Perpetual Motion: Technology, Slavery, and History

Once we stop thinking of the past as a failed but noble attempt at the present, many of its inexplicable, repulsive, or ridiculous aspects take on a new colour. A good example is alchemical transmutation, an evident impossibility that nevertheless occupied — and not just occupied, but motivated — the likes of Newton or Boyle, men celebrated for creating the science we now measure alchemy against. On the other hand, many familiar ideas turn out to have had hidden dimensions, unsuspected resonances, or tacit limitations that make them unrecognizable to us — and that threaten, if seriously considered, to make us (or “our” histories) unrecognizable to ourselves. Universal principles turn out to have been particular in meaning and peculiar in application. Trying to see the logic of the now illogical and the strangeness of the now familiar can challenge us to grasp, and to write, a new history. Or it can provoke us to cling more tightly to the old, and to fight over its labels: Enlightenment, Scientific Revolution, Western Civilization.

Consider the case of perpetual motion. This is now the stuff of magic, fantasy, or scientific hoax. But in the seventeenth century it was, as Vera Keller has recently shown, a philosophical desideratum of great interest to those at the forefront of experimental science and technological innovation.[1] So it should not surprise us that in the thousands of pages of manuscripts that comprise the Hartlib Papers are, buried amid the myriad natural-historical and alchemical queries, astronomical and astrological observations, agricultural improvements, educational reforms, and mechanical inventions that occupied members of Samuel Hartlib’s scientific correspondence network in the 1630s, ’40s and ’50s, more than a couple of proposals for a perpetual motion machine.[2]

Hartlib, German-born, lived in London, and his “Circle” included such future Fellows of the Royal Society as Robert Boyle and my own sometime muse William Petty. As an “intelligencer”, the hub of a correspondence network, Hartlib connected his friends in England both to each other and to leading Protestant lights across Europe and (more tentatively) the Atlantic. He also connected people now in science’s pantheon with those they left in the dust of obscurity: craftsmen, mechanics, agriculturalists, mystics, utopians — and “projectors”, hawkers of plans for a better future, for themselves, for their country, for their religion, and (as they were not shy to suggest) for humankind. In the 1640s and 1650s, as the Thirty Years’ War drew to a close and the English Civil Wars gave way to a decade of constitutional experimentation, the time was ripe for scheming.[3]

There was probably no “typical” member of the Hartlib Circle, but a reasonable proxy might be Cressy Dymock. Like many mid-level projectors, Dymock is a shadowy figure; even his exact birth and death dates, to say nothing of richer biographical details, are unknown. He was evidently educated. He may have been from Lincolnshire or Nottinghamshire.[4] He was certainly enthusiastic about new agricultural techniques, and had land on which to try them out. And he was a believer in the “reformation” of knowledge and society that Hartlib and many of his associates sought in promoting and disseminating new science. His remains are the projects he shared with Hartlib: schemes for enclosing and dividing farmland, breeding rabbits, and planting fruit trees; a seed drill (or “engine for setting Corne”); and a “perpetuall motion engine”.

He announced his machine to Hartlib in a letter of late 1648, describing it as useful for small-scale operations such as “turning of grind stones[,] winnowing of Corne, churning of butter, or the like”, as well as for much larger tasks including “drayning of waters,” — the drainage of the fens was then a major concern, expected to increase the arable land available for more productive farming — “Iron mills, Corne mils, sugar mils, oyle mils & alsoe for the mooving of carriages of all sorts either about home, or the high wayes”.[5] It was, in short, an all-purpose labor-saving device, applicable to virtually any purpose and at virtually any scale imaginable. Indeed, a printed pamphlet for the thing, An Invention of Engines of Motion lately Brought to Perfection (London, 1650) expanded Dymock’s list of uses — and perhaps widened the net for investors — still further:

  • To grind Malt or hard Corne.
  • To grind Seed for the making of Oyle.
  • To grind Colours for Potters, Painters or Glasse-houses.
  • To grind Bark for Tanners.
  • To grind Woods for Dyers.
  • To grind Spices or Snuffe-Tobacco.
  • To grind Brick, Tile, Stones, or Earth for plaster.
  • To grind Sugar-Canes.
  • To draw up Coales, Stones, Ure or the like, or Materialls for great and high buildings.
  • To draw Wire.
  • To draw water from Mines.
  • To draw water from Meers or Fens.
  • To draw water to serve Cities, Townes, Castles, &c.
  • To draw up water to flood dry grounds, or to water grounds.
  • To draw or hale ships, boats, &c. up Rivers against the stream.
  • To draw Carts, Wagons, &c. as fast without Cattel.
  • To draw the Plough without Cattel to the same dispatch if need be.
  • To brake Hemp, Flax, &c.
  • To beat Hemp, Flax, &c.
  • To weigh Anchors with less trouble and sooner.
  • To spin Cordage, or Cables.
  • To bolt meale faster and finer.
  • To saw stone.
  • To saw Timber.
  • To pollish any stones, or Mettalls.
  • To turne any great works in wood, Stone, Mettalls, &c. that could hardly be done before.
  • To file much cheaper in all great works.
  • To bore Wood, Stone, Mettalls.
  • To thrash Corne if need be.
  • To winnow Corne at all times, better, cheaper, &c.
  • For Paper-Mills, Thread-Mills, Iron-Mills, Plate-Mills, Cum multis aliis, &c.[6]

The list may seem preposterous — the whole idea may seem preposterous — but it calls to mind a world in which animal labor was essential and human effort everywhere, assisted sometimes by wind and water; a world in which the food supply was uncertain, anchors were heavy, and water had to be fetched. In proposing to solve such problems, Dymock pursued an idea we now know impossible; but in its orientation to the practical challenges of essential, everyday work it was nothing if not realistic. Perpetual motion didn’t promise to put men on the moon. It promised easier ploughing.

Yet Dymock’s pamphlet is also a reminder of the different and better future that new technology seemed to hold out, a vision familiar today. True, Dymock trimmed his enthusiasm with providential effusions, describing himself as “impregnate” by “divine blessing” and brought to bed of “a living male childe” — his machine — “cal’d the Marriage of Strength and tyme”.[7] But the perpetual motion’s impact lay in the production of food. As Dymock’s work progressed, the elimination of labor gave way to the reduction of it, in particular to replacing draught animals with fewer, cheaper human complements: “Usually”, he noted, “men have in their teemes to plough 4 -5- or -6 horses & 6 or 8 oxen… with which they plough about one acre a day[.]” But “I hope without any horse with 6 men onely or lesse to plough with two ploughs att once… two acres a day of the same or the lyke ground[.]”[8] By replacing animal with human labor, the engine would free land used for fodder for more wheat; it would also, Dymock thought, employ more people on the land — preventing rural depopulation while easing the pressure of numbers on resources, feeding the poor while setting them to work.

Through the rational application of new technology, a happy future beckoned. The physical impossibility of a real “perpetual motion” notwithstanding — and Dymock’s own shift of emphasis to the reduction of labour makes this detail easy to massage away — there is a readymade story here about the benefits of scientific approaches to nature. Indeed, Dymock himself described the challenge of winning over reluctant farmers attached to “old customes” to the side of “reason” and “reall experience”.[9] Not unlike present-day tech billionaires, or self-appointed defenders of the Scientific Revolution and the Enlightenment, Dymock and his fellow Hartlibians were prone to appropriate “reason” and “experience” to their side, and prone too to insist that their interests were — and, once victorious, would be seen to be — identical with those of the nation, true religion, and the human race. Now, of course, we are more likely to call “true religion” by the name of “progress”. But the narrative is familiar.

But wait, Dymock might have said, there’s more.

Perpetual motion had, as we have seen, nearly infinite uses in England. As Dymock noted in an undated “Memorandum about Engines“, however, it had still further uses farther afield:

If my engine bee made use of in the Barbados for the grinding of sugar there will nessesarily follow (besids all private benifitts) this publique advantage that whereas they are now forced to lett many acres ly for fother [i.e., fodder] for those draught cattle winter & somer the proffitt thence arrising beeing farre short of what the same land would yeild if planted with sugar canes, cotton, Indico, or the lyke, by this meanes all that land may bee converted to those more beneficiall uses, to the great increase & trade of those more staple comodityes.[10]

In Barbados, just as in England, the engine would replace animal with human labour, liberating lands now used to feed animals for other purposes. In the colony, however, these purposes were the increased production of cash crops — especially sugar, cultivated on a large scale in Barbados since the 1640s and well on its way to becoming England’s dominant Caribbean commodity.[11]

Different crops, and different hands. Another paper — anonymous but, given its close consistency in form and content with Dymock’s writing about the engine, likely his — makes explicit what would have been obvious:

[F]or that in the plantations horses etc are dearer, & shorter lived then Negroes, & more troublesome and charegeable to keep then Negroes, it is generally Concluded, that, could an Invention bee found, wher by the hands of 4 or 6 Negroes at a spell the same worke could bee dispatched, both as to strength and time, which is now done by 4 horses or 8 cattle; it would bee a noble usefull designe, particularly for sugar workes, & merite a large reward[.][12]

The same technology, the same logic, the same appeal to efficiency, usefulness, and nobility, even the same estimates of animal labour we have seen elsewhere shaped the pitch. Now, however, the noble and useful project was the replacement of costly and troublesome horses and cattle with cheap, manageable “Negroes”. And indeed Barbados was on the verge of an explosion in slavery: the island’s enslaved population, under 6,000 in 1645, would reach 42,000 by the end of the century.[13] Dymock’s machine had nothing to do with this, of course; but the labour problems it was meant to solve, and the will to solve them — explored in Abigail Swingen’s recent book — were central.[14] The import of reason’s triumph, the fruit of science’s victory over custom, would be the extension of slavery.

Here, then, is a rather different storyline. How do we resolve the discrepancy? A popular move among “defenders” of Science (or the Scientific Revolution) and Reason (or The Enlightenment) is to break out the “man of his time” canard, the idea being that contributions to science or civilization as we now like to think of them must be separated out from unfortunate aspects of their historical existence, which are attributed to the lamentable influence of “the times” or, more vaguely, “context”. This will not do. If one says that Dymock accepted (or sought to extend) slavery as “a man of his time”, then one has to admit that it was equally as “a man of his time” that he accepted (or promoted) science, reason, experiment, and technology in the first place — and we’re back at square one. Historical figures, considered historically, do not become timeless heroes just when we agree with them and “men of their time” just when we don’t. (Though it is perhaps understandable that people who identify “history” with statues often seem to think this way.) Their words and deeds do not need to be consistent, but our analysis does.

We are here, I think, confronted with the situation described at the outset. A ridiculous idea, perpetual motion, turns out to have something to tell us about the history of science and technology, and to have a logical relationship to the concrete problems of the world in which it was pursued. But among these eminently rational, scientific uses was one that estranges us from our familiar ideas of science and “reason” — or at least from our understanding of the Scientific Revolution and the Enlightenment as the historical moments at which these “modern values” came to be articulated and embraced in recognizable forms. Do we deny that Dymock’s “reason” was the same as ours? Maybe; but he linked it to the kind of science that we still see as such, in much the same terms that we often do. Do we perhaps imagine that his reason was close to ours but incomplete — limited by “its time”, no doubt — and that some missing pieces were somehow, very helpfully, added later?

Or do we recognize that Dymock’s technological fantasy was perhaps just as much about slavery in Barbados as it was about improvement in England, and in all probability for the same reasons — however we end up characterizing these? That no more than “racism” can “reason” — like science, or technology, as historical phenomena rather than mere labels — be isolated or abstracted from the circumstances and purposes of its use? “Defending” the Scientific Revolution or the Enlightenment against this idea is not so much a thankless task as a pointless one. This is not because “we” (read here liberals, “The Left”, and/or academics) used to think these were good and now think they were bad, as is pretended, but rather because even if this kind of judgment could meaningfully be given of historical periods or processes that lack agency it would get us no closer to understanding them. The whole phoney war on “critical” histories of these subjects, prosecuted almost wholly by the “defending” side, is at best a distraction from historical analysis. And only careful, unflinching analysis, oblivious to the honour of labels, will give us a history that makes sense of the sources we have.


1 Vera Keller, Knowledge and the Public Interest, 1575-1725 (Cambridge University Press, 2015).
2 M. Greengrass, M. Leslie, and M. Hannon, The Hartlib Papers. Published by HRI Online Publications, Sheffield [available at:]. Hereafter cited as HP.
3 The most comprehensive overview is Charles Webster, The Great Instauration: Science, Medicine and Reform 1626-1660 (Duckworth, 1975).
4 M. Greengrass, “Dymock, Cressy (fl. 1629–1660), agriculturist”, Oxford Dictionary of National Biography. Retrieved 24 Jun. 2018, from
5 Dymock to Hartlib, 25 December 1648, HP 62/50/2a. On fen drainage projects, see Eric Ash, The Draining of the Fens: Projectors, Popular Politics, and State Building in Early Modern England (Johns Hopkins University Press, 2017).
6 Dymock, An Invention of Engines of Motion lately Brought to Perfection (London, 1650), 8-9. 
7 Dymock to [Hartlib?], 25 October 1649, HP 62/50/9a.
8 Dymock, “Memo on Perpetual Motion”, HP 67/17/1a.
9 Dymock to Hartlib, undated, HP 62/9/2b.
10 Dymock, “Memorandum about Engines” (undated), 62/8a.
11 See Hilary McD Beckles, “The ‘Hub of Empire’: The Caribbean and Britain in the Seventeenth Century”, in Nicholas Canny (ed.), The Origins of Empire: British Overseas Enterprise to the Close of the Seventeenth Century (Oxford University Press, 1998), 218-40. See also Susan Dwyer Amussen, Caribbean Exchanges: Slavery and the Transformation of English Society, 1640-1700 (University of North Carolina Press, 2007).
12 “Memo on Types of Mills” (undated), HP 67/8/1b.
13 Beckles, “The ‘Hub of Empire'”.
14 Abigail L. Swingen, Competing Visions of Empire: Labor, Slavery, and the Origins of the British Atlantic Empire (Yale University Press, 2015).

3 thoughts on “Perpetual Motion: Technology, Slavery, and History

  1. Hi, Ted,

    Thanks for this blog post. There’s a lot here that’s worth thinking about.

    These are what I take to be the central points—please correct where I’ve erred.

    First, the historiographical points:
    • Cressy Dymock proposed a fantastical labour-saving machine to increase agricultural production in England. He also (probably) compassed a device that would save animal labour in sugar production by substituting it with slave labour from Africa.
    • In both instances, he employed what some (many?) might call reason as part of his case for the machines’ usefulness and efficiency.
    • Therefore, it makes sense to state that in the middle of 17th century, it was perfectly reasonable to devise labour saving technologies that saved animal labour by employing slaves. This mode of reasoning was also employed to save labour in the West Indies—a real world problem–which meant in practice the extension of slavery.
    • This mode of reasoning is one that estranges us from familiar ideas about science and reason. This estrangement is in part because we have not fully recognized the extent to which reason and science and technology were just as much about slavery as improvement, ‘and in all probability for the same reasons’.

    Second, the methodological points, or perhaps propositions:

    • Historical periods and processes lack agency.
    • Historical processes cannot be isolated or abstracted from their circumstances and purposes of use.
    • Historical analysis is about making sense of the sources. In other words, the goal of historical analysis is to understand historical periods and processes.

    So, in the hope that I’ve not misunderstood your arguments, here are my questions.

    1) Can processes have a ‘purpose of use’ without an agent generating a telos? Can we understand historical processes and periods that lack agency without understanding the actors who populated them?

    2) On what basis, or by what method, are we to understand actions and beliefs in the past? What is the relationship between actors with agency and processes without it? Or, could you make your argument without telling us about what Dymock believed and did?

    3) On what basis could a historian determine the extent or amount (how much—see above ‘just as much’) a given phenomenon, say television or Christianity, was about ameliorative Outcome A [e.g. increased concern for victims] versus detrimental Outcome B [the Crusades]?

    4) Is historical analysis primarily a hermeneutical act? How is one to determine whether or not one method of sense-making is better than another one (see q. 6)?

    5) Whose sense is determinative in and for historical analysis? Is it the sense-making of historical actors encountered via the sources, or what makes sense to the historian and her colleagues [members of the tribe of WEIRD—Western Educated Industrial Rich and Democratic]?

    6) In what way might the following statement be said not to make sense: ‘Soviet communism was just as much about killing peasants as raising peasants’ standard of living’.


  2. 1. I think a lot of confusion could be avoided if we stopped implicitly conferring agency or intent on labels like The Enlightenment or The Scientific Revolution by imbuing them with unitary agendas (something perhaps few historians do in their own work, these days, but which many lapse into in public debate), and if we spoke less of agendas and more of effects.

    2. I think agents’ ideas are significant both on their own account and in relation to the effects of their actions. (I could hardly have written a book on Petty otherwise.) What interests me here is how an agent in a process now celebrated both for its participants’ intentions and for its long-term effects fused ideas (scientific progress, technology, efficiency) we applaud with others (enslavement as a desirable and noble cost-saving measure) we abhor. That his intentions anticipated the real effects of the larger-scale processes in which he sought to participate (the expansion of plantation slavery) is a separate point. But it seems worth noting, inasmuch as this was the work of actors with ideas like his own, and work to which he intended his ideas to contribute.

    We are often encouraged to imagine a past in which good and bad actors simply pursued opposed agendas (science vs slavery) or one in which actors essentially, as historic figures, pursued good things (like science) and only accidentally, as men of their time, participated in bad ones (like slavery). Neither view is compelling.

    3. When I say Dymock’s machine was “about” slavery I am describing Dymock’s thinking about the purposes of his work; perhaps that is unclear. I don’t think a historian can say what a phenomenon like Christianity was “about” in the same sense, since it seems either to imply that the phenomenon has intentions or that the historian has a perspective from which its meaning can be totally and finally decided. Most phenomena I can think of are more complicated, and more subject to reassessment, than that. When I say “just as much” I mean that there is no good reason to privilege Dymock’s goals for England’s poor over his goals for Barbados’s enslaved in thinking about his purposes (or to treat one set of goals as evidence of his commitment to science and the other as a vestige of his time). I don’t know how one could come up with a formula for measuring these exactly, or what the point of doing so would be.

    4. In one sense or another, any work with sources has to be, doesn’t it?

    5. I am not really sure what you are asking here. I don’t think a historian ever encounters the sources innocent of preconceptions, or enjoys unmediated access to the “sense” of historical agents.

    6. I have no problem with the sentence as it might be used in ordinary language, i.e. to describe effects. Obviously it’s more problematic if it is taken specifically to ascribe intent or agency to a set of ideas. But if you are asking what the difference is between saying that and saying what I say about what Dymock’s machine was “about”, it’s that Dymock himself (implicitly in the paper known to be by him, explicitly in the anonymous paper I have attributed to him here) indicates the extension of slavery as a goal, indeed a benefit, of his engine.


  3. Thanks very much for your responses, Ted. They’ve clarified my thinking. Here are my responses to your responses 🙂

    1. Would there be less confusion if rather than speaking of labels we (historians and others) spoke more about institutions and agents? Perhaps we do already and it is other folk who talk about things like The Enlightenment or The Reformation is singular phenomenon.
    2. What difference does it make for the historian’s assessment of an agent if her ideas or actions had effects that were neither intended nor imagined? I also think there is a connection between the move to celebrate or abhor and the mode of interpretation a given historian uses. By that I mean, the audiences of the historian’s efforts to make sense (point 5 below). One way I might frame the problem to myself is, ‘in what way am I obligated, morally and historically, to make sense of the magistrates who thought it an act of Christian charity to burn Anabaptists?’
    3. I suspect that it makes a difference if one analyzes Christianity or The Church as an institution instead of a phenomenon. For what it’s worth, I think institutions do have intentions, and that some of them change over time. I do get the sense that many people, historians and otherwise (Sam Harris, Richard Dawkins, V. I. Lenin), are quite prepared to make ultimate pronouncements on the Church’s or churches’ meaning for history and humanity, and act thereupon.
    4. I agree.
    5. I think this is where we part ways in how we think about the task of historical interpretation. I will respond in the future at greater length.
    6. I think I agree viz ascribing agency to ideas. But now I think I need to think about the relation between ideas and outcomes. Where we might disagree is the extent to which the ideas in themselves are/were sources for reprehensible actions, e.g. the Spanish Inquisition is not the fault of the Sermon on the Mount; I am less certain that the elimination of kulaks and the Gulag were unrelated to the spirit and intent of dialectical materialism. But perhaps we would need to work out what is meant by ‘at fault’ and ‘related’. As a revolutionary ideology, communism as a set of beliefs does seem, to me at least, to intend massive change for which incidental suffering is acceptable—breaking eggs to make omelets, as they said under Stalin.



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