### Boy Trying on Hat and Looking at His Reflection

An illustration of a boy trying on a hat and looking at his reflection in the mirror.

### Brilliant Cut

A cut of a gemstone. A brilliant cut stone has fifty-eight facets.

### Ellipse Inscribed In A Circle

Illustration of an ellipse, whose major axis is vertical, inscribed in a circle whose diameter is equal…

### 16 Rotated Concentric Ellipses

Illustration of 16 concentric congruent ellipses that are rotated about the center at equal intervals…

### 2 Ellipses Inscribed In A Circle

Illustration of 2 concentric ellipses, whose major axes are vertical, inscribed in a circle whose diameter…

### 2 Rotated Concentric Ellipses

Illustration of 2 concentric congruent ellipses that are rotated about the center at 90°. The ellipses…

### 4 Rotated Concentric Ellipses

Illustration of 4 concentric congruent ellipses that are rotated about the center at equal intervals…

### 8 Rotated Concentric Ellipses

Illustration of 8 concentric congruent ellipses that are rotated about the center at equal intervals…

### Ellipses Inscribed In A Circle

Illustration of concentric ellipses, whose major axes are vertical, inscribed in a circle whose diameter…

### Ellipses Inscribed In A Circle

Illustration of concentric ellipses, whose major axes are vertical, inscribed in a circle whose diameter…

### Girl

A girl looking at her reflection in the water.

### Vertical Line of Symmetry, Isosceles Triangle With

Isosceles Triangle with a dotted vertical line that is a line of symmetry.

### Vertical Line of Symmetry, Letter A With

Letter A with a dotted vertical line that is a line of symmetry.

### Horizontal Line of Symmetry, Letter B With

Letter B with a dotted horizontal line that is a line of symmetry.

### Focus of a Concave Mirror

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

### Convex Mirror

"To explain this, let us suppose that the arrow a, is diminished by reflection from the convex surface,…

### Plane Mirror

"Suppose the arrow a to be the object reflected b the mirror d c; the incident rays a, flowing from…

### Statue of Narcissus

This statue of Narcissus a Greek Mythological hero who was renown for his beauty. In this statue, he…

### Lines of Symmetry, Oval With

Oval with dotted vertical and horizontal lines that are lines of symmetry.

### Parabolic Profile

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

### Parabolic Reflector

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

### Parabolic Reflector

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

### Paraboloid

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

### Young Person Thinking

A young person adopts an attitude of thoughtful consideration when listening to Christ preaching. Detail…

### 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…

### Cathetal Prism

"Cathetal prisms readily yield the phenomena of total reflection as shown, and are often used when light…

### Divergent Rays

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

### Law of Reflected Motion

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

### Reflection

"Let S be the position of the spectator; O and B the position of distant objects. The rays O R and B…

### Reflection

"Here, of the rays S A, S B, and S C, only the ray S C meets the eye of the spectator D. The spot C,…

### Reflection

"Reflection of sound." -Comstock 1850

### Reflection of Light

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

### Reflection of Light from a Broken Surface

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

### Angle of Incidence and Reflection

"Mirror A/B is only half of person C's height. C is able to view his entire body through such a small…

### Irregular Reflection or Diffusion

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

### Reflection of Light

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

### 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

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

### Reflection of Light from a Smooth Surface

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

### Parabolic, Reflector

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

### Revolving Light

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

### Revolving Light

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

### Direct Vision Spectroscope

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

### Lines of Symmetry, Square With

Square with dotted vertical, horizontal, and diagonal lines that are lines of symmetry.

### Line of Symmetry, Tree With

Tree with dotted vertical line that shows symmetry.

### Symmetry, Tree With No

Tree that has no symmetry.

### Lines of Symmetry, Triangle With

Square with dotted lines that are lines of symmetry.

### Constructive Interference

"Start a trough from A. At the moment of its reflection as a crest a B, start a crest at A as shown.…

### Whispering Gallery

"It is apparent that the auditor, in this case, must be placed in the centre from which the sound proceeds,…

### Woman Looking in Mirror

An illustration of a woman looking at her reflection in a mirror.

### Woman Looking in Mirror

An illustration of a woman looking at her reflection in a mirror.

### Woman Looking in Mirror

An illustration of a woman looking into a mirror.

### Woman Looking in Mirror

An illustration of a woman looking at her reflection in a mirror.