MEN OF TRIBOLOGY1

by DUNCAN DOWSON2 2 GUILLAUME AMONTONS (1663-1705)

3 JOHN THEOPHILUS DESAGULIERS (1683-1744) 2

GUILLAUME AMONTONS Downloaded from http://asmedigitalcollection.asme.org/tribology/article-pdf/100/1/2/5659654/2_1.pdf by guest on 30 September 2021 (1663-1705)

"Now, having sufficiently established what friction is, its nature and its laws, it only remains to say something about the rules by which it may be reduced to calculation in order to know how much friction there is in the most complicated machines."

(Memoires de l'Academie Royale, 1699)

Biography classical contribution to tribology yielded the two laws of friction now Amontons was born in Paris on August 31st 1663 and he died on known as Amontons' laws. It is important to appreciate that at the October 11th 1705. His opportunity to pursue a career in a conven­ end of the seventeenth century there was a totally inadequate un­ tional profession was curtailed by deafness during adolescence. As derstanding of friction. Indeed, many students of mechanics chose a result of this disability Amontons devoted himself to his studies and, to ignore friction altogether in their analyses, and Amontons like many others before and since his time, he indulged in vain at­ wrote; tempts to develop a perpetual motion machine. This frustration "among all those who have written on the subject of clearly influenced the direction of his early studies, for he decided to moving forces, there is probably not a single one who has given read mathematics and works on the physical sciences. It might also sufficient attention to the effect of friction in machines" have been an important ingredient in his resolve to study in later years The apparatus used by Amontons in his "Experiment con­ the question of losses caused by friction in machines. cerning the rubbing of various materials one against the other" .... Amontons' father was a lawyer who moved from Normandy to Paris was exceedingly simple. The test specimens were loaded together by before Guillaume was born. It is known that the family opposed springs, whilst the force required to initiate sliding was measured by Guillaume's idea of studying the physical sciences, but it appears that means of another spring attached to the slider. The materials tested his resolve won the day. After studying drawing, surveying, and ar­ were of copper, iron, lead and wood in various combinations. In each chitecture he obtained experience of the practical side of applied experiment the surfaces were coated with fat and although the laws mechanics by working on various public works projects. At a later enunciated by Amontons are invariably described as the laws of dry stage he studied celestial mechanics and also applied himself to the friction, it is clear from the seventeenth century manuscript that the improvement of hygrometers, barometers, and thermometers. experiments were conducted under conditions which would now be Thermometry was to be one of Amontons' major areas of scientific described as boundary lubrication. investigation, but he also developed an optical telegraph system and Amontons' major findings were that the resistance caused by rub­ championed the case for the clepsydra as a timing apparatus to im­ bing depended directly on the normal load, but was independent of prove navigation at sea. the apparent area of contact. He also found that the resistance was Apart from some extracts from letters in the Journal des Savants more or less the same for all the materials considered and equal to one for March 8th and May 10th 1688, Amontons published some thirteen third of the normal load. The latter conclusion was similar to the view papers in the Memoires de l'Academie des Sciences in the six years held by Leonardo da Vinci, but Leonardo preferred a ratio of one following 1699. His first substantial published work was a book on the quarter. clepsydra published in Paris in 1695. His work on friction, published There was more to Amontons' work than the measurement of in the middle of the period 1695-1703 when he was much concerned friction, for he went on to ... . "consider carefully the nature of with thermometry, represented his sole yet distinctive contribution friction." He attributed friction to the force required to lift inter­ to tribiology. locking asperities over each other in sliding motion and thus estab­ lished the mechanistic view of the process. An interesting sequel to Friction this implication of the role of surface roughness in the friction process The first known detailed study of the question of losses attributable was that Amontons recognized that the argument was valid for both to friction was presented by Amontons on December 19th 1699. This rigid and elastic asperities. The conceptual features of his view of the friction process, established long before studies of engineering surfaces became available, is one of the most interesting features of his work. 1 Based upon a series of biographical sketches of "Men of Tribology" from a It seems clear that mechanical problems of the day prompted forthcoming book The History of Tribology to be published early in 1978 by Amontons' work on friction, since he concluded his extensive paper Longman Group Limited, Longman House, Burnt Mill, Harlow, Essex, England. with some practical guidance on the calculation of losses of effective American enquiries to Longman Inc., 19 West 44th Street, New York, N.Y. motive force attributable to friction in machines. He considered not 2 Professor of Engineering Fluid Mechanics and Tribology, Institute of Tribology, Department of Mechanical Engineering, The University of Leeds, only wheel bearings, but also the tightness of ropes or cords wrapped England. round shafts and pulleys.

2 / VOL 100, JANUARY 1978 Copyright © 1978 by ASME Transactions of the ASME Summary I have been unable to trace a portrait for reproduction in this article. I am, however, grateful to Professor Robert Courtel, Director de Re­ Guillaume Amontons lived for a mere forty-two years, yet his early cherche au C.N.R.S., Laboratoire de Mecanique des Surfaces and and major contribution to studies of friction ensures him of an ho­ Professor Maurice Godet, Institut National Des Sciences Appliquees noured position in any history of tribology. He provided simple laws de Lyon, Laboratoire de Mecanique des Contacts for their efforts and (If great utility for many generations of engineers, demonstrated how advice in this quest. It appears that we must remain ignorant of the to account for friction in determining the behaviour ofmachines and appearance of the man whose name is invariably linked with the laws established the mechanistic concept of the friction process. of friction. [t. is a rewarding experience to return to Amontons' original paper on friction. Some of his concepts have yielded to further under­ Bibliography slanding of the complex nature of surface interactions in the process, Amontons, G. (1699), "De La Resistance Calls'ee Dans Les Machines," Mem· oires De L'Acadelllie Royale Des Sciences, A Amsterdam, Chez Gerard Kuyper, ~'et the basic feat.ures of his findings have retained credance for nearly 1706, pp. 257-282. three hundred years. Magee, W. A. (1963), A Source Booll of Physics, Harvard University Press.

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JOHN THEOPHILUS DESAGULIERS Downloaded from http://asmedigitalcollection.asme.org/tribology/article-pdf/100/1/2/5659654/2_1.pdf by guest on 30 September 2021

(1683-1744)

"As it is easier to raise most bodies from the ground than to breall them in pieces; that force by which the parts cohere, is stronger than its gravity" (Philosophical Transactions of the Royal Society of London, 1725, Vol. 33, p. 345)

From a portrait In Nlchols's Literary Anecdotes 01 the 18th. Century, 1815, Vol. 9, pp. 640-641

Journal of Lubrication Technology JANUARY 1978, VOL 100 / 3 Biography "As it is easier to raise most bodies from the ground than to The natural philosopher John Theophilus Desaguliers was born break them in pieces; that force by which the parts cohere, is on March 13th 1683 at La Rochelle. His father was pastor of a prot- stronger than its gravity. That force, whatever be its cause, we estant congregation at Aitre who fled to England with his son John shall call the Attraction of Cohesion. This attraction is stron­ after the Bldict of Nantes in 1685. It has been said that John was gest, when the parts of the bodies touch one another; but de­ concealed in a barrel while fleeing on board the refugee ship. After creases much faster than gravity, when the parts that were a short stay in Guernsey, Desaguliers' father moved to London where before in contact, cease to touch; and when they come to be at he established a school at Islington and also became minister of the any sensible distance, this attraction of cohesion becomes al­ French chapel in Swallow Street. most insensible." Desaguliers entered Oxford shortly after the death of his father. He matriculated at Christ Church and took the degree of B.A. in 1710. Friction He was appointed Lecturer on Experimental Philosophy in Hart Hill In his second lecture, Desaguliers emphasised the need to consider in the same year and proceeded to the degree of M.A. in 1712. The the effect of friction upon machine performance in a passage which following year he moved to London where he took up residence in amply illustrated his concern to apply scientific principles to engi­ Channel-Row, Westminster. From this address Desaguliers continued neering systems. to present lectures and he is said to have been the first person to de­ "we are to have regard to the Imperfections of Engines Downloaded from http://asmedigitalcollection.asme.org/tribology/article-pdf/100/1/2/5659654/2_1.pdf by guest on 30 September 2021 liver lectures on learned subjects to the general public. A notice at the and Materials, and the quantity of Stickage or Friction; end of Volume I of his work on A Course of Experimental Philosophy which differ according to the number of combination of Parts (1734) gives details of the arrangement. and Nature of the materials, of which the several engines con­ "The Course of Experimental Philosophy, of which the first sist: And having made use of the best Methods we can to dis­ volume contains half, is performed by the Author at his house cover the Imperfections above mentioned in each particular Channel-Row, Westminster (where Catalogues of the Experi­ machine; we are to take care to allow enough to be deducted ments may be had) on such Days, and at such Hourse, as shall from the Calculation made concerning an Engine suppos'd be agreed upon by the Majority of the Auditors. N.B. Every Mathematically true." Auditor is to pay Three Guineas, when the number is not less It was in his fourth lecture that Desaguliers turned his attention than twelve Persons; but any Three or Four, nay any Person, to.... Several Methods of Finding the Quantity of Friction in En­ may have a Course to themselves paying the Price of Twelve. gines. He quoted Amontons' findings, but also undertook experiments "A Short but full Course of Astronomy, will also be performed of his own to measure friction with a sledge and pulley arrangement by means of the PLANETARIUM, to any Number of Persons, which anticipated in many ways the form of apparatus used by not less than Ten, at a Guinea each; or to any less Number, Charles Augustin Coulomb in 1781. Sledges made of wood, iron, and who are willing to pay 10 Guineas, upon giving a Days No­ wood shod with iron, lead, and possibly brass and copper were caused tice." to slide upon wooden boards or metal plates in the presence of water, grease or oil, or simply under dry conditions. A strong silk thread It appears that Desaguliers was the inventor of the Planetarium passed over a pulley fitted with fine pivots to a silken purse which and his skill as an experimentor and lecturer was recognized by his could receive a number of small lead balls to initiate and maintain election as a Fellow of the Royal Society and the subsequent invitation motion. to become demonstrator and curator of the Society. He was concerned with studies of light, colours, the barometer and, of course, mechanics. Desaguliers clearly agreed with the current view that surface He lost no opportunity to emphasise that observations by our senses roughness was responsible for the major part of the force of friction, could be explained in terms of the laws of physics without recourse but he also introduced his understanding of cohesion and noted that to the occult. He was apparently held in high esteem by the current when the sliding surfaces were highly polished the force of friction President of the Royal Society, Sir Isaac Newton. might actually rise, since; Desaguliers completed the degrees of bachelor and doctor of laws "the attraction of Cohesion becomes sensible when we at Oxford in 1718 and in 1742 he was awarded the Copley gold medal bring the Surfaces of Bodies nearer and nearer to Contact." of the Royal Society in recognition of his successful experiments. His religious teaching continued throughout this time. He became chaplin Lubrication to the Duke of Chandos in 1714, having taken deacon's orders in 1710. The measurements of friction for various solids in the presence of He lectured before King George I at Hampton Court in 1717 and was water, grease or oil, provided interesting yet apparently contradictory later appointed chaplin to Frederick, Prince of Wales. results. Desaguliers found that the presence of a lubricant generally The rebuilding of Westminster Bridge, about which Desaguliers increased friction, but he cautioned against the hasty conclusion that was consulted frequently by Parliament, led to the demolition of lubricants should not be used in engines "because we know them Channel-Row and his own home. He then moved to lodgings in the to be of use in great machines." He noted that water usually produced Bedford Coffee-house overlooking Covent Garden, where he contin­ a higher resistance than grease and oil and that even in small machines ued his lectures with great success. He also erected a Ventilator, at like pocketwatches, where oil caused slower running, it produced a the request of Parliament, in a room over the House of Commons. more uniform motion and better timekeeping. Desaguliers considered friction and recognized for the first time These studies, dominated by the prevailing view that the force of that cohesion, or adhesion, might play an important role under some friction resulted from surface imperfections, induced Desaguliers to circumstances. believe that the role of a lubricant was to fill up the holes or surface imperfections in the sliding pairs and to facilitate movement by acting The Concept of Cohesion as rollers. The main exposition of Desaguliers' views on friction is contained within his remarkable book A Course of Experimental Philosophy, Summary but he had previously presented an account of his studies of the Desaguliers' name merits recognition in the history of tribology cohesion of lead to the Royal Society in 1724. He took two lead primarily because he recognized the possible role of cohesion or ad­ spheres, cut small segments off each, pressed them together with a hesion in the friction process. His ideas were not fully developed, but little twist and then measured the finite and by no means insignificant an important ingredient had entered the unfolding story of tribolo- force required to separate them. In the first of his lectures, Desaguliers gical research. He planted the seed of an idea which was to take two emphasised the nature and magnitude of cohesive forces in a simple centuries to germinate. yet persuasive manner. An impressive feature of Desaguliers' studies of friction, which was

4 / VOL 100, JANUARY 1978 Transactions of the ASME totally in keeping with the contributions of other physical scientists Bibliography of the day, was his concern to relate his work to an understanding of the functioning of machines. Desaguliers, J. T. (1734), A Course of Experimental Philosophy, 2 Desaguliers was said to have an unattractive personal appearance, Vols. to be short and thickset and of irregular features; some, but not all, Nichols, J. (1815), Literary Anecdotes of the Eighteenth Century, of these characteristics being evident in the portrait from Nichols's Volume IX, London. Literary Anecdotes reproduced in this article. Stephen, L. (Editor) (1888), Dictionary of National Biography, Vol. At the time of his death, Desaguliers was apparently suffering from 14, London. poverty. He died just short of his sixty-first birthday on February 29th Bowden, F. P., and Tabor, D. (1964), The Friction and Lubrication 1744 and was buried in the Savoy on March 6th. of Solids, Part II, Oxford University Press, London. Downloaded from http://asmedigitalcollection.asme.org/tribology/article-pdf/100/1/2/5659654/2_1.pdf by guest on 30 September 2021

Journal of Lubrication Technology JANUARY 1978, VOL 100 / 5