The Correspondence of Antoine Thomas，SJ（1644-1709）as a Source for the History of Science

Noël Golvers

（F.Verbiest Instituut-Fac.Letteren，Katholieke Universiteit Leuven）

The Correspondence of Antoine Thomas，SJ（1644-1709）as a Source for the History of Science

Noël Golvers

（F.Verbiest Instituut-Fac.Letteren，Katholieke Universiteit Leuven）

Antoine Thomas—successor of Ferdinand Verbiest in the Peking Astronomical Bureau—left behind an extensive，unpublished correspondence，also interesting for the history of sciences.Among the topics：hismathematical curriculum in Europe（Douai-Coimbra）；the progress of his textbook Synopsis Mathematica；his European reference books；his role in creating—in Peking—more systematic contacts with Paris academicians；the progress of his Chinese work on algebra；his composition of other textsof a didactical import.Hismain target public was the Kangxi Emperor and the officials of the Astronomical Bureau.Hewas consulted in mattersmeteorologic，defending a purely“natural”explanation against Chinese superstitions.His competences in geodetics were also applied when measuring an“earth’s degree”.Some talents in the fabrication and manipulation of（new）mathematical instrumentsaremanifestwith regard，among others，to a“pyxisastronomica”（astronomical compass）.From this，he appears as a genuinemathematical talent，with sound didactical principles，who was very instrumental in the introduction ofWestern science in China.

Jesuit Mission，Jesuit correspondence，China，Antoine Thomas，history of Sino-European mathematics

One possible way to get a grip on a historical personality is to look athim from the perspective of his closest contacts，either relatives or colleagues，who offer—provided there are sufficient and relevant sources at hand—an original outlook‘from the side’on his activities and opinions，and show how he behaved in a social context and network.This is the way I tried to explore with regard to Ferdinand Verbiestwhen Idescribed，on the occasion of the T.Pereyra Conference in Lisbon（Oct.2008），the group dynamics and work division within the Xitang residence after the arrival of Tomás Pereyra in 1671.One othermember of this same‘group’，who joined the Jesuits in the Xitang as late as November 1685，i.e.some three years before the death of F.Verbiestwas Antoine Thomas（1644-1709），who—unlike other collaborators of Verbiest—may have had some closer relationswith the latter：as a fellow country-man（butmember of the Jesuit Provincia Gallo-Belgica，with other centers and othernetworks，and though there are no exp licit signs in the sources which prove that this element was of any relevance）and very soon also as his‘personal’assistant，secretary and expected successor at the Observatory（which had probably nothing to do with some feeling of‘regional solidarity’but had only a professional basis）.A.Thomaswas amulti-faceted characterwith rich competences，a very good observer and reporter；this and the circumstances in which he lived and worked inside China and the China Mission make his correspondence a very good mirror of the many different projects and situations，in which he was involved；here Iwish to focus on his profile as a‘scholar’，as reflected by this correspondence to Europe，looking in his letters for his particular interests，his sources，the level of his research，etc.，with particular attention to his professional interaction with the Jesuit and Chinese context.

As A.Thomas’letters have so far not been collected and have remained almost completely unpublished，I should startwith a short reflection on this basic level，and survey，to the best ofmy personal experience，the various locationswhere his letters are now preserved，without pretending to present an absolutely exhaustive，let alone a‘definite’list，a target themore unrealistic as his contacts in Europe weremanifold and diversified.①A list of letters is to be found in Mme YVESDE THOMASDEBOSSIERRE，Un belgemandarinàla Cour deChine aux XVIIeet XVIIIe siècle.Antoine Thomas1644-1709，Paris，1977，pp.157-162；recently，a reflection on Thomas’correspondence wasmade by P.Rule，“Correspondence of Antoine Thomas：a Major Source for the History of the Jesuits in China and for the Reign of Kangxi”，presented during the last Symposium of the F.Verbiest Institute in Peking（August2009）.

1.Overview of Thomas'correspondence

1.1. The by farmost voluminous group of letters is collected in the two files in the Jesuit archives of Rome；②ROMA.ARCHIVUM ROMANUM SOCIETATIS JESU（=ARSI），Section Japonica Sinica（=JS），148 and 149；other letters are dispersed over several other files，such as JS 150，157，160，etc.these were only constituted after the Jesuit archives of the General（the“Tabularium”or“Archivum Generale”）were removed in the 1870s from Rome to Exaeten（Holland），and were organized and classified in separate files in the next decades；③See on this phase of the centralarchivesof the JesuitSociety：TESCHITELJ.，DasGeneralarchiv derGesellschaft Jesu in Rom，in：Römische Historische Mitteilungen，vol.4，1960-1961，pp.247-254.the documents from these archives，which Henry Bosmans（1852-1928），SJhad used for his studies on the‘Belgian’Jesuits in China，including Antoine Thomas，he had seen either in photographs or afterwards also‘in situ’；they were first published with a reference to the“Archivesen possession de la Compagnie de Jésus”，and only later did the first Jap（onica）Sin（ica）numbers appear；this happened also with the few transcriptions of A. Thomas’s letters Bosmans had published.Basically，and quite naturally，this collection—stemming from the Tabularium or Archivum Generale in the Jesuit Curia Generalizia in Rome—contains the letters of A.Thomas to the General；some other Thomas documents—especially his Siberiamapswhich originally were part of this Archivum—had been separated from them in 1870，and were filed in the Fondo Gesuitico collection of the Archivio di Stato di Roma，and were never restituted to the Society of Jesus. 1.2. In addition，a number of fragments of information are dispersed over several other collections，reflecting A.Thomas’smany contacts，also outside the Society；this is the less well-known and most incomp lete group of letters，as we are not certain in what different directions we have to look.After preliminary research，Ihave located the following（partly destroyed and partly also very recently relocated）groups of items：

1.2.1. Letters（and other documents）from the private（Plantin-）Moretus collections，partly still in the Museum Plantin-Moretus（MPM）in Antwerp and partly dispersed since the late-19th century：Ihave collected so far 24（+1）items，from different places，which originally belonged to the private archives of the Moretus family，and published them in 2008；①GOLVERSN.，“The XVIIth century Jesuit Mission in China and its‘Antwerp connections'（II）.The twenty-five China-letters from the original Plantin-Moretus archives（MPM），1669-1690”，in LIAS 34，2007，pp.205-248；the Thomas-items are the nos.14-20.seven Thomas items are among them，covering the years 1683-1685，i.e.the period he was staying in Macau.The“Officina Plantiniana”of Moretus was，indeed，in the 2ndhalf of the 17thcentury，a turning point formail from China to the rest of Europe；not rarely thismail was accompanied by covering letters addressed to members of the Moretus family；other documents，which were not addressed to them，were transcribed by professional transcribers（‘amanuense s’）of the firm，and some of these are still preserved there today；②Onemore new Thomas document—unsigned and only extant as a contemporary copy—may be from his hand，viz.the anonymous Demonstratio Juris Imperatoris Tartari ad Possidendum Imperium Sinicum,contra Navarretem，addressed to“Rdo in Christo Patri Alexandro Bonmon Soc.tis Jesu，Duaci”，and dated 20 April1684：now in ANTWERP，MUSEUM PLANTIN-MORETUS（=MPM），M 30，f°9-16（accompanied by a letter of A.Thomas，s.d.）.

1.2.2. Some dispersed items are also to be found in the archives of the Missions Etrangères de Paris（MEP）；no particular correspondent；

1.2.3. Previously，Joseph Krzyszkowski，SJ in 1937 mentioned letters of A.Thomas in the National Library of Warsawa；③KRZYSZKOWSKIJ.，“Misyjny rekopisWarszawskiej Biblioteki Narodowej”，in Misje Katolickie，56，1937，pp.269-272.they were in all probability destroyed during the 2ndWorld War.Comparing these references to the rest of the preserved letters，it appears thatmost of the lettersmentioned are known from other collections；the only exceptions are two letters of 15.VIII.1697 and of 15.X.1695.

1.2.4. Most important，not only in quantitative respect but also for their contents，were Thomas’s letters to Maria de Guadalupe（1630-1687），the Duchess of Aveyro，hismain sponsor and psychological support outside the SJ；these letters constitute a true“correspondance suivie”，covering the years 1678-1694；these were safely kept in the private archives of the Lancaster family until the20thcentury. After they were publicly sold，the first time in 1924（Maggs Bros，London），the second time in 1963（Kraus Bookshop，New York）these letters ended up in two different private collections in Japan；thanks to splendid photographic editions，these letters are accessible to the researcher.④Recently，however，I found out that several letters，ofwhich the textwas summarized and translated into English by P. Harting，in：Biblioteca Asiatica.Part II.The Catholic Missions in India,China,Japan,Siam and the Far East,in a series of Autograph Letters of the Seventeenth Century，London（Maggs Bros.，no.455），1924 are not reproduced in the photo albums，so that the autograph texts of these items（especially nos 1281，1283，1284，1285，1286，1287，1288；1289，1292，1293，1296）can no longer be checked.See also BOSMANS，H.，“Sur les lettresmanuscrites des PP. Verbiestet Thomas，analysées dans le Catalogue n°455 de la librairie Maggs Bros.de Londres”，in Annales de la SociétéScientifique de Bruxelles，vol.47，1927，pp.14-19.

1.2.5. Five letters（1682-1689），all contemporary copies，of which one to Andreas Cleyer，Dutch physician in Batavia，and four to Alexandre（de）Bo（n）mont in Douaiare in the Archives de la Province de France de la Compagnie de Jésus:Brotier 117（Vanves-Paris）；these were part of the few dossiers which Gabriel Brotier（1722-1789），last librarian of the Collège Louis-le-Grand in Paris could save from the original archives during the confiscation at the end of the Ancient Régime（1762）；afterwards the China related files were in 1825 bought from Brotier’s descendants，and distributed among the BnP and the Jesuit Collège Sainte-Geneviève，in the Rue des Postes（rue Lhomond）;from there，they weremoved in 1901 to the Jesuit Maison Saint-Louis in Jersey，where H.Bosmans located them；afterwards transferred to the Jesuit Archives in Chantilly（ASJP），and now Vanves，under the original denomination Brotier 117；also Brotier 94（f°77-79）is a Thomas letter to François d’Aix de La Chaise.①H.Bosmans，“L’oeuvre scientifique d’Antonie Thomas”，in：Annales de la Sociétéscientifique de Bruxelles,44，1924-25，pp.180-208（passim）；on Gabriel Brotier’s papers：H.O（mond），“Chardon de la Rochette et lesmanuscrits du P.Brotier”，in：Bibliothèque de l'Ecole des Chartes,77,1916,pp.399-403；Joseph Dehergne，“Les archives des Jésuites de Paris et l’histoire desmissions aux XVIIe et XVIIIe siècles”，in：Euntes Docete,21，1968，pp.191-213（more precisely p.311）；Joseph Dehergne，Inventaire de la mission de Chine aux XVIe,XVIIe et XVIIIe siècles，1974，p.25.

1.2.6. Some items，before in the Royal Archives（“Archives Générales du royaume”）in Brussels and originally stemming from the pre-1773 Jesuit collegesare now in the State Archives in Antwerp：ARA：Archief van de Nederduitse Provincie der Jezuïeten，nos.3398 and 3414.

1.2.7. Finally，rather rare are Thomas’letters preserved among the remnants of the central archives of the Chinese vice-province in Macau，now inmid-18thcentury copies in Ajuda（Lisbon）. This brings us to the successive publication projects of this rather voluminous correspondence.A first attemptwas the transcription of the entire corpus by H.Bosmans for an edition，a project that was postponed by his death in 1928.The projectwas resumed first by Henri Josson，SJ（†1939）and afterwards in 1948 by Ms.Van Bombergen（from the Musées du Cinquantenaire in Brussels）and Henri Bernard-Maître，SJ，but due to the failed collaboration of Bernard-Maître this also remained without result.②N.Golvers，‘Henri Bosmans，S.J.，et lamission jésuite en Chine’，in：Académie Royale de Belgique.Bulletin de la Classe des Sciences,6e série.Tome XXI，Bruxelles，2010，pp.135-152.Afterwards，in the 1990s，the F.Verbiest Institute of the K.U.Leuven started the digitalization of a first series of letters（up to 1688），inserting also a series of new items discovered since Bosmans；this project，too，was prematurely（and temporarily？）stopped.

2.The sciences in this correspondence

Themain point of interest of this contribution concerns the elements to be found in this correspondence regarding Antoine Thomas’swork as a scientist in China，mostly in itsmore external or practical aspects，with only some indications as to his sources and the methods he used.Iwill basically follow here a chronological path，which enables us to recognizie some evolution or‘professional growth’in his profile.

2.1. Personal formation

I think one aspect in A.Thomas’s formation is worth being emphasized，viz.his rather early，deliberate and immediate preference for the Far Eastern missions，in which he differs from several other Jesuitmissionaries for China（“Indi-petae”，or more precisely“Sini-petae”），including Ferdinand Verbiest.Already in his letters of 27 Jan.and 24 May 1672 from Douai he had selected for himself an entire series ofmathematical sciences，explicitly in preparation of being sent to the China mission.According to his own information，this included the study of：（1）Euclid’s Elementa；（2）the calculation of solar and lunar movements，and their eclipses，followed in a third phase（3）by unspecified“aliasmatheseosscientias”；for these and other partsof his curriculum he indicated“studium privatum”as themost appropriateway.Thismay also be of importance to understand the origin of themathematical‘experience’（knowledge）of other Jesuits，more precisely F.Verbiest himself，in whose case also“studium privatum”is involved，according to such an eyewitness as F.de Rougemont.More information on thismathematical‘private study’at the basis of Jesuitmathematical talents，at least in the Belgian provinces will be discussed later on.

Another theme of his letters concerns themathematical instruction he provided，in an‘official’didactical function，to the Jesuit novices（“nostris”：‘to our fellow-fathers’）and some external students at the Colégio das Artes（Coimbra）and the composition of his SynopsisMathematica.①For amore comprehensive contribution on this treatise，itsgenesis，contents，sourcesand impact，through an analysis of the extant copies，seemy“The Jesuit Sinipetae and their Textbooks：Antoine Thomas，SJ（Namur 1644-Peking，1709）and his SynopsisMathematica（Coimbra；Douai1685；1729）”（forthcoming）.According to the“Ad Lectorem”，this work was probably already started—at least at the level of intentions—before he came to Coimbra（in 1678），but thems.was completed during his stay there，parallel and thus also in interaction with themathematical courses he taught.In fact the public of these courseswas largely the same，as several of his pupils were/would become‘Indipetae’，and his Synopsis was written as a comprehensive text book on allmathematical sciences，on a basic level，explicitly in favor of a future applicant for the Chinamission（“Sinipeta”）.In this sense，an analysis of the contentsmay give a more precise idea of the level ofmathematical preparation thatwas expected of a‘Sinipeta'in the late 1670s.②F.Verbiestalso gives an outline of themathematical competences he expected from a candidate for the China（and especially Peking）mission in his letter of1677，preserved only as a long quotation in DUNYN-SZPOT，Th.I.，Collectanea pro historia（Missionis Sinensis）facta，in ARSI，JS 109，II，pp.120-129（especially pp.123-124）.For an analysis of the contents of the Synopsis，see BOSMANSH.，“L’oeuvre scientifique d’Antoine Thomas”，in Annales de la SociétéScientifique de Bruxelles,vol.44，1924-1925，n°2，pp.169-208.One of these Sinipetae hemet later in Peking was JoséSuarez（JS 149，f°508）.This was，by the way，not so‘original’an idea，for we know that already in the 1640s，some thirty years earlier，Mario Bettini，SJconceived his Apiaria Universae PhilosophiaeMathematicae（1642）and Aerarium PhilosophiaeMathematicae as comprehensive‘textbooks’precisely for（Italian）Indipetae，in order to put at their disposal all basic or necessary texts，as a substitute for the specialized books they would not have at hand in China：“integra bibliotheca in uno libro”（to express it in Andreas Tacquet’swords）.Thomas’successive letters to the Duchessof Aveiro—the final sponsor of the publication—offer a kind of‘progress report’on the completion of thiswork，albeit only in generallines，without particular details of the contents，which were certainly not expected by his addressee. One more aspect，which interests us is that of the possible‘sources’A.Thomas used when composing his work.A previous occasion to inspect one of the rare copies revealed me the names of，a.o.，Ismael Bullialdus（Boulliau）［II，372］，Tycho Brahe，de Rojas，Claude-François Milliet de Chales，Gemma Frisius；Johann Kepler（I，250），Giovanbattista Riccioli，SJ；Andreas Tacquet，SJ（I，21；II，367；394），GodfridusWendelinus（II，367；381；406），in addition to various Ephemerides（Cassini；Longomantanus［II，515］，Lansbergius）；a thorough reading would probably reveal more names.①The closest complete copy Iknow—the one Ihave consulted—is that of the BnF（8-V-27036（1）and（2））.It remains unclear whether these references already stem from the first preparations of his Synopsis in Douai，from books he had brought with him from Belgium to China as a personal‘library’，or from the Jesuit library in Coimbra；the latter seems the less probable hypothesis，as already at the start of his teaching，he complains about the‘poor’condition of the local library，with regard tomathematical books，②Cf.his letter of 28.III and 4.VII.1678（The Far Eastern Catholic Missions，II，p.151 and 157 respectively）. Hartogvelt’s remark is to be found in his letter of23 May 1655 from Coimbra to an unnamed addressee，either Balthasar IIMoretus or his father，sent on 23 May 1655 from Coimbra，now in ANTWERP，ALGEMEEN RIJKSARCHIEF（=ARA），Fonds Prov.Flandro-Belgica，no.3407.thus repeating a remark of Ignatius Hartoghvelt，SJ（1629-1658）some twenty years before.He finished the manuscript before leaving Portugal on 4 April 1680；the dedication to the Duchess is signed in Lisbon，25 March 1680；for unknown reasons，it was published in Douaionly in 1685.Iknow only some 30 extant copies，among them two copies of a 2ndedition，published in Douai：Charles-Louis-Joseph Derbaix，1729.For a further research on the（17th-18th-century）geographical distribution of these copies，and an interpretation of this figure in the light of the application of new candidates for the Chinamission，see a next contribution.

Also in Coimbra，more precisely on 29.VIII.1678，A.Thomasmade his first observations of eclipses，mentioned in Journal desSçavans of1679（pp.63-64），under the title“Longitudesd'Avignon& de Coimbre déterminées sur les observations faites en ces deux lieux de l'Eclipse de lune du 29 Octobre dernier 1678”.③“Comme l’observation des eclipses de Lune a toûjours eu pour but principal la connoissance des Longitudes,au lieu du detail de l’Observation de cetteeclipseque leR.P.Bonfa Jesuitea faitàAvignon avec M.de Beauchamp&de celleque le P.Ant.Thomas jésuitemissionnaire de la Chine a faiteàCoimbre,nous nous contenterons etc.”.Already at this early date，the results of his observations were communicated in a French（but also international）network of scientific information.

2.2. Practical astronomer and his personal‘library'on the road

According to a briefmention in a letter of1 October 1681，④JS 148，f°24v.-25v.；cf.JS 149，f.477（Siami，1.X.1681）：“Praefectus Hollandusme humanissimeexceptit,rogavitque ut secum remanerem Tutucurini,et aliquam explanationem de praesenti cometa scriberem,onus in se recipiens procurandimihi transitum in Bataviam Novam.Scripsi igitur libellum de Cometa,dedicatum D（omi）no GeneraliBataviae,quieodem tempore traductus est in linguam Hollandicam a dicti generalis nepote,qui Tutucurinimorabatur，etc.”.Thomasmade a description of the comet of that same year，which was apparently published；a Dutch translation，manuscript or printed，was made as well，but both remain lost too.But probably already before his arrival in Siam he made asimilar description，if he is indeed the author of the“Breve Tratado do cometa que apareceu nomês de Novembro de1680,o qual tratado fes na Cidade de Goa hum Padre da Comp.a Mathematico estrangeiro que veyo do Reyno”；①Thems.copy is preserved in the University of Coimbra，see MENDES SIMOESDE CASTRO，A.，Catalogo de manuscritos（codices1 a 250），Coimbra，1940，p.205；for the attribution to A.Thomas，see U.Baldini，in SARAIVA L.&LEITAO H.（eds.），The Practice of Mathematics in Portugal，2004，pp.393-394.at least the date answers to the period A.Thomas was in Goa，a period ofwhich we have almost no echoes in his extant letters.

We are better informed on another observation Thomasmade in Ayutthaya（Siam）；for thiswe rely on A.Thomas’s letter of 29.06.1682 to Alexandre de Bonmont，sent from the‘Chinese Sea’（“exmari Sinensi”）.②Autograph in Jesuit Missions Japan；analysis in BOSMANSH.，“L’oeuvre scientifique d’Antoine Thomas”，pp.179-208.Of course，Thomas was not the first Jesuit tomake observations on the road，think only ofWenceslas Pantaleon Kirwitzer and Martino Martini；norwere these the first observationsmade by A.Thomas，aswe have heard already of his observationsmade in Coimbra and in Siam.This letter，written during his forced leisure（“otium”）on his way from Siam to Macau，describes the astronomical observations hemade，with all duemethodological“diligentia”（‘diligence’）he imposed on himself.As such，it is a typical，but in the correspondence of A.Thomas rare example of a letter with a primarily scientific purpose：to communicate the results of an observation，exp lainingwith technical detail the circumstances in which it happened，giving the exact numerical and astronomical coordinates，and referring to a small series of scientific reference books.③On the circumstances of the observations Thomas is very clear in the two opening paragraphs of the letter，which are very instructive for hismethodological professionalism：after apologizing for the observations he omitted for reasons of time，he starts emphasizing his scrupulosity：“Quantum permisit otium,feci omnino quod potui eâque diligentiâ,quae a me poterat expectari（！）.Neque deinceps id a me potest exigi,quod olim in Conimbricensi otio meo［potuit exigi］, cum nunc plus sibi temporisnova caelo inserenda sidera quam observant requirant”.The detailed explanation hemade to the attention of de Bonmontand his colleagues，as abasis for their assessmenton the reliability ofhis observations：“Ut autem R（everenti）a V（estr）a cognoscatquantum fidei cuiqueobservationi adhiberidebeat,distincte proferam instrumenta etmodum quo illae factae sunt,ne scrupulusaliquis relinquatur,ad quod vix trium annorum spatio posset responsum expectari”.See for further comments，on the basis of the reports to the French academy HENNEQUIN L.，“Les premières observations astronomiques occidentales par le Père Thomas de la Sociétéde Jésus au Siamàla fin du XVIIe siècle”，in Aséanie，13，juin 2004，pp.63-102（especially pp.63-75）.From the fact this letterwaswritten‘from the sea’（“exmari”），and certainly before A.Thomas arrived in Macau（on 4 July 1682），we have to assume that the books，towhich he refers in his letterwere at his disposal either in Siam，or rather during the journey from Siam to China；by implication，this latter assumption implies that he had these books in his‘private’luggagewhen he left Lisbon.④Ihad not the occasion to check，whether one orother of these titleswas alreadymentioned in the textof the Synopsis Mathematica.Thiswas certainly not an uncommon situation，especially not in the case of a‘professional’mathematician，as we know explicitly from other colleagues，such as P.van Hamme or Ignaz Kögler.

The reference books he mentions are：

a.Ptolemaeus.Isuppose Thomas is referring to the Almagestum（sub 8：“the Longitudo of Caput Eridani for 134 CE）；revealed are the‘notable differences between Ptolemy’s and Thomas’observations’（“tam notabilis differentia inter Ptolemaei etmeasobservationes”）；from the same context（sub 13），it appears that the results of Ptolemy were taken over from an anonymous intermediary author.On his value for the Stella Canopi for the year 138：cf.sub par.15；

b.The old Tabulae Alphonsinae；these were consulted with regard to the Stella Canopi；

c.Julius Schiller’s Tabula fixarum ex nauclerorum observationibus composita ad an.1625;taken from his Coelum Stellatum Christianum,Augustae Vindelicorum，1627（for the“Stella Canopi”）；thiswas a popular book，as it tried to substitute a Christian zodiac for the traditional one；

d.Bullialdus’s（Boulleau’s）Astronomiae Philolaicae（1stprint Paris，1645）；this was consulted more precisely for an Arabic table of 1115 published at the end（“in calce”）of this book；also consulted for the position of the“Stella Canopi”；

e.Gb.Riccioli：both his Almagestum Novum（1st pr.Bononiae，1651）and Astronomia Reformata（1st pr.Bononiae，1665）arementioned；the reference（sub 6）to the Almagestum concerns a series of relations on the use of a plumb line（“perpendiculum”）；the reference to Astronomia Reformata concerns the table of the year 1700，and Scaliger’s valuesmentioned there；

f.Gassendi in his“Epistola ad Vendelinum quae est in fine tomi 4ti Operum Gassendi”（printed 1658），used for the table of an anonymous astronomer for the year 1361（again on the position of“Stella Canopi”）；elsewhere（sub 8 of the same letter）Thomas refers to Gassendi’s longitude of Caput Eridani in 1364，taken“ex anonymo”.

All in all，these look all like authentic references，also for the details they mention.In a tentative assessment of these sources，Iwould like to point to the quite various composition of this small collection，consisting of a Classic reference work，the Medieval Alphonsine Tables，in a more recent and more or less updated but unidentified edition；some 17thcentury German，French and Italian authors；both Jesuit and not-Jesuit；not very‘new’，as they were published all between 1625 and 1665，but not out-dated，asmost of theworksmentioned were still in use：cf.F.Verbiest’s demand in the early 1670s-through Intorcetta-for Riccioli’s works and J.-F.Foucquet’s use of Bullialdus（ca.1718）. Quite obviously，what raised the author’s interestmostwere the tables they contained，and reporting observations of 1115，1361 and 1625；these‘old values’were used to confront the results of his own observations，to show towhat extent they indeed constituted progress.Ifmy assumption is correctand these books were really part of his‘personal’luggage‘in via’，this small collection reflects a careful selection of sources before he left Europe as a determined missionary and a well prepared astronomical observer；even then these few titles do not exclude that Thomas had many other books with him（for instance the books from which he quoted already in Coimbra？）.

2.3. Temporary stay in Macau

For Thomas’s stay in Macau，very little direct information remains.Yet there is one curious item，viz.an undated letter of F.Verbiest，certainly from 1683 or 1684，of which I found a unique contemporary copy in the aforementioned archives of the Moretus family in Antwerp.①MPM 30；see for the textand commentaries GOLVERS，N.，“An Unnoticed Letter of F.Verbiest，S.J.on his Geodesic Operations in Tartary（1683/1684）”，in Archives internationales d’histoire des sciences，vol.50，2000，pp.86-102.In this letter，F.Verbiest describes the geometrical problems he had experienced during his geodetic measurements in Tartary，as ordered by the Sino-Manchu Emperor Kangxi in 1682 or 1683.Therefore，he consulted an unnamed correspondent，who resided in Macau and who had more time（and more competences？）to make accurate calculations than he himself had in Peking.①MPM 30，p.19，l.18：“cuiplusestotii”；ibid.：“cum autem haec sitmaximenecessaria pro eiusmodimappis,opera pretium erit Macai diligentiâillam excolere”.This original addressee was almost certainly A.Thomas，at that time in the Colégio Madre de Deus in Macau；he is also themost plausible candidate to have transmitted Verbiest’s letter to Alexandre de Bonmont，SJ in Douai，his favored correspondent in Europe and personal link with the Académie des Sciences de Paris.As I published this letter already before，I can be brief here on this particularly important item：important，for it shows how Verbiest in Peking was already occupied with the preparations for a topographical&cartographical project of Tartary of huge proportions，a projectwhich got its continuation and conclusion only much later；it is also the only known document，to my knowledge，which shows the technical details-and limitations-of Verbiest’s own geometrical and geodetic practice/experience，and offers diagrams in addition；also only indirectly survived，in a ms.copy made by one of the local‘amanuenses’（‘transcribers’）of the officina Plantiniana in Antwerp，itgivesus a clear insight in the level of Verbiest’smathematical thinking.But it demonstrates at the same time that Verbiest had serious‘confidence’in Thomas’s professional competences as a mathematician，and consulted him for that，also before he was officially invited to Peking，precisely for this kind of support he could offer the old Court astronomer.Last but not least，it is an exceptionalwritten example，which proves that，on particular occasions，already in the 1680s a kind of‘network’of scientific communication existed，connecting Peking，over Macao，to the young European academic world，in this case in France，a practice which in the 18thcentury becamemuch more common，and a network which gotmore complex；that it was this time Douai that delivered the information required is a consequence of A. Thomas’s background.Other contacts in the same period—also including the communication of observations—were directed to Andreas Cleyer，physician of the VOC in Batavia.②Cf.A.Thomas’letter of13 October1683（with references to Gb.Riccioli，Astronomia Reformata）：cf.BOSMANS H.，“L’oeuvre scientifique d’Antoine Thomas”，pp.200 etc.Togetherwith his contacts—through A.de Bonmont，SJ—with Thomas Gouye，SJ，member of the Académie Royale des Sciences，these were really the start of the engagement of this prestigious and prominent scientific organ in the‘exploration’of China.

2.4. Presence as an‘omni-practician'in Peking

2.4.1. Therefore，when A.Thomas arrived in Peking（Nov.1686），he must have immediately been integrated in Verbiest’s activities at the Astronom ical Bureau，in the‘routine’of observation，calculation and bureaucratic reporting.Among these official reports of Verbiest were the eclipse maps，with their derivations for European addressees，the famous Type eclipsis.My research of the extant copies of thesemaps suggests that Verbiest started their diffusion to Europe—and the production of a Latin title page，which was immediately connected to it—after the arrival of A.Thomas；many of the Latin addresses and title labelswere for thatmatter alsomade（or at least：written）byA.Thomas.Some of the addressees who can be recognized in the inscriptionswere also linked to his own network of personal acquaintances，such as Jean-Chrysostôme Briséde Mon（t）pleinchamp，former Jesuit from Namur but afterwards secular priest in Brussels（1641-1724）.Maybe Thomas，more than anyone else，understood the importance of this information for European astronomers，more precisely for the control and improvement of the current tables of calculation.At any rate，this aspect of his activities he mentions only very rarely throughout his letters.The same letters show how nervous and uncertain he was on the occasion of the first eclipse he had to calculate，some months after F. Verbiest’s death，viz.the lunar one of 16 April 1688，followed shortly later by an almost complete solar eclipse on 24 May；his fear was that especially in the latter case the slightest calculation error would immediately be very apparent，in themost literal sense of the word.①JS 148，f.124v.：“Si enim tantillum cresceret ultra calculum,fiebat totalis,cum maxima famae iactura.”

An interesting question，which is raised here as well，is that of the mutual transmission of information，competences and experiences from F.Verbiest to A.Thomas and vice versa；unfortunately，but for obvious reasons in this aspect too the letters of both Verbiest and Thomas remain almost completely silent.One detail，however，may be revealing：from one sole reference in a letter of1690 we know that A.Thomas，after the death of Verbiest and his appointment as his successor at the Astronomical Bureau，at least temporarily occupied Verbiest’s personal room（“cubiculum”）；②In a letter of6 Oct.1690 to Thyrsus Gonzalez：“Hodie casu incidens in cubiculomeo in exemplar autographum Epistulae generalis PraefectiMacaensis ad P（atrem）Ferdinandum super 5 Patribus nostris Gallis,iudicavi inserendum huic fasciculo,ut R（everen）da Paternitas V（est）ra fontem ipsum videatperturbationum domesticarum”（JS 148，f.161）. On 23.01.1692 hemoved to the rebuilt Dongtang（JS 148，f°165r./v.），originally with Alessandro Ciceri，who left on 16.09.1695（ibid.，f°198）.Later hewasaccompanied by，a.o.，the“pharmacopola”（or pharmacist）Baudino and his pharmacopoea，and the French Jesuits Régis and Rhodes.there he found not only Verbiest’s personal annotations（which he intensively used in his Obituary before destroying them），and other delicate documents concerning the mission（such as a letter from Macau authorities），but also all the documentswith regard to the technical questions concerning the Bureau，and，I suppose a specialized library.③That his“cubiculum”wasalso a depository ofnewly arrived instruments—completely in linewith the Collegio Romano traditions—we know from one small remark in Thomas’s letter of4 Sept.1688：“（Imperator）laudavitmachinasplanetarum et eclipsium,quas attulerunt Patres,suntque nunc in meo cubiculo”.This‘succession’—also in terms of location—was not only a question of practical logistics，but followed the model of，for instance，the“Cubiculum mathematicum”in the Collegio Romano（from Chr.Clavius over Chr.Grienberger to A.Kircher onwards）④Cf.the observation of GORMAN M.J.，Between the Demonic and theMiraculous:Athanasius Kircher and the Baroque Culture of Machines（http：//www.stanford.edu/group/shl/Eyes/machines/p.6 ff.）.and probably elsewhere.

2.4.2. Another reference informs us the Emperor consulted Thomas on meteorological questions；this happened in 1689，on the occasion of a period of extreme drought.Probably thiswas nothing exceptional，and belonged to the current responsibility of a Chairman of the Astronomical Bureau.⑤Compare thiswith F.Verbiest’s-forced-contribution to the production of so-called astro-meteorological reports since 1677，and his description in Astronomia Europaea,chapter 10（“De prognosticis naturalibus”）.As we could expect，when asked for his opinion A.Thomas offered a very natural exp lanation for the or-igin of‘rain’，viz.vaporization on the earth’s surface followed by condensation in the higher areas of the air；in case of great，long lasting heat，the vaporization is almost inexistent，and the air is too warm to generate condensation.This is an explanation in the style of themeteorological explanations Alfonso Vagnone had given with regard to the origin of rain，in his Chinese treatise Kong jigezhi（ca. 1633）.①“Quae esset causa tantae siccitatis（…）：duas praecipue causas ad efficiendam pluviam concurrere,scilicet vapores ascendentes e terra,ac frigus in aerissuperiori regione,quo iivapores tenues in aquam concrescerent;hoc autem anno exiguos//admodum e terra vapores assurgere superioremque aeris regionem igneis exhalationibus nunc incaluisse;unde fieret ut aliquoties vaporibus caelum impleretur,nec tamen pluvia decideret”（JS 148，f°140v.-141r./v.（28.08.1689）.

2.4.3. Precise scientific observation is of course amatter of appropriate instruments；we don’t hear much about Thomas and the building or refining of these instruments，contrary to what happens in the case of F.Verbiestand T.Pereyra.One could even argue that itwasprecisely because of the activities of the latter that A.Thomaswas not forced to spend his energy in this field.At any rate：itwas rather common that Jesuit（and other）astronomers in the 17thcentury built their own instruments，and some competences in this field are attributed to A.Thomas aswell.So，according to his own reports，Thomas built a special compass-like instrument called“pyxisquadrata”（‘square compass’），‘which combined outside an astronomical quadrant and an astronomical watch for the position of the sun，the moon and the stars to a series of drawn astronomical and geometrical instruments inside’.②JS 149，f°533v.：“Eodem tempore iussit fabricari instrumentum argenteum,inmodum pyxidisquadratae uniuspedis,in qua forissculptuseratquadransastronomicus,et in opposita partehorologium astronomicum,ad solem,stellaset lunam. Ea utrimque aperiebatur,et in singulis4 superficiebus internis,diversa erant exarata Astronomiae ac geometriae instrumenta”.All thishas to dowith the insistent demand of the Chinese Emperor for new‘devices and applications’，which was certainly one of themost dynamic forcesbehind the Court Jesuit’s occupationswith instruments，aswe can see in Verbiest’s Astronomia Europaea.③On the Emperor’s demand for European specialists inmechanics，esp.for‘horologia rotatilia’（‘gear clocks’）see also JS 148，f.318.Both the Emperor’s interest and Thomas’competences were also joined in an original composition，certainly in Chinese，on the use of the proportional compass，called in Latin“de usu circini proportionis”；④“Eodem tempore scripsi libellum de usu circini proportionis ac de logarithmorum usu,de quibus nullam adhuc notitiam acceperat”（JS 149，f.532r.；12.X.1696）.This could correspond to aChinese title*Bi ligui jie，which in fact isnot attested as a Thomas title，because itwas in all probability never printed.in one and the same breath，A.Thomas alsomentions another Chinese treatise“de logarithmorum usu”，recalling tomind that he was in the very first place a‘pure’mathematician.

2.4.4. Other geodesic measurements to determine the dimension of a Chinese“li”in accordance with ameasured earth’s degree are abundantly discussed in Thomas’Latin treatise-report，titled“de dimensione uniusgradusorbis terrae facta in Prov(incia)Pekinensi Regni Sinarum Anno1702”（148，f.589ff.：8.IX.1703）；an analysis of this reportwasmade by H.Bosmans and J.W.Witek.①BOSMANSH，L’oeuvre scientifique d’Antoine Thomas，pp.154-181；WITEK J.W.，“The role of Antoine Thomas，SJ（1644-1709）in determining the terrestrialmeridian line in eighteenth-century China”，in VANDE WALLE W.& GOLVERSN（eds.），The History of the Relations between the Low Countries and China in theQing Era（1644-1911）, Leuven（Leuven Chinese Studies，vol.14），2003，pp.89-103.

2.4.5. When in 1685/1686 the Jesuits were engaged in various projects ofwatermanagement，A. Thomaswas also involved in the building of two huge hydrau lic machines，to be transferred to the Emperor’s‘garden’outside Peking，and typologically compared to the famous“rota Bremensis”.②JS 148，f°.124v：“duaemachinae hydraulicae in villa regia,erectae ad vastum campum irrigandam”.Sunt duae magnae rotae,in quibusdam similes celebri rotae Bremensi”.This refers to the Bremen water wheel，built in 1394，which A.Thomas in all probability knew through the illustration in Cl.Fr.Milliet De Chales，Cursus seu Mundus Mathematicus（his general reference work anyway，also in the SynopsisMathematica），Tomus Secundus（in the 1674 ed.），and Tomus Tertius，p.164 of the1690 edition.On thiswaterwheel，see Herbert Schwarzwälder，“Das Grosse Rad an derWeserbrücke in Bremen”，in：Frontinus-Gesellschaft，ed.，DieWasserversorgung in der Renaissancezeit. Von Zabern，Mainz，2000，pp.219-226；an illustration is in Wikipedia：http：//de.wikipedia.org/wiki/Wasserkunst-（Bremen）.Iowe this information to Albert Koenig（Berlin），for which Iam very thankful.

2.4.6. But probably themost genuine aspect of Thomas’talents we find in his repeated didactical comm itments in mathematics-both in oral and written form—which we find at differentmoments of his curriculum.After his first period in Coimbra，which Idiscussed before，there are themathematical lessons to the Emperor，accompanied—as during his Coimbra period-by the composition of a textbook on algebra，the developmentwe can follow through his letters：starting in 1694，he continued working on it—apparently with the help of Alexander Ciceri，SJ③Alex.Ciceri’s stay in the Dongtang residence can be situated between January 1692（cf.JS 148，f°180）and September 1695（ibid.，f°198v.）.—also the following year 1695，writing in the Palace，as the Emperor feared this precious knowledge would become more generally spread；after some interruption，the work was resumed and finished in 1700，but still in 1704 A. Thomas shortly reports living for awhile in the Palace，as the Emperorwould‘repeat’the same algebra，as a“repetens”student in the best of Jesuit traditions.④For the testimonia，see the appendix at the end of this text；on this Algebra-textbook text，see Han Qi，“Antoine Thomas，SJ，and his Mathematical Activities in China：A preliminary Research through Chinese Sources，”in The History of theRelations Between the Low Countriesand China in theQing Era（1644-1911），ed.W.F.VandeWalle（Leuven：Leuven University Press，2003），pp.105-114.See also Han Qi&Jami，C.，“康熙时代西方数学在宫廷的传播——以安多和《算法纂要总纲》的编纂为例”（The Circulation ofWestern Mathematics at the Court during the Kangxi Period：A Case Study of the Compilation of the Suanfa Zuanyao Zonggang by Antoine Thomas），自然科学史研究（Studies in the History of Sciences），22：2（2003），145-155（in Chinese）；JAMIC.，A discreetmathematician:Antoine Thomas（1644-1709）and his textbooks，in GOLVERS N.&LIEVENS S.（eds.），A Lifelong dedication to the China Mission:Essays presented in honor of Father J.Heyndrickx,CICM（…）.Leuven Chinese Studies，XVII（Leuven，2007），pp.447-468.Elsewhere，in 1708 we also hear of his mathematical lessons to Kaspar Castner and Luigi Gonzaga，this time in the buildings of the Dongtang.⑤JS 149，f°460/1：“erudiendos in rebusmathematicis”.

2.4.7. Finally，to complete this already multicolored picture I could mention still other projects，realized or not，such as hismap of India（149，f.483r.：1.XII.1681），the mapping of the GreatWall（149，f.460v.；464r.）；the successive stages of hismap of the“itinera terrestria ex Europa in Chinam,et e China in Europam”（149，f.518 r./v.；arrived in Rome on 19.X.1692），but these are only very brieflymentioned in his correspondence，while others（such as hismap of the route（s）between China and Europe）deserve a separate study，also in comparison with the data on Verbiest’s map of the same route.

3.Concluding observations

However‘marginal’the theme of sciencemay be in this correspondence，it reflects A.Thomas as a professional mathematician，demonstrating his methodological discipline in observations，and his‘versatility’in looking for new applications in the domain of instruments，of the same kind we also find in F.Verbiest.Although his letters contain nothing very spectacular，and are by far not of the level of the correspondence of Antoine Gaubil or Ignaz Kögler，yetwe are confronted herewith several‘epoch-making’scientific projects of the Jesuits in China in their very first phase：the geodetic measurements for the Tartarmap；the measurements of the terrestrial degree；the‘algebra-project’，the start of amore‘professional’communication network with European academic institutions，in the first place the Académie des Sciences.

As far as we can see，of the Jesuitmissionaries in China A.Thomas was indeed the first—since Johann Terrentius（†1630）①On Terrentius’scholarly correspondence from China to Europe，see the documents published by GABRIELIG.，“Giovanni Schreck Linceo，gesuita emissionario in Cina e le sue lettere dall’Asia”，in Rendiconti della Reale Accademia dei Lincei,Classe di Scienze Morali,Storiche e Filologiche，serie VI，vol.XII，5-6，1936，pp.462-514.—who was interested in a more systematic learned communication with European colleagues，both in reporting on his own observations and updating the sources of information he had at his disposal，more than his immediate predecessors，including Verbiest.Ifmy analysis of the extant evidence does not deceive me，the latter also only started to send copies of his eclipse maps，calendars and other astronomical‘documents’to Europe in 1686，i.e.almost immediately after the arrival of Antoine Thomas in Peking.This points to a changed attitude of Verbiest towardshis European basis，which may have been inspired by Thomas，who knew the importance of astronomical observations from outside Europe for the improvement of tables and maps.In thiswe certainly see the influence of his own professional formation，the level of his know ledge，and，last but not least，the atmosphere of the new European scientist and academician，who was in preparation.In this sense，and according tomy assessment，A.Thomasmay be the transition between the‘older’generation of Jesuit-scientists in China，of whom Verbiestwas the last，and the‘modern’one，which Thomas announced butwhich manifested itself definitely in the generation who arrived about1720，with Kögler，etc.

N091：O11

A Article ID 1000-0224（2014）02-0131-14

Received：2014-04-05

Biography：Noël Golvers（1950-），PhD Classical Philology，Senior Researcher at the Katholieke Universiteit Leuven，and lecturer of Latin at the Katholieke Hogeschool Leuven，studied since themid-1980s Latin（Portuguese，etc.）texts on the Jesuitmission in China，especially in the early Qing period.