ClipArt ETC
An illustration showing a triangle with angles A, C, and D inscribed in a circle which is tangent to a line.

Triangle Inscribed In A Circle

An illustration showing a triangle with angles A, C, and D inscribed in a circle which is tangent to…

This chart of comparisons can be used with the following questions: "Which line is twice B? Which two added make H? Which line is the difference between F and D? Call A 5; name the others. Call A 6, and name the others." -Foster, 1921

Comparisons Chart

This chart of comparisons can be used with the following questions: "Which line is twice B? Which two…

Diagram of a soccer field.

Soccer Field

Diagram of a soccer field.

An illustration showing a model of a circle with an exterior angle formed between a tangent and a secant that illustrates the following geometric relationship: a:t = t:b, t&sup2 = ab

Model Of Geometric Relationships In A Circle

An illustration showing a model of a circle with an exterior angle formed between a tangent and a secant…

An illustration showing a model of a circle with angles formed between tangents and secants that illustrates the following geometric relationship: t&sup2 = (a + b)(a - b).

Model Of Geometric Relationships In A Circle

An illustration showing a model of a circle with angles formed between tangents and secants that illustrates…

An illustration showing a model of 2 circles with tangent lines, diameters, and radii that illustrates the following geometric relationship: "x = aR/(R - r), a = √(t&sup2 + (R - r)&sup2), t = √(a&sup2 - (R - r)&sup2, sin.v = t/a."

Model Of Geometric Relationships In 2 Circles

An illustration showing a model of 2 circles with tangent lines, diameters, and radii that illustrates…

An illustration showing a model of 2 circles with tangent lines, diameters, and radii that illustrates the following geometric relationship: " t = √(a&sup2 - (R + r)&sup2, a = √(t&sup2 - (R + r)&sup2 "

Model Of Geometric Relationships In 2 Circles

An illustration showing a model of 2 circles with tangent lines, diameters, and radii that illustrates…

An illustration of a segment of a sphere.

Segment Of Sphere

An illustration of a segment of a sphere.

Illustration used to resolve a motion into two components, one of which is perpendicular, and the other parallel, to a given line, as ef. Vector ad represents the motion; ab = ad cos(dab), the component parallel to ef; and ac = ad sin(dab), the components perpendicular to ef.

Vector Motion Into Two Components - Resultant

Illustration used to resolve a motion into two components, one of which is perpendicular, and the other…

Illustration for rigidly-connected points. "If two points are so connected that their distance apart is invariable and if their velocities are resolved into components at right angles to and along the straight line connecting them, the components along this line of connection must be equal, otherwise the distance between the points would change."

Velocities Of Rigidly-connected Points

Illustration for rigidly-connected points. "If two points are so connected that their distance apart…

Illustration for rigidly-connected points. In the series of links shown, c and d are fixed axes and f slides on the line ff<sub>1</sub>.

Velocities Of Rigidly-connected Points

Illustration for rigidly-connected points. In the series of links shown, c and d are fixed axes and…

A diagram of an annulosa showing its external skeleton made up of segments or rings arranged along a longitudinal line, and consisting mostly of hardened skin. Labels: 1, vascular system,; 2, digestive organs; 3, ganglia.

Diagram of an Annulosa

A diagram of an annulosa showing its external skeleton made up of segments or rings arranged along a…

A diagram of the external structure of an insect. Labels: 1, The head carrying the eyes and the antennae. 2, First segment of thorax with first pair of legs. 3, The second segment of the thorax with the second pair of legs and the first pair of wings. 4, The third segment of the thorax with the third pair of legs and the second pair of wings. 5, Abdomen without legs.

Diagram of the External Structure of an Insect

A diagram of the external structure of an insect. Labels: 1, The head carrying the eyes and the antennae.…

In birds the muscles system is remarkable for their marked line of attachment to their tendons. Labels: 1, Occipito-Frontalis. 2, Orbicularis Palpaebrarum. 3, Temporal. 4, Masseter. 5, Sterno-cleido-Mastoid. 6, Trapezius. 7, Latissimus Dorsi. 8, Pectoralis. 9, Deltoid. 10, Biceps. 11, Triceps. 12, Gluteii. 13, Levator Caudae. 14, Rectus Femoris. 15, Gastrocnemius muscle.

The Superficial Muscles of a Hawk

In birds the muscles system is remarkable for their marked line of attachment to their tendons. Labels:…

A side view of the chest and abdomen in respiration. Labels: 1, The cavity of the chest. 2, The cavity of the abdomen. 3, The line of direction for the diaphragm when relaxed in expiration. 4, The line of direction for the diaphragm when contracted in inspiration. 5, 6, The position of the front walls of the chest and abdomen in inspiration. 7, 8, The position of the front walls of the abdomen and chest in expiration.

A Side View of the Chest and Abdomen in Respiration

A side view of the chest and abdomen in respiration. Labels: 1, The cavity of the chest. 2, The cavity…

"Generalized columnar section, northern Black Hills." -Walcott, 1901

Strata Thickness

"Generalized columnar section, northern Black Hills." -Walcott, 1901

"Effect of removal of a leaflet from a palmately compound leaf (e.g. Woodbine). B, normal leaf; C, after removal of upper right-hand leaflet. A, Unbroken lines represent average normal position of leaflets; dotted lines, average position of leaflets after operation; barred line, position of leaflet removed." -Gager, 1916

Leaflet Removal

"Effect of removal of a leaflet from a palmately compound leaf (e.g. Woodbine). B, normal leaf; C, after…

Vertical section of a molar tooth. Labels: a, enamel of the crown, the line of which indicate the arrangement of its columns; b, dentine; c,cement; d, pulp cavity.

Vertical Section of a Molar

Vertical section of a molar tooth. Labels: a, enamel of the crown, the line of which indicate the arrangement…

Diagram of the appearance in fresh muscle fiber. Labels: A, At low focus (B) the muscle columns appear dark and in a line with the granules, sarcoplasm light. At high focus (A) the sarcoplasm is dark, muscle columns light, and two rows of granules appear in a line with the sarcoplasm and alternating with the muscle columns.

Muscle Fiber

Diagram of the appearance in fresh muscle fiber. Labels: A, At low focus (B) the muscle columns appear…

Section of the aorta, to show the action of the semilunar valve. A is intended to show the valves, represented by the dotted lines, lying near the arterial walls, represented by the continuous outer line. B (after Hunter) shows the arterial wall distended into three pouched (a), and drawn away from the valves, which are straightened into the form of an equilateral triangle, as represented by the dotted line.

Action of Semilunar Valve

Section of the aorta, to show the action of the semilunar valve. A is intended to show the valves, represented…

The axes of rotation of rib movement is two; one corresponding with a line drawn through two articulations which the ribs forms with the spine (a, b); and the other with a line drawn from one of these (head of rib) to the sternum (A, B); the motion of the rib around the latter axis being somewhat after the fashion of raising the handle of a bucket.

Movement of Ribs

The axes of rotation of rib movement is two; one corresponding with a line drawn through two articulations…

Dorsal or posterior view of the medulla, fourth ventricle, and mesencephalon. Labels: p.n., line of the posterior roots of the spinal nerves; p.m.f., posterior median fissure; f.g., funiculus gracilis; cl., its clava; f.c., funiculus cuneatus; f.R., funiculus of Rolando; r.b., restiform body; c.s., calamus scriptorius; l, section of ligula or taenia; part of choroid plexus is seen beneath t; l.r., lateral recess of the ventricle; str., striae acusticae; i.f., inferior fossa; s.f., posterior fossa; between it and the median sulcus is the fasciculus teres; cbl., cut surface of the cerebellar hemisphere; nd., central or gray matter; s.m.v., superior medullary velum; lng., ligula; s.c.p., superior cerebellar peduncle cut longitudinally; cr., combined section of the three cerebellar peduncles; c.q.s., c.q.i., corpora quadrigemina (superior and inferior); fr., fraenulum; f; f., fibers of the fillet seen on the surface of the tegmentum; c, crusti; l.g., lateral groove; c.g.i, corpus geniculum internus; th., posterior part of the thalamus; p., pineal body. The Roman numbers indicate the corresponding cranial nerves.

Medulla

Dorsal or posterior view of the medulla, fourth ventricle, and mesencephalon. Labels: p.n., line of…

Longitudinal and vertical diagrammatic section of a vertebrate brain. Mb, midbrain: what lies in front of this is the fore-, and what lies behind, the hindbrain; Lt, lamina terminalis; Olf, olfactory lobes; Hmp, hemispheres; Th. E, thalamencephalon; Pn, pineal gland; Py, pituitary body; F. M., foramen of Munro; cs, corpus striatum; Th, optic thalamus; CC, crura cerebri; the mass lying above the canal represents the corpora quadrigemina; Cb, cerebellum; I-IX, the nine pairs of cranial nerves; 1, olfactory ventricle; 2, lateral ventricle; 3, third ventricle; 4, fourth ventricle; +, iter a tertio ad quartum ventriculum. Lamina terminalis is represented by the strong black line joining Pn and Py.

Vertical Section of a Vertebrate Brain

Longitudinal and vertical diagrammatic section of a vertebrate brain. Mb, midbrain: what lies in front…

Brain of dog, viewed from above and in profile. F, frontal fissure sometimes termed crucial sulcus, corresponding to the fissure of Rolando in man. S, fissure of Sylvius, around which the four longitudinal convolutions are concentrically arranged; 1, flexion of head on the neck, in the median line; 2, flexion of head on the anterior limb; 5, 6, flexion and extension of posterior limb; 7, 8, 9, contraction of orbicularis oculi, and the facial muscles in general. The unshaded part in that exposed by the opening of the skull.

Brain of a Dog

Brain of dog, viewed from above and in profile. F, frontal fissure sometimes termed crucial sulcus,…

Embryo chick (36 hours), viewed from beneath as a transparent object (magnified). Labels:pl, outline of pellucid area; FB, forebrain, or first cerebral vesicle: from its sides project op, the optic vesicles; SO, backward limit of somatopleure fold, "tucked in", under head; A, head-fold of true amnion; a', reflected layer of amnion, sometimes termed "false amnion;" sp, backward limit of splanchnopleure folds, along which run the omphalomesaraic veins uniting to form h, the heart, which is continued forwards into ba, the bulbus arteriosus; d, the foregut, lying behind the heart, and having a wide crescentic opening between the splanchnopleure folds; HB, hindbrain; MB, midbrain; pv, protovertebrae lying behind the foregut; mc, line of junction of medullary folds and of notochord; ch, front end of notochord; vpl, vertebral plated; pr, the primitive groove at its caudal end.

Embryo Chick

Embryo chick (36 hours), viewed from beneath as a transparent object (magnified). Labels:pl, outline…

Diagram of part of digestive tract of a chick (4th day). The black line represents hypoblast , the outer shading mesoblast; lg, lung diverticulum with expanded end forming primary lung vesicles; St, stomach; l, two hepatic diverticulum, with their terminations united by solid rows of hypoblast cells; p, diverticulum of the pancreas with the vesicular diverticula coming from it.

Digestive Tract of a Chick

Diagram of part of digestive tract of a chick (4th day). The black line represents hypoblast , the outer…

"The Watered Pecten belongs to the scallop-shells. The shell is generally nearly circular, more or less elongated, and terminated toward the summit in a straight line."

Pecten Pseudamussium (Chenu.)

"The Watered Pecten belongs to the scallop-shells. The shell is generally nearly circular, more or less…

Showing the average position of the abdominal viscera with their surface markings. Labels: A, sterno-ensiform point; A', sterno-ensiform line; B, mid-epigastric point; B', mid-epigastric or transpyloric line; C, umbilical point; C', umbilical line; D, mid-hypogastric point; D', mid-hypogastric line; E, outer border of the right and left rectus abdominis; F, Monro's point- on the right spino-umbilical line at the outer border of the rectus abdomninis.

Abdominal Region

Showing the average position of the abdominal viscera with their surface markings. Labels: A, sterno-ensiform…

"Ruby-eyed Limpet, from the Antilles. If the common Limpet is alarmed, no human force, pulling in a direct line, can remove it."

Patella Granatina (Linnaeus)

"Ruby-eyed Limpet, from the Antilles. If the common Limpet is alarmed, no human force, pulling in a…

Showing the position of the viscera in the condition of visceroptosis (Glenard's disease). Labels: A, sterno-ensiform line: it crosses above the fifth costal cartilage; B, mid-epigastric line; C, umbilical line; D, mid-hypogastric line; a, pericardium; b, stomach (greatly elongated and dilated); c, liver; c', the lingual or Riedel's process; d, duodenum; e, caecum; f, transverse colon; g, rectum; h, elongated gastro-hepatic omentum.

Position of the Viscera in the Condition of Visceroptosis

Showing the position of the viscera in the condition of visceroptosis (Glenard's disease). Labels: A,…

Diagram showing the line used by Nelaton to test upward displacement of the femur, and another which serves to indicate the position for trephining the sacro-iliac joint. Labels: A.S.S., anterior superior spine of ilium; P.S.S., posterior superior spine of ilium.

Displacement of the Femur

Diagram showing the line used by Nelaton to test upward displacement of the femur, and another which…

Diagram showing that the pubic spine (tubercle) and the tip of the great trochanter are on the same horizontal plane (McCurdy's line), and that the lower border of the neck of the femur and the inner border of the obturator foramen form a continuos arch (Shenton's) when the femur has its normal relationships.

Pubic Spine

Diagram showing that the pubic spine (tubercle) and the tip of the great trochanter are on the same…

"Dip, in geology, the name given to the angle of slope of inclined rock strata, as dip in the diagram...The horizontal direction at right angles to the line of dip is called the strike, shown by st in the diagram." -Foster, 1921

Dip

"Dip, in geology, the name given to the angle of slope of inclined rock strata, as dip in the diagram...The…

Diagram to show mechanism of fracture of the patella by muscular action. a, Line of action of quadriceps muscle; b, femur; c, tibia.

Mechanism of Fracture of the Patella by Muscular Action

Diagram to show mechanism of fracture of the patella by muscular action. a, Line of action of quadriceps…

Epiphyseal lines in the neighborhood of the knee joint and their relationship to the synovial membrane.

Epiphyseal lines in the Knee Joint

Epiphyseal lines in the neighborhood of the knee joint and their relationship to the synovial membrane.

Lifrac's operation consists in amputation through the tarsometatarsal line of joints. Labels: a, b, c, inner, middle and outer cuneiform bones; d, cuboid; e, f, the metatarsal bones; g, tibialis anticus; h, extensor proprius hallucis; i, extensor communis digitorum; j, extensor brevis digitorum; k, extensor tendons; l, dorsalis pedis artery.

Lisfranc's Amputation at the Tarsometatarsal Joint

Lifrac's operation consists in amputation through the tarsometatarsal line of joints. Labels: a, b,…

"Perspective- Place roofs and tree tops above the horizon line, and the tree trunks and main part of the houses, below." -Foster, 1921

Landscape Perspective

"Perspective- Place roofs and tree tops above the horizon line, and the tree trunks and main part of…

A football field labeled with yard lines and measurements.

Football Field

A football field labeled with yard lines and measurements.

In this chart of single stroke letters, the capitals are arranged in "family order," first the straight letters, then slant line and curved letters. Each letter is shown in a square, so that the proportion of its width to height may be easily learned. In this style many of the letters just about fill the square. The arrows and figures give the order and direction of strokes, which must be learned for each letter, Vertical strokes are all made downward and horizontal strokes from left to right.

Single Stroke Vertical Capitals

In this chart of single stroke letters, the capitals are arranged in "family order," first the straight…

Words lettered in lower case or "small" letters are easier to read than when made in capital letters. These letters are made with bodies two-thirds the height of the capitals, the ascenders (b, d, f, etc.) extending up to the cap line and the descenders (g, p, q, etc.) dropping the same distance below.

Single Stroke Vertical Lower Case Letters

Words lettered in lower case or "small" letters are easier to read than when made in capital letters.…

In this chart of single stroke letters, the capitals are arranged in "family order," first the straight letters, then slant line and curved letters. Each letter is shown in a square, so that the proportion of its width to height may be easily learned. In this style many of the letters just about fill the square. The arrows and figures give the order and direction of strokes, which must be learned for each letter, Vertical strokes are all made downward and horizontal strokes from left to right.

Single Stroke Inclined Capitals

In this chart of single stroke letters, the capitals are arranged in "family order," first the straight…

Words lettered in lower case or "small" letters are easier to read than when made in capital letters. These letters are made with bodies two-thirds the height of the capitals, the ascenders (b, d, f, etc.) extending up to the cap line and the descenders (g, p, q, etc.) dropping the same distance below.

Single Stroke Inclined Lower Case Letters

Words lettered in lower case or "small" letters are easier to read than when made in capital letters.…

Sagittal section of face, a little to the left of the middle line, showing the vomer and its relations.

Section of Face Showing Vomer

Sagittal section of face, a little to the left of the middle line, showing the vomer and its relations.

Diagram of articular synovial membranes. The cartilages are represented as drawn apart for the sake of clearness. The synovial membrane is shown by a broken line.

Synovial Membrane

Diagram of articular synovial membranes. The cartilages are represented as drawn apart for the sake…

Section of the head immediately below the orbits, at the level of Reid's base line exposing the maxillary sinus.

Cross Section of Head Exposing Maxillary Sinus

Section of the head immediately below the orbits, at the level of Reid's base line exposing the maxillary…

Section on a line with the deep palmar arch of the right hand.

Cross Section on a Line with the Palmar Arch of the Hand

Section on a line with the deep palmar arch of the right hand.

Line of pressure between hip and knee.

Line of Pressure Between Hip and Knee

Line of pressure between hip and knee.

Schematic diagram, showing epiphysis and diaphysis and line of ossification. Labels: Ep, epiphysis of endochondral bone; zpt, zone of proliferation; zc, zone of calcification; ca, cartilage.

Bone Ossification

Schematic diagram, showing epiphysis and diaphysis and line of ossification. Labels: Ep, epiphysis of…

Longitudinal section of head of left humerus.

Longitudinal Section of Head of Humerus

Longitudinal section of head of left humerus.

Longitudinal section of head and neck of femur.

Longitudinal Section of Head of Femur

Longitudinal section of head and neck of femur.

"A distinct species, which exists in a little lake of mineral waters in France, where visitors amuse themselves by fishing for them with a line baited with bits of red cloth, which it attacks."

Gyrinus Distinctus

"A distinct species, which exists in a little lake of mineral waters in France, where visitors amuse…

"Portions of the rotting pulp were placed on a microscopic slide, divided into hundredths and thousandths of an inch. Fig. 21, A B, represents such a scale, the larger division, A B, representing the one-hundredth of an inch, and the smaller subdivision the one-thousandth of an inch; 7, 8, 9, 10, 11, 12, represent the cells of which the apples are mostly composed. The granular dottings represent apple starch. The branching cellular structure represents the mycelium of a fungus penetrating the cells. At 9, three small starch granuals are represented in a line, and are confined within the division of the one-thousandth of an inch." -Watts, 1874

Microscopic view of a fermented apple

"Portions of the rotting pulp were placed on a microscopic slide, divided into hundredths and thousandths…

"The shell advances beyond this simple type by a process of linear budding, the first cell being spherical, with an opening through which a second segment is formed, generally a little larger than the first. This new growth is followed by others developed in the same way, until the organism attains its maturity."

Dentalina Subarcuata

"The shell advances beyond this simple type by a process of linear budding, the first cell being spherical,…

One group will take the spherical form and produce a shell in the shape of the nautilus. In this case, the new segments are arranged alternately on opposite sides of the central line.

Textularia Variabilis

One group will take the spherical form and produce a shell in the shape of the nautilus. In this case,…

One group will take the spherical form and produce a shell in the shape of the nautilus. Some are more or less oblong, each new segment being nearly equal to the entire length of the shell.

Spiroloculina Depressa

One group will take the spherical form and produce a shell in the shape of the nautilus. Some are more…

One group will take the spherical form and produce a shell in the shape of the nautilus. Some are more or less oblong, each new segment being nearly equal to the entire length of the shell.

Rotalia

One group will take the spherical form and produce a shell in the shape of the nautilus. Some are more…

While not exceptionally high, the Niagara Falls are very wide. More than six million cubic feet (168,000 m³) of water falls over the crest line every minute in high flow,[1] and almost 4 million cubic feet (110,000 m³) on average.

Niagara Falls (American Side), from Goat Island

While not exceptionally high, the Niagara Falls are very wide. More than six million cubic feet (168,000…

It occupies a "unique position" as one of the holiest sites and as "the greatest of all churches of Christendom". In Catholic tradition, it is the burial site of its namesake Saint Peter, who was one of the twelve apostles of Jesus and, according to tradition, was the first Bishop of Antioch, and later first Bishop of Rome and therefore first in the line of the papal succession.

St. Peter's and the Vatican, from the Tiber Banks

It occupies a "unique position" as one of the holiest sites and as "the greatest of all churches of…

An axillary node is a lymph node of the upper extremity. Shown is the scheme of the axillary nodes. The dotted line indicates the position of the clavicle.

Lymph Node of Upper Extremity

An axillary node is a lymph node of the upper extremity. Shown is the scheme of the axillary nodes.…

Segment of large intestine showing the characteristic feature of its structure.

Structure of Large Intestine

Segment of large intestine showing the characteristic feature of its structure.