Machine Philosophy: Demonstration Devices in Georgian Mechanics Author(s): Simon Schaffer Source: Osiris, 2nd Series, Vol. 9, No., Instruments (1994), pp. 157-182 Published by: The University of Chicago Press on behalf of The History of Science Society Stable URL: http://www.jstor.org/stable/302004 Accessed: 12-08-2014 18:15 UTC Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. The University of Chicago Press and The History of Science Society are collaborating with JSTOR to digitize, preserve and extend access to Osiris. http://www.jstor.org This content downloaded from 140.247.28.59 on Tue, 12 Aug 2014 18:15:39 UTC All use subject to JSTOR Terms and Conditions Machine Philosophy: Demonstration Devices in Georgian Mechanics By Simon Schaffer* For the Skrew, Axle and Wheel, Pulleys, the Lever and inclined Plane are known in the Schools. For the Centre is not known but by the application of the members to matter. For I have shown the Vis Inertiae to be false, and such is all nonsense. For the Centre is the hold of the Spirit upon the matter in hand. For FRICTION is inevitable because the Universe is FULL of God's works. -Christopher Smart, "JubilateAgno" (ca. 1760)1 DEMONSTRATION DEVICES, ranging from orreries and astronomical globes to the philosophicaltables with which mechanicalprinciples were taught, pro- vided the stock-in-tradefor makersof natural-philosophicalinstruments in Georgian Britain.These devices were deployedin publiclectures to recruitaudiences by using artifice to display a doctrine about nature. For example, the pulleys and falling weights involved in the instrumentsof Newtonianmechanics were designed inge- niously to minimizefriction and distinguishinertia from gravity.The aim of demon- strationwas to make a specific doctrinalinterpretation of these devices' perfor- mance seem inevitableand authoritative.Such an aim requiredhard work from the demonstrator.But this work needed to be carefullymanaged lest the audience'sat- tentionbe drawntowards the artificeinvolved in the demonstration.So demonstra- tion demandeda means of renderingtacit the gesturesof the demonstratorand thus demandedrigorous training in the use of these devices. Differentmeans of instru- mental instruction,training, and performancewere properto differentsocial set- tings. This article explores the different settings in which demonstrationdevices were used andthe differentforms of authorityinvested in workwith these machines. Whetherconducted in coffee-houses, salons, or universities,lectures were both performancesin frontof audiencesand also collaborativeproductions by interested practitioners.The term demonstrationcaptures this range of uses ratherwell, be- cause in Georgian vocabulary it might refer either to geometrical synthesis-the extractionof a proof fromundeniable axioms-or else to theatricalshowmanship the display of dramaticphenomena. The relationshipbetween mathematicalcer- tainty and public shows was always troublesome. The trouble focused on the * Departmentof History and Philosophy of Science, CambridgeUniversity, Free School Lane, Cambridge,England CB2 3RH. l ChristopherSmart, "Jubilate Agno," fragment B, lines 180-185, SelectedPoems, ed. KarinaWil- liamson and Marcus Walsh (Harmondsworth:Penguin Books, 1990), p. 70. Smart, resident poet in Cambridgefor 1739-1749, composed these verses in St. Luke's lunatic asylum between 1759 and 1763. @1994by The History of Science Society. All rights reserved.0369-7827/94/0008-00010$01.00 OSIRIS1994, 9: 157-182 157 This content downloaded from 140.247.28.59 on Tue, 12 Aug 2014 18:15:39 UTC All use subject to JSTOR Terms and Conditions 158 SIMON SCHAFFER authority and role of the performer. Some natural philosophers, such as Joseph Priestley, well-experienced in teaching chemistry, electricity, mechanics, and optics, contrasted machines for demonstration with those of philosophy. Only the latter could properly be said to transmit the messages of creation. Philosophicalinstruments are an endless fund of knowledge.By philosophicalinstru- ments, however,I do not here mean the globes, the orrery,and others, which are only the means thatingenious men have hit upon to explaintheir own conceptionsof things to others;and which, therefore,like books, have no uses more extensivethan the view of humaningenuity; but such as the air pump,condensing engine, pyrometer ... which exhibitthe operationsof nature,that is of the God of naturehimself.2 Priestley's distinction placed demonstration devices firmly in the context of artifice. He made philosophical instruments, in contrast, the unproblematic transmitters of God's messages. Others, such as the mathematical masters of Cambridge University, reckoned that singular showmanship was illustrative, but insufficient to convey de- monstrative force. They required such force because their university was under pres- sure to reform the means it used to propagate the truths of mathematics and natural theology. The masters designed complex and elegant devices backed up with aca- demic authority to instruct their students in Newtonfs truths. These differences, dem- onstration versus philosophy in Priestley's sense, or the Cambridge distinction be- tween illustration and demonstration, indicate the varying roles that demonstration might play in the formation of different audiences for enlightened natural phi- losophy.3 Demonstration devices were often treated as means by which the esoteric truths of mathematical philosophy might be diffused through innumerate and polite social milieus. In 1718 Willem 'sGravesande, newly appointed professor of astronomy and mathematics at Leiden, told Newton: "I have had some success in giving a taste of your philosophy in this University; as I talk to people who have made very little progress in mathematics I have been obliged to have several machines constructed to convey the force of propositions whose demonstrations they had not understood." In 1720 the London lecturer J. T. Desaguliers translated 'sGravesande's book, pro- fusely illustrated with the Leiden machines. He dedicated his edition to Newton, reiterating the points that instruments would diffuse the light of the Principia to the mathematically ill-informed and that machines "may not always prove, but some- times only illustrate a proposition."4 Illustrations, but potent ones, machines were 2 Joseph Priestley,History and PresentState of Electricity,2 vols., 3rd ed. (London, 1775), Vol. I, p. xi. For the context see Willem Hackmann,"Scientific Instruments: Models of Brass and Aids to Discovery,"in The Uses of Experiment:Studies in the Natural Sciences, ed. David Gooding, Trevor Pinch, and Simon Schaffer (Cambridge:Cambridge Univ. Press, 1989), pp. 31-65, on pp. 42-43. 3 For a similar debate about "demonstration"between Thomas Beddoes and Lavoisier in 1792 see Jan Golinski, Science as Public Culture:Chemistry and Enlightenmentin Britain, 1760-1820 (Cambridge:Cambridge Univ. Press, 1992), pp. 153-155. For the pedagogic context of the laterterm scientific instrumentsee DeborahJean Warner,"What Is a Scientific Instrument,When Did It Be- come One, and Why?"British Journalfor the History of Science, 1990, 23:83-93, on p. 86. 4 Willem 'sGravesandeto Isaac Newton, 13/24 June 1718, in A. R. Hall, "FurtherNewton Corre- spondence,"Notes and Records of the Royal Society, 1982, 37:7-34, p. 26. For the Leiden cabinet see C. A. Crommelin,Descriptive Catalogueof the Physical Instrumentsof the EighteenthCentury (Leiden: Rijksmuseumvoor de Geschiednis der Naturwetenschappen,1951), pp. 24-41. For Desa- guliers's translationsee I. B. Cohen, Franklinand Newton (Cambridge,Mass.: HarvardUniversity Press, 1956), p. 236. This content downloaded from 140.247.28.59 on Tue, 12 Aug 2014 18:15:39 UTC All use subject to JSTOR Terms and Conditions DEMONSTRATIONDEVICES IN GEORGIANMECHANICS 159 used to insinuatethe very high philosophicalstatus of public showmanship.They were also used to establish the authorityof consulting engineers by representing their mastery over nature'spowers. Desaguliers, the leading engineer of early eighteenth-centuryLondon, explained that "a greatmany Persons get a considerable Knowledge of NaturalPhilosophy by Way of Amusement;and some are so well pleas'd with what they learn that Way,as to be induc'd to study Mathematicks,by which they at last become eminentPhilosophers." Desaguliers reckoned that philo- sophicaleminence acquiredthrough the study of demonstrationdevices would also promote commercialwelfare and gentlemanlypatronage for reliable engineering schemes.5The statusproblems of mathematics,philosophy, showmanship, and engi- neeringwere fundamentallyconcerned with the relationsof natureand art.Demon- strationdevices were designed to teach truthsabout nature, and the gestureswhich accompaniedthem were supposed to be invisible. In 1713 the journalistRichard Steele puffedthe newfangledorrery as "aMachine which illustrates,I may say dem- onstrates, a System of Astronomy to the meanest Capacity.... It is like the receiving a new Sense, to Admit into one's Imaginationall that this Inventionpresents to it with so much Quicknessand