T  H  E      S  C  I  E  N  T  I  F  I  C       R  E  V  O  L  U  T  I  O  N
C O R R E S P O N D E N C E     N E T W O R K S
Dr Robert A. Hatch  -  University of Florida

Letters were the most common form of writing in the seventeenth century. Because they were 'swift, certain, and cheap,' letters were easily adapted to the needs of the New Science and quickly earned an enduring niche in the exchange of information. Throughout the Scientific Revolution, the size and number of 'correspondence networks' continued to expand, and in the course of the century, 'intelligencers' adapted the Renaissance ideal of a Republic of Letters to the realities of the New Science  -  a learned world divided by time, distance, and censorship. 

Although historians have long acknowledged the importance of scientific correspondence, no synthetic study of 'intelligencers' or detailed analysis of correspondence networks has been undertaken. Scholars generally agree, however, that as traditional boundaries of learning were redrawn (between universities, court culture, private patronage, and informal societies) new lines of communication emerged with the expansion of the postal system and increased use of print. Some scholars have focused on the mid-1660s. In these accounts, if the first half of the century was marked by the proliferation of private societies and correspondence networks, the second half was dominated by state-sponsored academies and printed journals. Although 'explicit theories' about these changes have yet to appear, several scholars, among them Elizabeth Eisenstein, have suggested that 'intelligencers' were 'replaced' by the periodical press. What remains unclear is the nature and pace of these changes. 

However humble and ordinary, handwritten letters were a powerful form of communication and a fact of daily life. By existing standards, letters were not only convenient and inexpensive, they were the fastest and most unrestricted form of science writing. From the first decades of the century, letters could be sent and received within weeks anywhere in Europe, and before the century was over, the 'ordinary' post combined with diplomatic couriers to establish wider, faster and more reliable service that extended to the Levant. 

The letter was particularly suited to a small, diverse, and isolated community. Although book stalls and salons were popular meeting places, most members of the Republic of Letters never met face to face. The letter was perfectly suited to these conditions, as it easily cut across traditional boundaries of space, time, language, class, and confessional domain. The speed of the letter made it useful for organizing simultaneous observation of events (for example in astronomy), and for disseminating and comparing 'time sensitive' information from widely dispersed sites. 

Characteristically, scientific letters were relatively free from censorship. In an age of vested interests, regimentation, and systematic persecution, the great correspondence networks were unrivaled throughout the century as a vehicle for 'free' expression. Letters could be dangerous; but with proper precautions, controversial issues circulated freely 'under the cloak' or under the 'seal of friendship.' Here questionable opinions were often expressed in 'half-words' or with full-blown irony, that is, with a meaning clear to the recipient but not (should the letter be intercepted) to a potential censor. Less rhetorical precautions were also employed.  Strong opinions were often written in a second language or, if particularly suspect, in personal code, cipher, or anagram. When anonymity was required, authors often replaced their signature with a pseudonym, acronym, or simply sent the letter unsigned. Ironically, while these 'masks' veiled authorship and collusion from public view, they also tended to dramatize identity and group cooperation within the community. Free thinkers had to be thick as thieves. 

Freedom of expression took various forms, from idle gossip to critical debate. Against the claim of several historians, no issue was beyond discussion, indeed, ridiculing Richelieu or commenting on the undergarments of Queen Christina was fair game. Many topics flirted with heresy or reprisal. Even in the 1630s scholars 'openly' discussed the Galileo affair, Copernicanism, immortality of the soul, and the mysteries of transubstantiation. Unthinkable in print, private opinions shared in these letters would not be publicly debated until the next century. In this context, the significance of Galileo's trial might easily be 'misconstrued' if judged solely on the printed word--whether from the 1630s or the mid-1660s. Here 'public opinion' and 'public reason' were dubious ideals in the face of certain realities-- excommunication, incarceration, or execution. 

Practical considerations, however, do not account for the traditional form or changing dynamic of the Republic of Letters. Here harsh facts were often softened by social convention, though the appearance of stability sometimes masked subtle change. If the Republic of Letters was an ideal community and a working reality, justice and enforcement reflected ancient codes as well as existing hierarchies. Aristocratic in structure, the Republic underscored group virtues of modesty and cooperation undergirded by self-control, personal honor, and intellectual tolerance. In practice, classical virtues supplied legitimacy while serving to minimize competition, conflict, and threats of external control. Although 'Citizens' extolled the virtues of 'humanity'--the privilege of friendship, reciprocal service, and the unity of knowledge--daily commerce exposed unequal relations. Truth, friendship, and power were continually re-negotiated. 

To all appearances, the Republic of Letters reflected civil society more generally, its patterns of patronage and forms of polite conversation. But scientific correspondence challenged more substantial matters. Arguably, letters supplied what daily relations lacked, they socially intervened and personally persisted as no printed text could. Although epistolary conventions continued to reflect stability and order, the daily circulation of scientific letters tended to erase social boundaries while the New Science shifted grounds of knowledge and belief. If the New Science undermined the old order--and there is evidence it did--scientific correspondence challenged traditional hierarchies by substituting natural ability for social status, acquired skill for inherited wealth. 

More than any other form of science writing, correspondence opens an historical window on these changes. Spontaneous and fresh, letters show science in the making. At the most practical level, letters help historians pinpoint the date of an observation or experiment, or more generally, they explain problem selection, changes in approach, or the fate of a failed hypothesis. Letters sometimes provide frank appraisals of the work of others, and often supply the only written record of private activities, friendships, and rivalries, not to mention the collaborations, controversies, and inner workings of informal groups. Unlike the printed book, letters repeatedly fail to separate public and private. At their best, they tell the story behind the book--the first inklings, second guesses, second thoughts. 

A great deal of scientific correspondence has been published. While the best known editions are associated with the major figures of the Scientific Revolution-- Copernicus, Tycho Brahe, Kepler, Galileo, Descartes, Pascal, Hobbes, Flamsteed, Huygens, and Newton-- the major 'intelligencers' (discussed below) are also well represented. Serving as 'unofficial secretaries' in the 'Commonwealth of Learning,' these self-styled 'conduit pipes' sent and received letters which were often copied, forwarded, circulated in groups, and read aloud at informal meetings. Though often described as 'invisible,' these correspondence networks were real and their 'geography' can be mapped. Surveyed in sequence, they offer a glimpse of the Republic of Letters in transition. 

Known as the 'Prince of Erudition,' N-C Fabri de Peiresc (1580-1637) once sent 42 letters in a single day, and not uncommonly he sent two or three to the same person. At his death he left some 10,000-- 14,000 letters, about half of which are extant; of these some 3200 letters (to or from Peiresc) have been published (1598--1637). Boasting nearly 500 correspondents throughout Europe, Peiresc's network focused on the 'major centers' of learning, particularly Paris and Rome. Although he took an active interest in astronomy and optics-- and conducted numerous experiments and dissections-- Peiresc's chief influence was mediating intellectual commerce across space, time and theme, traditionally representing the translation of learning from Italy to France, Provence to Paris, Humanism to 'Science.' 

One of Peiresc's chief contacts in Paris came to be known as the 'mailbox of Europe.' Representing the second generation of 'intelligencers,' Marin Mersenne (1588-1648) was a prominent publicist for Galileo and a principal correspondent of Descartes. His interests in mathematics, mechanics, music, theology, and languages are immediately evident in his published letters (Correspondance du P. Marin Mersenne, 16 vols., 1932-1986). Often cited as one of the major networks of the century, the actual number of letters (to or from Mersenne, 1617--1648) is surprisingly small (1,100), the early years actually containing more entries for Peiresc. Although it focused heavily on relations between Paris and the provinces, Mersenne's network dominated the second quarter of the seventeenth century. Its importance was in cutting across national and religious boundaries that traditionally divided France, Belgium, England, Germany, Holland, and Italy. 

Samuel Hartlib (c.1600-1662) was known to contemporaries as the 'great Intelligencer of Europe.' Committed to 'universal learning,' Hartlib was a tireless promoter and his correspondence supplies an important context for understanding reform movements (educational, religious, utopian) and the 'useful arts' (agriculture, commerce, medicine). The vast majority of Hartlib's letters (letters sent) are presumed lost, though some 2000 letters sent to Hartlib for the years 1640--1661 have been published in electronic form (CD Rom). Although Hartlib was not a practising 'scientist,' the significance of his network is its portrayal of learning during the middle third of the century and the clear outline it provides of an emerging 'Invisible College.' 

A friend of Peiresc and Mersenne, Ismaël Boulliau (1605-1694) represents the middle generation of 'intelligencers.' Although his letters have not been published, Boulliau's network was one of the most extensive of the century, representing some 5,000 letters for the years 1632--1693. An early Copernican and admirer of Kepler and Galileo, Boulliau used his network to coordinate and compare astronomical observations, and he was a major correspondent of Gassendi, Hevelius, Leopold, and Huygens. Although his letters reflect strong interests in classical studies, philology, politics and diplomacy, the significance of Boulliau's network is its sharper scientific focus and broader geographical scope, which now stretched beyond France, Holland, Italy, and England to Poland, Scandinavia, and the Levant. 

Henry Oldenburg (1618?-1677)--first Secretary of the Royal Society and editor of the Philosophical Transactions (1665)--has been called the English 'clearing house' of science. As his letters make clear (Correspondence of Henry Oldenburg, 13 vols, 1975-1986), Oldenburg sought to realize Hartlib's hopes for a universal 'office of address.' Oldenburg's published correspondence includes some 3,100 letters for the years 1641-1677. As editor and 'intelligencer', Oldenburg extended his network beyond Europe and the Levant to the American Colonies, and the frequency of his letters as Secretary is unrivaled by any predecessor. 

From the earliest decades of the Scientific Revolution letters foreshadowed and underwrote subsequent forms of 'scientific exchange.' As is clear from Oldenburg's career, handwritten letters were daily facts of life that entered his work from start to finish-- as part of the editorial process and as 'prototype' for the final published product. The difficulty embodied in Oldenburg's career as 'intelligencer' and editor is not in distinguishing two roles, two functions, or two technologies but in imagining how 'scribal and print culture' could be 'kept apart.' The mistaken impression that printed journals 'overshadowed' or suddenly 'replaced' intelligencers overlooks the order and pace of events, it assumes competing technologies, it separates facts of life that actually belong together.

    Robert A. Hatch


Dewald, Jonathan.  Aristocratic experience and the origins of modern culture, France, 157-1715.  University of California Press, 1993. 

Eisenstein, Elizabeth L.  The printing press as an agent of change:  Communications and cultural transformations in early-modern Europe.  (2 vols) Cambridge, 1979. 

Goodman, Dena.  The Republic of Letters:  A cultural history of the French Enlightenment.  Cornell U. Press, 1994. 

Goldar, Anne.  Impolite learninng:  Conduct and community in the Republic of Letters, 1680-1750.  Yale U. Press, 1995. 

Hatch, Robert A. 'Between Erudition & Science: the Archive & Correspondence Network of Ismaël Boulliau.' Archives of the Scientific Revolution:  The formation and exchange of ideas in seventeenth-century Europe.  (Chpt. 4) Boydell & Brewer, 1998. 

Hatch, Robert A. 'Peiresc as Correspondent: The Republic of Letters & the Geography of Ideas.'  Science unbound:  Geography, space, discipline, (Chpt. 1) Umeå, 1998. 

Sutton, Geoffrey V.  Science for a polite society, Westview Press, 1995. 

Ultee, Maarten. 'The Republic of Letters: Learned Correspondence, 1680-- 1720.'  Seventeenth century II, no. 1 (Jan. 1987): 95-112.

A version of this brief article will appear in The Scientific Revolution, ed. by W. Applebaum, Garland Publications (In-Press, forthcoming - 1999).