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"A piston and rod shown with attached weight. The valve, A, can be opened and closed as needed so that the piston can be moved." —Hallock 1905

Piston and Rod

"A piston and rod shown with attached weight. The valve, A, can be opened and closed as needed so that…

A balance used for measuring weight.

Balance

A balance used for measuring weight.

"When bodies of equal weight are supported by the arms of a lever, they will balance each other when placed at equal distances from the fulcrum." —Quackenbos 1859

Balance

"When bodies of equal weight are supported by the arms of a lever, they will balance each other when…

In the common balance there is a stiff piece of metal called the beam, which turns about the sharp edge of a steel wedge forming part of the beam. The scale pans rest upon the hooks of the wedges.

Balance

In the common balance there is a stiff piece of metal called the beam, which turns about the sharp edge…

A balance of great delicacy with the glass case that contains it.

Balance for Purposes of Accuracy

A balance of great delicacy with the glass case that contains it.

An illustration of a balance scale.

Balance Scale

An illustration of a balance scale.

This antique Roman balance from Pompeii has one pan that hangs from a rod.

Antique Roman balance from Pompeii

This antique Roman balance from Pompeii has one pan that hangs from a rod.

A weighing apparatus somewhat resembling the steelyard, but differing from it by having the fulcrum movable.

Danish Balance

A weighing apparatus somewhat resembling the steelyard, but differing from it by having the fulcrum…

"A form of balance in which the weight of the body under examination is measured by the stretching (torsion) of an elastic wire in the form of a long spiral. A common use of the simple form of spiral balance is in determining the specific gravity of small fragments of minerals, which for this purpose are weighed first in the upper pan and then in that below, which is immersed in water." —Whitney, 1889

Spiral Balance

"A form of balance in which the weight of the body under examination is measured by the stretching (torsion)…

"Combinations of pulleys are made in great variety. In the forms most commonly used, one continuous cord passes around all the pulleys. Frequently two or more sheaves are mounted in the same block and turn on the same axis, as in the common block and tackle." — Avery, 1895

Block and tackle

"Combinations of pulleys are made in great variety. In the forms most commonly used, one continuous…

A conoid shaped metal bob or weight attached to the end of a plumb line.

Plumb Bob

A conoid shaped metal bob or weight attached to the end of a plumb line.

A conoid shaped metal bob or weight attached to the end of a plumb line.

Plumb Bob

A conoid shaped metal bob or weight attached to the end of a plumb line.

A conoid shaped metal bob or weight attached to the end of a plumb line.

Plumb Bob

A conoid shaped metal bob or weight attached to the end of a plumb line.

A conoid shaped metal bob or weight attached to the end of a plumb line.

Plumb Bob

A conoid shaped metal bob or weight attached to the end of a plumb line.

An illustration of a vertical cross section of the spherical zones of a casting with a diameter of 16 inches.

Vertical Cross Section of Spherical Zones of a Casting

An illustration of a vertical cross section of the spherical zones of a casting with a diameter of 16…

"Why does a person carrying a weight upon his back stoop forward? In order to bring the center of gravity of his body and the load over his feet. If held in this position, he would fall backwards, as the direction of the center of gravity would fall beyond his heels." — Wells, 1857

Center of Gravity

"Why does a person carrying a weight upon his back stoop forward? In order to bring the center of gravity…

"Why does a person carrying a weight upon his back stoop forward? In order to bring the center of gravity of his body and the load over his feet, he assumes this position." — Wells, 1857

Center of Gravity

"Why does a person carrying a weight upon his back stoop forward? In order to bring the center of gravity…

"Where five blocks are placed in this position, the point of gravity is near the centre of the thrd block, and is within the base as shown by the plumb line. But on adding another block, the gravitation point falls beyond the base, and the whole will now fall by its own weight." -Comstock 1850

Center of Gravity of Standing Blocks

"Where five blocks are placed in this position, the point of gravity is near the centre of the thrd…

This illustration shows an arrangement by which the proportion by weight of hydrogen and oxygen in water can be determined.

Composition by Weight

This illustration shows an arrangement by which the proportion by weight of hydrogen and oxygen in water…

"In compound levers, equilibrium is established when the power, multiplied by the first arms of all the levers, is equal to the weight multiplied by the last arms of all the levers." —Quackenbos 1859

Compound Lever

"In compound levers, equilibrium is established when the power, multiplied by the first arms of all…

"Compound pulleys using one fixed and two moveable pulleys to pull a weight up by applying a downward force." -Avery 1895

Compound Pulley

"Compound pulleys using one fixed and two moveable pulleys to pull a weight up by applying a downward…

"Compound pulley designed to use very little power to lift heavy weights." -Avery 1895

Compound Pulley

"Compound pulley designed to use very little power to lift heavy weights." -Avery 1895

"... shows one of the commonest (sic) forms in which this kind of lever appears,-the crowbar. The power is applied at the handle. The weight is at the other end, and consists of something to be moved. The fulcrum is a stone on which the crowbar rests." —Quackenbos 1859

Crowbar

"... shows one of the commonest (sic) forms in which this kind of lever appears,-the crowbar. The power…

"They took Jesus therefore: and he went out, bearing the cross for himself, unto the place called The place of a skull, which is called in Hebrew, Golgotha..." John 19:17 ASV <p>Illustration of Jesus bearing his cross as his mother, Mary, falls to her knees in front of him. A disciple stands in the background (right). Simon stands behind Jesus with his left hand on the cross and a length of rope in his raised right hand. Behind Simon is another man, carrying a ladder. A crowd is following, including a soldier on a horse.

Jesus Carrying the Cross on the Way to Calvary

"They took Jesus therefore: and he went out, bearing the cross for himself, unto the place called The…

"Place a known weight (say 100 g.) in the scale-pan, and to this weight add the weight of the clevis and the scale-pan, and call the sum the load. Measure the deflection of W caused by the load. Double the load, and measure the deflection thus caused." -Avery 1895

Deflection of Wood Using Known Weights

"Place a known weight (say 100 g.) in the scale-pan, and to this weight add the weight of the clevis…

"A Lever of the First Kind is one in which the fulcrum is between the power and the weight... where F represents the fulcrum, P the power, and W the weight." &mdash;Quackenbos 1859

First Class Lever

"A Lever of the First Kind is one in which the fulcrum is between the power and the weight... where…

In the first order of levers, the fulcrum is between the power and the weight.

First Orders of Lever

In the first order of levers, the fulcrum is between the power and the weight.

"A fixed pulley is one whose block is not movable. In this case, if the weight W be lifted by pulling down P, the other end of the cord W will evidently move the same distance upwards that P moves downwards; hence, P must equal W." &mdash; Hallock, 1905

Fixed Pulley

"A fixed pulley is one whose block is not movable. In this case, if the weight W be lifted by pulling…

"[This illustration] represents a fixed pulley. The block is attached to a projecting beam. P is the power, and W the weight. For every inch that P descends, W ascends the same distance." &mdash;Quackenbos 1859

Fixed Pulley

"[This illustration] represents a fixed pulley. The block is attached to a projecting beam. P is the…

A hand holding a pointed weight suspended from a string.

Hand holding weight

A hand holding a pointed weight suspended from a string.

"Suppose the inclined plane, to be two feet from A to B, and one foot from C to B, then, as we have already seen, a power of one pound at P, would balance a weight of two pounds at W." -Comstock 1850

Inclined Plane

"Suppose the inclined plane, to be two feet from A to B, and one foot from C to B, then, as we have…

"The power required to force a given weight up an inclined plane, is in proportion to its height, and the length of its base, or in other words, the force must be in proportion to the rapidity of its inclination." -Comstock 1850'

Inlined Plane with Weight

"The power required to force a given weight up an inclined plane, is in proportion to its height, and…

"The object W to be lifted is called the weight; the force is represented by P; the point, or pivot, F is called the fulcrum." &mdash;Hallock 1905

Lever

"The object W to be lifted is called the weight; the force is represented by P; the point, or pivot,…

"The object W to be lifted is called the weight; the force is represented by P; the point, or pivot, F is called the fulcrum." &mdash;Hallock 1905

Lever

"The object W to be lifted is called the weight; the force is represented by P; the point, or pivot,…

"The object W to be lifted is called the weight; the force is represented by P; the point, or pivot, F is called the fulcrum." &mdash;Hallock 1905

Lever

"The object W to be lifted is called the weight; the force is represented by P; the point, or pivot,…

An illustration of a lever with weights m and n with distances a and b from fulcrum. Illustration could be used with proportions.

Lever Balanced on fulcrum With Weights

An illustration of a lever with weights m and n with distances a and b from fulcrum. Illustration could…

"The lever of the first class has the fulcrum between the power and the weight." Examples: a common crowbar, a pump handle, scissors, a seesaw. -Foster, 1921

First Class Lever

"The lever of the first class has the fulcrum between the power and the weight." Examples: a common…

This illustration shows the first class of lever. This class employs a fulcrum between the power and the weight.

First Class of Lever: Fulcrum Between Power and Weight

This illustration shows the first class of lever. This class employs a fulcrum between the power and…

"The lever of the second class has the weight between the power and the fulcrum." Examples: a nutcracker, a wheelbarrow. -Foster, 1921

Second Class Lever

"The lever of the second class has the weight between the power and the fulcrum." Examples: a nutcracker,…

"In the second order of levers, the resistance is between the fulcrum and the power; and, as before, P : W :: BF : AF, but the pressure of the fulcrum is equal to W-P, or the weight less the power."&mdash;Pettigrew, 1874

Second Kind of Lever

"In the second order of levers, the resistance is between the fulcrum and the power; and, as before,…

Illustration of an ordinary steel-yard being used as a lever. F represents the fulcrum. Weight P is used to balance weight W.

Steel-yard Used as a Lever

Illustration of an ordinary steel-yard being used as a lever. F represents the fulcrum. Weight P is…

"The lever of the third class has the power between the weight and the fulcrum." Examples: sewing machine treadle, forearm. -Foster, 1921

Third Class Lever

"The lever of the third class has the power between the weight and the fulcrum." Examples: sewing machine…

An old fashioned weight lifter. A is a plug s the air stays compressed. B is the rod portion of a piston.

Weight Lifter

An old fashioned weight lifter. A is a plug s the air stays compressed. B is the rod portion of a piston.

Illustration of a hydraulic machine. "A principle known as Pascal's Law states that pressure exerted on a liquid in a closed vessel is transmitted equally and undiminished in all directions." If a, A, p, and P respectively represent the areas and pressures, then the following proportion holds: a:A = p:P.

Hydraulic Machine Exerting Pressure

Illustration of a hydraulic machine. "A principle known as Pascal's Law states that pressure exerted…

"Get a lamp-chimney, preferably cylindrical. With a diamond or a steel glass-cutter, cut a disk of window glass a little larger than the cross-section of the lamp-chimney. Pour some fine emery powder on the disk, and rub one end of the chimney upon it, thus grinding them until they fit accurately...place [the chimney] under the water as shown. the upward pressure of the water will hold the disk in place. Pour water carefully into the tube; the disk will fall as soon as the weight of the water in the chimney plus the weight of th disk, exceeds the upward pressure of the water." -Avery 1895

Water Pressure Experiment

"Get a lamp-chimney, preferably cylindrical. With a diamond or a steel glass-cutter, cut a disk of window…

"By measuring the weight required to move the end cap of any of the shown tubes filled with water, it may be ascertained that the water required is only dependent on the level of water, not the weight." -Avery 1895

Water Pressure Independent of Vessel

"By measuring the weight required to move the end cap of any of the shown tubes filled with water, it…

An experimental verification of the Principle of Archimedes.

Experimental Verification of Principle of Archimedes

An experimental verification of the Principle of Archimedes.

"A pulley is a grooved wheel, around which a rope is passed, and is either fixed or moveable." &mdash; Goodrich, 1844

Pulley

"A pulley is a grooved wheel, around which a rope is passed, and is either fixed or moveable." —…

"The pulley is a lever with equal arms of the first or second class, but, when it moves. the attachments of the forces are moved. The underlying fact that enables the pulley to afford any mechanical advantage is the uniformity of the tension of the cord in all of its parts, the pulley itself serving only to diminish the friction." &mdash; Avery, 1895

Pulley

"The pulley is a lever with equal arms of the first or second class, but, when it moves. the attachments…

"Many wheels may be combined together, and in many ways, to form compound pulleys. Whenever there is but one rope running through the whole, as shown here, the relation of power and resistance is known by the number of folds, or turns, of the rope which supports the weight." — Goodrich, 1844

Compound Pulley

"Many wheels may be combined together, and in many ways, to form compound pulleys. Whenever there is…

"Pulleys designed to allow the weight to be pulled up while the power is applied downwards." -Avery 1895

Pulleys

"Pulleys designed to allow the weight to be pulled up while the power is applied downwards." -Avery…

"A screw is a cylinder with a helical proection winding around its circumference. This helix is called the thread of the screw. The distance that a point of the helix is drawn back or advanced in the direction of the length of the screw during one turn is called the pitch of the screw." &mdash;Hallock 1905

Using a Screw to Raise Weight

"A screw is a cylinder with a helical proection winding around its circumference. This helix is called…

An instrument used to determine the weight of an object.

Scale

An instrument used to determine the weight of an object.

This is a hydraulic weighing scale were the object is placed on a base and later water is filled into the vessel to accurately measure the objects weight.

Weighing Scale

This is a hydraulic weighing scale were the object is placed on a base and later water is filled into…

Scales found at Pompeii

Scales

Scales found at Pompeii

Five students are learning how to use scales to measure a book. They have balanced the book with some weights.

Children Using Scales

Five students are learning how to use scales to measure a book. They have balanced the book with some…

A diagram illlustrating the principal of the screw.

Diagram of a Screw

A diagram illlustrating the principal of the screw.

"A Lever of the Second Kind is one in which the weight is between the power and the fulcrum." &mdash;Quackenbos 1859

Second Class Lever

"A Lever of the Second Kind is one in which the weight is between the power and the fulcrum." —Quackenbos…

In the second order of levers, the weight is between the power and the fulcrum.

Second Order of Lever

In the second order of levers, the weight is between the power and the fulcrum.

"A contrivance extensively employed in Egypt and the East, generally for raising water. It consists of a long stout rod suspended on a frame at about one fifth of its length from the end. The short end is weighted so as to serve as the counterpoise of a lever, and from the long end a bucket is suspended by a rope. The shadoof is extensively used in Egypt for lifting water from the Nile for irrigation" &mdash;Whitney, 1889 <p>This illustration shows two men using a shadoof to raise water. There is a sailboat in the background.

Shadoofs, Two Men Raising Water

"A contrivance extensively employed in Egypt and the East, generally for raising water. It consists…