Chair:  Henk Meijer, Head Science Department, Roosevelt Academy, Middelburg

Henrique Leitão, Centro de História das Ciências, Universidade de Lisboa, Portugal

In the years 1615-1617 the Italian Jesuit Giovanni Paolo Lembo (1570-1618) taught the mathematical course at the Jesuits’ college in Lisbon. Lembo had played a central role building telescopes and carrying out astronomical observations at the Jesuits’ Roman College during the hectic months between 1610 and early 1611; indeed, he had made many observations independently of Galileo’s findings. Years later, in his mathematical course in Lisbon, among other subjects, he addressed many topics related to the telescope.

Lembo’s lecture notes provide direct access to the ideas and the knowledge of one of the most competent and skilled users (and builder) of early telescopes. The students who attended that course were exposed to detailed discussions of the new astronomical observations and to lengthy analysis of their cosmological implications. Perhaps even more important, they were instructed on how to make a telescope as Lembo gave specific and practical indications about its manufacture.

Lembo’s notes have been mentioned in the literature, but no detailed description of its contents and importance has ever been made.  In this presentation I will not only examine in detail these notes but will also describe the profound impact this course had in Jesuit scientific circles in Lisbon.

Antoni Malet, Universitat Pompeu Fabra (Barcelona) - REHSEIS (Paris)

The making of the first telescopes used in astronomical discoveries prompted a renewed interest in optical theory, in the geometry of light rays, and in the very notion of optical image.  This paper will review the first theories that explained the telescope magnifying effect and their relation to earlier, perspectivist optics.  It will pay particular attention to Descartes' and Kepler's theories of the telescope, the latter being the most widely known and influential explanation of the instrument up to the 1660s. Finally this contribution will analyse the preconditions for the articulation of the modern notion of geometrical optical image.  It will deal with the fact that while the underlying mathematics of geometrical images was introduced by Kepler, he did not use this notion as Barrow and Newton and others would in the 1660s.

Discussion 

Coffee break 

Fokko Jan Dijksterhuis, University of Twente, The Netherlands 

It is a classic story how the news of the telescope quickly spread through Europe after Lipperhey demonstrated his 'spyglass' to Maurits in November 1608. And how Galileo heard of the instrument and was able to build his own, improved ones. Apparently the news got to Alkmaar quickly as well, as Jacob Metius contested Lipperhey's priority within weeks. However, if we look at various sources, diffusion of knowledge of telescopes in the Dutch Republic did not go so smooth during the following years. Adriaan Metius, Jacob's brother and professor in Franeker, had to go through quite some trouble in 1620 to get to an actual telescope. It is telling that he travelled to Middelburg rather than Alkmaar. In Rotterdam and Dordrecht, Isaac Beeckman was gripped by telescopes and made various efforts to acquire good lenses, eventually apprenticing himself with lens makers. Like Metius, he had to travel  throughout the Republic to get the knowledge and things he desired.

These are only two examples of men that became curious after the telescope and wanted to know more of it. In this paper I will trace out the ways various kinds of knowledge of telescopes was diffused in the Dutch Republic during the first decennia after its invention.

Albert Clement, Roosevelt Academy, Middelburg / Utrecht University 

The invention of the telescope had an influence on a number of disciplines, music included. Although we are inclined to regard music purely as an art or a discipline belonging to the humanities nowadays, this has not always been the case. The idea of  ‘music of the spheres’ is a well-known Pythagorean doctrine postulating harmonious relationships among the planets governed by their proportionate speeds of revolution and by their fixed distance from earth. The position of music as a Liberal Art in the medieval Quadrivium was, in fact, a result of the central importance of neo-Pythagorean thought in late antiquity. In the first decades of the 17th century, a new musical practice – the so-called ‘seconda pratica or stile moderno’ – was developed, and Vincenzo Galilei (‘the father of’) belonged to its most prolific advocates. Although this new type of music with its emphasis on rhetoric clearly moved towards the humanities (the medieval Trivium), one should not fail to notice that the concept of music as a science still remained important. Heinrich Schütz stated: ‘Ut sol inter planetas, ita musica inter artes liberales in medio radiat’ (1640). This contribution will therefore focus on the aspects of music as a science, related to the invention of the telescope and the worldview of composers in the early baroque. 

Lunch 

Chair:  Albert Clement

Jan Parmentier, Ghent University, Belgium 

It is general knowledge that during the last decade of the sixteenth century the Dutch economic and maritime expansion emerged to the Atlantic and Indian Ocean. Moreover from the early sixteenth century already ships from Middelburg and Flushing crossed in the Atlantic the equator to transport Brazilian cane sugar to Antwerp. On these ventures in open sea traditional coastal navigation became impossible and the need of astronomical instruments to determine latitude and longitude vital. Navigation books from the sixteenth century, made in Iberia, England and the Low Countries, described extensively the methods to use marine astrolabes, nautical quadrants and cross-staffs. Seldom these navigators or scientists paid attention to the spyglasses on board. In this paper we will try to reveal when the ‘verre siende bril’ appeared as a part of the navigational equipment by looking at the production of nautical instruments, navigation books, nautical instructions and also ship’s journals of the late sixteenth and early seventeenth century.

Henk Zoomers, Asian Historical Consultancy, Amsterdam

Using contemporary sources, I will describe the visit of the first Siamese embassy to the United Provinces, against the background of the Eighty Years War (1568-1648) against the Spanish king, the foundation of the VOC (Dutch East India Company) in 1602, her establishment in Southeast Asia and the negotiations of the Twelve Years Truce, which was concluded in April 1609. During the sojourn of the Siamese (1608-1610) the newly invented telescope was presented in The Hague.

I will also elaborate on the spread of the telescope in 17-century Asia (besides Siam countries like Japan, China, Laos and Burma). Two Siamese kings showed a personal interest in using the telescope for scientific reasons: king Narai (r. 1656-1688) and king Mongkut (r. 1851-1868).  

Albert van Helden