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Use a drawing board and T-square to test the accuracy of the 90 degree angle.

Testing Triangles

Use a drawing board and T-square to test the accuracy of the 90 degree angle.

Triangles are used in drawing lines at right angles to the T-square.

Drawing Vertical Parallel Lines

Triangles are used in drawing lines at right angles to the T-square.

A triangle and a T-square can be used in conjunction to draw a rectangle.

Drawing Rectangles

A triangle and a T-square can be used in conjunction to draw a rectangle.

Diamond pattern exercise: Divide A D and A B into 4 equal parts, then draw horizontal lines through E, F, and G and vertical lines through L, M, and N. Draw lines from A and B to the intersection O of lines E and M, and from A and D to the intersection P of lines F and L. Similarly, draw D J, J C, C I, and I B. Also connect the points O, P, J, and I, thus forming a square. The four diamond-shaped areas are formed by drawing lines from the middle points of A D, A B, B C, and D C to the middle points of lines A P, A O, O B, I B, etc.

Diamond Exercise

Diamond pattern exercise: Divide A D and A B into 4 equal parts, then draw horizontal lines through…

Square pattern exercise: Divide A D and A B into 4 equal parts and draw horizontal and vertical lines. Now divide these dimensions, A L, M N, etc., and E F, G B, etc., into 4 equal parts- each 1/4 inch- and draw light pencil lines with the T-square and triangle.

Square Exercise

Square pattern exercise: Divide A D and A B into 4 equal parts and draw horizontal and vertical lines.…

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…

To fasten the paper, lay a sheet on the board with the left edge an inch or so from the ending, place a T-square in position and "true up" the paper with the T-square.

Adjusting the Paper

To fasten the paper, lay a sheet on the board with the left edge an inch or so from the ending, place…

All lines in a mechanical drawing are made with the aid of an instrument. Horizontal lines are drawn with the upper edge of the T-square blade as a guide.

Drawing a Horizontal Line

All lines in a mechanical drawing are made with the aid of an instrument. Horizontal lines are drawn…

Vertical lines are drawn by using a triangle held against the T-square.

Drawing a Vertical Line

Vertical lines are drawn by using a triangle held against the T-square.

Parallel lines are drawn by using a triangle in combination with a T-square. To draw a line parallel to the one given, place a triangle against the T-square and move them together until the hypotenuse of the triangle matches the line. Hold the T-square firmly and slide the triangle in the direction of the arrow until the desired position of the parallel line is reached.

Drawing Parallel Lines Exercise

Parallel lines are drawn by using a triangle in combination with a T-square. To draw a line parallel…

Lines perpendicular to each other may be drawn by using a triangle in combination with the T-square. To draw a line perpendicular to a given line place a triangle against the T-square and move them together until the hypotenuse of the triangle matches the line. Turn the triangle on its right angled corner until the perpendicular line can be drawn on the hypotenuse of the triangle.

Drawing Perpendicular Lines Exercise

Lines perpendicular to each other may be drawn by using a triangle in combination with the T-square.…

Square with diagonal drawn.

Square With Diagonal

Square with diagonal drawn.

One of the earliest square towers near Orleans, France.

Tower of Beaugency

One of the earliest square towers near Orleans, France.

Eye of the phalaena or butterfly, magnified, consisting of 11,300 square sections. The eye of the mordella is similar, containing 25,088 prisms.

Eye of the Butterfly

Eye of the phalaena or butterfly, magnified, consisting of 11,300 square sections. The eye of the mordella…

Hanover Stamp (1 gutengr.) from 1850

Hanover 1 Gutengr Stamp, 1850

Hanover Stamp (1 gutengr.) from 1850

The figure shows the harmony and syzygy of tides in four different places (the four corners of the square).

Tide Theory, Square

The figure shows the harmony and syzygy of tides in four different places (the four corners of the square).

The figure shows the harmony and syzygy of tides in four different places (the four corners of the square).

Tide Theory, Square

The figure shows the harmony and syzygy of tides in four different places (the four corners of the square).

The figure shows a 30 degree triangle made from a square depicting the harmony and syzygy of tides in four different places (the four corners of the square).

Tide Theory, Triangle

The figure shows a 30 degree triangle made from a square depicting the harmony and syzygy of tides in…

The figure shows a 30 degree triangle made from a square depicting the harmony and syzygy of tides in four different places (the four corners of the square).

Tide Theory, Triangle

The figure shows a 30 degree triangle made from a square depicting the harmony and syzygy of tides in…

"Outline of tangential section of wood of oak, to show frequency of medullary rays. The section is 1 mm. square. The number of rays shown is below the average for woodyplants." -Stevens, 1916

Oak Wood

"Outline of tangential section of wood of oak, to show frequency of medullary rays. The section is 1…

Illustration of a square divided in half.

Square, 1/2 Fraction

Illustration of a square divided in half.

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

1/3 Square

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

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…

A square stem.

Square Stem

A square stem.

"The first sensation in descending under water in a suit of armor is the sudden, bursting roar in the ears, cause by the air driven into the helmet from the air-pump. The flexible air-hose has to be strong enough to bear the pressure of twenty-five to fifth pounds to the square inch." -Lupton

Early Scuba diving

"The first sensation in descending under water in a suit of armor is the sudden, bursting roar in the…

An illustration showing how to construct a square upon a given line. "With AB as radius and A and B as centers, draw the circle arcs AED and BEC. Divide the arc BE in two equal parts at F, and with EF as radius and E as center, draw the circle CFD. Join A and CB and D, C and D, which completes the required square."

Square Constructed Upon A Given Line

An illustration showing how to construct a square upon a given line. "With AB as radius and A and B…

An illustration showing how to construct a square inscribed in a circle. "Draw the diameter AB, and through the center erect the perpendicular CD, and complete the square as shown in the illustration."

Construction Of A Square Inscribed In A Circle

An illustration showing how to construct a square inscribed in a circle. "Draw the diameter AB, and…

An illustration showing how to construct a square circumscribed about a circle. "Draw the diameters AB and CD at right angles to one another; with the radius of the circle, and A, B, C, and D as centers, draw the four dotted half circles which cross one another in the corners of the square, and thus complete the problem."

Construction Of A Square Circumscribed About A Circle

An illustration showing how to construct a square circumscribed about a circle. "Draw the diameters…

An illustration showing how to construct a regular octagon from a square by cutting off the corners of the square. "With the corners as centers, draw circle arcs through the center of the square to the side, which determine the cut-off."

Construction Of An Octagon From a Square

An illustration showing how to construct a regular octagon from a square by cutting off the corners…

"A regular township, according to United States surveys, is 6 miles square and is divided into 36 equal parts or sections, each section containing 640 acres and measuring one mile square...How many acres or land in 4.75 sections? How many more acres in 7.5 sections than there are in 3 sections? How many acres of land in .5 section?, 2.5 sections?, 5 sections? How many more acres in 3.5 sections than in 2 sections?" -Foster, 1921

Land Measurement

"A regular township, according to United States surveys, is 6 miles square and is divided into 36 equal…

A species of masonry very common among the ancients, in which the stones are square and laid lozenge-wise, resembling the meshes of a net, and producing quite an ornamental appearance. It is the opus reticulate of the Romans.

Reticulated Work

A species of masonry very common among the ancients, in which the stones are square and laid lozenge-wise,…

An illustration showing how to construct a parabola using a pencil and a string. "Having given the two axes, vertex, and focus of the parabola. Take a square cde, and fix to it a string at c; fix the other end of the string at the focus f. The length of the sting should be such that when the square is in the position of the axis Af, the string should reach to the vertex A. Move the square along BB, and the pencil P will describe the parabola."

Construction Of A Parabola

An illustration showing how to construct a parabola using a pencil and a string. "Having given the two…

An illustration showing how to construct a spiral with compasses and four centers. "Given the pitch of the spiral, construct a square about the center, with the four sides together equal to the pitch. Prolong the sides in one direction as shown by the figure, the corners are the centers for each arc of the external angles."

Construction Of A Spiral

An illustration showing how to construct a spiral with compasses and four centers. "Given the pitch…

An illustration showing how to square binomial (a + b). (a + b)² = a² + 2ab + b².

Squaring Binomial (a + b)

An illustration showing how to square binomial (a + b). (a + b)² = a² + 2ab + b².

An illustration showing how to square binomial (a - b). (a - b)² = a² - 2ab + b².

Squaring Binomial (a - b)

An illustration showing how to square binomial (a - b). (a - b)² = a² - 2ab + b².

This fraction chart can be used for students to find A, B, and C in percentage. It can also be used to answer these questions (if it is 2.5 by 2 inches): "How many square inches in the entire figure? How many square inches in C? What part of a square inch is B? How large is A when compared to C? How large is B when compared to A? Into how many quarter-inch squares could you divide the whole figure?" -Foster, 1921

Fraction Chart

This fraction chart can be used for students to find A, B, and C in percentage. It can also be used…

A grid representing 100 square yards with 1/4 shaded.

1/4 of 100 Square Yards

A grid representing 100 square yards with 1/4 shaded.

This 24x24 square shows how square root can be taught. It is divided up into 4x4 and 20x20.

Square Roots

This 24x24 square shows how square root can be taught. It is divided up into 4x4 and 20x20.

An illustration used to "square a circumference".

Square And Circle

An illustration used to "square a circumference".

An illustration used to "square a cirleplane".

Square And Circle

An illustration used to "square a cirleplane".

The door-panel architectural frame was a square that is surrounded by an ornament that is symmetrical on all sides without regard to the top and bottom.

Door-Panel Frame

The door-panel architectural frame was a square that is surrounded by an ornament that is symmetrical…

The stove-tile architectural frame of the 17th century, was a square surrounded by an ornate frame that is symmetrical on all sides, without regard to the top and bottom.

Stove-Tile Frame

The stove-tile architectural frame of the 17th century, was a square surrounded by an ornate frame that…

"A large thick and weighty shell, round-bellied and deeply furrowed; it is yellow, or rust-colored, marked my square, brown spots."

Turbo Margaritaceus (Linnaeus)

"A large thick and weighty shell, round-bellied and deeply furrowed; it is yellow, or rust-colored,…

"The Episcopal Miter, from the Indian ocean is white, ornamented with square spots of a fine red, and capable of high polish. It emits a purple liquid, having a nauseous odor, when irritated."

Mitra Episcopalis (Lamarck)

"The Episcopal Miter, from the Indian ocean is white, ornamented with square spots of a fine red, and…

Illustration of a square prism; a prism whose bases are squares.

Square Prism

Illustration of a square prism; a prism whose bases are squares.

Illustration used to show finding the volume of a square prism.

Volume Of Square Prism

Illustration used to show finding the volume of a square prism.

Illustration comparing the fundamental units of measure 1 square yard and 1 square meter.

Comparison Of Units Of Square Measure

Illustration comparing the fundamental units of measure 1 square yard and 1 square meter.

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…

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…

"In order to get them to leave their old food and feed upon the bright and newer leaves, a net is spread over them, on which is laid the supply of tender leaves. The worms at once leave the old food, crawl through the meshes of the net, and all begin feeding on the new leaves."

Silkworm, Square Net

"In order to get them to leave their old food and feed upon the bright and newer leaves, a net is spread…

"The accompanying engraving is an illustration of a new style vertical mill in which an attempt is made to embody all the improvements which have been suggested by experience, and to furnish a complete vertical cane mill. In this machine the hearing is placed between the rolls, giving access to the boxes; the small wheels are lapped, bringing the minor rolls close together, and dispensing with the guide plate or 'dumb returner;' the main roll has a wide flange; the sweep cap has a square eye fitted to the squared end of the main shaft removable by hand; the weight of the rolls is supported upon the ends of the shafts in adjustable oil-tight boxes; the feed roll is fluted to facilitate the entrance of the cane to the mill; the top and bottom plates are diagonally braced as represent, and the construction of the whole machine is such that the mill may be taken entirely apart by simply unscrewing the corner bolts, no keys being used in any part of the machine." -Commissioner, 1865

Vertical Cane Mill

"The accompanying engraving is an illustration of a new style vertical mill in which an attempt is made…

An illustration of the Pulanski monument located in Savannah, Georgia. Pulaski was laid out in 1837 and is named for General Casimir Pulaski, a Polish-born Revolutionary War hero who died of wounds received in the Siege of Savannah (1776). It is one of the few squares without a monument -- General Pulaski's statues is actually in nearby Monterey Square.

Pulaski Monument

An illustration of the Pulanski monument located in Savannah, Georgia. Pulaski was laid out in 1837…

Whitehall is a road in Westminster in London, England. It is the main artery running north from Parliament Square, towards traditional Charing Cross, now at the southern end of Trafalgar Square and marked by the statue of Charles I, which is often regarded as the heart of London. Recognised as centre of HM Government, the road is lined with government departments/ministries; "Whitehall" is therefore also frequently used as a metonym for governmental administration, as well as being a geographic name for the surrounding district.

Whitehall in the Seventeenth Century

Whitehall is a road in Westminster in London, England. It is the main artery running north from Parliament…

Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London (and historically as The Tower), is a historic monument in central London, England, on the north bank of the River Thames. The Tower of London is often identified with the White Tower, the original stark square fortress built by William the Conqueror in 1078. However, the tower as a whole is a complex of several buildings set within two concentric rings of defensive walls and a moat. The tower's primary function was a fortress, a royal palace, and a prison (particularly for high status and royal prisoners).

Procession to the Tower of London

Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London (and historically…

Charterhouse, originally Sutton's Hospital in Charterhouse, is a prominent boys independent or public school. Founded by Thomas Sutton in London in 1611 on the site of the old Carthusian monastery in Charterhouse Square, Smithfield, it is one of the original nine English public schools as defined by the Public Schools Act 1868. Today pupils are still referred to as Carthusians, and ex-pupils as Old Carthusians or OCs. It is one of Britain's most expensive schools, with annual boarding and tuition fees per pupil of more than £27,000.

Charterhouse School, 18th Century

Charterhouse, originally Sutton's Hospital in Charterhouse, is a prominent boys independent or public…

With the plane, one can make rough wood true, smooth and beautiful. The name plane, perhaps, comes from the work it does, for it is used to smooth or reduce wood to a true plane.

Core Box Plane

With the plane, one can make rough wood true, smooth and beautiful. The name plane, perhaps, comes from…

The American Bison (Bison bison) is a bovine mammal, also commonly known as the American buffalo. 'Buffalo' is something of a misnomer for this animal as it is only distantly related to either of the two "true buffaloes", the water buffalo and the African Buffalo. The bison once inhabited the Grasslands of the United States and Asia in massive herds, ranging from the Great Slave Lake in Canada's far north to Mexico in the south, and from eastern Oregon almost to the Atlantic Ocean, taking its subspecies into account. Its two subspecies are the Plains Bison (Bison bison bison), distinguished by its smaller size and more rounded hump, and the Wood Bison (Bison bison athabascae), distinguished by its larger size and taller square hump. Wood Bison are one of the largest species of cattle in the world, surpassed in size only by the massive Asian gaur and Wild Asian Water Buffalo, both of which are found mainly in India and Southeast Asia.

North American Bison

The American Bison (Bison bison) is a bovine mammal, also commonly known as the American buffalo. 'Buffalo'…

The National Palace is the seat of the federal executive in Mexico. It is located in Mexico City's main square, the Plaza de la Constitución.

National Palace, Mexico City

The National Palace is the seat of the federal executive in Mexico. It is located in Mexico City's main…

"The inflorescence of Maryland Figwort (Scrophularia Marylandica). a, the flower; b, the fruit; c, a seed; d, a leaf." -Whitney, 1911

Maryland Figwort

"The inflorescence of Maryland Figwort (Scrophularia Marylandica). a, the flower; b, the fruit; c, a…