1 Time and the Cosmos: The Orrery in the Eighteenth-Century Imagination

Jesse Molesworth, Indiana University [email protected]

[This is a draft. Please do not cite or recirculate without permission]

Abstract: The first modern orrery, a mechanical device presenting the motion of the solar system, was

produced in 1704 by the eminent English clockmakers George Graham and Thomas Tompion. Typically

driven by a clockwork mechanism and featuring the planets and their moons revolving around the sun,

such devices served throughout the eighteenth century as a crucial means of illustrating the new

Copernican view of the cosmos. But it is in this capacity that they served the ulterior purpose of

demonstrating precisely the smallness of the individual in relation to the vastness of the cosmos. This

paper examines the ways in which those living in the eighteenth century—scientists, artists, writers—

reckoned with this unwelcome and ultimately terrifying facet of modernity.

This paper concerns the invention of what Walter Benjamin described as “empty, homogeneous”

time. “Invention” is of course too strong a word, for it seems absurd to suggest that humans might

legitimately invent time; perhaps “discovery” would be safer. Still, I use “invention” for its etymological

root invenio, “to come upon.” Rather than simply a process of measuring or recording, the description of

time during the eighteenth century was a confrontation. As such, it was an unpredictable affair,

sometimes congenial, sometimes rude.

Benjamin’s theory of course rests on the rude confrontation with time. In describing the node-like

“moment of danger,” Benjamin recounts an episode from the July Revolution, in which guns are turned on

the tower clocks themselves, thereby suggesting the fullness of present moment (Benjamin’s Jetztzeit), in which time has come to a stand-still.1 For Benjamin time is property made interesting by its absence.

The characteristics ascribed to clock-time, “emptiness” and “homogeneity” (leere and homogene) are

unequivocally negative; and his focus on the moment outside of time (what the Greeks called kairos)

1 Benjamin, “Theses on the Philosophy of History,” in Illuminations, ed. Hannah Arendt, trans. Harry Zohn (New York: Schocken Books, 1968), 253-64; at 262. 2 rather than the continuum of time (chronos) is a prejudice shared by virtually every theorist of time,

from Nietzsche to Derrida to Agamben.

But what of the opposite urge, the urge not to shoot out the clock but, rather, to dwell in the

fullness of its continuum? It is a topic that has been broached before, in various histories of chronos

authored by Benedict Anderson, David Landes, Stuart Sherman, and E. P. Thompson through the

substantially different lenses of print media, technological innovation, and industrial capital. The

emphasis here will fall on eighteenth-century astronomy, whose popularization fuelled concepts as

radically different as Newton’s (Enlightenment) model of the cosmos and Kant’s (Romantic) theory of the

mathematical sublime. Chronos was, for those described in this essay, perhaps homogeneous but hardly

empty. Rather than diminishing the wonder of the cosmos, it enhanced it—or even vindicated such

wonder.

The central object in this essay is the orrery, a mechanical device driven by a clockwork

mechanism and illustrating the movement of the earth and moon (and sometimes the planets) around

the sun. About its early history we know a few sketchy details. The first was apparently devised in 1704

by the English clockmakers George Graham and Thomas Tompion, who lent it to the London instrument

maker John Rowley, who eventually presented one to his patron, Charles Boyle, 4th Earl of Orrery.2 It

therefore borrowed from earlier gear-driven planetary models, such as those devised by Ole Rømer or

Christiaan Huygens in the previous century, but radically increased their complexity and capability. For

example, Rowley’s original model featured an earth that both orbited the sun and revolved in time while

doing so. Orbiting this earth was a revolving moon, appropriately painted half-black and half-white

according to its periods of shadow and light [see Figure 1].

2 This widely accepted account was first given by J. T. Saguliers, who insisted that Graham was “the first person in England, who made a movement to shew the motion of the Moon round the Earth, and the Earth and Moon round the Sun, about 25 or 30 years ago.” See J. T. Desaguliers, A Course of Experimental Philosophy, i (London, 1734), 430. For more on the early development of the orrery, see especially Henry C. King, Geared to the Stars: The Evolution of Planetariums, Orreries, and Astronomical Clocks (Toronto and Buffalo: University of Toronto Press, 1978), esp. pp. 150-67; see also John R. Millburn, “Benjamin Martin and the Development of the Orrery,” The British Journal for the History of Science, Vol. 6, No. 4 (Dec., 1973), pp. 378-99. 3 One of Rowley’s earliest admirers was Sir Richard Steele, who in 1714 wrote glowingly of the

instructive potential of the orrery:

This one consideration should incite any numerous Family of Distinction to have an Orrery as necessarily as they would have a Clock. This one Engine would open a new Scene to their Imaginations: and a whole Train of useful Inferences concerning the Weather and the Seasons, which are now from Stupidity the Subjects of Discourse, would raise a pleasing, an obvious, an useful, and an elegant Conversation.3

Steele’s prediction—that the orrery would achieve the ubiquity of the clock within the modern home—

was bound to fail, for any number of reasons. Expense, utility, and intricacy of design were all against it;

the very name “orrery” of course implied a cultural prestige not typical of the clock.

What Steele did predict correctly, though, was that the orrery would become more than simply the

plaything of princes. By the middle of the eighteenth century, it gained widespread exposure as a prop used in astronomical lectures, particularly those offered by Benjamin Martin (1704/5-1782) and James

Ferguson (1710-76), two energetic popularizers of science. It is in this capacity—as lecture aid—that it is

probably best known: as the dramatically illuminated object of fascination within Joseph Wright of

Derby’s iconic painting, A Philosopher Lecturing on the Orrery (ca. 1766) [see Figure 2]. In fact, though

Isaac Newton is often claimed as the inspiration for the white-haired lecturer (illuminator) in Wright’s

painting, the far likelier model is Ferguson, the similarly white-haired Scotsman who lectured regularly

on experimental philosophy from 1748 to his death in 1776.

Demand followed exposure, and supply soon rose to meet demand. By the end of the eighteenth

century, a fully functioning orrery, featuring representations of the sun, earth, and moon, along with all of

the known planets and their moons, might be acquired for 2£. 12s. 6d.—well within the means of any

bourgeois home.4 Whereas the earliest orreries tended to be ornate and sometimes quite large—Thomas

Wright’s Great Orrery (1730) measured four feet in diameter, as though mimicking the grandiosity of the

universe itself—the newer orreries were streamlined, smaller, and even portable. Those marketed in the

1780s and 90s by the ingenious entrepreneur William Jones came in pieces in a mahogany case, to be

3 Steele, The Englishman No. 11 (October 29, 1714). 4 See William Jones, The Description and Use of a New Portable Orrery (London, 1787), 43. 4 assembled by its owner much in the manner of an Ikea bookshelf [see Figure 3]. Others might even be assembled using pasteboard, scissors, and pins—which when properly put together would yield, according to one commentator, “an exceeding good manual Orrery, that will show you as much as those usually sold for 2£. 12s. 6d. or three Guineas.”5

Still, what had changed between the first and last decades of the eighteenth century was more than simply size and price. Orreries had traditionally attempted to strike a balance between the twin aims of Science and Art. But the latter aim faded decidedly in importance, so much so that by 1771

Martin proposed eliminating the bulky hemispherical coverings once popular within orreries, for the simple reason that “there is really no such Thing in Nature.”6 Unlike the earliest orreries, newer models made less of an attempt to hide the wheelwork—the guts of the apparatus—away from view. Textbook illustrations of orreries even began to give prominence to the wheelwork, beginning perhaps with

Martin’s Philosophia Brittanica (1747), which offers a diagram of the wheelwork featured in his important double-cone orrery without an accompanying depiction of the actual platform supported by it.7 Ferguson’s texts would follow suit, elaborating the wheelwork within a dazzling technical and visual language in which the face of the orrery is easily lost [see Figure 3]. Such illustrations served most obviously to document the extent of Ferguson’s own achievement; but he also hoped that they might, when rendered in exquisite detail, inspire others to copy the design: “I therefore freely give the following account of it to the Public, in the best Manner that I can; and do wish the description may be generally understood. To any Clock-maker I hope it will be plain, and to every Orrery-maker I believe it will be quite so.”8

5 G. Wright, The Description and Use of Both the Globes, the Armillary Sphere, and Orrery (London, 1783), 97. 6 As Martin continues, “the Orrery I propose is a bare Representation of the Solar System in its native Simplicity, and is, in its self, sufficiently grand, and pompous; it stands in Need of none of the useless, expensive, and cumbersome Embellishments of Art.” See Martin, The Description and Use of an Orrery of a New Construction (London: 1771), 11-12. 7 Martin, Philosophia Brittanica (London, 1747), Plate XII. 8 Ferguson, Select Mechanical Exercises, 2nd ed. (London: 1778), 72-73. 5 The orrery, then, transformed from physical object to abstract concept over the course of the

eighteenth century, ultimately finding a place within what John Bender and Michael Marrinan have described as the culture of diagram.9 Unlike the “Rowley orrery” or “Wright’s Great Orrery,” both of

which referred explicitly to things, phenomena like the “Ferguson four-wheeled orrery” and the “Martin

double-cone orrery” referred to designs, or sets of ideas that might be concretized as things. The orrery’s status was furthermore complicated by the fact that such designs, and the things made from them,

accomplished little more than the representation of another concept, the motions of the planets. Though

it was most frequently described as a “machine,” in Dr. Johnson’s sense of “any complicated piece of

workmanship,” the orrery was also described more abstractly by Martin and Ferguson as a “structure,” a

“universal representation,” and even a “system.” Among machines the orrery was special, so Martin

recognized relatively early in its history; for it represented nothing less than the grandest idea that might

be conceived, “the true System of the World.”10

Though Martin and Ferguson would die in the last decades of the eighteenth century, their

legacy—as popular promoters of the Newtonian “true System”—would last well into the next century. In

1782, the year of Martin’s death, the astronomical lecturer Adam Walker debuted his theatrical

entertainment Eidouranion, or Large Transparent Orrery at the Theatre Royal, Haymarket. Mixing science

and spectacle, Walker’s show centered on a giant orrery, produced through back projection on a screen.

Throughout numerous incarnations, it was advertised as fifteen feet, twenty feet, and ultimately twenty-

four feet in diameter [see Figures 4 and 5]. Imposing though this may sound, it was just the beginning;

9 See Bender and Marrinan, The Culture of Diagram (Stanford: Stanford University Press, 2010). 10 As Martin wrote in 1747, “An orrery then adapted to an Armillary Sphere, is the only Machine that can exhibit a just Idea of the true System of the World.” He wrote similarly in 1771, “this is no less than a universal Representation of the Mundane System, and a Explication thereby of all its numerous Phenomena.” See Martin, Philosophia Brittanica, 370; Martin, Description, Preface. The term “true System of the World,” referring to the Copernican model of the universe (contrasted with the “vulgar” Ptolomaic model), migrated from cosmology into any number of disciplines during the late eighteenth century. See especially Clifford Siskin, “Mediated Enlightenment: The System of the World,” in Clifford Siskin and William B. Warner (eds.), This is Enlightenment (Chicago: The University of Chicago Press, 2010). 6 copycat performances like John Handsford’s Celestial Orrery and R. E. Lloyd’s Dioastrodoxon would up the ante with each passing year, producing orreries of thirty feet and still greater dimensions.

On the one hand such orrery shows, especially Walker’s, offered a great deal of content. The

Eidouranion explored, for example, how gravitational forces cause spring tides and neap tides, the precise

alignments of solar and lunar eclipses, and how to use astronomical means to obtain latitude and

longitude while at sea. Perhaps even more excitingly, they served to showcase William Herschel’s recent

astronomical discoveries, including the existence of a new planet, “Georgium Sidus” (Uranus). On the

other hand, they were unquestionably entertainments, first and foremost. Uncontent simply in

communicating a series of scientific facts, Walker’s show, and others like it, divided itself into five

discrete “scenes,” progressing in a narrative arc. Beginning with the Earth’s movement around the sun

(Scene I), the Eidouranion then took up the motion of the moon (Scene II), the seasons and tides (Scene

III), and the motion of the other lunar planets and their satellites (Scene IV), before offering a bold climax

in the unveiling of Herschel’s discoveries (Scene V).

Perhaps even more tellingly, Eidouranion shows implemented a variety of dazzling stage effects,

sending comets flying throughout the theatre and captivating the audience with the otherworldly tones of

a celestina, a type of glass organ. No one has captured this spectacle better than Maria Edgeworth, who

describes a visit to the Eidouranion in her children’s story “Frank”:

While they were counting the row of lights, which were before the stage, these began to sink down, and the other lamps in the house were shaded, so that all were nearly in darkness: and at the same moment soft music was heard, and the curtain began to draw up. The music was from an harmonica, which was concealed behind the scenes. While this soft music played, the curtain drew up slowly, and they beheld two globes, that seemed self-suspended in air. One seemed a globe of fire, with some dark spots on its surface; a blaze of light issuing from it in all directions, and its rays half enlightened the other globe, of which half remained in darkness.11

This mixture of wonder and story, combined with a relatively early starting time of seven o’ clock, made such shows exceptionally popular among children. “Orrery! oh delightful orrery!”: so enthuses Frank, the

precocious adolescent at the center of Edgeworth’s story, at the prospect of attending an Eidouranion

11 Edgeworth, “Frank, A Sequel to Frank,” in Works of Maria Edgeworth, 13 vols. (Boston, 1825), XII: 275. 7 performance.12 Walker’s death in 1821 did little to halt the momentum achieved by his creation, which had long since passed into the capable hands of his sons William and D. F. In one form or another, the

Eidouranion would captivate audiences, in London and throughout Britain, for another forty years.

Steele’s prediction was therefore realized, though perhaps not in the form that he envisioned. For by the end of the eighteenth century the orrery had navigated a slow but steady path from expensive luxury item (Rowley) to abstract scientific model (Martin, Ferguson) to bourgeois acquisition (Jones) to subject of mass spectacle (Walker’s Eidouranion). It perhaps failed to achieve ubiquity itself; but that which it represented, Martin’s “true System of the World,” did. Hence, the question: what was the nature of that system?

For Walker, it concerned the question of scale. What differentiated the Eidouranion from ordinary orreries was not necessarily its spectacle or even its value as an entertainment. Rather, what marked it superior was precisely its ever-expanding size: “It is certainly the nearest approach to the magnificent simplicity of nature, and to its just proportions, as to magnitude and motion, of any Orrery yet made.”13

As with the grand orreries of the early eighteenth century, bigger was better; for the point was rather to communicate some sense of the vastness of the cosmos.

Others, though, met this claim to representing the vastness of the cosmos with some skepticism. It is surely a great irony, for example, that an instrument partially dedicated to teaching William Herschel’s astronomical discoveries would later be dismissed by his son, the astronomer John F. W. Herschel, as

“those very childish toys called orreries”—precisely because they so often failed to represent the true proportions of solar system with any accuracy.14 The problems posed by translating the very large to the relatively small ultimately proved insoluble. Given that the Earth’s distance to the Sun is roughly one- twentieth of Uranus’s, any attempt to represent Herschel’s new planet with any degree of proportionality was doomed to push Mercury, Venus, Earth, and Mars into an incomprehensible inner cluster

12 Edgeworth, Frank, 274. 13 Adam Walker, An Account of the Eidouranion, or Transparent Orrery (Bury St. Edmund’s, 1793), 3. 14 Herschel, A Treatise on Astronomy (London, 1833), 287. 8 surrounding the Sun. Worse still, the radius of the Sun is roughly 109 times larger than that of the

Earth, and any attempt to represent its magnitude proportionally was bound to squeeze smaller planets like Earth, Mars, Mercury, and Venus into invisibility. One commentator, writing in 1750, stated the problem thus: “a proportional Sun cannot be made use of; for, to an Earth of three Tenths of an Inch in

Diameter, the Sun would be above two Foot in Diameter, and consequently fill more than the Orbit or

Path of Jupiter in the Machine, and thereby exclude all the Planets except Saturn from the Orrery.”15

Put simply, the massive scale of the solar system and its planets made it all but incomprehensible to most orreries; larger solar objects dwarf smaller solar objects to the point of rendering them trivial. A marble-sized Earth (mean radius: 6,371 km) would have to be matched with a basketball-sized Jupiter

(mean radius: 69,911 km). But within such an arrangement, Mercury (mean radius: 2,440 km) would appear to be the size of a pea, while the Sun (mean radius: 696,000 km) would still remain impossibly large.

Some orreries sought to solve this latter problem by offering planets of varying sizes. One designed by J. T. Desaguliers, for instance, featured two Saturns and two Jupiters: smaller models to illustrate their movements and larger models to illustrate their relative size [see Figure 7].16 Others were flexible enough that planets might be moved in and out of their proper orbits, as convenience or accuracy dictated. (Some even featured replaceable parts and variable gear trains, so that the Sun and its planets might be removed entirely, in order to examine the movement of the four Galilean moons around

Jupiter). Still, Martin would exercise caution when describing what the orrery could and could not model:

“The Orrery is, therefore, an adequate representation of a TRUE SOLAR SYSTEM, and gives a just Idea of the Number, Motions, Order, and Positions of the heavenly Bodies: But the Proportion of Magnitude and

15 Isaac Thompson, A Description of the Orrery (London, 1750), 13. 16 As Desaguliers describes it, “When the Spectators have look’d long enough upon the Machine, to have a compleat Idea of the proportionable Bigness of the Planets; Jupiter and Saturn are taken off, an then there are put on another Jupiter and another Saturn 3 times less than the former, in order to put Satellites about them.” See J. D. Desaguliers, A Course of Experimental Philosophy (London, 1734), 434. 9 Distances of the Planets is not to be expected from the Orrery.”17 A merely “adequate representation”

therefore becomes a “just Idea” by shifting the focus from magnitude to movement, from distance to

motion. Subsequent commentators would learn from Martin’s example, similarly emphasizing planetary

movement: “Orreries were essentially mechanical models for demonstrating motions; proportional sizes

can be adequately illustrated by static diagrams.”18

The problem here is that the orrery’s claim to representing the motions of the planets is equally

dubious. Astronomers since Kepler have known that planets move in elliptical rather than circular orbits.

But few orreries attempted to reproduce such movement, even in cases when the eccentricity of the

elliptical orbit is visibly pronounced, as with Mercury. Simplicity favored circles over ellipses. Circles were good enough for Galileo, as they were for Ptolomy; likewise, they were good enough for the orrery.

What the orrery could and did represent, sometimes with extraordinary fidelity, was time. This was not clock time, of course—for such would have been an unnecessary adornment. Rather, what the orrery offered was cosmological time, the sense that celestial objects orbited the Sun (and other celestial objects) within predictable time frames. Furthermore, with the proper combination of wheels and gears,

such time frames could be represented in their proper proportions. Witness the way that one early

admirer described it:

Every Turn of the Handle answers to one Rotation of the Earth round her Axis, and 365 ¼ Turns will carry her once round the Sun. Twenty-seven Turns and about one third of a Turn more will bring the Moon once round the Earth. And in a little less than 322 Turns will carry Mars round the Sun. And 4335 Turns of the Handle and one quarter of a Turn more, will carry Jupiter once round the Sun. Lastly, 10766 turns and one half Turn more of the Handle will carry Saturn once round the Sun.19

To be sure, there lurks a certain absurdity within the notion of cranking the handle of an orrery 10,766

times in succession—surely few possess such patience. Such absurdity, though, does much to reveal the

importance of the number 10,766, or rather the proportion that it represents. To offer any other number,

17 Martin, Philosophia Brittanica, 357-59. 18 Millburn, “Benjamin Martin,” 398n.89. 19 Deane, The Description of the Copernican System (London, 1738), 103. 10 so as to shorten (or to lengthen) this proportion, would mean to commit violence to the system, which

is constructed on and understood through the terrestrial day.

The orrery therefore depicted a cosmos as envisioned not by the astronomer—for let us not forget

Herschel’s dismissive comment. Rather, it offered a cosmos as envisioned by the clockmaker, with gear-

driven planets sweeping around regularly like the ticking hands of a watch. When Ferguson offered a

table “for regulating Clocks and Watches to true equal Time, by the daily Revolutions of the Stars,”20 he did so under the assumption that cosmological time structures and gives meaning to clock time—that

cosmological time precedes clock time.

To a certain extent, then, the orrery literalized and substantiated two important metaphors: the

cosmos as gigantic machine and the cosmos as clock. The first of these would be drawn most forcefully

by Thomas Paine, who saw the orrery as a tool for converting Christians to Deism: “Or could a model of

the universe, such as is called an orrery, by presented before him [a Christian] and put in motion, his

mind would arrive at the same idea [Deism].”21 The second metaphor would be drawn most forcefully by

William Paley in Natural Theology (1802), though it was certainly available in earlier writings by Kepler,

Descartes, and Boyle, among others.22 Indeed, clockmaking and astronomy had long stood as analogous

disciplines. Much of Martin’s and Ferguson’s information concerning the periodic orbits of the planets

and their satellites, for instance, had its roots in a dazzling treatise by William Derham called The

Artificial Clock-Maker (1696), which served, simultaneously, as a standard textbook on both astronomy

and clockmaking for many years.23

20 Ferguson, Select Mechanical Exercises (London, 1778), 34. 21 Paine, The Age of Reason: Part the Second, 2nd ed. (London: 1796), 83. 22 Indeed, Daniel Boorstin traces the God-as-clockmaker metaphor all the way to Bishop Nicole d’Oresme (1330?-1382). For more on the history of the metaphor, see Boorstin, The Discoverers (New York: Vintage Books, 1983), 71-2. 23 Not coincidentally, Derham would later write an important early deist tract called Astro-Theology (1715) in which he explicitly described the universe as a gigantic mechanical apparatus. On Derham’s importance, see James A. Herrick, The Radical Rhetoric of the English Deists: The Discourse of Skepticism, 1680-1750 (Columbia: The University of South Carolina Press, 1997), 186-87. 11 Despite the convenience and availability of such metaphors, though, it is perhaps equally important to note the substantial differences between the orrery’s notion of time and that of a clock. For while the fundamental unit of time within the orrery—the terrestrial day—is uniform in length, it is not uniform in quality. Rather, each day is conceived of consecutively but ultimately separately, such that each possesses unique and therefore defining characteristics. Such characteristics might be observed within any standard orrery, but they positively glowed within those orreries in which a lamp could be placed in the position of the Sun, casting its light on the rotating bodies. Consider Martin’s description of the resulting scene:

when the Orrery is put into Motion, the Earth moving with its Axis always parallel to itself, yet always inclined to the Plane of the Ecliptic, will sometimes have the Northern Parts turn’d more directly to the Sun, and most enlighten’d; and at other times the Southern Parts will be so. Hence the various Alterations of Heat and Cold, and Length of Days and Nights, will ensue in the Course of the Revolution of the Earth about the Sun, which will constitute all the Variety of Seasons, as will most naturally and evidently be shewn in the Orrery.24

Like the time given by a clock, the orrery’s time is therefore both uniform and proportional. But unlike clock time, it is also strongly progressive. Some days were relatively unremarkable. Others produced regular occurrences like solstices or equinoxes. Still others might produce something truly special: a solar eclipse, a lunar eclipse, or, even more remarkable, a transit of Venus (pairs of transits occur roughly eight years apart; but such pairs are separated by intervals of over one hundred years).

The prospect of witnessing special time (kairos) reveal itself within the continuum of time

(chronos) was therefore the particular pleasure of the orrery. Perhaps the biggest difference between the clock and the orrery had to do with a feature implied but not mentioned within Martin’s quotation above: the winch. Many standard orreries might, of course, be set like a clock to operate in real time, ticking steadily away and modeling the orbits and rotations of the planets as they actually occurred. But few ran this way, if contemporary descriptions are to be believed. Nothing could be duller than a real-time orrery, in which motions could scarcely be detected and the passage of time was scarcely observable. Let

24 Martin, Philosophia Brittanica, 374. 12 Ferguson’s comment speak for an overwhelming consensus: “When such a Machine is turned by Clock-

work, it is instructive only in a slow tedious Way to those who can have daily recourse to it.”25

By contrast, the winch offered something different, something more appealing. This was the

ability to accelerate movement and, with it, time:

Mr. DEAN hath contrived, by a Winch, or Handle, to turn the Axis swiftly round about, and, by that Means, to shew all the Phaenomena, or Appearances, in a very little Time. And by turning the Handle backward or forward, you may see what Eclipses, Transits, &c. have happen’d in any Time past; or what will happen for any Time to come, without doing any Injury to the Instrument.26

Turing winch may have been “the most instructive Way of shewing the planetary Motions,” as Ferguson

described it.27 More than that, though, it made visible the fantasy promoted by the orrery: that of reversible time, of a cosmos free of entropy. Time flowed forward in a continuous stream, but it also

flowed backward just as easily, so that the past might be recaptured and even replayed.

Reflecting on the intimate connection between time and the cosmos, Martin wrote the following: TIME is in itself a flowing Quantity, measuring the Duration of Things; and its Flux is always equable and uniform; and therefore to estimate the Quantity of Time, we should measure it by something that is in its own Nature always of one and the same Tenor. For this Purpose we have no Expedient so convenient as that of Motion; and because the Measure of Time ought to be permanent, we can find no other Motion fit for this Purpose but that of the Heavenly Bodies.28

Benjamin’s empty, homogeneous time therefore finds expression here, though couched in different

adjectives: “flowing,” “equable,” and “uniform.” Time measures, but it also makes. It serves to record the

movement of the planets, but also proceeds precisely as the natural consequence of that movement.

25 Ferguson, The Use of a New Orrery (London, 1746), 41 26 Deane, Description, 94. 27 Ferguson, New Orrery, 42. 28 Martin, Philosophia Brittanica, 411. 13 List of Figures

Figure 1. John Rowley’s original orrery (1712-13), now housed in the Science Museum, London

14 Figure 2. Joseph Wright of Derby, A Philosopher Lecturing on the Orrery (ca. 1766), Derby Museum and

Art Gallery, Derby, England

15 Figure 3. Portable orrery designed by William Jones; in Jones, Description and Use of a New Portable

Orrery (1787)

16 Figure 4. Wheelwork for an orrery designed by James Ferguson; in Ferguson, Select Mechanical

Exercises (1778)

17 Figure 5. An Eidouranion performance at the English Opera House in 1817, featuring Walker’s large transparent orrery

18 Figure 6. Playbill for Walker’s Eidouranion, or Large Transparent Orrery (1789)

Figure 7. Planetarium designed by J. T. Desaguliers; in Desaguliers, A Course of Experimental Philosophy

(1734) 19

20 Additional Illustrations of Eighteenth-Century Orreries (not referenced)

“Rowley’s orrery” (John Rowley’s second model); as illustrated in John Harris’s Astronomical Dialogues

(London, 1745). Fate unknown.

21 Thomas Wright’s Great Orrery; in Samuel Fuller, Practical Astronomy (Dublin, 1732)

Orrery designed by James Ferguson; in Ferguson, The Use of a New Orrery (1746)

22

23 Four-wheeled orrery designed by James Ferguson; in Ferguson, Description and Use of a Four-Wheeled

Orrery (1746)

24 New manual orrery designed by Benjamin Martin; in Martin’s Description and Use of Both the Globes,

The Armillary Sphere, and the Orrery (1758)

25 Orrery designed by Benjamin Martin; in Martin, The Description and Use of an Orrery of New

Construction (1771)