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An illustration of strata bent at a line of fault. In geology and related fields, a stratum (plural: strata) is a layer of rock or soil with internally consistent characteristics that distinguishes it from contiguous layers. Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural forces.

Strata with Fault Line

An illustration of strata bent at a line of fault. In geology and related fields, a stratum (plural:…

A reverse fault is the opposite of a normal fault — the hanging wall moves up relative to the footwall. Reverse faults are indicative of shortening of the crust. The dip of a reverse fault is relatively steep, greater than 45°.

Reverse Fault

A reverse fault is the opposite of a normal fault — the hanging wall moves up relative to the…

An illustration of undulating strata cut by a fault with alternate throw in opposite directions.

Diagram of Undulating Strata Cut by a Fault

An illustration of undulating strata cut by a fault with alternate throw in opposite directions.

An illustration of the plan of a strike fault. The fault surface is usually near vertical and the footwall moves either left or right or laterally with very little vertical motion. Strike-slip faults with left-lateral motion are also known as sinistral faults. Those with right-lateral motion are also known as dextral faults. A special class of strike-slip faults is the transform faults which are a plate tectonics feature related to spreading centers such as mid-ocean ridges.

Plan of a Strike Fault

An illustration of the plan of a strike fault. The fault surface is usually near vertical and the footwall…

An illustration of a trough fault.

Trough Fault

An illustration of a trough fault.

"Riding-boom. A boat-boom or long spar working in a hinge or goose-neck, designed to be lowered from abreast the fore-rigging to a horizontal position at right angles with the keel of the vessel ... a, life-line; b, lift; c, riding-boom; d, rope ladder; e, outhaul; f, after-boom guy." -Whitney, 1911

Riding Boom

"Riding-boom. A boat-boom or long spar working in a hinge or goose-neck, designed to be lowered…

Solar aspect of the hoof. Labels: a, bars; b, solar border of wall; c, line of union between wall and sole; d, inferior aspect of sole; d', d, posterior branches of sole; e, cleft of the frog; f, bulbs of the frog; g, point of the frog.

Hoof of a Horse

Solar aspect of the hoof. Labels: a, bars; b, solar border of wall; c, line of union between wall and…

These volutes, or scrolls, when viewed from the side, appear to meet in the middle, and form a wavy line over the echinus. The intervals of the spiral coils are slightly hollowed, in order to bring them into more relief, and in this way the so-called channel is formed, which is continued in the horizontal portion which connects the volutes.

Side View of the Ionic Capital from the Temple of Minerva Polias at Priene

These volutes, or scrolls, when viewed from the side, appear to meet in the middle, and form a wavy…

These volutes, or scrolls, when viewed from the side, appear to meet in the middle, and form a wavy line over the echinus. The intervals of the spiral coils are slightly hollowed, in order to bring them into more relief, and in this way the so-called channel is formed, which is continued in the horizontal portion which connects the volutes.

Section of a Volute of an Ionic Capital

These volutes, or scrolls, when viewed from the side, appear to meet in the middle, and form a wavy…

These volutes, or scrolls, when viewed from the side, appear to meet in the middle, and form a wavy line over the echinus. The intervals of the spiral coils are slightly hollowed, in order to bring them into more relief, and in this way the so-called channel is formed, which is continued in the horizontal portion which connects the volutes.

Top View of the Ionic Capital from the Temple of Minerva Polias at Priene

These volutes, or scrolls, when viewed from the side, appear to meet in the middle, and form a wavy…

The Greek antefix is found in the lower roof line, in front of the imbrices (overlapping roof tiles). Its located in the Pathenon, Athens.

Greek Antefix

The Greek antefix is found in the lower roof line, in front of the imbrices (overlapping roof tiles).…

This Greek antefix is found in the propylaea which is the entrance to the Acropolis of Athens. This design is found on the lower roof line in front of the imbrices (overlapping roof tiles).

Greek Antefix

This Greek antefix is found in the propylaea which is the entrance to the Acropolis of Athens. This…

The Roman antefix is is found in the temple of Jupiter Stator in Rome, Italy. This design is found on the lower roof line in front of the imbrices (overlapping roof tiles).

Roman Antefix

The Roman antefix is is found in the temple of Jupiter Stator in Rome, Italy. This design is found on…

The modern French antefix is found in the theater of Celestines in Lyons, France by Architect Renaud. This design is found on the lower roof line in front of the imbrices (overlapping roof tiles).

Modern French Antefix

The modern French antefix is found in the theater of Celestines in Lyons, France by Architect Renaud.…

"A, a, Cephalic plate; b, Tergum of segment bearing first pair of legs (d); c, Tip of palpognath; e, Antenna; f, toxicognath; g, Last pair of appendages, enlarged and directed backwards." (Britannica, 1910)

Centipede

"A, a, Cephalic plate; b, Tergum of segment bearing first pair of legs (d); c, Tip of palpognath; e,…

An illustration of the reproductive system of a female earthworm which is located in the eleventh to the fourteenth segment. "sp. o, its external orifice; sp. sac, spermathecal sac; av, sac containing ovary; r.o, egg; od, oviuct." (Britannica. 1910)

Female Earthworm Reproductive System

An illustration of the reproductive system of a female earthworm which is located in the eleventh to…

An illustration of a sectional view of a Acanthobdella, a member of the annelid family. "c, Coelom; c.ch, Coelomic epithelium (yellow cells); cg, glandular cells; cl, Muscle cells of lateral line; cp, Pigment cells; ep, Ectoderm; g, Nerve cord; m, Intestine; mc, Circular muscle; ml, Longitudinal muscle; vd, Dorsal vessel; ww, Ventral vessel." (Britannic, 1910)

Sectional View of Acanthobdella

An illustration of a sectional view of a Acanthobdella, a member of the annelid family. "c, Coelom;…

An illustration of a sectional view of a Acanthobdella, a member of the annelid family. "c, Coelom; c.ch, Coelomic epithelium (yellow cells); cg, glandular cells; cl, Muscle cells of lateral line; cp, Pigment cells; ep, Ectoderm; g, Nerve cord; m, Intestine; mc, Circular muscle; ml, Longitudinal muscle; vd, Dorsal vessel; ww, Ventral vessel; cn, nerve cord; nf, parts of nephridium; on, external opening of nephridium; ov, ova; t, testis." (Britannica, 1910)

Sectional View of Acanthobdella

An illustration of a sectional view of a Acanthobdella, a member of the annelid family. "c, Coelom;…

"Suppose we have a pipe A B laid in a horizontal position so that the centre line is exactly at the same level all along the pope, and differences of level may be neglected. Let water be delivered b this pipe at a steady from a reservoir provided with a constant supply which keeps the free surface level always the same. If the pipe A B is of uniform sectional area throughout, and is at all points offers a uniform frictional resistance to the flow of the water, the pressure will gradually become less at points along it more and more distanct from the reservoir. This is no lonfer the case when the pipe is larger at one place than another, as shown in the [figure]." (Britannica, 1891)

Water Flow in Pipes

"Suppose we have a pipe A B laid in a horizontal position so that the centre line is exactly at the…

"Brain of Skate (Raia batis), an elasmobranchiate fish. A, from above; s, olfactory bulbs; a, cerebral hemispheres, united in the middle line; b, thalamencephalon; c, mesencephalon; d, cerebellum; aa, plaited bands formed by the restiform bodies; I, II, IV, V, first (olfactory), second (optic), fourth, and fifth pairs of cerebral nerves; f, medulla oblongata; w, a blood-vessel. " -Whitney, 1911

Skate Brain

"Brain of Skate (Raia batis), an elasmobranchiate fish. A, from above; s, olfactory bulbs; a, cerebral…

"Strawberry False-worm (Emphytus maculatus). 1, 2 pupa, ventral and lateral views (line shows natural size); 3, fly, enlarged (wings on one side detached); 4, larva; 5, fly with wings closed; 6, larva curled up; 7, coccoon; 8, antenna; 9, egg. (4, 5, 6, and 7 natural size; 8 and 9 enlarged.)" -Whitney, 1911

Strawberry Sawfly

"Strawberry False-worm (Emphytus maculatus). 1, 2 pupa, ventral and lateral views (line shows natural…

Illustration showing a section of the rolling surfaces by a plane perpendicular to their straight line of contact.

Section of Rolling Surfaces

Illustration showing a section of the rolling surfaces by a plane perpendicular to their straight line…

Illustration showing the periodic center of motion as it often happens when two positions of a line are known and they are moving in the same plane and we wish to find an axis about which this line could revolve to occupy the two given positions.

Periodic Center of Motion

Illustration showing the periodic center of motion as it often happens when two positions of a line…

Illustration showing that the rolling of non-cylindrical surfaces. "If the angular velocity ratio of two rolling bodies is not a constant, the pitch lines take, the conditions of pure rolling contact should be fulfilled, namely, the point of contact must be on the line of centres, and the rolling arcs must be of equal length.

Rolling of Non-cylindrical Surfaces

Illustration showing that the rolling of non-cylindrical surfaces. "If the angular velocity ratio of…

In this illustration, "the driven surface of the slide coincides with the tangent to the spiral, the line of centres being from o through c to infinity and perpendicular to the direction of motion of the slide.""

Logarithmic Spiral Sector

In this illustration, "the driven surface of the slide coincides with the tangent to the spiral, the…

"Diagram of Vertebrate Encephalon ... in longitudinal vertical section. Mb, mid-brain; in front of it all is forebrain, behind it all is hind-brain; laminaterminalis, represented by the heavy black line in upper figure; Olf, olfactory lobes; Hmp, cerebral hemispheres; ThE, thalamencephalon; Py, pituitary body; FM, foramen of Monro; CS, corpus striatum; Th, optic thalamus; CQ, corpora quadrigemina; CC, crura cerebri; Cb, cerebellum; PV, pons Varolii; MO, medulla oblongata; I, olfactory nerves; II, optic nerves; III, point of ext from brain of the oculimotores; IV, of the pathetici; VI, of the abducentes; V-XII, origins of other cerebral nerves; 1, olfactory ventricle; 2, lateral ventricle; 3, third ventricle; 4, fourth ventricle." -Whitney, 1911

Encephalon

"Diagram of Vertebrate Encephalon ... in longitudinal vertical section. Mb, mid-brain; in front of it…

"Segment of Endoskeleton from Thoracic Region of Crocodile. C, centrum of a vertebra, over which rises the neural arch, inclosing the neural canal and ending in NS, the neural spine; Z, prezygapophysis; Z', postzygapophysis; Tt, transverse process which articulates with t, tubercle of a rib; Cpt, that which articulates with Cp, capitulum of a rib; Vr, ossified vertebral rib, or pleurapophysis; Vr', cartilaginous part of same; Str, sternal rib, or hemapophysis; St, segment of sternum; Pu, uncinate process of a rib or epipleura. From Cpt to St, on either side, is the hemal arch." -Whitney, 1911

Crocodile Thoracic Region

"Segment of Endoskeleton from Thoracic Region of Crocodile. C, centrum of a vertebra, over which rises…

Also known as fish lice, this is a species of copepod, a parasitic crustacean. "Female of Chondracathus gibbosus, enlarged; and example of the crustaceous Epizoa. B, ventral view; a, head; b, c, appendages; d, d, mediodorsal processes; e, e, medioventral processes; f, i, h, lateral processes; g, ovisacs; k, terminal segment; l, minute male lodged in vulva of female; m, n, mediodorsal ovarian tubes; p, lateral ovarian tubes; o, o, oviduct; 2, 3, antennules; 4, 5, 6, antennae, gnathites." -Whitney, 1911

Copepod

Also known as fish lice, this is a species of copepod, a parasitic crustacean. "Female of Chondracathus…

"If two equal ellipses, each turning about one of its foci, are placed in contact in such a way that the distance between the axes O<SUB>1</SUB> and O<SUB>2</SUB> is equal to the major axis of the ellipses, we shall find that they will be in contact on the line of centres and that the rolling arcs are of equal length."

Rolling of Equal Ellipses

"If two equal ellipses, each turning about one of its foci, are placed in contact in such a way that…

Diagrammatic section of Florida along the line N.S. showing the relative position of the shore.

Florida Shore

Diagrammatic section of Florida along the line N.S. showing the relative position of the shore.

A Paleozoic brachiopod shell partly broken to show the internal spiral arm-supports. Mississippian limestones. Note the symmetrical character of the shell with reference to a median line drawn through the apex of beak.

Brachiopod

A Paleozoic brachiopod shell partly broken to show the internal spiral arm-supports. Mississippian limestones.…

Ammonite, side view. Where the shell has been partly worn away near the aperture, the complex "suture line" is shown.

Ammonite

Ammonite, side view. Where the shell has been partly worn away near the aperture, the complex "suture…

Illustration used to show how to bisect a straight line.

Bisect A Straight Line

Illustration used to show how to bisect a straight line.

Illustration used to show how to draw a perpendicular to a straight line from a given point on the line when the point is at or near the center of the line.

Perpendicular To Straight Line Construction

Illustration used to show how to draw a perpendicular to a straight line from a given point on the line…

Illustration used to show how to draw a perpendicular to a straight line from a given point on the line when the point is near the end of the line.

Perpendicular To Straight Line Construction

Illustration used to show how to draw a perpendicular to a straight line from a given point on the line…

Illustration used to show how to draw a perpendicular to a straight line from a given point that is not on the line and which lies nearly over the center of the line.

Perpendicular To Straight Line Construction

Illustration used to show how to draw a perpendicular to a straight line from a given point that is…

Illustration used to show how to draw a perpendicular to a straight line from a given point that is not on the line and which lies nearly over one end of the line.

Perpendicular To Straight Line Construction

Illustration used to show how to draw a perpendicular to a straight line from a given point that is…

Illustration used to show how to draw a straight line parallel to a straight line through a given point.

Parallel To Straight Line Construction

Illustration used to show how to draw a straight line parallel to a straight line through a given point.

Illustration used to show how to divide a given straight line into required number of equal parts.

Construction Of Dividing A Line

Illustration used to show how to divide a given straight line into required number of equal parts.

Illustration used to show how to divide a given straight line into required number of equal parts.

Construction Of Dividing A Line

Illustration used to show how to divide a given straight line into required number of equal parts.

Illustration used to show how to "draw a straight line through any given point on a given straight line to make any required angle with that line."

Construction Of Angle On Straight Line

Illustration used to show how to "draw a straight line through any given point on a given straight line…

Illustration used to show how to pass a circumference through any three points not in the same straight line.

Construction Of Circumference

Illustration used to show how to pass a circumference through any three points not in the same straight…

Illustration used to show how to "find an arc of a circle having a known radius, which shall be equal in length to a given straight line."

Construction Of Arc

Illustration used to show how to "find an arc of a circle having a known radius, which shall be equal…

Illustration used to show how to find a straight line of the same length as a given arc of a circle.

Construction Of Line Equal To Arc

Illustration used to show how to find a straight line of the same length as a given arc of a circle.

Illustration of straight line AB projected upon HK.

Projection Of A Line

Illustration of straight line AB projected upon HK.

Illustration of curved line AB projected upon a flat surface.

Projection Of A Line

Illustration of curved line AB projected upon a flat surface.

Illustration of a circle inside of 2 concentric rectangles whose vertices are connected by line segments.

Circle Inside Concentric Rectangles

Illustration of a circle inside of 2 concentric rectangles whose vertices are connected by line segments.

"If a straight line is perpendicular to each of two straight lines at their point of intersection it is perpendicular to the plane of those lines."

Line Perpendicular To Plane

"If a straight line is perpendicular to each of two straight lines at their point of intersection it…

"All the perpendiculars to a straight line at the same point lie in a plane perpendicular to the line."

Plane Perpendicular To Line

"All the perpendiculars to a straight line at the same point lie in a plane perpendicular to the line."

"If from the foot of a perpendicular to a plane a straight line is drawn at right angles to any line in the lane, and its intersection with that line is joined to any point of the perpendicular, this last line will be perpendicular to the line in the plane."

Perpendicular To Line In Plane

"If from the foot of a perpendicular to a plane a straight line is drawn at right angles to any line…

"Two planes perpendicular to the same straight line are parallel."

Planes Perpendicular To A Line

"Two planes perpendicular to the same straight line are parallel."

Illustration of three intersecting planes. "The straight line perpendicular to one of two parallel lanes is perpendicular to the other."

3 Intersecting Planes

Illustration of three intersecting planes. "The straight line perpendicular to one of two parallel lanes…

"If two straight lines are cut by three parallel planes, the corresponding segments are proportional."

3 Parallel Planes

"If two straight lines are cut by three parallel planes, the corresponding segments are proportional."

"If two planes are perpendicular to each other, a line in one of them perpendicular to the intersection is perpendicular to the other."

Perpendicular Planes

"If two planes are perpendicular to each other, a line in one of them perpendicular to the intersection…

"Through a given line oblique to a plane, one, and only one plane, can be passed perpendicular to the given plane."

Plane Passed Perpendicular To A Given Plane

"Through a given line oblique to a plane, one, and only one plane, can be passed perpendicular to the…

One way to spread water over a hillside field, "f m is the main ditch and the slope of the hill as shown by the arrows; t o, r p, and s q are small ditches or plow furrows cut on a level line around the face of the hill. The water is let into the field by the short ditch at i, and is then spread over the space b c t o by means of a marginal ditch y z, from which it is made to flow in small streams and in a regular manner over the space between it and the lower ditch t o." -Department of Agriculture

Irrigation by Furrows

One way to spread water over a hillside field, "f m is the main ditch and the slope of the hill as shown…

"Human Eye, in Median Vertical Anteroposterior Section. (Ciliary processes shown, through not all lying in this section.) A, anterior, and A', posterior chambers of aqueous humor; a, central artery of retina; C, cornea; Ch, choroid; cj, conjunctiva; cm, ciliary muscle; cp, ciliary processs; H, hyaloid; I, iris; L, crystalline lens in its capsule (the reference-line passes through the pupil); l, l', insertion of tendon of superior and inferior rectus muscles; o, optic nerve; P, canal of Petit; R, retina; S, sclerotic; s, s', circular sinus or canal of Schlemm; V, vitreous body filling back part of the eye." -Whitney, 1911

Median Vertical Anteroposterior Section of Eye

"Human Eye, in Median Vertical Anteroposterior Section. (Ciliary processes shown, through not all lying…

"Right Eyeball of Bird, seen from behind, showing the following muscles; a, rectus superior; b, rectus externus; c, rectus inferior; d, rectus internus; e, obliquus superior; f, obliquus inferior; g, quadratus; h, pyramidalis, with its tendon, k, passing through a pulley in the quadratus (as shown by dotted line) to keep it off the optic nerve, i, then passing around the edge of the ball to its insertion in the nictitating membrane." -Whitney, 1911

Right Eyeball of Bird

"Right Eyeball of Bird, seen from behind, showing the following muscles; a, rectus superior; b, rectus…

"Fake. Naut., one of the circles or windings of a cable or hawser as it lies in a coil; a single turn or coil, as one of the oblong loops into which a shot-line is wound in being placed in a faking-box." -Whitney, 1911

Rope Coiled in Fakes on Deck

"Fake. Naut., one of the circles or windings of a cable or hawser as it lies in a coil; a single turn…

"Skull of Cat (Felis catus), showing the following bones, viz. : na, nasal; pm, premaxillary; m, maxillary; l, lacrymal; f, frontal; j, jugal; pa, palatine; p, parietal; sq, squamosal; ip, interparietal; so, supra-occipital; eo, exoccipital (the line leads to the occipital condyle); t, tympanic bulla; smf, stylomastoid foramen; mf, mental foramen; c, coronoid process of mandible; ar, ascending ramus of mandible; hr, horizontal ramus of mandible; an, angle of jaw." -Whitney, 1911

Domestic Cat Skull

"Skull of Cat (Felis catus), showing the following bones, viz. : na, nasal; pm, premaxillary; m, maxillary;…