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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.

A piece in clocks and watches that converts rotational motion into oscillation, as in a pendulum.

Deadbeat Escapement

A piece in clocks and watches that converts rotational motion into oscillation, as in a pendulum.

A piece in clocks and watches that converts rotational motion into oscillation, as in a pendulum.

Recoiling Escapement

A piece in clocks and watches that converts rotational motion into oscillation, as in a pendulum.

A gravity escapement uses a small weight or a weak spring to give an impulse directly to the pendulum. The earliest form consisted of two arms which were pivoted very close to the suspension spring of the pendulum with one arm on each side of the pendulum. Each arm carried a small dead beat pallet with an angled plane leading to it. When the pendulum lifted one arm far enough its pallet would release the escape wheel. Almost immediately another tooth on the escape wheel would start to slide up the angle face on the other arm thereby lifting the arm. It would reach the pallet and stop. The other arm meanwhile was still in contact with pendulum and coming down again to a point lower than it had started from. This lowering of the arm provides the impulse to the pendulum. The design was developed steadily from the middle of the 18th century to the middle of the 19th century. It eventually became the escapement of choice for turret clocks.

Bloxam's Gravity Escapement

A gravity escapement uses a small weight or a weak spring to give an impulse directly to the pendulum.…

A gravity escapement uses a small weight or a weak spring to give an impulse directly to the pendulum. The earliest form consisted of two arms which were pivoted very close to the suspension spring of the pendulum with one arm on each side of the pendulum. Each arm carried a small dead beat pallet with an angled plane leading to it. When the pendulum lifted one arm far enough its pallet would release the escape wheel. Almost immediately another tooth on the escape wheel would start to slide up the angle face on the other arm thereby lifting the arm. It would reach the pallet and stop. The other arm meanwhile was still in contact with pendulum and coming down again to a point lower than it had started from. This lowering of the arm provides the impulse to the pendulum. The design was developed steadily from the middle of the 18th century to the middle of the 19th century. It eventually became the escapement of choice for turret clocks.

Mudge's Gravity Escapement

A gravity escapement uses a small weight or a weak spring to give an impulse directly to the pendulum.…

"The electrometer of Henley, sometimes called Henley's quadrant Henley electrometer, may be taken as the type of single pendulum electroscopes. It consists essentially of a pendulum A hinged to meter a verticle support C, which carries a vertical graduated semicircle B, by means of which the deviation of A from the vertical can be indicating the state of electrification of the prime conductors of electric machines. The stem is screwed into the conductor, and the divergence of the pendulum indicated roughly the charge." — Encyclopedia Britannica, 1893

Henleys Electrometer

"The electrometer of Henley, sometimes called Henley's quadrant Henley electrometer, may be taken as…

A Memograph is a clock that is designed to make a loud sound at a specific time. The primary use of these clocks is to awaken people from their sleep in order to start their days in the mornings, but can also be used for short naps; they are sometimes used for other reminders as well.

Memograph Clock

A Memograph is a clock that is designed to make a loud sound at a specific time. The primary use of…

"A pendulum has a strong tendency to maintain its plane of oscillation, a fact that has been used in the experimental demonstration of the earth upon its axis. The chief function of the wheel-work of a clock is to register the number of vibrations of the pendulum. If the clock gains time, the pendulum is lengthened by lowering the bob, if it loses time, the pendulum is shortened by raising the bob." — Avery, 1895

Pendulum

"A pendulum has a strong tendency to maintain its plane of oscillation, a fact that has been used in…

"A pendulum consists of a heavy ball suspended in such a way as to swing to and fro." —Quackenbos 1859

Pendulum

"A pendulum consists of a heavy ball suspended in such a way as to swing to and fro." —Quackenbos…

"From a cross piece, A, on a stout framework, a heavy block of wood, B, is suspended, in such a way as to move freely backward and forward. A ball fired into this block will drive it back to a distance proportioned to the ball's velocity. All other things being known, the ball's velocity can be discovered." —Quackenbos 1859

Ballistic Pendulum

"From a cross piece, A, on a stout framework, a heavy block of wood, B, is suspended, in such a way…

"When the pendulum is drawn from its vertical position, the force of gravity, MG, is resolved into two components, one of which, MC, produces pressure at the point of support, while the other, MH, acts at right angles to it, producing motion toward N." -Avery 1895

Motion of a Pendulum

"When the pendulum is drawn from its vertical position, the force of gravity, MG, is resolved into two…

"When the pendulum hands at rest in a vertical position, as Pa, it has no energy at all. Considered as a mass of matter seperate from the earth; it certainly has potential energy; but considered as a pendulum, it has not." — Avery, 1895

Path of a pendulum

"When the pendulum hands at rest in a vertical position, as Pa, it has no energy at all. Considered…

"Firmly fasten one end of a piece of spring-brass wire, about No. 27 and about 1 m. long so that the wire hangs vertical. To the lower end of the wire fasten a weight of 75 or 100 g. To this weight attach a pointer so that it extends horizontally from the direction of the wire. Turn the weight througha considerable angle, thus twisting the wire. Release the weight, and notice the rapid movements of the pointer of the torsional pendulum." -Avery 1895

Torsional Pendulum

"Firmly fasten one end of a piece of spring-brass wire, about No. 27 and about 1 m. long so that the…

"An apparatus devised by Mach for the illustration of the pendular motions of the particles of a medium transmitting waves of any kind, longitudinal or transverse, stationary or progressive." — Avery, 1895

Line of pendulums

"An apparatus devised by Mach for the illustration of the pendular motions of the particles of a medium…

"The front view of a large quarter clock of Sir E. Beckett's design, with all the wheels on the great horizontal bed, a gravity escapemen, and a compensated pendulum. They are made in two sizes, one wih a great striking wheels 18 inches wide, and the other 14. The striking is done by cams cast on the great wheels, about 1.125 inch broad in the large-sized clocks, which are strong enough for an hour bell of thirty cwt., and corresponding quarters. Wire ropes are used, not only because they last longer, if kept greased, but because a sufficient number of coils will go on a barrel of less than half the length that would be required for hemp ropes of the same strength, without overlapping, which it is as well to avoid, if possible, though it is not so injurious to wire ropes as it is to hemp ones. by this means also the striking cams can be put on the great wheel, instead of the second wheel, which saves more in friction than could be imagined by any one who had not tried both. In clocks of the common construction two-thirds of the power is often wasted in friction and in the bad arrangement of the hammer work, and the clock is wearing itself out in doing nothing." — Encyclopedia Britanica, 1893

Quarter Clock

"The front view of a large quarter clock of Sir E. Beckett's design, with all the wheels on the great…

"The sine electrometer of August, is a modification of the single pendulum electroscope, analogous in principle to Pouillet's sine compass. A is a pendulum suspended by two threads to secure motion in one plane; B is a ball fixd to the case, and connected with a suitable electrode." — Encyclopedia Britannica, 1893

Sine Electrometer

"The sine electrometer of August, is a modification of the single pendulum electroscope, analogous in…

A hand with bar demonstrating the attractive properties of static electricity.

Demonstration of Static Electricity

A hand with bar demonstrating the attractive properties of static electricity.

An illustration of a price computing weighing machine using an even even balance and pendulum.

Price Computing Weighing Machine

An illustration of a price computing weighing machine using an even even balance and pendulum.