Illustration of an ellipse, whose major axis is vertical, inscribed in a circle whose diameter is equal…
Illustration of 16 concentric congruent ellipses that are rotated about the center at equal intervals…
Illustration of 2 concentric ellipses, whose major axes are vertical, inscribed in a circle whose diameter…
Illustration of 2 concentric congruent ellipses that are rotated about the center at 90°. The ellipses…
Illustration of 4 concentric congruent ellipses that are rotated about the center at equal intervals…
Illustration of 8 concentric congruent ellipses that are rotated about the center at equal intervals…
Illustration of concentric ellipses, whose major axes are vertical, inscribed in a circle whose diameter…
Illustration of concentric ellipses, whose major axes are vertical, inscribed in a circle whose diameter…
"A concave mirror reflects from a curved surface hollowing in like he inside of an orange." —Quackenbos…
"When the rays diverge form a point at a distance from the mirror less than that of the principal focus,…
"A convex mirror reflects from a curved surface rounding out like the outside of an orange." —Quackenbos…
"Parallel rays strike the convex mirror, reflect, and diverge as if they had originated from a virtual…
"Suppose the arrow a to be the object reflected b the mirror d c; the incident rays a, flowing from…
"A plane mirror reflects from a flat surface, like a common looking glass." —Quackenbos 1859
"A prism is a piece of glass, having for its sides three plane surfaces and for its ends two equal and…
"Consider a beam of light as made up of a number of ehter waves moving forward in air and side by side,…
"Let a ray pass towards a mirror in the line a, c, it will be reflected off in the direction of c, d,…
A polished surface of metal, or any other suitable material, applied for the purpose of reflecting rays…
"...represents two parabolic reflectors, mn and op. It is a peculiarity of such reflectors that rays…
"The reflecting telescope has an objective a concave mirror, tecnically called a speculum. The images…