Leaves - simple; alternate; edge toothed. Outline - oval. Apex - pointed. Base - rounded or slightly pointed. Leaf - four to six inches long, one and a half to two and a half inches wide, soon becoming smooth, with a decided acid taste (whence the name). Bark - of trunk, rough and deeply furrowed. Flowers - white, in loose and long one-sided clusters. Found - from Pennsylvania and Ohio southward, chiefly along the Alleghany Mountains, and usually in dry, gravelly soil. General Information - A tree forty to sixty feet high, with hard, close-grained wood, which is used for the handles of tools, the bearings of machinery, etc. Name from two Greek words meaning sour and tree.

Genus oxydendrum, D. C. (Sorrel Tree)

Leaves - simple; alternate; edge toothed. Outline - oval. Apex - pointed. Base - rounded or slightly…

Triangles are made of various substances such as wood, rubber, celluloid, and steel.

45 Degree Triangle

Triangles are made of various substances such as wood, rubber, celluloid, and steel.

Triangles are made of various substances such as wood, rubber, celluloid, and steel.

30-60 Degree Triangle

Triangles are made of various substances such as wood, rubber, celluloid, and steel.

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.

It is possible to draw lines forming angles of 15 and 75 degrees by arranging two triangles.

Drawing Lines at an Angle 15 and 75

It is possible to draw lines forming angles of 15 and 75 degrees by arranging two triangles.

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.

Compasses are used for drawing circles and arcs of circles.

Compasses and Attachments

Compasses are used for drawing circles and arcs of circles.

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…

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.

The bow spacer is used when working with small distances.

Bow Spacer

The bow spacer is used when working with small distances.

A boy and a girl are gardening sunflowers.

Gardening

A boy and a girl are gardening sunflowers.

A boy holding a hammer and saw.

Boy with Tools

A boy holding a hammer and saw.

"Hall's Experiment illustrating contortion" of rocks." -Geikie, 1893

Contortion of Rocks

"Hall's Experiment illustrating contortion" of rocks." -Geikie, 1893

"Showing the manner of holding the knife blade on the glass ways, and, by the arrow, the direction of sliding he knife while cutting the sections." -Stevens, 1916

Microtome and Razor

"Showing the manner of holding the knife blade on the glass ways, and, by the arrow, the direction of…

"A sliding microtome of simple construction, adapted to cutting all kinds of sections." -Stevens, 1916

Sliding Microtome

"A sliding microtome of simple construction, adapted to cutting all kinds of sections." -Stevens, 1916

"Showing the manner of honing the section knife or razor." -Stevens, 1916

Cutting Plant Sections

"Showing the manner of honing the section knife or razor." -Stevens, 1916

"Illustrating how the section knife or razor is drawn across the strop." -Stevens, 1916

Cutting Plant Sections

"Illustrating how the section knife or razor is drawn across the strop." -Stevens, 1916

"Turn table for cementing coverglasses to slides. For use where the mounting medium is glycerine or glycerine jelly." -Stevens, 1916

Mounting Plant Sections

"Turn table for cementing coverglasses to slides. For use where the mounting medium is glycerine or…

Chopping tools used as hand axes in the Chellean age.

Chellean Age Chopping tools

Chopping tools used as hand axes in the Chellean age.

Three pictures of early stone implements during the Mousterian age.

Mousterian Age stone implements

Three pictures of early stone implements during the Mousterian age.

Early stone implements use by true men during the Reindeer age. These stones include scrapers and points.

Reindeer Age Stone Implements

Early stone implements use by true men during the Reindeer age. These stones include scrapers and points.

Five different reindeer horn. Crafted during the Reindeer age.

Reindeer age articles, Reindeer horns

Five different reindeer horn. Crafted during the Reindeer age.

Pebble cup mortar. Crafted during the Reindeer age.

Reindeer age articles, Pebble cup mortar

Pebble cup mortar. Crafted during the Reindeer age.

Bone points and bone needles. Crafted during the Reindeer age.

Reindeer age articles, Bone points and needles

Bone points and bone needles. Crafted during the Reindeer age.

Throwing sticks made from reindeer horn. Crafted during the Reindeer age.

Reindeer age articles, Throwing sticks

Throwing sticks made from reindeer horn. Crafted during the Reindeer age.

Arrow straighteners made from reindeer horns. Crafted during the Reindeer age.

Reindeer age articles, Arrow Straighteners

Arrow straighteners made from reindeer horns. Crafted during the Reindeer age.

A throwing stick being used by Australian natives. Crafted during the Reindeer age.

Reindeer age articles, Throwing stick being used

A throwing stick being used by Australian natives. Crafted during the Reindeer age.

"Palaeolithic Flint Implements from Kent's Cavern, Torquay." -Taylor, 1904

Flint Stone Tools

"Palaeolithic Flint Implements from Kent's Cavern, Torquay." -Taylor, 1904

A boy building a wooden shelf in shop class.

Shop Class

A boy building a wooden shelf in shop class.

Addition, subtraction, and multiplication wheels students use to spin and find the solutions.

Number Wheels

Addition, subtraction, and multiplication wheels students use to spin and find the solutions.

A fishing pole and landing net.

Fishing Pole and Net

A fishing pole and landing net.

In prehistoric times, a woman finds sleeping men from a different tribe and studies them.

Prehistoric People

In prehistoric times, a woman finds sleeping men from a different tribe and studies them.

The bow pencil is used to draw small circles and arcs.

The Bow Pencil

The bow pencil is used to draw small circles and arcs.

This bow pencil is used to make small curves.

Bow Pencil

This bow pencil is used to make small curves.

Depicted is a hand reaching out for a bow pencil.

Bow Pencil

Depicted is a hand reaching out for a bow pencil.

In wood working there are a number of fine tools used in cutting wood, in which a single or double shearing blade is used.

Wood Cutting Tool

In wood working there are a number of fine tools used in cutting wood, in which a single or double shearing…

A lathe is a machine tool which spins a block of material to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.

Foot-power Wood-working Lathe

A lathe is a machine tool which spins a block of material to perform various operations such as cutting,…

A lathe is a machine tool which spins a block of material to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.

Large Power Lathe

A lathe is a machine tool which spins a block of material to perform various operations such as cutting,…

This carriage bolt has a rounded head and a slotted drive.

Carriage Bolt

This carriage bolt has a rounded head and a slotted drive.

"Screw-punch. a, bed; b, yoke, on the inner sides of which are slides for the cross-head c; d, the punch proper; e, nut for the screw; f, weighted lever by which the screw is made to exert its power upon the punch d." -Whitney, 1911

Screw Punch

"Screw-punch. a, bed; b, yoke, on the inner sides of which are slides for the cross-head c; d, the punch…

A hex bolt used in carpentry is identified by its hexagonal head and (shown here) fully threaded.

Hex Bolt

A hex bolt used in carpentry is identified by its hexagonal head and (shown here) fully threaded.

A carriage bolt with a truss head and a wing nut.

Truss Carriage Bolt and Wing Nut

A carriage bolt with a truss head and a wing nut.

A wood screw with a flat head and slotted drive. Wood screws are unthreaded below the head and designed for attaching two pieces of wood.

Wood Screw

A wood screw with a flat head and slotted drive. Wood screws are unthreaded below the head and designed…

A wood screw with a flat head and slotted drive. Wood screws are unthreaded below the head and designed for attaching two pieces of wood.

Wood Screw

A wood screw with a flat head and slotted drive. Wood screws are unthreaded below the head and designed…

A wood screw with a flat head and slotted drive. Wood screws are unthreaded below the head and designed for attaching two pieces of wood.

Wood Screw

A wood screw with a flat head and slotted drive. Wood screws are unthreaded below the head and designed…

"A handle for holding the threaded die by which the thread is cut on a bar, a nut, or a pipe; a die-stock; a screw-plate." -Whitney, 1911

Screw Stock

"A handle for holding the threaded die by which the thread is cut on a bar, a nut, or a pipe; a die-stock;…

"The cutting-tool in a screw-cutting machine; a screw-plate." -Whitney, 1911

Screw Cutting Die

"The cutting-tool in a screw-cutting machine; a screw-plate." -Whitney, 1911

A section of a screw-cutting die.

Screw Die Section

A section of a screw-cutting die.

"Jewelers' box of dies, stocks, and taps (called a screw-plate set." -Whitney, 1911

Screw-Plate Set

"Jewelers' box of dies, stocks, and taps (called a screw-plate set." -Whitney, 1911

A young woman stands in the doorway holding her knitting tools.

Woman Standing in a Doorway

A young woman stands in the doorway holding her knitting tools.

"Endless screw, a mechanical arrangement consisting of a screw the thread of which gears into a wheel with skew teeth, the obliquity corresponding to the angle of pitch of the screw." -Whitney, 1911

Endless Screw and Wheel

"Endless screw, a mechanical arrangement consisting of a screw the thread of which gears into a wheel…

"Two pieces of metal placed in a hole in a stone which is to be split a wedge-shaped key or plug being driven between them for this purpose." -Whitney, 1911

Feather and Tare

"Two pieces of metal placed in a hole in a stone which is to be split a wedge-shaped key or plug being…

"Files. a, cotter-file when large, and verge- or pivot-file when small; b, square file (parallel or taper); c, banking or watch-pinion file when parallel, and knife-file when tape; d, half-round, nicking, piercing, or round-off file; e, round, gulleting, or rat-tail file; f, triangular, three-square, or saw file; g, equaling, clock-pinion, or endless-screw file when parallel, and slitting, entering, warding, or barrel-hole file when tape; h, cross- or double-half-round file; i, screw-head, feather-edge, or slitting file." -Whitney, 1911

Types of Files

"Files. a, cotter-file when large, and verge- or pivot-file when small; b, square file (parallel or…

A typewriter is a mechanical or electromechanical device with a set of "keys" that, when pressed, cause characters to be printed on a medium, usually paper. For much of the 20th century, typewriters were indispensable tools for many professional writers and in business offices. By the end of the 1980s, word processor applications on personal computers had largely replaced the tasks previously accomplished with typewriters. Typewriters, however, remain popular in the developing world and among some niche markets, and for some office tasks.

Typewriter

A typewriter is a mechanical or electromechanical device with a set of "keys" that, when pressed, cause…

A typewriter is a mechanical or electromechanical device with a set of "keys" that, when pressed, cause characters to be printed on a medium, usually paper. For much of the 20th century, typewriters were indispensable tools for many professional writers and in business offices. By the end of the 1980s, word processor applications on personal computers had largely replaced the tasks previously accomplished with typewriters. Typewriters, however, remain popular in the developing world and among some niche markets, and for some office tasks.

Open Typewriter

A typewriter is a mechanical or electromechanical device with a set of "keys" that, when pressed, cause…

An illustration of a small hand saw.

Hand Saw

An illustration of a small hand saw.

Illustration showing the correct and incorrect position of a right line pen against a T-square, triangle, or straight edge when doing geometric constructions.

Positioning Pen for Constructions

Illustration showing the correct and incorrect position of a right line pen against a T-square, triangle,…

The Scythe was an old method for cutting grass for hay. It was one of the severest labors on the farm. It called to play nearly every voluntary muscle in the body, requiring not only the more frequent and regular movements of the muscles, but also a great exertion of muscular power.

Scythe

The Scythe was an old method for cutting grass for hay. It was one of the severest labors on the farm.…