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Illustration of a regular octagon inscribed in a circle. This can also be described as a circle circumscribed about a regular octagon.

Regular Octagon Inscribed In A Circle

Illustration of a regular octagon inscribed in a circle. This can also be described as a circle circumscribed…

Illustration of a regular octagon circumscribed about a circle. This can also be described as a circle inscribed in a regular octagon.

Regular Octagon Circumscribed About A Circle

Illustration of a regular octagon circumscribed about a circle. This can also be described as a circle…

Illustration of a regular nonagon inscribed in a circle. This can also be described as a circle circumscribed about a regular nonagon.

Regular Nonagon Inscribed In A Circle

Illustration of a regular nonagon inscribed in a circle. This can also be described as a circle circumscribed…

Illustration of a regular nonagon circumscribed about a circle. This can also be described as a circle inscribed in a regular nonagon.

Regular Nonagon Circumscribed About A Circle

Illustration of a regular nonagon circumscribed about a circle. This can also be described as a circle…

Illustration of a cyclic pentagon, a pentagon inscribed in a circle. This can also be described as a circle circumscribed about a pentagon. In this illustration, the pentagon is not regular (the lengths of the sides are not equal).

Cyclic Pentagon

Illustration of a cyclic pentagon, a pentagon inscribed in a circle. This can also be described as a…

Illustration of a cyclic quadrilateral, a quadrilateral inscribed in a circle. This can also be described as a circle circumscribed about a quadrilateral. In this illustration, the quadrilateral is not regular (the lengths of the sides are not equal).

Cyclic Quadrilateral

Illustration of a cyclic quadrilateral, a quadrilateral inscribed in a circle. This can also be described…

Illustration of a cyclic hexagon, a hexagon inscribed in a circle. This can also be described as a circle circumscribed about a hexagon. In this illustration, the hexagon is not regular (the lengths of the sides are not equal).

Cyclic Hexagon

Illustration of a cyclic hexagon, a hexagon inscribed in a circle. This can also be described as a circle…

Illustration of a cyclic hexagon, a hexagon inscribed in a circle. This can also be described as a circle circumscribed about a hexagon. In this illustration, the hexagon is not regular (the lengths of the sides are not equal).

Cyclic Hexagon

Illustration of a cyclic hexagon, a hexagon inscribed in a circle. This can also be described as a circle…

Illustration of a hexagon in a circle. Four of the six vertices of the hexagon are bound by the circle (are tangent to the circle). Because all six vertices are not on the circle, the hexagon is not cyclic; it is not inscribed in the circle.

Hexagon In A Circle

Illustration of a hexagon in a circle. Four of the six vertices of the hexagon are bound by the circle…

Illustration of a 5-point star inscribed in a circle. This can also be described as a circle circumscribed about a 5-point star.

Star Inscribed In A Circle

Illustration of a 5-point star inscribed in a circle. This can also be described as a circle circumscribed…

Illustration of a 6-point star created by two equilateral triangles (often described as the Star of David) inscribed in a circle. This can also be described as a circle circumscribed about a 6-point star, or two triangles.

Star Inscribed In A Circle

Illustration of a 6-point star created by two equilateral triangles (often described as the Star of…

Illustration of a 6-point star (convex dodecagon) inscribed in a circle. This can also be described as a circle circumscribed about a 6-point star, or convex dodecagon.

Star Inscribed In A Circle

Illustration of a 6-point star (convex dodecagon) inscribed in a circle. This can also be described…

Illustration of a 6-point star (convex dodecagon) inscribed in a large circle and circumscribed about a smaller circle.

Star Inscribed And Circumscribed About Circles

Illustration of a 6-point star (convex dodecagon) inscribed in a large circle and circumscribed about…

Illustration of a 6-point star (convex dodecagon) circumscribed about a circle. This can also be described as a circle inscribed in a 6-point star, or convex dodecagon.

Star Circumscribed About A Circle

Illustration of a 6-point star (convex dodecagon) circumscribed about a circle. This can also be described…

Illustration of an 8-point star, created by two squares at 45° rotations, inscribed in a circle. This can also be described as a circle circumscribed about an 8-point star, or two squares.

Star Inscribed In A Circle

Illustration of an 8-point star, created by two squares at 45° rotations, inscribed in a circle.…

Illustration of an 8-point star, or convex polygon, inscribed in a circle. This can also be described as a circle circumscribed about an 8-point star.

Star Inscribed In A Circle

Illustration of an 8-point star, or convex polygon, inscribed in a circle. This can also be described…

Illustration of an 8-point star (convex polygon) inscribed in a large circle and circumscribed about a smaller circle.

Star Inscribed And Circumscribed About Circles

Illustration of an 8-point star (convex polygon) inscribed in a large circle and circumscribed about…

Illustration of an 8-point star (convex polygon) circumscribed about a circle. This can also be described as a circle inscribed in an 8-point star, or convex polygon.

Star Circumscribed About A Circle

Illustration of an 8-point star (convex polygon) circumscribed about a circle. This can also be described…

Illustration of a triangle with its incircle and three excircles constructed.

Triangle With Circle Constructions

Illustration of a triangle with its incircle and three excircles constructed.

A section across the forearm a short distance below the elbow-joint. R and U, its two supporting bones, the radius and ulna; e, the epidermis, and d, the dermis of the skin; the latter is continuous below with bands of connective tissue, s, which penetrate between and invest the muscles, which are indicated by numbers; n, n, nerves and vessels.

Forearm, Section of

A section across the forearm a short distance below the elbow-joint. R and U, its two supporting bones,…

Bones of the arm. Labels: A, arm in supination; B, arm in pronation. H, humerus; R, radius; U, ulna.

Bones of the Arm

Bones of the arm. Labels: A, arm in supination; B, arm in pronation. H, humerus; R, radius; U, ulna.

Bow compasses should be used on all arcs and circles having a radius of less than 3/4 inch.

Bow Pencil

Bow compasses should be used on all arcs and circles having a radius of less than 3/4 inch.

Bow compasses should be used on all arcs and circles having a radius of less than 3/4 inch.

Bow Pen

Bow compasses should be used on all arcs and circles having a radius of less than 3/4 inch.

Bow compasses should be used on all arcs and circles having a radius of less than 3/4 inch.

Bow Divider

Bow compasses should be used on all arcs and circles having a radius of less than 3/4 inch.

For larger circles beam compasses are used. The two parts called channels which carry the pen and the needle point are clamped to a wooden beam at a distance equal to the radius of the circle. The thumb nut underneath one of the channel pieces makes accurate adjustment possible.

Beam Compasses

For larger circles beam compasses are used. The two parts called channels which carry the pen and the…

Circle pattern exercise: Draw diagonals A C and D B, and with the T-square draw the line E H. Now mark off on E H distances of 1.4 inch, and with H as a center describe, by means of the compasses, circles having radii respectively 2 inches, 1.5 inches, 1 inch, 0.75 inch, 0.5 inch, and .25 inch. Similarly with H as a center and a radius of 1.75 inch and 1.25 inches respectively raw the arcs F G and I J and K L and M N, being careful to end the arcs in the diagonals.

Circle Exercise

Circle pattern exercise: Draw diagonals A C and D B, and with the T-square draw the line E H. Now mark…

Arteries of the palm of the head and front of the forearm. Labels: 3, deep part of the raised pronator of the radius; 4, long supinator muscle; 5, long flexor of the thumb; 6, square pronator; 7, deep flexor of the fingers; 8, cubital flexor of the wrist; 9, annular ligament; 10, the brachial artery; 12, radial artery; 13, recurring radial artery joining the end of the upper deep one; 4, superficial veins; 15, cubital artery; 16, superficial palmary arch; 17, magna artery of the thumb and radial artery of the index; 18, back cubital recurring artery; 19, front interosseous artery; 20, back interosseous artery.

Arteries of the Hand and Forearm

Arteries of the palm of the head and front of the forearm. Labels: 3, deep part of the raised pronator…

In changing the compass from a small to large radius, hold the legs together with one hand and spin the nut with the other, in order to save wear on the threads.

Adjusting the Compass

In changing the compass from a small to large radius, hold the legs together with one hand and spin…

Always draw a circle in one stroke, inclining the compass in the direction of the line and rolling the handle between the thumb and finger.

Inking a Circle

Always draw a circle in one stroke, inclining the compass in the direction of the line and rolling the…

"Hands on hips. Twist the trunk around in a circle, first one way, then the other." -Foster, 1921

Exercise

"Hands on hips. Twist the trunk around in a circle, first one way, then the other." -Foster, 1921

"Tense the muscles of the neck and turn head... forward and back and around in a circle." -Foster, 1921

Exercise

"Tense the muscles of the neck and turn head... forward and back and around in a circle." -Foster, 1921

"Arms outstretched horizontally. Make the hands describe a full circle forward and back." -Foster, 1921

Exercise

"Arms outstretched horizontally. Make the hands describe a full circle forward and back." -Foster, 1921

"Arms outstretched horizontally. Make the hands describe a full circle forward and back." -Foster, 1921

Exercise

"Arms outstretched horizontally. Make the hands describe a full circle forward and back." -Foster, 1921

The radius, a bone of the arm.

Radius

The radius, a bone of the arm.

A little girl sitting among flowers. The circle is bordered with hand games and images of playing.

Girl

A little girl sitting among flowers. The circle is bordered with hand games and images of playing.

A man exercising with the quarter circle used for chest and arms.

Quarter Circle

A man exercising with the quarter circle used for chest and arms.

"Fore and Hind Leg of a Tapir. A, scapula; I, ilium, or shinbone of pelvis; H, humerus; F, femur; O, olecranon, or tip of the elbow; P, patella; U, ulna; T, tibia; R, radius; Fi, fibula." -Cooper, 1887

Tapir Legs

"Fore and Hind Leg of a Tapir. A, scapula; I, ilium, or shinbone of pelvis; H, humerus; F, femur; O,…

These diagrams show that the bigger the circle or sphere, the more space in between.

Spheres

These diagrams show that the bigger the circle or sphere, the more space in between.

This figure shows "the cotidal lines and lines of equal amplitude for a diurnal tide in a circular sea of 20 degrees radius, the latitude of the center being 30 degrees north." -Coast and Geodetic Survey, 1901

Diurnal Cotidal Lines

This figure shows "the cotidal lines and lines of equal amplitude for a diurnal tide in a circular sea…

This figure shows "the cotidal lines and lines of equal amplitude for a diurnal tide in a circular sea of 20 degrees radius, the latitude of the center being 30 degrees north." -Coast and Geodetic Survey, 1901

Diurnal Cotidal Lines

This figure shows "the cotidal lines and lines of equal amplitude for a diurnal tide in a circular sea…

A caliper used for measuring the diameter of a circle.

Caliper

A caliper used for measuring the diameter of a circle.

"The inner circle incloses a map upon which the horizontal direction of the lower currents is shown by unbroken arrows, and that of the upper currents by broken arrows. The map is surrounded by a vertical section of the atmosphere in which the up-and-down are also shown by arrows. Near the equator the air rises and moves westward, and near the tropics it moves eastward and descends." -Dryer, 1901

Atmospheric Circulation

"The inner circle incloses a map upon which the horizontal direction of the lower currents is shown…

The diagram "shows the isotherms in a cyclone of, say, 500 miles in diameter, as indicated by the circle, along which also the direction of the wind is shown by means of arrows." -Waldo, 1896

Isotherms in a Cyclone

The diagram "shows the isotherms in a cyclone of, say, 500 miles in diameter, as indicated by the circle,…

Illustration of a circle divided in half.

Circle, 1/2 Fraction

Illustration of a circle divided in half.

Illustration of a circle divided into thirds. One third is shaded.

1/3 Circle

Illustration of a circle divided into thirds. One third is shaded.

Illustration showing the definition of a circle as a conic section. The section of a right circular cone made by a plane that is perpendicular to the axis (or parallel to the base).

Conic Section Showing A Circle

Illustration showing the definition of a circle as a conic section. The section of a right circular…

"Ideal fore limb. H., Humerus; R., radius; U., ulna; r'., radiale; u'., ulnare; i., intermedium; c., centrale; 1-5, carpalia bearing the corresponding digits with metacarpals (mc.) and phalanges (ph)." -Thomson, 1916

Vertebrate Fore Limb

"Ideal fore limb. H., Humerus; R., radius; U., ulna; r'., radiale; u'., ulnare; i., intermedium; c.,…

"Diagram of Teleostean circulation. A., auricle; V., ventricle; v.a., ventral aorta; a.br., afferent branchials; e.br., efferent branchials; c.c., cephalic circle; e., carotids; A.c.v., anterior cardinal veins; P.C.V., posterior cardinal veins; d.c., ductuss Cuvieri; d.a., dorsal aortaa; c.v., caudal vein; c.a., caudal artery; K., kidney." -Thomson, 1916

Teleostean Circulation

"Diagram of Teleostean circulation. A., auricle; V., ventricle; v.a., ventral aorta; a.br., afferent…

"Fore-limb and hind-limb compared. H., Humerus; R., radius; U., ulna; r., radiale; u., ulnare; C., distal carpals united to carpo-metacarpus; CC., the whole carpal region; MC.I., metacarpal of the thumb; I., phalanx of the thumb; MC.II., second metacarpus; II., second digit; MC.III., third metacarpus; III., third digit. F., femur; T.T., tibio-tarsus; Fi., fibula; Pt., proximal tarsals united to lower end of tibia; dt., distal tarsals nited to upper end of tarso-metatarsus (T.MT.); T., entire tarsal region; MT.I., first metatarsal, free; I.-IV., toes." -Thomson, 1916

Bird Limbs

"Fore-limb and hind-limb compared. H., Humerus; R., radius; U., ulna; r., radiale; u., ulnare; C., distal…

"Wing of dove. h., Humerus; s.f., secondary feathers; r., radius; u., ulna; c., carpals; mc., carpo-metacarpus; p.f., primary feathers." -Thomson, 1916

Dove Wing

"Wing of dove. h., Humerus; s.f., secondary feathers; r., radius; u., ulna; c., carpals; mc., carpo-metacarpus;…

"Fore-limb and shoulder-girdle (I.) and hind-limb (II.) of rabbit. SC., Scapula; A., acromion; M., metacromion process; H., humerus; O., olecranon process; U., ulna; R., radius; C., carpals; MC., metacarpals; D., five digits; F., femur; P., patella; FI., fibula; T., tibia; OC., os calcis; AS., astragalus; DT., distal tarsals; MT., metatarsals; D., four digits." -Thomson, 1916

Rabbit Limbs

"Fore-limb and shoulder-girdle (I.) and hind-limb (II.) of rabbit. SC., Scapula; A., acromion; M., metacromion…

"Left fore-limb of Balaenoptera. Sc., Sca pula with spine (sp.); H., humerus; R., radius; U., ulna; C., carpals embedded in matrix; Mc., metacarpals; Ph., phalanges." -Thomson, 1916

Whale Forelimb

"Left fore-limb of Balaenoptera. Sc., Sca pula with spine (sp.); H., humerus; R., radius; U., ulna;…

"Skeleton of male gorilla. cl., Clavicle; sc., tip of scapula; S., praesternum; H., humerus; r., radius; u., ulna; Il., ilium; C., coccyx; P., pubis; Is., ischium; F., femur; t., tibia; f., fibula." -Thomson, 1916

Gorilla Skeleton

"Skeleton of male gorilla. cl., Clavicle; sc., tip of scapula; S., praesternum; H., humerus; r., radius;…

View of the heart with its several chambers exposed and the vessels in connection with them. Labels: 1, the superior vena cava. 2, the inferior vena cava. 3. the chamber called the auricle. 4. the right ventricle. 5. the line marking the passage between the two chambers, and the points of attachment of one margin of the valve. 6. the septum between the two ventricles. 7. the pulmonary artery, arising from the right ventricle, and dividing at 8 into right and left, of the corresponding lungs. 9. the four pulmonary veins, bringing the blood from the lungs into 10, the left auricle. 11. the left ventricle. 12. the aorta, arising from the left ventricle, and passing down behind the heart, to distribute blood to every part of the system. Thus the blood moves in a double circle, one from the heart to the body, and from the body back to the heart, called the systemic circle; the other, from the heart to the lung, and from the lung back to the heart, called the pulmonic circle.

Heart and its Chambers

View of the heart with its several chambers exposed and the vessels in connection with them. Labels:…

Illustration showing a circle with a radius of 2 in. intersecting a circle with a radius of 3 in..

2 Intersecting Circles

Illustration showing a circle with a radius of 2 in. intersecting a circle with a radius of 3 in..

Illustrations used to construct an ellipse. Fig. 59 shows a compass at C used to strike a circle. Where the circle intersects the line at D and B, place pins. These pins represent the foci of the ellipse. Use a cord and a pencil to draw the ellipse as shown in figure 60. This illustrates the definition of an ellipse.

Construction Of An Ellipse

Illustrations used to construct an ellipse. Fig. 59 shows a compass at C used to strike a circle. Where…

"A circle may be considered as made up of triangles whose bases form the circumference, and whose altitude is the radius (1/2 diameter) of the circle." This is clearly shown by the cut at the left.

Circle Made Up Of Triangles

"A circle may be considered as made up of triangles whose bases form the circumference, and whose altitude…

An illustration of a circle inscribed in a square. It can be used to show that the area of a circle is .7854 of the area of a square whose sides are equal to its diameter.

Circle Inscribed In A Square

An illustration of a circle inscribed in a square. It can be used to show that the area of a circle…

"Diagrams of the girdles and appendages in a typical Vertebrate. A, anterior; B, posterior. ac., acetabulum, articulation of the humerus with its girdle; c, coracoid; ca., carpals; c.e., centralia; d.c., distal carpals; d.t., distal tarsals; el., elbow joint; f, fibula; fe., femur; fi., fibulare; gc., glenoid cavity, articulation of arm with girdle; h, humerus; il., ilium; in., intermediale; is. ischium; kn., knee joint; m.c., metacarpals (1-5); m.t., metatarsals (1-5); p, pubis; ph., phalanges (1-5); pr.c., precoracoid; r, radius; ra., radiale; sc., scapula; t, tibia; ta., tarsals; ti., tibiale; u., ulna; ul., ulnare." -Galloway, 1915

Vertebrate Appendages

"Diagrams of the girdles and appendages in a typical Vertebrate. A, anterior; B, posterior. ac., acetabulum,…

"Skeleton of crocodile. C, causal region; D, thoracic region of spinal column; F, fibula; Fe, femur; H, humerus; I, ischium; L, lumbar region; R, radius; Ri, ribs; S, sacrum; Sc, scapula; Sta, abdominal ribs; T, tibia; U, ulna." -Parker, 1900

Crocodile Skeleton

"Skeleton of crocodile. C, causal region; D, thoracic region of spinal column; F, fibula; Fe, femur;…