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"The angle under which the rays of light, coming from the extremities of an object, cross each other at the eye, bears a proportion directly to the length, and inversely to the distance of the object." -Comstock 1850

Angle of Vision

"The angle under which the rays of light, coming from the extremities of an object, cross each other…

"Because of their greater refrangibility, the focus of the violet rays is nearer the lens than the focus of the red rays, as illustrated. If the screen is as near the lens as the focus marked v, the outer fringe is red. If the screen is as far from the lens as the focus marked r, the outer fringe is violet. This difference in the deviation of differently colored rays is called chormatic aberration." -Avery 1895

Chromatic Aberration

"Because of their greater refrangibility, the focus of the violet rays is nearer the lens than the focus…

"EASTERN CROWN. A crown with rays proceeding from a circle, called by heralds an Eastern crown, is found in ancient achievements. The annexed cut shows its form." -Hall, 1862

Eastern Crown

"EASTERN CROWN. A crown with rays proceeding from a circle, called by heralds an Eastern crown, is found…

This divider has leaves and small round kernels featured in a design on the sides. The center area has rays coming out from a blank, rectangular center. It can be used as a divider or banner.

Divider with Leaves and Sun Rays

This divider has leaves and small round kernels featured in a design on the sides. The center area has…

Illustration modeling the illumination on a surface when the surface is not perpendicular to hte rays of light from a source of light.

Illumination of a Surface When the Surface is not Perpendicular to the Source

Illustration modeling the illumination on a surface when the surface is not perpendicular to hte rays…

"Thus the pencils of converging rays, are rendered still more convergent by their passage through the lens, and are therefore brought to a focus nearer the lens, in proportion to their previous convergency." -Comstock 1850

Converging Rays and a Double Convex Lens

"Thus the pencils of converging rays, are rendered still more convergent by their passage through the…

"If diverging rays fall on the surface of the same lens, they will, by refraction, be rendered less divergent, parallel, or convergent, according to the degrees of their divergency, and the convexity of the surface of the lens." -Comstock 1850

Diverging Rays from a Double Convex Lens

"If diverging rays fall on the surface of the same lens, they will, by refraction, be rendered less…

"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…

"The focus of a concave mirror is the point where the rays are brought together by reflection." -Comstock 1850

Focus of a Concave Mirror

"The focus of a concave mirror is the point where the rays are brought together by reflection." -Comstock…

"Thus, were the rays falling on the mirror parallel, the focus would be at a' but in consequence of their previous convergency, they are brought together at a less distance than the principal focus." -Comstock 1850

Convergent Rays in a Concave Mirror

"Thus, were the rays falling on the mirror parallel, the focus would be at a' but in consequence of…

"...be made obvious...where the diverging rays 1, 2, 3, 4 form a focus at the point o, whereas, had they been parallel, their focus would have been at a." -Comstock 1850

Divergent Rays in a Concave Mirror

"...be made obvious...where the diverging rays 1, 2, 3, 4 form a focus at the point o, whereas, had…

"When the rays diverge form a point at a distance from the mirror less than that of the principal focus, the reflected rays diverge as if from a point back of the mirrir. This point, b, is a virtual focus." -Avery 1895

Rays Diverging from Beyond the Center of Curvature on a Concave Mirror

"When the rays diverge form a point at a distance from the mirror less than that of the principal focus,…

"The focus of each point chose may be determined by tracing two rays from the point, and locating their real or apparent intersection after reflection by the mirror. The two rays most convenient for this purpose are teh oen that lies along the axis fo the point, and the one that lies parallel to the principal axis of the mirror." -Avery 1895

Concave Mirror with Image and Focus

"The focus of each point chose may be determined by tracing two rays from the point, and locating their…

"...let us suppose the object a, to be placed before the mirror, and nearer to it than the principal focus. Then the rays proceeding from the extremities of the object without interruption, would continue to diverge in the lines o and n, as seen behind the mirror' but by reflection they are made to diverge less than before, and consequently to make the angle under which the meet more obtuse at the eye b, than it would be if they continued onward to e, where they would have met without reflection. The result therefore, is to render the image h, upon the eye, as much larger than the object a, as the angle at the eye is more obtuse than the angle at e." -Comstock 1850

Object Within the Focus in a Concave Mirror

"...let us suppose the object a, to be placed before the mirror, and nearer to it than the principal…

"Let us suppose that a, is a luminous point, from which a pencil of diverging rays falls upon a convex mirror. These rays, as already demonstrated, will be reflected more divergent, and consequently will meet the eye at e, in a wider state of dispersion that they fell upon the mirror at o." -Comstock 1850

Convex Mirror

"Let us suppose that a, is a luminous point, from which a pencil of diverging rays falls upon a convex…

"The incident rays, a and b, being parallel before they reach the reflectors, are thrown off at unequal angles in respect to each other, for b fallson the mirror more obliquely than a, and consequently is thrown off more obliquely in a contraty direction, therefore, then angles of reflection being equal to those of incidence, the two rays meet at c." -Comstock 1850

Plane Inclined Mirrors

"The incident rays, a and b, being parallel before they reach the reflectors, are thrown off at unequal…

"...a tube with a slit at the further end through which the light enters, and at the other end a collimating lens which brings the rays into a parallel beam (the slit is formed between two parallel edges the distance between which can be varied at will)..." —Whitney, 1889

Prism Spectroscope from the Late 19th Century

"...a tube with a slit at the further end through which the light enters, and at the other end a collimating…

"Azure, a pale, or, radient. RADIENT. Any charge having rays or beams about it." -Hall, 1862

Radient

"Azure, a pale, or, radient. RADIENT. Any charge having rays or beams about it." -Hall, 1862

An instrument which serves to transform radiant energy into mechanical work. Have 4 vanes, with one side white and the other black.

Radiometer

An instrument which serves to transform radiant energy into mechanical work. Have 4 vanes, with one…

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration points down.

Ray Pointing Down

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration…

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration points down and toward the left.

Ray Pointing Down and Left

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration…

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration points down and toward the right.

Ray Pointing Down and Right

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration…

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration points toward the left.

Ray Pointing Left

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration…

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration points toward the right.

Ray Pointing Right

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration…

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration points up.

Ray Pointing Up

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration…

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration points up and toward the right.

Ray Pointing Up and Right

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration…

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration points up and toward the left.

Ray Pointing Up and Right

A ray has one endpoint and extends indefinitely in the other direction. The ray in this illustration…

"These pencils of rays not only flow from the points designated in the figure, but in the same manner from every other point on the surface of a visible object." -Comstock 1850

Pencils of Rays

"These pencils of rays not only flow from the points designated in the figure, but in the same manner…

"From the surface of a plane mirror, parallel rays are reflected parallel; but the convex mirror causes parallel rays falling on its surface to diverge, by reflection." -Comstock 1850

Divergent Rays

"From the surface of a plane mirror, parallel rays are reflected parallel; but the convex mirror causes…

"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

"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,…

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…

"Thus, when erher waves that constitute light are transmitted through glass, they are hindered by the molecules of the glass, and impart some of their motion to those molecules' i.e., a part of the light is absorbed. When a beam of light, as represented by ABC moves forward in the air, the wave-front, MN, continues parallel to itself and moves forward in a straight line. As the wave front advances, A strikes the glass first, and is retarted, the retardation of B and C later change the direction of the rays." -Avery 1895

Explanation of Refraction

"Thus, when erher waves that constitute light are transmitted through glass, they are hindered by the…

"The rose argent of the House of York, surrounded with rays, as of the sun."—Aveling, 1891

Rose-en-Soleil

"The rose argent of the House of York, surrounded with rays, as of the sun."—Aveling, 1891

Illustrations of a segment, a ray, and a line that can be used when providing definitions.

Definitions, Segment, Ray, Line

Illustrations of a segment, a ray, and a line that can be used when providing definitions.

These placoid scales are found in cartilaginous fishes. They are also called dermal denticles. These scales do not grow in size, more are simply added as the fish grows larger.

Placoid Scales of a Shark

These placoid scales are found in cartilaginous fishes. They are also called dermal denticles. These…

"Skate is the popular name for any individual of a section of the genus Raia, differing from the rays proper in having a long pointed snout."—(Charles Leonard-Stuart, 1911)

Skate

"Skate is the popular name for any individual of a section of the genus Raia, differing from the rays…

"...an instrument which gives a spectrum when the source of the light is in a straight line with the eye—that is, which gives dispersion without deviation—is called a direct vision spectroscope..." —Whitney, 1889

Direct Vision Spectroscope

"...an instrument which gives a spectrum when the source of the light is in a straight line with the…

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence of which gives name to the acanthopterygian fishes; a spinous fin-ray, as distinguished for a soft ray." <p>Illustration of the ventral fin of the acanthopterygian fish.

One Spine on the Ventral Fin of a Bony Fish

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence…

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence of which gives name to the acanthopterygian fishes; a spinous fin-ray, as distinguished for a soft ray." <p>Illustration of the dorsal fins of the acanthopterygian fish.

Ten Spines on the Fins of a Bony Fish

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence…

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence of which gives name to the acanthopterygian fishes; a spinous fin-ray, as distinguished for a soft ray." <p>Illustration of the anal fin of the acanthopterygian fish.

Three Spines on the Anal Fin of a Bony Fish

"A fin-spine; one of the unjointed and unbranched sharp bony rays of the fins, such as those the presence…

The Greek square panel is found on the coffer of the Propylaea ceiling, the entrance to the Acropolis in Athens. The design is of many rays of stars.

Greek Square Panel

The Greek square panel is found on the coffer of the Propylaea ceiling, the entrance to the Acropolis…

"Suppose a, to be a distinct object, from which pencils of rays flow from every point toward the object lens b. The image of a, in consequence of the refraction of the rays by the object lens, is inverted at c, which is the focus of the eyeglass d, and through which the image is then seen, still inverted." -Comstock 1850

Refracting Telescope

"Suppose a, to be a distinct object, from which pencils of rays flow from every point toward the object…

Torpedo is a group of rays, commonly called electric rays or torpedoes. It is the only genus in the family Torpedinidae, in the order Torpediniformes. They are slow-moving bottom-dwellers capable of generating a electricity as a defense and feeding mechanism. There are 15-22 extant species.

Torpedo

Torpedo is a group of rays, commonly called electric rays or torpedoes. It is the only genus in the…