Draft. Forthcoming in Baroque Imaginary: The World of Athanasius Kircher, S. J. (1602-80), ed. Paula Findlen, Routledge, 2002
In October 1639, the Jesuit missionary Martino Martini found himself adrift in the Atlantic. On route to Goa, the Portuguese vessel that contained nine Jesuits destined eventually for the Chinese mission had met with catastrophic conditions. The boat, along with its companion vessel, was forced to make an unplanned forty-six day stop on the Guinean coast that drained its supplies, infected its passengers with horrific maladies and forced a return to Lisbon. “To tell the truth to Your Reverence”, Martini wrote to his erstwhile mathematical mentor at the Collegio Romano, Athanasius Kircher, “the land and sea along that coast generally called Guinea appear to have been damned from all eternity, such are the heat, the rain, the pestilence, things that you would never believe”.
Dejected at their aborted mission, the Jesuits and their companions turned back towards Portugal, passing close to the Azores, where Martini noticed the abundant Sargosso grass floating in the water. In addition to indicating to the mariners their position with respect to the islands, Martini noted, the round berries of the flax-like sea-grass were reputed to be an indispensable remedy for gallstones.
On October 1, the vessel was hit by a violent storm. “The water was higher than mountains”. With all sails taken down except for one the size of a sheet, the boat was driven along by the wind for almost seventy leagues. After the winds had finally subsided, the nobles and sailors on board entertained themselves by making bets as to their distance from the Portuguese coast.
Martini, armed only with a chart on which he had been tracking every step of the ship’s voyage, and a compass specially adapted to allow him to calculate the declination of the magnetic needle from true North, defeated both noblemen and mariners in his calculations. “I said that we were to the East of the island of Terceira and only one hundred leagues from the mainland”. In exact accordance with Martini’s predictions, the ship arrived in Portugal early in the morning of October 14.
How did a Jesuit priest with almost no seafaring experience defeat the estimates of seasoned navigators with expert knowledge of sea currents, winds and marine phenomena? Martini’s reasoning went thus: “if we had been to the West of the Azores, the magnet should have declined to the West, but as it declined to the East, we could not have been to the West. Some said that we were in the midst of the Islands, but I demonstrated that this could not be true, as, even though we were at their latitude we did not see them, and that was impossible”. Sceptics challenged Martini, wondering why, given that the islands extended for 120 leagues from East to West, they had never been seen during the course of the storm. “Precisely because even before the storm we were to their East”, rebutted Martini, supporting his claim with a detailed mathematical analysis of the ship’s meandering route.
“I write this”, Martini flattered Kircher, “not so as to praise myself, but so that Your Reverence may see all that I have learned from you, especially in the field of magnetic declination”.
Martini had spent a mere two months as Athanasius Kircher’s “private disciple in mathematics” in the Jesuit Collegio Romano, but this brief apprenticeship, occurring shortly after Kircher had taken up the post of mathematics professor, apparently had a transformative effect on him. At the end of the sixteenth century, Christoph Clavius had created a private mathematical academy in the Collegio Romano, with the express goal of providing advanced training to those destined to teach mathematics in Jesuit colleges in the different provinces, and to those destined for the Chinese mission, for which mathematical skills were regarded as particularly relevant. Matteo Ricci, the most famous representative of the first generation of Jesuit missionaries to China, was himself an alumnus of Clavius’s original academy. The academy really consisted in informal advanced training that took place in the bedroom of the senior mathematician of the College, also known as the “mathematical museum” (musaeum mathematicum), where valuable instruments and mathematical manuscripts were kept under lock and key. After the death of Clavius’s successor Christoph Grienberger, control of the mathematical museum and the serious task of training senior mathematicians in advanced trigonometry, astronomy and hydraulics passed to the more playful hands of Athanasius Kircher, who rapidly transformed the sober mathematicians’ bedroom into a dazzling showcase of speaking tubes, perpetual motion machines, sunflower clocks, optical tricks and hydraulic devices, only later to be transferred into the more commodious halls of the Musaeum Kircherianum.
Martini’s floating microcosm -- his cabin aboard ship, filled with charts, astrolabes, quadrants, compasses and the astronomical works of Clavius, Peter Apian and Tycho Brahe -- is a fascinating mirror of Kircher’s cubiculum in the Collegio Romano. While Kircher would draw heavily on Martini’s reports in compiling his Magnet, or on the Magnetic Art, Martini used the mathematical techniques he had learned from Kircher during his two-month apprenticeship in Rome to demonstrate his navigational superiority over the ship’s pilots. Pitting his own book-knowledge, charts and instrumental abilities acquired from Kircher against the accumulated experience, dead-reckoning and reliance on natural signs of the Portuguese mariners, Martini claimed multiple victories. On his subsequent voyage to Goa, his judicious use of the magnetic needle saved his ship, carrying the Viceroy of the Indies, from certain destruction on a shoal of treacherously sharp rocks.
In his aspirations to universal knowledge, Athanasius Kircher relied crucially on Martini and his ilk, Jesuit missionaries inflamed by their Ignatian training to endure every sacrifice to advance the glorious achievements of their Order. Conversely, the mathematical skills of Jesuit missionaries, in addition to their willingness to nurse the sick, hear confessions and even parade as flagellants during Easter week, helped to ensure them a welcome place aboard the heavily charged Portuguese ships destined for the Indies.
Kircher’s audacious attempt in the late 1630s and early 1640s to carry out a great “Geographical Plan” (Consilium Geographicum), aimed at harnessing the global network of Jesuit missionaries in order to reform geographical knowledge and to resolve the problem of calculating longitude at sea constitutes a vivid demonstration of the nature of the organic connections between Kircher’s Roman cell, on the one hand, and the missionary spaces inhabited by Jesuits like Martini, on the other. The global distribution of Jesuit missionaries was absolutely essential to Kircher’s attempt to reshape terrestrial geography – by fixing the longitudes and latitudes of Jesuit missions and colleges – and to reform navigation – by devising a foolproof method for calculating longitude at sea.
The primary “enabling technology” for Kircher’s project was correspondence – frequent epistolary contact with mathematically trained Jesuits. In his essay in this volume, Noel Malcolm argues convincingly that Kircher’s “oracular” correspondence was atypical of the fluid, multi-directional model of correspondence endorsed by the seventeenth century Republic of Letters. Kircher’s Geographical Plan constitutes a particularly striking example of his conception of the role of the centralized accumulation of correspondence in the reform of natural knowledge, and makes explicit the monarchical power-structure that characterized his epistolary community. The ultimate failure of his geographical project, which quite literally vanished, as we will see, and his dispute with Jesuit astronomer Giambattista Riccioli over the relative merits of global correspondence and exquisite local instrumentation, illustrate a clash between two contrary social models for the prosecution of research in astronomy and geography.
In his 1641 work The Magnet, or on the Magnetic Art Kircher outlined his proposal for a Magnetic Geography that would be magnetic in two respects - both in seeking magnetic solutions to geographical and navigational problems and in drawing the observations performed by mathematicians, navigators and missionaries throughout the world together in Rome, as if by some occult force of attraction. Kircher likened his project to the reform of the calendar reform carried out under Pope Gregory XIII in 1582, suggesting that just as the convergence of the authorities of Pope, princes and universities had reformed the temporal order governing religious and civil affairs so might a similar initiative allow geographical knowledge, clearly in disarray, to be reformed.
Like the Gregorian reform of the calendar, Kircher argued, geographical reform could not be carried out by a single individual. Instead, it was seen to require a "unanimous conspiracy of mathematicians". The religious orders were particularly suited to such a task, but most appropriate of all was the Society of Jesus, "distributed throughout the whole globe, provided with men skilled in mathematics and, above all, enjoying a unanimous harmony of minds".
Kircher was urged to embark upon the reform of geographical knowledge through the use of Jesuit informants by a number of sources, and especially by the General Muzio Vitelleschi, who ordered him to compose a Geographical Plan" (Consilium Geographicum), "a treatise in which I would display the methods and procedures for restoring Geography, and would explain by what means, with which instruments, and in which place, state and time observations might be carried out fruitfully. I would try to show briefly and clearly that this business would not be difficult work for the religious orders". Kircher's plan for a Jesuit-led global observational imperative would go far beyond mere cartography: "I would also provide instructions for what they should observe about the flux and reflux of the tides, the constitution of lands and promontories, the natures and properties of winds, bodies of water, rivers, animals, plants and minerals, and, finally, about the customs, laws, languages and religious rites of men".
Although Jesuit missionaries, from Matteo Ricci to José de Acosta, had been enormously active in accumulating observations of just this kind in the first century of the Society's existence, at the beginning of the second century Kircher wished to discipline and coordinate such reports. By doing so he would avail of the mobility, mathematical expertise and self-effacing obedience of his Jesuit colleagues. Inscribed into Kircher's larger geographical project was an attempt to resolve the recalcitrant navigational problem of calculating longitude at sea, a problem of the utmost importance for navigation in the seventeenth century. Latitude calculation was simple (given clear skies) – measure the angular elevation of the sun at noon, or of the pole star at night and you had your latitude. Longitude calculation, without a mechanical clock that could remain reliable during a sea-voyage, was a very different matter. A huge number of solutions to the longitude problem were proposed after Philip III offered a perpetual pension of 6,000 ducats to anyone who could find a workable method of maritime longitude-determination in 1598. Galileo had proposed using the eclipses of the newly discovered satellites of Jupiter as a "celestial clock" which sailors might consult to determine their position, a project frustrated by the difficulty of making accurate telescopic observations of the Jovian moons aboard a moving ship. Oronce Finé, followed by Jean-Baptiste Morin, proposed an immensely complicated method involving the movement of the moon against the background of the fixed stars, of which Kircher later complained that its use required the mathematical ability of a Euclid or a Ptolemy. Michael Florent van Langren attempted to use the motion of the terminator shadow across the lunar disc as a painfully slow celestial sundial. Kircher approached the problem in a different way, through magnetic variation -- the deviation of a compass needle from North as determined by the pole star – a technique previously suggested by Giambattista della Porta in the late sixteenth century and by mathematicians and navigators in England. The famous series of engravings of New Discoveries carried out in the late sixteenth-century by the Flemish artist Jan van der Straet, or Stradanus, and printed by Jean Galle included, along with such celebrated inventions as gunpowder, eye-glasses and the printing-press, an illustration of “the longitudes of the globe discovered by the declination of the magnet from the pole” (fig. 1). In the illustration, a sailor aboard a ship in stormy seas, calculates the position of the meridian by observing the position of the sun, and compares it to the direction of the magnetic needle to calculate the declination.
Despite the unbridled optimism of Jan van der Straet, however, it was by no means obvious to most navigators in the early seventeenth century just how the measurement of magnetic declination could allow longitude to be calculated at sea. The Jesuit missionary Cristoforo Borri, who traveled to Macao and Indochina between 1615 and 1622, was reputed to have discovered a method. Kircher clearly knew about Borri’s efforts, and endeavoured to use Martini to discover further details of his method. The technique, at least according to Martini, seems to have involved the construction of a chart mapping points of equal magnetic declination, an azimuthal compass (i.e. a magnetic compass equipped with a sighting device or shadow-casting device to allow the astronomical meridian to be determined) and a technique for measuring the declination at any time of day.
In 1639 Marin Mersenne wrote to Gabriel Naudé in Rome in 1639 to suggest that Kircher should "order some Reverend of the Society in each college, by whatever means possible, to note the variation of the magnet and the height of the pole star accurately. Let him order that one or another lunar eclipse be observed in these same houses and colleges". "If this task were completed", Mersenne continued, "and if the authority of the supreme pontiff would lend itself to this task, the result would be that some time under the happy auspices of Urban VIII we would know the magnetic variation of the whole world, the altitudes of the pole star, and the longitudes so long sought after".
Mersenne's suggestion was similar in tone to one made some years before by Pierre Gassendi, who proposed to Kircher's patron Nicholas Claude Fabri de Peiresc that either Urban VIII or his nephew Cardinal Francesco Barberini should incite missionaries to make accurate eclipse observations to reform the geographical art. Interestingly, Gassendi did not restrict his suggestion to the Jesuits, having made previous use of the observational powers and mathematical expertise of other peripatetic counter-reformation orders such as the Capuchins and the discalced Carmelites in collecting reports of eclipses.
While Peiresc and Gassendi could use Capuchins and discalced Carmelites to transfigure the Mediterranean, however, the Atlantic space remained far less accessible to their network of informants. Additionally while eclipse observations might allow longitude to be established at a terrestrial location, they were of little use to a lost ship's captain unless his predicament happened to coincide with a lunar eclipse.
Kircher responded swiftly to Mersenne to inform him that he had already embarked on just such a project. Having performed numerous observations of the magnetic declination during his own peregrinations through Europe, and armed with the observations collected by his predecessors in the Collegio Romano, he wrote to distinguished mathematicians throughout Europe to solicit their measurements of the magnetic variation of their place of residence. He hoped that in this way they "would all be inspired to perform careful observations to determine this variation and other matters with which our Geographical Plan is concerned". The outcome of this first attempt was disappointing. Kircher had "almost no news at all from the more famous mathematicians". This required a change of plan. Taking advantage of a meeting of the Procurators (responsible for the financial affairs of each Province of the Jesuit order) in Rome in November 1639, Kircher asked each Procurator to solicit observations of local magnetic declination from the Jesuit mathematicians resident in the different cities of his Province. In addition to sending observations, each mathematicians was to explain in detail exactly what precautions had been taken, and what type of equipment had been used. Unlike the more famous mathematicians, a great number of their Jesuit contemporaries responded immediately.
Kircher published their observations along with those made by others in his Magnes. In recognition of the labours of his Jesuit helpers, performing observations of the magnetic variation in places as far apart as Goa, Paris, Macao, Alexandria, Constantinople, and Vilnius, Kircher published their names in a large table reporting the magnetic declination and the latitude of the place at which the observation was made [fig. 2]. Behind this table lies an enormous amount of labour, in the performance of observations in different urban centres, their transmission to Kircher and their tabulation.
Politically, it has often been observed that the Jesuit order has a monarchical organizational structure, with great emphasis on obedience to commands issued to the periphery from the Roman center. Such a structure, to be contrasted with the capitular structure of the older monastic and mendicant orders, clearly lends itself extremely well to projects like the measurement of global magnetic variation.  One of Kircher's more expert correspondents on magnetic matters, the French Jesuit Jacques Grandamy, made the congruence of absolute power and global observation very explicit when he suggested in a book published four years after Kircher's Magnet that kings and princes should order their subjects to measure magnetic variation diligently in the cities of under their rule, and that the General of the Society of Jesus should order his subordinates - Jesuit priests and lay brothers in different parts of the world - to do the same. Although Kircher makes frequent reference to a "Republic of Letters" in his works, both he and Grandamy are clearly conscious that in the world in which they live, the command of an absolute authority, whether secular or clerical, was the most effective way of galvanising observers into action.
The letters sent to Kircher by his Jesuit informants reveal the difficulties of constructing a collective experimental enterprise. Joannes Ciermans, writing to Kircher from Louvain, writes in highly charged language: "Although the sky here is cold and cloudy, this is not true of my breast, under which something is warm and lives in ready obedience to Your Reverence. To accumulate together in the Father that which you estimate to bring splendour to his name and to that of our Mother, the Society, you will have a strong helper in me if you wish. For we know that it is not for one man to repair [instaurare] astronomy and geography, but requires the works of many mathematicians to be gathered together in one." In Lithuania, on the request of the Provincial, Oswald Krüger took time away from his cooking-duties to observe the magnetic declination of Vilnius and two neighbouring towns and wrote to the Polish Provincial to encourage Jesuit mathematicians in the Polish province to do likewise.
A correspondent in Mainz, a city where Kircher had previously taught for several years, though keen to send Kircher his measurements, was unable to be of any use because the marauding Swedish armies had taken every mathematical instrument in the Jesuit college, down to the last pair of compasses. At the other end of the scale, Jacques Grandamy boasted of a new instrument which he had designed to measure both magnetic declination and inclination, or dip, with the utmost accuracy. Others clearly didn't understand what they were supposed to do, and asked Kircher for clarification, while sending observations of questionable meaning. Along with the numerical measurements, Kircher's obedient observers often sent diagrams and other information to make their observational practices as transparent as possible to the "mathematical prince of our Society" in Rome [fig. 3].
Occasionally the task of observation was delegated by Kircher's correspondents to their subordinates: "The declination of the magnet from the Meridian, required by Your Reverence, has been investigated by Master Gaspar Schiess, the private mathematical disciple of Fr. Cysat", Jacobus Imhofer wrote to Kircher from Innsbruck on 15 January 1640. "He has used various needles, all of which disagree with each other, some indicating 4, some 6 and some 10 degrees [of declination]. He says that he is waiting for the arrival of Fr. Cysat, who has the best magnets locked-up, and that he will then make observations most diligently and send them to Your Reverence." Jesuits worldwide begged Kircher to turn them into more efficient measurers. "If Your Reverence has some information about this practice", wrote Jacques Durand, "I would be most grateful if you could send it to me". Some sent reflections of a philosophical nature, querying the source of terrestrial magnetism, and Gilbert's suggestion that the earth was a large magnet. Others reported on magnetic magic, particularly Francis Line's magnetic clock composed of globe suspended in water that rotated to indicate the hours of day and night, reputedly driven by a cosmic force emanating from the sun.
Martino Martini himself provided Kircher with a vast number of measurements made during his voyages, from Portugal to Cape Verde and the Azores, from Goa to Macao. Martini was also perhaps most optimistic amongst Kircher’s correspondents of the possibility of solving the famous problem of longitude. A letter he wrote to Kircher from Goa, later published proudly in the Magnet, claimed that “the discovery of longitudes by the magnet is no longer held by me to be impossible, indeed, I believe it has already been discovered”. Martini’s extravagant claim was followed by a description of a technique for using a chart marked with magnetic meridians to calculate longitude.
However, a number of correspondents wrote independently to advise Kircher of some anomalous observations recently performed in England. The measurements of magnetic declination performed in Limehouse by William Borough, Edmund Gunter and Henry Gellibrand appeared to show a decrease in magnetic declination between 1580 and 1634. Mersenne, Gassendi, Pierre Bourdin and Jacques Grandamy all reported the same phenomenon to Kircher in their letters and speculated on its possible causes. Similar changes had been observed by Jesuit mathematicians in Rome and Bologna. Although Kircher recognized the difficulty which such observations posed to his project of using charts marked with lines of equal declination to calculate longitude – if magnetic declination in a single locale was unstable, the value of such charts would be at best temporary – he was hesitant to pronounce on the cause of this phenomenon, and effaced many of the cosmological speculations of his informants from the published work.
There is a fine balance, in this episode, between acknowledging the fallibility of the single observer or instrument and emphasising the immense power of a Jesuit experimental collectivity. Kircher's reaction to the observations of the English mathematicians, which were eventually to quash hopes for a geomagnetic solution to the problem of longitude, is indicative of this tension. Every observer was born with original sin in Kircher's world. "A perfect observation, free of all error and falsehood could only be carried out by an angel", he claims in Magnes, so mere mortals must acknowledge their fallibility before jumping to conclusions of the nature of terrestrial magnetism or other questions of cosmological import. "While I assert this", Kircher continues, "nobody should think that I wish to detract from the most useful and absolutely necessary study of observations. I only wish to show how much caution, circumspection, industry and indefatigable labour is required in making observations, for them to be reliable".
Kircher's 1646 Ars Magna Lucis et Umbrae renewed Kircher's promise to publish his Consilium Geographicum for the collective restoration of all terrestrial knowledge. In the meantime, he provides his readers with a Horoscopium Catholicum - a composite sundial in the form of an olive tree representing the different provinces of the Jesuit order that Kircher displayed to visitors to his museum in the Collegio Romano [fig. 4]. When a stylus was placed in each Province, and the device was positioned vertically so that the Roman time was given correctly, the clock allowed the time in all the different Jesuit provinces to be read correctly. In this way, the viewer could perceive that the Society of Jesus was performing its religious duties - masses, confessions, sermons and catechesis - throughout the world, day and night, with no interruption and in all known languages.
Following emblematic themes developed in the 1640 Imago Primi Saeculi Societatis Iesu, [Image of the First Century of the Society of Jesus] celebrating the first centenary of the Jesuit order, Kircher's universal horoscope is the apotheosis of Jesuit globalism and pious synchronicity. Initially a cruciform version of the paper instrument was displayed, and dedicated to the new General Vincenzo Carafa on the day of his election. Surmounted by a Habsburg eagle, carrying an Austrian [Austri-acus] compass-needle, a feature removed from the Amsterdam edition of the Ars Magna for the peace of mind of a Protestant readership, the olive-tree sun-dial was designed so that the shadows of the small gnomons, when aligned, spell the abbreviated name of Jesus, IHS, which appears to 'walk over the world' with the passing of time, like the synchronized, uniformly trained members of the Jesuit order who used the abbreviation as their symbol. Kircher's idealised Jesuit geography, placed on display to visitors in the Roman centre, situated the prime meridian emphatically in Rome.
But what of the great Geographical Plan? Giambattista Riccioli wrote to Kircher in 1642 to ask about when the Consilium Geographicum might at last appear in print. Riccioli had collected a vast number of observations himself, and conducted a lengthy series of experiments on precision time-measurements using pendulums which he applied to making eclipse observations. In some ways providing a competing model to Kircher's distributed information-community, Riccioli surrounded himself with local disciples willing to observe pendulum oscillations for consecutive periods of up to twenty-four hours at a time, and extremely precise observational instruments.
Riccioli's impatience to see Kircher's Consilium Geographicum in print was in vain. In the 1654 edition of the Magnes, edited and amplified by Kircher's disciple Gaspar Schott, it became clear that the great geographical plan would never be revealed. "When I was keeping the work, composed with no small effort, amongst other things, in my Museum, and waiting for the right moment to publish it for the good of the Republic of Letters”, Kircher wrote, “it was secretly removed by one of those people who come to me almost every day from all over the world to see my Museum". Kircher's project for a universal reform of terrestrial knowledge through the concerted agency of the Jesuit order was stolen!
The mysterious theft of the Consilium from Kircher's museum conveniently relieved him from the need to produce a method for determining longitude by magnetic declination, an obligation that had become increasingly complicated by further observations of the temporal instability of declination, despite the optimism of Kircher's Jesuit disciples for the magnetic reform of geography and hydrography. Even before the disappearance of the Consilium, Kircher's longitudinal concerns had swung decisively landwards. He wrote to Gassendi in 1642 to say that Cardinal Francesco Barberini was urging him to coordinate eclipse observations, in the same way that he had coordinated measurements of magnetic declination two years previously. As with the declination observations, Kircher demanded that his informants on eclipses provide him with all of the details of the circumstances under which the observations were carried out, the names of those who were present as "indicators [indices] and witnesses of the said eclipses".
Giambattista Riccioli probably received a similar request at this time. In any case, he wrote to Kircher shortly afterwards to say:
I have exquisite instruments [organa] in which, for reasons explained in an astronomical work that I have in my hands, I place my trust more than in those of Tycho himself, even though that great man got very close to the truth. I also have four of ours [i.e. Jesuits] who are extremely well trained and are both my witnesses and my assistants in conducting observations.
In the end, it was Riccioli, not Kircher, who published a Reformed Geography, incorporating many of the observations previously published by Kircher into his tables and adding observations performed by himself and supported by the financial resources of the extremely wealthy Grimaldi family of silk-merchants. Well before he did so, however, he was subjected to a process of censorship that reveals something of the tension between local and non-local modes of natural investigation in the Jesuit order.
On 24 November 1646, Riccioli was forwarded a copy of an anonymous censure from Rome. The letter requested him to "send to Rome that part of his work which is entitled 'On my own Discoveries', so that it can be known what he will put forward that is new with respect to the most excellent artificers Tycho, Kepler and Lansberg whose expenses in this matter of such great importance were supported for all their lives by Emperors and Kings". The anonymous Censor also asked "What methods and instruments were used to observe the motions of the stars", and insisted that Riccioli "should also send that part of the work which he calls Instrumental Geography, so that it can be known from this what method he will use in emending and assigning the true longitudes of regions. For this is a task not for a single man, but such as deserves the unanimous collaboration of all the mathematicians of the Society".
The tone of the censure clearly recalls Kircher's geographical project, and, indeed the handwriting of the anonymous text is a convincing match with Kircher's letters from the period, providing further confirmation of his authorship. Riccioli sent a chastened official response to the Roman Censor, but Kircher sent a further, private letter to him at this time that included a number of more damning criticisms voiced by other people both inside and outside the Jesuit order. To this second letter, Riccioli responded at some length.
Dismissing as absurd the criticism that Riccioli, a theologian, should not engage in mathematics because it was "unbecoming for a single person to profess two different faculties", Riccioli invoked a number of illustrious polymaths, ranging from Thales to Tycho Brahe and Kircher himself. "To speak freely to you", he continued to Kircher, "it was worthwhile procuring a vacation from theology, and refusing the administrative offices that I was offered more than once, acquiring from whatever source the money necessary for the construction of instruments and observational glasses, and wearing away my health by so many long night vigils, that all of whatever mind I had, nay, not mind, but back and upper-arms, has been expended as if from rolling a great weight ahead of me." Riccioli also defended himself strenuously against the accusation that he relied solely "on the judgements of [his] pupils", inverting the traditional Jesuit hierarchy of authority. The following objection, however, was that Riccioli was a "private man" - "that is, as I interpret it, that I do not supply the expenses necessary for this business, but that they are supplied by my disciples from most noble families, Fr. Alfonsus Gianoti rector of this College, Marquis Cornelius Malvasia and, in the first place, by the Grimaldi, a most opulent family of this city". Riccioli did not deny the charge - "Certainly our metal instruments are present in the college, and I did not create them out of nothing". However, the expenses incurred in instrument-building were justified by their capacity to enhance the reputation of the Society for mathematics and to bring direct returns:
To inspect and to be witnesses on one occasion or another, were not only ours [i.e. Jesuits], but also other men of this city, and they were astonished by the agreement of the different instruments, directed towards the same star, to the minutes. And, among others the same Rocca [i.e. Giannantonio Rocca] remarked that he would trust (hold back your envy of the word) my observations no less than those of Tycho himself. Dr. Antonio Roffini was so captivated by [the instruments], that although he was previously hostile to ours [i.e. the Jesuits], he will bequeath his library, most richly provided with mathematical books, to our College.
Perhaps most revealingly, Riccioli politely refused Kircher's request that he should move to Rome:
I say sincerely that there are reasons why I cannot do so without great damage to my work. Where you are, I cannot hope for the instruments and the books which, in addition to the library I already mentioned, I am given freely by the Marquis Malvasia, P. Cavalieri, P. Ricci, Dr. Manzini and others who are extremely well provided with them, far less the enormous gnomon which I use in the church of S. Petronius. Two Coriolians, engravers of figures in wood that are so fine that they seem to be in copper, and who are now obliged to me, as is the caster of new print-characters; the said D. Cornelius Malvasia Vexillifero, now a Senator, who encourages me and helps to cover my expenses together with the Most Eminent Cardinal [Girolamo Grimaldi] , who also expects the book to be dedicated to him -- all of these, I say, I cannot hope to find elsewhere.
Where Athanasius Kircher saw the acquisition of natural knowledge as operating through a centralised global epistolary network of Jesuits, Riccioli's project was irretrievably local. Apart from his own body, he could not even send the parts of his book that Kircher requested from Bologna to Rome because "the affectations of my health and my stomach pains" rendered copying out the different parts of the book an impossibly arduous task. 
Local patronage, books, instruments, artisans, and Ignazio Danti's utterly immobile meridian line in S. Petronio -- a fitting foil, perhaps, to Kircher's universal Jesuit horoscope -- conspired to prevent his removal to Rome.  Where Kircher concentrated his energies on marshalling a distant community of observers, Riccioli cultivated close local friends and disciples. Too close, occasionally - his celebrated relationship with Francesco Maria Grimaldi extended to allowing the latter to shave him and cut his hair, and the tendency for the older Jesuit to entertain his younger disciple in his bedroom late at night, after the other members of the community had gone to bed, led to rumours reaching the ears of the General, who obliged Riccioli, against his protestations of health problems, to move from Parma to Bologna, where Grimaldi would eventually join him.
When Riccioli published his extremely influential New Almagest (Almagestum Novum), stripped of the part containing the descriptions and illustrations of his expensive instruments that had so worried the Roman censors, he acknowledged his human fallibility in the frontispiece, by giving angelic wings to the figure of the goddess Astrea, in explicit acknowledgement of the truth of Kircher’s claim that perfect observations were only possible for an angel [fig. 5].
Kircher’s ideal observer was not an angelic individual, however, but a distributed collectivity of disciplined Jesuits, equipped with mathematical skills, azimuth compasses and an efficient postal system. Kircher’s geographical project was rooted in a particularly vivid vision of the role of his order in the reform of natural knowledge, a vision of synchrony, uniform training, and the centralized accumulation and publication of missionary reports.
He is likewise one of the most naked and good men that I have seen, and is very easy to communicate whatever he knows, doing it, as it were, by a maxim he has. On the other side he is reported very credulous, apt to put in print any strange, if plausible story that is brought unto him. He has often made me smile.
Robert Southwell, Letter to Robert Boyle, 30 March 1661
The question of Kircher’s “working epistemology” is one that is rarely addressed seriously. Rather than considering Kircher as possessing a particular conception of the correct path to knowledge, he is frequently subjected to alien epistemological standards based on the rejection of precisely the kinds of knowledge that he strove to accumulate. Unsurprisingly, when these standards are applied, with their emphasis on certain and demonstrable knowledge, Kircher fails to make the grade and his more exotic claims are heaped with ridicule.
What, however, if Kircher never had any intention of creating certain and demonstrable knowledge? What if his more humble goal was to accumulate and disseminate a body of probable knowledge that would, in time, be rejected or more strongly accepted as more facts came to light? More specifically, what if his ultimate concern was to create a social structure that would be optimally suited to the accumulation of probable, not certain, knowledge? Kircher’s approach to natural philosophy would then be very similar to the probabilistic stance of Jesuit theologians with regard to moral philosophy criticized so scathingly in Pascal’s Provincial Letters.
While we await a wholesale reevaluation of Kircher’s philosophy of knowledge, the history of the conception and execution of Kircher’s Geographical Project offers us a small, but revealing window on Kircher’s working conception of the relationship between natural knowledge and the senses. In seventeenth century Jesuit culture, certainties and experiential knowledge belonged to entirely different categories, and ultimately emanated from different sources. This position was expressed emblematically in the frontispieces to numerous Jesuit works on optics, perhaps most eloquently in Kircher’s own Great Art of Light and Shadow, which depicts the sources of knowledge in descending order of clarity: sacred authority, reason, sense (aided by instruments) and profane authority [fig. 6]. Making instrumentally-produced knowledge more than probable was simply nonsensical from this point of view, a point of view that is somewhat resonant with that of one of Kircher’s most avid readers, Robert Boyle. Like Boyle, Kircher endeavoured to craft a practical, social solution to the problem of knowledge, but the solution he settled upon – a centralized correspondence network of obedient Jesuit missionaries – was rather different from Boyle’s meticulously detailed experimental histories.
Kircher’s presentation of himself as a mediator of the opinions and observations of others rather than a forger of new dogmas and certainties was, moreover, a position that was well-adapted to the intellectual climate in Rome during Muzio Vitelleschi’s thirty-year reign as General of the Jesuit Order, a period characterized by increasingly fervent persecution of Jesuits who deviated from Aristotelian orthodoxy in matters of natural philosophy. Kircher’s angelic observer, azimuth compass in hand, embodies a powerful epistemological stance, at the center of which lies individual sensory weakness and fallibility.
I am very grateful to Noel Malcolm, Simon Schaffer, Carlos Ziller Camenietzki, Moti Feingold, Paula Findlen and Nick Wilding for comments, criticisms and stimulating arguments relating to previous versions of this paper.
 Martino Martini to Kircher, Evora, 6 February 1639, Archivio della Pontificia Università Gregoriana (=APUG) 567, ff. 74r-75v, published in Martini, 1998, 61-69. On Martini, see also Demarchi and Scartezzini, eds., 1996. All documents cited from the Kircher papers in APUG may be consulted online via the Athanasius Kircher Correspondence Project, http://archimede.imss.firenze.it/kircher/index.html
 On Clavius’s mathematical academy, see Clavius, 1992, I.1, 59-89 and Gorman, 2002. On Kircher’s museum, see especially Findlen, 1995. On the mechanical devices in the museum, see Gorman, 2001.
 Martino Martini to Muzio Vitelleschi, Goa, 8 November 1640, Archivium Romanum Societatis Iesu (=ARSI), Goa 34 1, ff.81r-86v, in Martini, 1998, pp. 97-140.
 On Jesuit involvement in Portuguese trade networks, see the important study by Alden, 1996.
 Kircher, 1641. Interestingly, Stanford University’s copy of the first edition of The Magnet [shelfmark QC751 .K58 1641] belonged to the important Baroque architect and mathematician Guarino Guarini (1624-1683). On Kircher’s Magnes, and his magnetic philosophy in general, the most comprehensive study remains Baldwin, 1987. See also Hine, 1988. For a different interpretation of Kircher’s collection of data on magnetic declination to that offered here see Baldwin, 2001 (on p. 33).
 Kircher, 1641, Lib. 2, Pars Quinta. Geographia Magnetica.
 Kircher, 1654, p. 293. The first reference to Kircher’s Geographical Plan that I have been able to find is in a letter from Martino Martini to Kircher, sent from Evora in Portugal on February 6, 1639. In this letter, Martini writes: “I am awaiting the Magnetic Philosophy [i.e. the Magnes] and the Mathematical Plan [Concilium Mathematicum]” (Martini, 1998, 57-70). The “mathematical plan” to which Martini alludes is almost certainly Kircher’s geographical plan, suggesting that Kircher may have conceived it in as early as 1637, when Martini was studying magnetic declination with him in Rome.
For an analysis of the relationship between travel and data-gathering in Jesuit culture see Harris, 1996, Harris, 1999 and Hsia, 1999.
There is an enormous literature on the longitude problem, but see especially, Andrewes, 1996 and Bedini, 1991.
Van Helden, 1996
Kircher, 1646, p. 552.
See Van de Vyver, 1977.
See Bennett, 1987, pp. 53-55.
 Martini to Kircher, Lisbon, 16 March 1640, in Martini, 1998, 87-92. On Borri, see Petech, 1971 and Mercati, 1951.
Marin Mersenne, [Treatise on the magnet, 1639?], BL Add. ms. 4279, ff. 145r-146v, in Mersenne, 1932-, VIII, 754-762, on p. 761.
 Gassendi to Peiresc, n.d., n.p., published in Gassendi, 1658, Tom. VI, p. 90.
See Gassendi to Diodati, Aix, 23 April 1636, in Gassendi, 1658, Tom. VI, pp. 85-90, on p. 88. On Peiresc and Gassendi’s attempts to coordinate eclipse observations made by missionaries, see especially Wilding, 2000, 132-139.
Before changing to magnetic variation, Kircher also attempted to use Jesuit missionaries to gather measurements of lunar eclipses with the help of a paper Rota Geographica which he distributed to correspondents. See Kircher, letter to an unidentified Jesuit, Rome, 14 October 1636, APUG 561 ff. 83r-84v.
 Kircher to Mersenne, Rome, 23 December 1639, Houghton Library, Harvard University, Fms. Lat. 306. 1 (3) [A copy, apparently in the hand of Gabriel Naudé]. This letter is not published in the Mersenne correspondence (Mersenne, 1932-)
Kircher, 1641, p. 430
ARSI Congr. 7 ff. 46r-48v: Acta Congregationis Procuratorum anni 1639. Two of the Procurators present at this congregation, P. Pierre Cazré and P. Nithard Biber subsequently corresponded with Kircher directly. See APUG 567 f. 192r (Cazré) and APUG 567 ff. 128r, 172r (Biber)
Kircher, 1641, p. 430
 Demoustier, 1995
On this point see O' Malley, 1993, p. 354 and the revealing comments made by Jeronimo Nadal in his Dialogus II (1562-1565), in Nadal, 1962, pp. 601-774, on pp. 764-770 (De ratione gubernationis), especially p. 767
 Grandamy,1645, p. 83
Ciermans to Kircher, Lovanij 7. Martij 1640, APUG 567 f. 90r.
Oswald Krüger to Kircher, Vilnius, 21 July 1639, APUG 567 f. 53r
Henricus Marcellus to Kircher, Mainz, 1 May 1640, APUG 567 f. 213r
Grandamy to Kircher, Touron, 9 May 1640, 557 ff. 400r-401v, on f. 400r
Henricus Marcellus to Kircher, Mainz, 1 May 1640, cit., my emphasis.
Jacobus Imhofer to Kircher, Innsbruck, 15 January 1640, APUG 567, f. 177r
Jacques Honoré Durand to Kircher, 12 March 1640, APUG 567 f. 202r
 Lorenz Mattenkloth to Kircher, 8 March 1640, APUG 567 f. 159r, P. Grégoire a St. Vincent to Kircher, 8 March 1640, APUG 567 f. 24r-v. On Line’s magnetic clock, see Hankins and Silverman, 1995, 14-36.
 Martino Martini to Kircher, Goa, 8 November 1640, in Martini, 1998, 71-86.
Gellibrand, 1635. On this episode, see Pumfrey, 1989
See APUG 557 ff. 41r-56v, and Kircher, 1654, Lib. II. Pars V, Caput VI, p. 340.
Kircher, 1641, p. 483
See Kircher, 1646, p. 553
Kircher, 1646, facing p. 554.
On Riccioli's time measurements see Koyré, , and Galluzzi, 1977. On Riccioli's early training, see Baldini, 1996. On Riccioli's cosmology see Dinis, 1989, which includes an extremely useful intellectual biography (Chapter 1).
Kircher, 1654 p. 294. For the true anguish of Kircher’s predicament, it is hard to do justice to the original Latin: "Dissimulare hic non possum animi mei iustum dolorem, quem ex iactua praefati consilii Geographici precepi: cum enim opus non sine vigilijs elaboratum, inter alia in Musaeo meo conservarem, tempusque opportunum in lucem publicam litterariae Reipublicae bono emittendi praestolarer; ab uno illorum, qui quotidie paene Musaei inspiciendi causa ad me undique confluebant, clam subductum est".
Kircher to Gassendi, Rome, 13 February 1642, published in Gassendi, 1658, Vol. VI, p. 446.
Riccioli to Kircher, Bologna, 5 July 1642, APUG 561 ff. 177r-178v, published in Gambaro,1989, pp. 44-52, on p. 44. For an excellent analysis of astronomical culture in Bologna during Riccioli’s time, see Heilbron, 1999.
 Riccioli, 1661, For Riccioli's consideration of the longitude problem and magnetic declination see Lib. VIII, Geomecographus, Cap. 12-16.
ARSI FG 662, f. 477 r, published in Gambaro, 1989, p. 40, and re-transcribed (with amendments) in Baldini, 1996, p. 176, note 55, emphasis added.
Gambaro (1989) adduces no hypothesis concerning the authorship of the censura, whereas Baldini (1996) explicitly dismisses the possibility of Kircher's authorship on the basis of a later letter from Riccioli to Kircher. However, the letter in question, discussed below, refers not directly to the anonymous censura, but to a letter, now lost, from Kircher to Riccioli reiterating some of the points in the original censure and adding a number of other points of contention concerning Riccioli's way of life. It is from these other points (particularly the inability of a single person to be proficient in two different faculties simultaneously) that Riccioli dissociates Kircher. Taken in its entirety, the existing evidence is entirely compatible with Kircher's authorship of the original anonymous censura of ARSI FG 662, f. 477 r.
Riccioli to the Roman Censor, n.p., n.d. [Bologna, between 24 November and 22 December 1646?], published in Gambaro, 1989, pp. 70-76.
Riccioli to Kircher, Bologna, 22 December 1646, published in Gambaro, 1989, pp. 77-81.
 ibid., on p. 78.
ibid., p. 81. See Riccioli, 1651, Sig. *Ar - A2r, letter of dedication to Prince Cardinal Girolamo Grimaldi. For the involvement of Francesco Maria Grimaldi in the work see Sig. A2r
ibid. Riccioli's decline in bodily powers during the period prior to the publication of the Almagestum Novum is corroborated by the Catalogi Triennales for the period: on 15 May 1645 his "vires" are reported to be "mediocres", by 15 September 1649 they have become "imbiscelles", and by 1 October 1651 they are reduced to "debiles". See ARSI Ven. 40 ff.18v, 48v: #11 (for 1645), ibid., ff. 94v, 125v: #16 (for 1649), ibid., ff.178r, 204r: #14 (for 1651).
On the use of meridian-lines in churches, including S. Petronio, to perform astronomical observations see Heilbron, 1989 and, especially, Heilbron, 1999, 82-119.
See Muzio Vitelleschi to the Provincial for the Veneto, 13 September 1636, ARSI Ven. 1, f. 318v, cited in Baldini, 1996, p. 174, note 40.
 Riccioli, 1651, Pars Prior, XVII.
 Boyle, 1772, VI: 297-300
 On Jesuit probabilism, see especially Kantola, 1994.
 Ashworth, 1989. For an important discussion of sources of knowledge in seventeenth century natural philosophy, see Dear, 1995. On the epistemological underpinnings of “preternatural philosophy” in the early modern period see Daston, 2000, especially pp.27-29.
 On Boyle’s experimental histories, see Shapin and Schaffer, 1985, Shapin 1994.