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The physics collection in the Yale Peabody Museum’s Division of Historical Scientific Instruments contains an unusually complete range of research and demonstration apparatus. Optical, mechanical, pneumatical and electrical devices are especially represented. For example:


The Yale Peabody Museum’s collections are available to legitimate researchers for scholarly use. Loans are issued to responsible individuals at established institutions. Loans and access to the collection can be arranged through the Collections Manager.

Atwood's Machine


An Atwood’s machine with magnetic drop mechanism and pendulum timer. Inscribed on clock: “Presented to Yale College by Mt. Richard S. Fellows.” “Secretan sucr. de Lerebours, Paris.” YPM catalog no. 1.370


The Atwood’s Machine, designed in 1770 by the Cambridge mathematician George Atwood, was used to study motion and acceleration. Sir Issac Newton, over 50 years earlier, had established his three laws of motion, but Atwood complained that in “books of mechanics no account is found of methods by which the principles of motion may be subjected to decisive and satisfactory trials.” Designed to control the effects of imposing factors such as wheel friction, Atwood’s machine could demonstrate Newton’s theories by modifying and measuring velocity, accelerating force and distance.

The machine has 2 equal weights A and B, suspended by a thread over a wheel. Weight C, released by a pendulum clock at a precise minute, provides the impetus for B to fall. To measure the velocity of B against A, a brass ring captures weight C once weight B has reached a desired velocity. The ring allows B to fall through unhindered. One-inch increments on the shaft measure distance. The release mechanism, the brass ring and the mechanism to stop the falling weight are all adjustable.

This Atwood’s machine was donated to Yale by Richard S Fellows. Unfortunately, neither the instrument nor the donation plaque is dated. But, the printed inscription on the clock face (see above) clearly indicates that this particular machine was made in France by Lerebours et Secretan. It is listed for 1,000 francs in their 1853 Catalogue et Prix des Instruments D’optique, de Physique, de Chime, de Mathematiques, d’Astronomie et de Marine.

Elias Loomis, Professor of Natural Philosophy and Astronomy at Yale College, describes the mechanisms of this machine in his Elements of Natural Philosophy (1860) and uses the same picture as featured in the Lerebours et Secretan Catalogue. Professor Derek J. de Solla Price, in his description of the machine, records the weight drop release mechanism to be “magnetic,” which is consistent with other descriptions of 19th century Atwood machines. Loomis, in contrast, describes the release of the weight as initiated by a lever that is displaced by a “wheel” with a “protruding shoulder.” The 1853 Catalogue does not mention the magnetic release mechanism. Future investigations into the origins of the machine and its mechanisms could resolve the inconsistencies in the record and perhaps provide a date of manufacture.

Bud, R., ed., Instruments of Science: An Historic Encyclopedia, 1998, pp.36–38.

Lerebours et Secretan, Catalogue et Prix des Instruments D’optique, de Physique, de Chime, de Mathematiques, d’Astronomie et de Marine, 1853, p. 141.

Loomis, E., Elements of Natural Philosophy Designed for Academies and High Schools, 1860, pp. 25–26.

Price Catalogue # 637, Atwood’s machine with magnetic drop mechanism, pendulum timer. Wooden supporting pole and base brass pulley, mechanism, and fittings.

Incandescent Bulbs


YPM catalog no. 1.141.
See also YPM 5.924, 1.80, 1.217.



Galvanometer (?) tangent.
YPM catalog no. 5.336.
See also YPM 5.17, 5.406,
5.620, 5.626, 5.964

Electrostatic Generators


YPM catalog no. 5.22.
See also YPM 1.50, 5.49



YPM catalog no. 29.4.


This calorimotor, used by Benjamin Silliman around 1820, is an early example of an electric battery. The voltaic pile, discovered in 1800, gave to the world for the first time a continuous source of electrical potential. Silliman had become interested in such electric batteries when in London in 1805 and he experimented with them in his chemistry laboratory when he returned to New Haven in 1806. Robert Hare of Philadelphia modified the pile as Volta had arranged it, and developed a zinc–copper plunge battery that he called a “calorimotor.”

The calorimotor produces a current when 2 cells of 10 zinc and 10 copper plates are dipped into a solution of sulphuric acid containing sodium chloride. Although there was no depolarizer, the very low internal resistance of the cell and its large plate area made it capable of delivering a current of high intensity that could quickly fuse a short piece of thick wire to produce a spectacular effect during demonstrations.

In a letter to Hare, Silliman observes,
…by the time the calorimotor is completely immersed in the acid solution, the wire in the forceps is rendered white hot, and takes fire, emitting the most brilliant sparks. In the interim, an explosion usually gives notice of the extrication of hydrogen in a quantity adequate to reach the burning wire. Immediately after the explosion, the hydrogen us reproduced with less intermixture of air, and rekindles, coruscating from among the forty interstices, and passing form one side of the machine to the other in opposite directions, and at various times so that the combinations are innumerable. The flame assumes various hues, from the solution of more of less of the metals and a blazing froth rolls over the side of the recipient. When the calorimotor is withdrawn from the acid solution, the surface appears for many seconds like a sheet of flaming foam.
—From The Sheffield Scientific School 1847–1947, “A Catalogue of Surviving Early Scientific Instruments of Yale College.



Top: Voltmeter by LaRoche Electric Works.
Bottom: Electrostatic voltmeters.
YPM catalog nos. 5.307, 5.356, 5.357.
See also YPM 5.1170.

Electromagnetic Motors


Electromagnetic engine.
YPM catalog no. 5.92.
See also YPM 1.377, 1.61, 1.9.

Engines and Motors


Diesel fuel injection carburator.
YPM catalog no. 3.52.
See also YPM 5.1006, 5.360.


Cutaway model of the fuel injection carburator used in the diesel engine. Donated by Cummings Engine Co., Columbus, Indiana.

Gear and Motion Demonstration Apparatus

Model of a 3-rod assembly.
YPM catalog no. 3.14.
See also YPM 3.29, 3.30, 3.31,
3.32, 3.38, 3.40, 3.50, 3.51.



YPM catalog nos. 5.1178 and 5.5..
See also YPM 5.1061, 5.381.



Edison phonographs.
YPM catalog nos. 19.3, 1.70.

Crooke's Tubes


Crooke’s radiometer.
YPM catalog no. 5.319.
See also YPM 5.380, 5.188.



Fresnel lenses (YPM 5.996),
burning lens (YPM 1.132) and
lens on a stand (YPM 5.150).

Radio Tubes


YPM catalog nos. 5.1276,
5.1264, 5.1273, RCA boxes.

See also YPM 5.1258, 5.1260–5.1262,
5.1265–5.1266, 5.1270–5.1272, 5.1279.