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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…

A historical astronomical instrument used to predict positions of the Sun, Moon, planets and stars.

Later Astrolabe

A historical astronomical instrument used to predict positions of the Sun, Moon, planets and stars.

A historical astronomical instrument used to predict positions of the Sun, Moon, planets and stars.

Regiomontanus' Astrolabe

A historical astronomical instrument used to predict positions of the Sun, Moon, planets and stars.

"The horizontal angular distance between two meridians. <em>Magnetic A.</em> the horizontal angular distance of the magnetic from the geographical meridian. <em>A. compass</em>; a variety of ship's compass." &mdash; Williams, 1889

Azimuth

"The horizontal angular distance between two meridians. Magnetic A. the horizontal angular…

"At sea the declination is generally observed by means of an azimuth compass invented by Kater. It consists of a magnet with a graduated compass card attached to it. At the side of the instrument opposite the eye there is a frame which projects upwards from the plane of the instrument in a nearly vertical direction, and this frame contains a wide rectangular slit cut into two parts by a wire extending lengthwise. The eye-piece is opposite this frame, and the observer is supposed to point the instrument in such a manner that the wire above mentioned shall bisect the sun's visible disk. There is a totally reflecting glass prism which throws into the eye-piece an image of the scale of the graduated card, so that the observer, having first bisected the sun's disk by the wire, must next read the division of the scale which is in the middle of the field of view." &mdash;The Encyclopedia Britannica, 1903

Azimuth Compass

"At sea the declination is generally observed by means of an azimuth compass invented by Kater. It consists…

An improvement upon the jackstaff from Davis, the Arctic navigator.

Backstaff

An improvement upon the jackstaff from Davis, the Arctic navigator.

"A Binnacle, corrupted from bittacle, a wooden case or box in which the compass on board a ship is kept to protect it from injury."&mdash;(Charles Leonard-Stuart, 1911)

Binnacle

"A Binnacle, corrupted from bittacle, a wooden case or box in which the compass on board a ship is kept…

A wooden case or box in which the compass on board a ship is kept to protect it from injury. A light is placed within it at night to insure that its indications are seen. It is placed immediately in front of the wheel or steering apparatus, and secured to the deck, usually by metal stays. The after portion has glass windows, so that the compass is at all times visible to the helmsman, who stands at the wheel.

Binnacle

A wooden case or box in which the compass on board a ship is kept to protect it from injury. A light…

Method to draw the bisector of a line

Bisect A Line

Method to draw the bisector of a line

Method to bisect an angle

Bisect An Angle

Method to bisect an angle

Depicted is a hand reaching out for a bow pencil.

Bow Pencil

Depicted is a hand reaching out for a bow pencil.

A center screw bow to draw circles. The adjustable screw is in the middle of the bow.

Center Screw Bow

A center screw bow to draw circles. The adjustable screw is in the middle of the bow.

"A rude form of the compass used by early Chinese sailors. The little wooden figure was set on a pivot, and in the outstretched arm was placed a bar of magnetized iron."&mdash;Myers, 1905

Chinese Magnet Figure

"A rude form of the compass used by early Chinese sailors. The little wooden figure was set on a pivot,…

A magnetic compass.

Compass

A magnetic compass.

A tool to know your direction.

Compass

A tool to know your direction.

A compass that tells direction.

Compass

A compass that tells direction.

An early compass.

Compass

An early compass.

"Compass, Mariner's, is the name given to the instrument by which sailors are enabled to steer their course on the ocean out of sight of land, and when neither sun nor stars are visible. the ancients, to whom it was unknown, could seldom venture to lose sight of the coast. The direct power of the magnet seems to have been unknown in Europe till late in the 12th century." &mdash; Chambers' Encyclopedia, 1875

Compass

"Compass, Mariner's, is the name given to the instrument by which sailors are enabled to steer their…

A tool used to tell direction.

Compass

A tool used to tell direction.

In some instruments joints are held in position by lock nuts allowing ample movement of the legs, yet gives proper stiffness

Compass

In some instruments joints are held in position by lock nuts allowing ample movement of the legs, yet…

To properly change the compass from one size to another, make sure to place legs together while turning the nut slowly.

Compass Adjustment

To properly change the compass from one size to another, make sure to place legs together while turning…

A test to check if the compass is aligned by bending the knuckle joints together and bringing the points together.

Compass Alignment

A test to check if the compass is aligned by bending the knuckle joints together and bringing the points…

Illustration of a compass with one leg at point A on the line segment and the other at Point B.

Compass and Line

Illustration of a compass with one leg at point A on the line segment and the other at Point B.

Illustration of a compass with one leg at point O on the line segment and the other at Point M.

Compass and Line

Illustration of a compass with one leg at point O on the line segment and the other at Point M.

Compass card, part of ship's compass.

Compass Card

Compass card, part of ship's compass.

"Three principal parts, the card, the needle on its lower suface, and the case. The whole is enclosed in the compass-box, or binnacle. the term compass is said to have been applied to the instrument because the card involves or compasses the whole plane of the horizon, or because the needle indicates the whole circle of possible variations of direction. The surface of the card is divided by radiating lines into 32 parts, each containing 11 degrees." &mdash; Encyclopedia Britannica, 1893

Compass Card

"Three principal parts, the card, the needle on its lower suface, and the case. The whole is enclosed…

"Plan and Transverse Section of Sir William Thomson's Compass-card. B, Corrector for quadrantal error; C, Box for corrector; a, Aluminium boss; b, Central cap of sapphire; c, Cords connecting rim and boss; d, Magnets; e, Threads connecting magnets; f, Aluminium rim; f, Cords supporting magnets; g,g', Knife edges for gimbals." &mdash; Encyclopedia Britannica, 1893

Compass Card

"Plan and Transverse Section of Sir William Thomson's Compass-card. B, Corrector for quadrantal error;…

Ritchie Liquid Compass. US Naval compasses have the degree around the rim marked from 0 to 360, east being 90, south being 180, etc.

Compass Card

Ritchie Liquid Compass. US Naval compasses have the degree around the rim marked from 0 to 360, east…

Diagram of points on a compass.

Compass Points

Diagram of points on a compass.

Adjusting the needle point so that it is slightly longer than that of the pencil.

The Tip of the Compass

Adjusting the needle point so that it is slightly longer than that of the pencil.

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…

The North Star (Polaris) varies so slightly from the true north that we may, for practical purposes, consider it true north. The North Star is easily identified by the pointers of the "Big Dipper."

Astronomical Compass

The North Star (Polaris) varies so slightly from the true north that we may, for practical purposes,…

Compass beam is used for large circles a compass or a lengthening bar cannot draw.

Beam Compass

Compass beam is used for large circles a compass or a lengthening bar cannot draw.

"It has four cardinal points, N, E, S, and W marked, as well as a circle graduated in degrees from sero to 360 degrees, clockwise around the circle." &mdash; Moss, 1914

Box compass

"It has four cardinal points, N, E, S, and W marked, as well as a circle graduated in degrees from sero…

A compass used to draw precise circles and arcs in mechanical drawing.

Drafting Compass

A compass used to draw precise circles and arcs in mechanical drawing.

A device used to determine geographic direction, usually consisting of a magnetic needle or needles horizontally mounted or suspended and free to pivot until aligned with the earth's magnetic field.

Route Compass

A device used to determine geographic direction, usually consisting of a magnetic needle or needles…

Diagram of a ship's compass.

Compass, Ship's

Diagram of a ship's compass.

A compass is a navigational instrument for determining direction relative to the poles.

Turning the Compass

A compass is a navigational instrument for determining direction relative to the poles.

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil and pen point are provided, either of which may be inserted into a socket in one leg of the instrument, for the drawing of circles in pencil or ink." &mdash; Hallock, 1905

Compasses

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil…

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil and pen point are provided, either of which may be inserted into a socket in one leg of the instrument, for the drawing of circles in pencil or ink." &mdash; Hallock, 1905

Compasses

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil…

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil and pen point are provided, either of which may be inserted into a socket in one leg of the instrument, for the drawing of circles in pencil or ink." &mdash; Hallock, 1905

Compasses

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil…

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil and pen point are provided, either of which may be inserted into a socket in one leg of the instrument, for the drawing of circles in pencil or ink." &mdash; Hallock, 1905

Compasses

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil…

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil and pen point are provided, either of which may be inserted into a socket in one leg of the instrument, for the drawing of circles in pencil or ink." &mdash; Hallock, 1905

Compasses

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil…

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil and pen point are provided, either of which may be inserted into a socket in one leg of the instrument, for the drawing of circles in pencil or ink." &mdash; Hallock, 1905

Compasses

"The compasses, next to the T square and triangles, are used more than any other instrument. A pencil…

Different compasses used in mechanical drawing.

Compasses

Different compasses used in mechanical drawing.

Compasses are used for drawing circles and arcs of circles.

Compasses and Attachments

Compasses are used for drawing circles and arcs of circles.

"On horizontal center line mark off eight points 3/8" apart, beginning at right side of space." &mdash;French, 1911

Drawing Concentric Arcs with Compass and Lengthening Bar

"On horizontal center line mark off eight points 3/8" apart, beginning at right side of space." —French,…

"On horizontal center line mark off eleven points 1/4" apart, beginning at left side of space. Draw horizontal limiting lines (in pencil only) 1 1/2" above and below center line." &mdash;French, 1911

Drawing Concentric Arcs with Compass

"On horizontal center line mark off eleven points 1/4" apart, beginning at left side of space. Draw…

"Draw Horizontal line throuch center of space. On it mark off radii for six concentric circles 1/4" apart. In drawing concentric circles always draw the smallest first. The dotted circles are drawn in in pencil with long dashes, and inked as shown." &mdash;French, 1911

Drawing Concentric Circles with Compass

"Draw Horizontal line throuch center of space. On it mark off radii for six concentric circles 1/4"…

Method to construct an equilateral triangle

Construct Equilateral Triangle

Method to construct an equilateral triangle

Method to construct a scalene triangle

Construct Scalene Triangle

Method to construct a scalene triangle

"Upon a tripod provided with levelling screws stands the pillar P, to which is fixed the graduated azimuthal circle CC. The compass box B, with the vernier V, attached to it, moves on the azimuthal circle by means of a pivot at the pillar P. Two uprights, U, U, are fixed to the side of the compass-box, on the tops of which rests the axis of the telescope T. A graduated are A, is fixed to the bottom of one of the uprights, and the angle of elevation of the telescope is marked by the vernier on the arm E, attached to the axis of the telescope. A level, L, is also hung on the axis of the telescope, for adjusting the instrument. Inside the compass-box is another graduated circle, F, the line joining the zero-points of which is parallel to the axis of the telescope. All the fittings are in brass or copper, iron, of course, being unsuitable." &mdash; Chambers' Encyclopedia, 1875

Declinometer

"Upon a tripod provided with levelling screws stands the pillar P, to which is fixed the graduated azimuthal…

"Circles up to perhaps three inches in diameter may be drawn with the legs straight but for larger sizes both the needle-point and the pencil leg should be at the knuckle joints so as to be perpendicular to the paper." &mdash; French, 1911

Drawing Large Circles with Compass

"Circles up to perhaps three inches in diameter may be drawn with the legs straight but for larger sizes…

Bow instruments can be used for drawing small circles. Hold the the left hand and spin the nut in or out with the finger to avoid wear and stripping the thread. "Small adjustments should be made with one hand, with needle point in position on the paper." &mdash; French, 1911

Drawing Small Circles with Bow Instrument

Bow instruments can be used for drawing small circles. Hold the the left hand and spin the nut in or…

The illustration shows the finger position of the compass after the revolution. &mdash; French, 1911

Compass Finger Position

The illustration shows the finger position of the compass after the revolution. — French, 1911

"Secure the two ends of the wire by double-pointed tacks. Place a small pocket compass upon the block thus wound, and turn the block until the coils of wire are parallel to the needle when the circuit is open. Then pass a current through the coil. The deflection of the needle is much stronger than before, although, owing to the weakening of the cell, the deflection falls off after a time." &mdash; Avery, 1895

Galvanoscope

"Secure the two ends of the wire by double-pointed tacks. Place a small pocket compass upon the block…

An illustration with multiple instruments used for navigation. These items include a globe, compass, map and books.

Globe

An illustration with multiple instruments used for navigation. These items include a globe, compass,…

The little finger on the left hand can guide the needle point of the compass to the center.

Guiding Needle Point of Compass to Little Finger

The little finger on the left hand can guide the needle point of the compass to the center.

A pair of hands, each holding a narrow bit of wire over a compass needle.

Hands with wires

A pair of hands, each holding a narrow bit of wire over a compass needle.

Draftsman's first method to draw a parabola

Hyperbola First Method

Draftsman's first method to draw a parabola