light from a candle decreases proportionally with an increase in distance from the…

"Rays of light are said to diverge, when they proceed from the same point, and constantly recede from each other, as from the same point a. Rays of light are said to converge, when they approach each other in such a drection as finaly to meet at a point, as at b." -Comstock 1850

Rays of Light

"Rays of light are said to diverge, when they proceed from the same point, and constantly recede from…

"An iron pile light erected at Haneda, in the Bay of Yedo, Japan." —The Encyclopedia Britannica, 1910

Lighthouse

"An iron pile light erected at Haneda, in the Bay of Yedo, Japan." —The Encyclopedia Britannica,…

The electrical symbol for lighting switches.

Lighting Switch

The electrical symbol for lighting switches.

Lamps using natural gas to produce light. Uses convention make the lamp very efficient.

Gas Lighting

Lamps using natural gas to produce light. Uses convention make the lamp very efficient.

An illustration of a man with a candle.

Man with Candle

An illustration of a man with a candle.

A splint of wood, with one end dipped in a chemical preparation of phosphorus.

Match

A splint of wood, with one end dipped in a chemical preparation of phosphorus.

"Parallel rays of light strike the concave mirror. The rays converge at the focus, F, which is halfway between the mirror surface and the center of the sphere that the mirror would form if it were a full sphere." —Quackenbos 1859

Reflection from Concave Mirrors

"Parallel rays of light strike the concave mirror. The rays converge at the focus, F, which is halfway…

"Parallel rays strike the convex mirror, reflect, and diverge as if they had originated from a virtual focus inside the mirror. Focus F is located between the surface of the mirror and the mirror's center if it were a full body sphere." —Quackenbos 1859

Reflection by Convex Mirrors

"Parallel rays strike the convex mirror, reflect, and diverge as if they had originated from a virtual…

A moth being attracted to candle light.

Moth

A moth being attracted to candle light.

From the well known nocturnal habits of moths, and the certainty of their being destroyed by a light, a cheap and effective mode of destroying them, shown in the annexed figure. It consists of a pan of viscid matter placed upon a stake, which is set in the field of cotton at suitable distances. A block of wood is placed in the center of the pan, upon which is placed a lighted glass lantern. The moths, being attracted by the light, dash against it and fall into the pan, and are thus destroyed before depositing their eggs upon the tender leaves of the growing plant.

Moth Lantern

From the well known nocturnal habits of moths, and the certainty of their being destroyed by a light,…

"Make a 'Newton disk', painting the prismatic colors in proper proportion as indicated." — Avery, 1895

Newton disk

"Make a 'Newton disk', painting the prismatic colors in proper proportion as indicated." — Avery,…

"In order strictly to equalize a fixed light over the whole horizon, which could not possibly be done with separate reflectors, Marcet proposed this ingenious instrument, which is generated by the revolution of the parabolic profile pp' round its parameter as a vertical axis, instead of round a horizontal axis, as in all former reflectors." —The Encyclopedia Britannica, 1910

Parabolic Profile

"In order strictly to equalize a fixed light over the whole horizon, which could not possibly be done…

"In 1763, or at latest before 1777, parabolic reflectors were first used for lighthouse illumination by Mr. Hutchinson, dockmaster of Liverpool. In his work on Practica Scamanship, published in 1777, he states that the Mersey lights were fitted with reflectors formed of small fucets of silvered glass, and made, as he says "as nearly as they can be to the parabolic curve." This is unquestionably the earliest published notice of the use of parabolic reflectors for lighthouse illumination." —The Encyclopedia Britannica, 1910

Parabolic Reflector

"In 1763, or at latest before 1777, parabolic reflectors were first used for lighthouse illumination…

"In 1763, or at latest before 1777, parabolic reflectors were first used for lighthouse illumination by Mr. Hutchinson, dockmaster of Liverpool. In his work on Practica Scamanship, published in 1777, he states that the Mersey lights were fitted with reflectors formed of small fucets of silvered glass, and made, as he says "as nearly as they can be to the parabolic curve." This is unquestionably the earliest published notice of the use of parabolic reflectors for lighthouse illumination." —The Encyclopedia Britannica, 1910

Parabolic Reflector

"In 1763, or at latest before 1777, parabolic reflectors were first used for lighthouse illumination…

"It will be seen that the parabolic mirror a is at best but a very imperfect instrument, for even if the radiant were strictly a mathematical point, the cone of rays (shown undotted) escaping past the lips of the mirror must be lost." —The Encyclopedia Britannica, 1910

Paraboloid

"It will be seen that the parabolic mirror a is at best but a very imperfect instrument, for even if…

"And the jailor, being roused out of sleep and seeing the prison doors open, drew his sword and was about to kill himself, supposing that the prisoners had escaped. But Paul cried with a loud voice, saying, Do thyself no harm: for we are all here. And he called for lights and sprang in, and, trembling for fear, fell down before Paul and Silas, and brought them out and said, Sirs, what must I do to be saved?" Acts 16:27-30 ASV <p>Illustration of the jailer kneeling on one knee at Paul's feet in the jail. Paul stands above him with arms open and Silas is sitting on a bench leaning toward and reaching out for the jailer. A lamp is burning on the ground next to the jailer's sword. The door to the jail is in the corner.

Paul and Silas in Jail - the Jailer Kneels Before Paul

"And the jailor, being roused out of sleep and seeing the prison doors open, drew his sword and was…

"And suddenly there came from heaven a sound as of the rushing of a mighty wind, and it filled all the house where they were sitting. And there appeared unto them tongues parting asunder, like as of fire; and it sat upon each one of them. And they were all filled with the Holy Spirit, and began to speak with other tongues, as the Spirit gave them utterance." Acts 2:2-4 ASV <p>Illustration of the apostles as the Holy Spirit descends upon them in the form of tongues of fire. Tiny flames float above their heads. A dove emanating light is at the top of the image. A large book sits on the left side of the image.

Descent of the Holy Spirit on the Apostles

"And suddenly there came from heaven a sound as of the rushing of a mighty wind, and it filled all the…

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

Prism

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

"The first R&eacute;verb&egrave;re --oil lantern-- with a metal reflector, used to light the streets of Paris. It was invented by Bourgeois de Ch&acirc;teaublanc in 1765, and used until the introduction of gas." -Bodmer, 1917

Réverbère Oil Lamp

"The first Réverbère --oil lantern-- with a metal reflector, used to light the streets…

"Azure, a ray of the sun issuing out of the dexter corner of the escutcheon. The lines on each side are not noticed. RAY. A stream of light proceeding from a luminous body." -Hall, 1862

Ray of Sun

"Azure, a ray of the sun issuing out of the dexter corner of the escutcheon. The lines on each side…

"The apparatus shown is used to prove that incident rays and reflected rays are equal." -Avery 1895

Reflected Light

"The apparatus shown is used to prove that incident rays and reflected rays are equal." -Avery 1895

"Angle of incidence equals angle of reflection." &mdash;Croft 1917

Reflection of Light

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

"Reflection of light from a broken surface." &mdash;Croft 1917

Reflection of Light from a Broken Surface

"Reflection of light from a broken surface." —Croft 1917

"Consider a beam of light as made up of a number of ehter waves moving forward in air and side by side, as represented by the rays A, B, C. Imagine a plane, MN, normal to these yars, attached to the waves and moving forward in a straight line. As the wave front advances beyond MN, the ray, A, strikes the reflecting surface, RS, and is turned back into the air in accordance with the law just given." -Avery 1895

Explanation of Reflection

"Consider a beam of light as made up of a number of ehter waves moving forward in air and side by side,…

"Thus, if a sunbeam, passing through a small aperure in the window shutter a, be permitted to fall upon the plane mirror, or looking glass, c, d, at right-angles, it will be reflected back at right-angles with the mirror, and therefore will pass back again in exactl the same direction in which it approached." -Comstock 1850

Reflection of Light

"Thus, if a sunbeam, passing through a small aperure in the window shutter a, be permitted to fall upon…

"Let a ray pass towards a mirror in the line a, c, it will be reflected off in the direction of c, d, making the angles 1 and 2 exactly equal." -Comstock 1850

Reflecion of Light

"Let a ray pass towards a mirror in the line a, c, it will be reflected off in the direction of c, d,…

"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…

"Reflection of light from a smooth surface." &mdash;Croft 1917

Reflection of Light from a Smooth Surface

"Reflection of light from a smooth surface." —Croft 1917

"Reflection of light form a smooth surface." &mdash;Croft 1917

Reflection of Light from a Smooth Surface

"Reflection of light form a smooth surface." —Croft 1917

"Light projected by a parabolic reflector." &mdash;Croft 1917

Parabolic Reflector

"Light projected by a parabolic reflector." —Croft 1917

A polished surface of metal, or any other suitable material, applied for the purpose of reflecting rays of light, heat, or sound in any required direction.

Parabolic, Reflector

A polished surface of metal, or any other suitable material, applied for the purpose of reflecting rays…

"Illustrating refraction of light from a source through glass, and the appropriate angles of refraction." &mdash;Croft 1917

Refraction of Light through Glass

"Illustrating refraction of light from a source through glass, and the appropriate angles of refraction."…

"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." &mdash;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…

"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." &mdash;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,…

"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…

In Gothic architecture, a lantern tower is frequently placed over the center of cross churches, and the light admitted by windows in the sides. This illustration shows the lantern tower at St. Ouen in Rouen, France

Lantern Tower at St. Ouen; Rouen, France

In Gothic architecture, a lantern tower is frequently placed over the center of cross churches, and…

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.

"Railway Semaphore. a, lever, which operates both b, blade, and c, lantern." -Whitney, 1911

Railroad Semaphore

"Railway Semaphore. a, lever, which operates both b, blade, and c, lantern." -Whitney, 1911

"An instrument described by Foucault for transmitting a beam of light along the optical axis of a fixed horizontal telescope."&mdash;Finley, 1917

Siderostat

"An instrument described by Foucault for transmitting a beam of light along the optical axis of a fixed…

"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,…

"C. Collimator; P, center of group of prisms; T, telescope; s, slit through which the ray of light enters, R, ray on its progress through prisms to telescope."&mdash;Finley, 1917

Spectroscope

"C. Collimator; P, center of group of prisms; T, telescope; s, slit through which the ray of light enters,…

"A spectroscope is an instrument used ot produce a spectrum of the light form any source, and for its study." -Avery 1895

Spectroscope

"A spectroscope is an instrument used ot produce a spectrum of the light form any source, and for its…

"A prism is used to disperse ordinary light, and slits are cut in paper S to only allow yellow and blue light to pass. These two simple colors will be blended by the lens, forming a light that is nearly white. The effect of mingling any two colors may be determined in this way." -Avery 1895

Color Spectrum

"A prism is used to disperse ordinary light, and slits are cut in paper S to only allow yellow and blue…

"A spectrum of sunlight is crossed by dark lines, many hundreds of whcih have been counted and accurately mapped. The more conspicious of these dark lines are distinguisged by letters of the alphabet. A few of these dark lines in the solar spectrum are due to absorption in the earth's atmosphere, but by far the greater number originate in the selective absorption of the solar atmosphere itself." &mdash; Avery, 1895

Visible spectrum

"A spectrum of sunlight is crossed by dark lines, many hundreds of whcih have been counted and accurately…

"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…

"Condensing Straight Prisms.&mdash;These, either by reflexion or refraction or both, cause a ray fr proceeding in any compass bearing from a fixed light apparatus AA to emerge in the direction, e.g., parallel to the corresponding ray fb, which proceeds in the same compass bearing from another part of the apparatus and so of any other ray fc which is bent parallel to the ray fa." &mdash;The Encyclopedia Britannica, 1910

Straight Prisms

"Condensing Straight Prisms.—These, either by reflexion or refraction or both, cause a ray fr…