A Bare Outpost of Learned European Culture on the

Transcription

“A Bare Outpost of Learned
European Culture on the Edge of the
Jungles of Java”
Johan Maurits Mohr (1716–1775) and the
Emergence of Instrumental and Institutional
Science in Dutch Colonial Indonesia
By Huib J. Zuidervaart* and Rob H. Van Gent**
ABSTRACT
The transits of Venus in 1761 and 1769 appear to mark the starting point of instrumental
science in the Dutch East Indies (now Indonesia). This essay examines the conditions that
triggered and constituted instrumental and institutional science on Indonesian soil in the
late eighteenth century. In 1765 the Reverend J. M. Mohr, whose wife had received a large
inheritance, undertook to build a fully equipped private observatory in Batavia (now Jakarta). There he made several major astronomical and meteorological observations. Mohr’s
initiative inspired other Europeans living on Java around 1770 to start a scientific movement. Because of the lack of governmental and other support, it was not until 1778 that
this offspring of the Dutch-Indonesian Enlightenment became a reality. The Bataviaasch
Genootschap van Kunsten en Wetenschappen tried from the beginning to put into effect
the program Mohr had outlined. The members even bought his instruments from his
widow, intending to continue his measurements. For a number of reasons, however, this
instrumental program was more than the society could support. Around 1790 instrumental
science in the former Dutch East Indies came to a standstill, not to be resumed for several
decades.
I
N THE MOMENTOUS DECADE when the Venus transits of 1761 and 1769 took place,
it could justly be argued, the best-equipped observatory on Dutch soil was to be found
not in the Netherlands itself but under the tropical skies of faraway Batavia, on the island
* Museum Boerhaave, P.O. Box 11 280, 2301 EG Leiden, The Netherlands.
** Institute for History and Foundations of Mathematics and the Natural Sciences, Utrecht, The Netherlands.
We are grateful to Maud Peereboom-Engelberts for her advice concerning the English translation of this article.
Isis, 2004, 95:1–33
䉷 2004 by The History of Science Society. All rights reserved.
0021-1753/04/9501-0001$10.00
1
2
“A BARE OUTPOST OF LEARNED EUROPEAN CULTURE . . .”
of Java in the Dutch East Indies (present-day Jakarta in the Republic of Indonesia). There,
in the mid 1760s, the German-Dutch Reformed parson Johan Maurits Mohr erected a wellequipped—almost royal—private observatory that, though it survived only briefly, was
unsurpassed in that corner of the world for more than 150 years.1 But at the time of the
first transit, in 1761, there was no clue that such a monumental observatory would be
erected so soon. It was only at the very last moment, and with very modest means, that
the 1761 transit was observed in Batavia at all. So questions arise: What persuaded a
clergyman with no scientific background, living in a purely commercial setting, to erect
such a huge astronomical building with no support apart from his wife’s inheritance? Why
did he make these efforts? Where did they lead? In other words, What triggered the rise
of instrumental science in this part of Asia, and what were its consequences?
In recent years the study and practice of science in a colonial context has attracted much
attention from historians of science. The scientific component of the Dutch colonial enterprise, however, remains underexplored. Although much of the later period has been
illuminated by Lewis Pyenson in his scholarly study on Indonesian colonial science, the
story of events that took place in the eighteenth century remains almost untold. The efforts
made by the Dutch present an interesting contrast to those of other colonizing countries,
such as Britain and France, that deserves a more thorough investigation. Harry Woolf, in
his influential study of the eighteenth-century transits of Venus, has outlined the costly
efforts made in the name of the monarchs of Great Britain, France, Sweden, and Russia
to support various astronomical expeditions; the pressing question arises, then, as to why
the leading authorities of the wealthy Dutch Republic—with a de facto imperial court in
Batavia and a heavy dependency on the astronomically oriented art of navigation—failed
to do more.2 This essay aims to narrow this gap in our knowledge and understanding of
this period of Dutch colonial rule.
THE DUTCH UNITED EAST INDIA COMPANY AND ITS ATTITUDE TOWARD SCIENCE
In the late eighteenth century the Indonesian islands had been ruled for more than 150
years by the Dutch United East India Company (Verenigde Oostindische Compagnie
[VOC]). This precursor of a multinational company was founded in the Dutch Republic
in 1602 under pressure from the counsel-general of the seven united provinces, the Staten
Generaal. The company united several rival Dutch trading companies that had sprung up
in the aftermath of the successful “First Voyage” (Eerste Scheepvaart) to the East, organized in 1595–1597 by the Amsterdam Far Lands Company (Compagnie van Verre).
The VOC was strongly backed by the central authorities of the Dutch Republic and was
supplied with considerable capital from private investors. It was governed by a general
1
A. Pannekoek, “Astronomy,” in Science in the Netherlands East Indies, ed. L. M. R. Rutten (Amsterdam:
De Bussy, [1929]), pp. 126–132; Lewis Pyenson, “Stars of the Southern Heavens,” in Empire of Reason: Exact
Sciences in Indonesia, 1840–1940 (Leiden: Brill, 1989), pp. 19–82; Rob H. van Gent, De Reizende Astronoom:
Nederlandse Sterrenkundige Expedities naar de Oost en de West (Leiden: Museum Boerhaave, 1993); and Huib
J. Zuidervaart, Van “Konstgenoten” en Hemelse Fenomenen: Nederlandse Sterrenkunde in de Achttiende Eeuw
[with an English summary] (Rotterdam: Erasmus, 1999), pp. 280–283, 314–320, 330–331.
2
Pyenson, Empire of Reason; and Harry Woolf, The Transits of Venus: A Study of Eighteenth-Century Science
(Princeton, N.J.: Princeton Univ. Press, 1959). Pyenson’s work was part of a trilogy surveying the exact sciences
in the colonial empires occupied by Germany, the Netherlands, and France. See also Lewis Pyenson, Cultural
Imperialism and Exact Sciences: German Expansion Overseas, 1900–1930 (New York: Lang, 1985); and Pyenson, Civilizing Mission: Exact Sciences and French Overseas Expansion, 1830–1940 (Baltimore/London: Johns
Hopkins Univ. Press, 1993). An overview of scholarly work on the history of science in a colonial setting is
given in Roy MacLeod, ed., Nature and Empire: Science and the Colonial Enterprise, Osiris, 2nd Ser., 2000, 15.
HUIB J. ZUIDERVAART AND ROB H. VAN GENT
3
board of seventeen directors (bewindhebbers), known as the “seventeen gentleman”
(Heeren XVII), who were chosen on a proportional basis from the directors of the six
participating chambers. The largest shareholder was the Chamber of Amsterdam, which
owned 50 percent of the company’s capital and fleet. Second was the Chamber of the
Province of Zeeland (25 percent), followed by the chambers of the cities of Delft, Rotterdam, Hoorn, and Enkhuizen (61⁄4 percent each). In the eighteenth century the VOC was in
possession of several strongholds spread along the coasts of Africa and Asia. It was also
by far the largest of the European companies trading with the Orient. Thanks to a patent
granted to the VOC by the Staten Generaal, the company could act almost as a sovereign
state in its overseas dependencies. The settlements of the VOC were administered by a
local governor, who reported to a governor-general in Batavia. The size of its fleet and
tonnage shipped annually outranked those of all its competitors combined.3 After a prosperous expansion period during the seventeenth century and gradual decline during the
second half of the eighteenth century, the company was dissolved in 1799, when it ran
into severe financial problems after the disastrous conclusion of the Fourth Anglo-Dutch
War of 1780–1784 and the collapse of the Dutch Republic in 1795.
Above all, the VOC was a commercial company, with no mission other than to make a
profit. The colonial policy of the Dutch therefore was quite different from that of most of
the other European colonizers: the aim of the VOC was the profitable exploitation of the
colonies, not the domination or colonization of the peoples or lands involved.
Nonetheless, from the outset some attention was given to the education of the local
population, especially in Christian belief and morality. Science, however, never played a
significant role in the policy of the VOC. It was only through the effort of various inquisitive individuals that some scientific investigations were carried out on the flora, fauna,
and geology of the Far East.4 Scholarly books and scientific instruments were rarely
shipped to Batavia. Only when commercial interests made it necessary did the VOC order
scientific books or instruments: for instance, when the Japanese shogun requested information on European society and science, such goods were shipped to the trading post of
Deshima in the harbor of Nagasaki.5
BATAVIA AND THE PROBLEM OF THE SOLAR PARALLAX
The VOC’s lack of interest in science is illustrated by the following case study. One of
the major astronomical problems of early eighteenth-century science was the determination
of the mean distance between the Earth and the Sun. This astronomical parameter (or the
solar parallax, which was directly related to it) was considered a fundamental constant in
3
See Jaap R. Bruijn and Femme S. Gaastra, eds., Ships, Sailors, and Spices: East India Companies and Their
Shipping in the Sixteenth, Seventeenth, and Eighteenth Centuries (Amsterdam: NEHA, 1993).
4
On education of the local populace see W. R. van Hoëvell, “Geschiedkundig Overzigt van de beoefening
van Kunsten en Wetenschappen in Neêrland’s Indië,” Tijdschrift voor Neêrland’s Indië, 1839, 1st Ser., 2(2):1–
115, esp. pp. 1–12. Regarding early scientific investigations see J. Bethlehem and A. C. Meijer, eds., VOC en
Cultuur: Wetenschappelijke en culturele relaties tussen Europa en Azië ten tijde van de Verenigde Oostindische
Compagnie (Amsterdam: Schiphouwer & Brinkman, 1993); and M. J. Sirks, Indisch Natuuronderzoek: Een
beknopte geschiedenis van de beoefening der natuurwetenschappen in de Nederlandsche Koloniën (Amsterdam:
Koloniaal Instituut, 1915).
5
Until 1853 this contact with the Dutch was the only way in which Japanese scholars could access Western
science and medicine. See Charles R. Boxer, Jan Compagnie in Japan, 1600–1817: An Essay on the Cultural,
Artistic, and Scientific Influence Exercised by the Hollanders in Japan from the Seventeenth to the Nineteenth
Centuries (1936; Tokyo/New York: Oxford Univ. Press, 1968), Chs. 1, 3; and Grant K. Goodman, Japan: The
Dutch Experience (London: Athlone, 1986).
4
the heliocentric planetary system. However, it was very difficult to determine this parameter with satisfying accuracy. In 1716 Edmund Halley, the future English astronomer royal,
came forward with a method to determine the solar parallax. Halley pointed to two rare
astronomical events: in June 1761 and again in June 1769 there would be a precise alignment of the Earth, the inner planet Venus, and the Sun. From the perspective of an observer
on Earth, Venus would pass across the disk of the Sun. As the positions and the orbits of
all the planets in the solar system are linked according to the laws described by Kepler
and Newton, Halley realized that this rare event offered an opportunity to a solve the
parallax problem. As early as 1691 he wrote: “This sight [of a transit of Venus] which is
by far the noblest astronomy affords, is denied to mortals for a whole century, by the strict
laws of motion. It will be afterwards shown, that by this observation alone, the distance
of the sun, from the earth, might be determined.” Halley published his proposals for
observing the transits in three articles in the Philosophical Transactions between 1691 and
1716. If the precise geographical location of an observer was known, he insisted, it should
be possible to determine the astronomical unit by comparing different sets of observations.
Considerations of accuracy required that observations be made at locations spread over
the planet. One of the preferred spots for an observation, Halley strongly recommended,
was Batavia on the Indonesian island of Java.6
Around 1760 astronomers throughout the Western world focused their attention on the
imminent Venus transit of June 1761. One of the first to take initiative was the French
astronomer Joseph-Nicolas Delisle (1688–1768). In November 1759 he presented a mémoire on the upcoming transit to the Académie Royale des Sciences. The main purpose
of Delisle’s article was to present a mappemonde of the most favorable places for observations of the transit. Halley’s proposal of 1716 had already listed a number of sites: the
North American Hudson Bay, he suggested would be the spot where the passage should
have the longest duration. But Delisle pointed out that while this was strictly true, it would
be useless to take observations at Hudson Bay: his own calculations showed that at that
spot both the ingress and the egress of Venus would occur below the horizon. Other
places—for instance, in the Far East—were preferable. Delisle’s initiative triggered some
action. One of his colleagues, Le Gentil de la Galaisière, suggested traveling to Pondichery,
a French colony on the shore of Coromandel (India). And off he went: in March 1760 Le
Gentil departed from the harbor of Brest, not to be seen again for ten years. A next step
was taken in April 1760, when the Russian tsarina Catherine the Great invited the Académie Royale des Sciences to send an astronomer on an expedition to Siberia. Jean-Baptiste
Chappe d’Auteroche accepted the offer and traveled to St. Petersburg later that year.7 Even
with these important observation posts occupied, Delisle still hoped to arrange for observations in the Malaysian Archipelago, for, as Halley had pointed out, from this spot the
transit could be seen completely and with a long duration.
Accordingly, on 18 May 1760 Delisle wrote to the Dutch astronomer Dirk Klinkenberg
6
Quoted in Woolf, Transits of Venus (cit. n. 2), p. 15. See also Edmund Halley, “Methodus singularis qua
solis parallaxis,” Philosophical Transactions, 1716, no. 347, pp. 454–464; “Batavia” is mentioned on p. 460.
7
J. N. Delisle, Mémoire [et mappemonde] présenté au Roi le 27 avril 1760, au sujet du passage de Vénus sur
le Soleil, qui doit arriver le 6 juin 1761 (Paris, 1760). The next spring Delisle published Avertissement au sujet
des observations qu’il conviendra de faire le 6 juin 1761, Vénus passant sur le Soleil (Paris, 1761). See also
Woolf, Transits of Venus, p. 55. Le Gentil would stay in the Far East more then ten years, deprived by cloudy
skies of observations of both transits of Venus. After his return to France he found his estate dispersed by his
heirs, who in the meantime had claimed that he had died. On Chappe d’Auteroche see Angus Armitage, “Chappe
d’Auteroche: A Pathfinder for Astronomy,” Annals of Science, 1954, 10:277–293.
5
(1709–1799), an official correspondent of the Académie Royale des Sciences, asking for
help in arranging an observation post in Batavia in the Dutch East Indies. Ten years before,
in 1751, Klinkenberg had helped Delisle in sending a French astronomical expedition, led
by Nicolas-Louis Lacaille, to Dutch territory at the Cape of Good Hope. Lacaille’s expedition was completely financed by the French king, but its success had depended in large
part on the cooperation of the Dutch authorities, including the VOC. At that time the Dutch
count Willem Bentinck van Rhoon had secured the personal support of the Dutch stadholder William IV of Orange for the expedition. So, as before, Klinkenberg went to Count
Bentinck for help. His reaction is known only from Klinkenberg’s reply to Delisle: Bentinck was prepared to arrange for a Dutch vessel to take a representative of the French
Académie to Batavia. But this was the only help the Dutch authorities were willing to
give. There was no interest at all in sending a Dutch astronomical expedition to the East
Indies, because—as Klinkenberg put it in the draft of his letter to Delisle—“the usefulness
of astronomy to mankind was not sufficiently appreciated in Dutch society.” According to
Klinkenberg, the only other possibility was to ask a qualified person already in Batavia to
observe the transit “with a proper attitude” and whatever instruments happened to be on
hand.8
Delisle knew what to do. To secure the cooperation of the Dutch authorities, he sent
several copies of his mémoire with the mappemonde of premier observing sites to the
Netherlands. Then he went to Versailles to plead with the French king for a royal grant,
with which he hoped to equip a French expedition to the Dutch East Indies. He recommended his own assistant, Charles Messier, as the best candidate for an expedition to
Batavia. But a complication arose: while they waited for the royal answer, rumors spread
that a British expedition was going to the Malaysian Archipelago. Ironically, Delisle himself had triggered the British developments. For in May 1760, on the same day on which
he had written to Klinkenberg—and despite the ongoing French-English war—he also
sent his mappemonde to London. In his accompanying letter to the English astronomer
John Bevis, Delisle had pleaded for British action regarding the coming transits. He had
appealed to national pride, reminding his correspondent that the method for using transit
observations to determine the solar parallax had been developed by a famous British
scholar. This appeal to patriotic sentiment worked: Delisle’s letter was read at a meeting
of the Royal Society, and support was found to equip two British expeditions. A first
mission, manned by the astronomers Charles Mason and Jeremiah Dixon, would be sent
to an English trading post on the coast of Sumatra in the Gulf of Bengal. A second
expedition, led by the astronomer Nevil Maskelyne, would travel to the British colony on
the Isle of St. Helena. The British scientists, too, briefly considered asking the Dutch East
India Company for help in transporting Mason and Dixon to the Far East. Dutch vessels
sailed for the Malaysian Archipelago much more frequently than those of the English
8
J. N. Delisle to Dirk Klinkenberg, 18 May 1760, Rijksarchief Noord-Holland, Haarlem, Archives of the
Koninklijke Nederlandse Instituut, no. 32: Klinkenberg Correspondence, 132 [received 26 May 1760], and
Archives Nationales, Paris, Delisle Correspondence, XIV, 176; and Klinkenberg to Delisle, 6 June 1760, Klinkenberg Correspondence, 133, and Delisle Correspondence, XIV, 178. See also Woolf, Transits of Venus, p. 68
(“omdat het nut dat de astronomie aan de menschelijke samenleeving heeft toegebracht, en nog kan toebrengen,
hier [in de Nederlanden] niet na waerde geprijseerd werd, en niet genoeg bekend is”). We found no record of
Bentinck’s actions on this subject in the correspondence of William Bentinck van Rhoon preserved in the Egerton
Papers, nos. 1745–1749, 1862, British Library, London. On Lacaille’s expedition see Woolf, Transits of Venus,
pp. 35–40; Angus Armitage, “The Astronomical Work of Nicolas-Louis de Lacaille,” Ann. Sci., 1956, 12:163–
191; Davis S. Evans, Lacaille: Astronomer, Traveler: With a New Translation of His Journal (Tucson, Ariz.:
Pachart, 1992); and Zuidervaart, “Konstgenoten” en Hemelse Fenomenen (cit. n. 1), pp. 252–268.
6
trading companies.9 But the “Dutch connection” was not put into practice. In retrospect,
this was apparently a bad decision. Sailing for the Gulf of Bengal on a British vessel,
Mason and Dixon were caught up in a fight with a French warship that caused serious
delays. As a result, they never reached the Far East: their expedition was stranded in
southern Africa, at the Cape of Good Hope. By an act of fate, then, one of the foreignfunded transit expeditions wound up on Dutch-governed territory.
In the meantime, in August 1760, the French Academie Royale des Sciences had given
its advice on Delisle’s request to mount additional expeditions. Once the British intentions
to observe the transit in Sumatra became known, the need for a French expedition to nearby
Batavia faded. For a time the French considered sending an astronomer to the African
Gold Coast, where both the Dutch and the Portuguese had trading posts, but eventually
this idea was abandoned. Instead, the astronomer Alexandre-Guy Pingré was sent to a
French colony in East Africa: to the Isle of Rodrigues, near Madagascar.10
In October 1760 Delisle could inform Klinkenberg that there was no longer any need
for Dutch transport to the East Indies. However, Batavia was far too promising an observation post to give up without one last effort. Besides, Delisle argued, there were no reliable
astronomical coordinates for Batavia, so any data provided in the course of observations
of the Venus transit there would be useful for navigational purposes. Delisle again asked
whether there was any VOC official, already on the spot, who could make observations:
a single skilled Dutch mathematician, capable of handling some nautical instruments,
would suffice. This simple effort, he promised, would produce results in which “all nations
would be interested, not only for the sake of Astronomy, but also for the advancement of
Geography.”11
Delisle’s supplication was not made in vain. In November 1760 Klinkenberg replied
that the prospects for a proper observation in Batavia remained meager but that some
hope glimmered on the horizon. He had given Delisle’s last letter to Count Bentinck and
to the Leiden professor of philosophy Jean Nicolas Sebastien Allamand. The latter had
promised to write to Governor-General Jacob Mossel of the VOC at Batavia, asking him
to look for “an able person on the spot” and persuade him to make the necessary observations. The same request would be sent to the governors-general of the Dutch settlements
at Ceylon and at the Cape colony, accompanied by a copy of Delisle’s instructions on
making the observations. The fate of Allamand’s letters is not known.12 However, a re9
Cf. Reynard to Klinkenberg, 19 June 1760, Klinkenberg Correspondence, 134. See also A. Vosmaer to
Delisle, 17 June 1760, Delisle Correspondence, XIV, 189. A list of the distribution of Delisle’s mappemonde is
published in Woolf, Transits of Venus, pp. 209–211. For Delisle’s appeal to British astronomy see Delisle to
John Bevis, May 1760, Delisle Correspondence, XIV, 177; the Royal Society’s response is discussed in Woolf,
Transits of Venus, pp. 71, 78. On Maskelyne see Derek Howse, Nevil Maskelyne: The Seaman’s Astronomer
(Cambridge: Cambridge Univ. Press, 1989).
10
Woolf, Transits of Venus, p. 66; and Angus Armitage, “The Pilgrimage of Pingré (1711–1796): An AstronomerMonk of Eighteenth Century France,” Ann. Sci., 1953, 9:47–63.
11
Delisle to Klinkenberg, 17 Oct. 1760, Klinkenberg Correspondence, 142 [received 28 Oct. 1760], and Delisle
Correspondence, XIV, 191. A copy of this letter was sent on 31 Oct. 1760 to the Dutch astronomers Johan Lulofs
and Nicolaas Struyck. The latter had organized Dutch support for the expedition led by Lacaille to South Africa
in 1751. See H. J. Zuidervaart, “Early Quantification of Scientific Knowledge: Nicolaas Struyck (1686–1769)
as Collector of Empirical Gathered Data,” in The Statistical Mind in a Pre-statistical Era: The Netherlands,
1750–1850, ed. Paul M. M. Klep and Ida H. Stamhuis (Amsterdam: Aksant, 2002), pp. 125–148.
12
Klinkenberg to Delisle, 29 Nov. 1760, Klinkenberg Correspondence, 147, and Delisle Correspondence, XIV,
198 a–c. A survey in the archives of the VOC in the National Archives of the Netherlands at The Hague has
produced no information on this subject; we thank A. C. Meijer, staff member, National Archives of the Netherlands. At the Cape colony observations were made by the British astronomers Mason and Dixon. In Ceylon
no observations were made: a local uprising during the spring and summer of 1761 left no room for topics of
7
construction of the chain of events at Batavia in June 1761 suggests that in all likelihood
it was Governor-General Mossel himself who ordered the observation of the Venus transit.
THE TRANSIT OF 1761, OBSERVED IN BATAVIA
At first glance, Mossel would seem to have had bad luck, for the person best equipped to
make the observations, the naval officer Lieutenant Pieter Hermanus Ohdem, had returned
to Holland in the summer of 1760. Appointed in 1743, Ohdem had been “preceptor in
mathematics and navigation” at the Naval Academy (Académie de Marine) of Batavia,
founded earlier that year.13 In 1753, two years before this academy was closed, he had
been named examiner of the sea maps compiled and drawn by the department of mapmakers of the VOC at Batavia. In 1759 Ohdem had made Batavian observations of Halley’s
comet that were published in the Verhandelingen (transactions) of the Hollandsche Maatschappij der Weetenschappen (Dutch Society of Sciences) in Haarlem.14 In his article
Ohdem lamented the fact that he had to make his observations without access to a permanent and elevated platform and without the help of an assistant. For the positional
measurements of the comet Ohdem had used a small portable alt-azimuthal instrument
(probably a kind of theodolite), equipped with a small telescope.
With Ohdem back in Holland, the most likely candidate was his next in line at the
department of mapmakers of the VOC, Lieutenant-Captain Gerrit de Haan (d. 1769), a
trained and highly skilled surveyor. In 1749 Gerrit de Haan had been appointed in Dordrecht as an official surveyor to the “Hof van Holland, Zeeland en West-Friesland.” That
same year he traveled to Batavia, where he soon became head of the department of VOC
mapmakers. In this capacity De Haan made a very important atlas that provided a complete
overview of the territories colonized by the VOC.15
And, indeed, it was evidently De Haan who was instructed to observe the transit. Toscientific interest. See Lodewijk Wagenaar, Galle: VOC-vestiging in Ceylon: Beschrijving van een koloniale
samenleving aan de vooravond van de Singalese opstand tegen het Nederlandse gezag, 1760 (Amsterdam:
Bataafsche Leeuw, 1994).
13
On Ohdem see J. Van der Bilt, Venus tegen de Zonneschijf: 1761, 1769: Een bladzijde uit de geschiedenis
der Nederlandse Sterrenkunde (Groningen/Batavia, 1940), p. 52; and G. Schilder, “Het cartografisch bedrijf van
de VOC,” in De VOC in de kaart gekeken: Cartografie en navigatie van de Verenigde Oostindische Compagnie
1602–1799, ed. P. van Mil and M. Scharloo (’s Gravenhage: SDU, 1988), pp. 17–45, esp. p. 42. On the Naval
Academy see F. de Haan, “De ‘Académie de Marine’ te Batavia, 1743–1755,” Tijdschrift Bataviaasch Genootschap der Wetenschappen, 1895, 38:551–621.
14
Pieter H. Ohdem, “Berigt van de Comeet van het jaar 1759, in Batavia waargenomen,” Verhandelingen
uitgegeeven door de Hollandsche Maatschappye der Weetenschappen te Haarlem, 1761, 6(1):421–435. Initially
Ohdem had reported his astronomical observations to Leiden University. Together with some simple meteorological observations, made at Batavia in the years 1758–1760 by the medical doctor S. C. Kriel, they were
offered by H. D. Gaubius, professor of medicine at Leiden, to the Hollandsche Maatschappij der Weetenschappen
(HMW). See H. D. Gaubius to C. C. H. van der Aa (secretary of the HMW), 28 Aug. 1760, Rijkarchief NoordHolland, Haarlem, HMW Archives. See also the advice of Johan Lulofs (professor of astronomy) to Van der Aa,
11 Sept. 1760, HMW Archives. The meteorological observations were printed in the next volume of the transactions: S. C. Kriel, “Waarnemingen te Batavia, gedaan door de heer Kriel M. D. aldaar,” Verhandel. Hollandsche
Maatsch. Weetensch. Haarlem, 1762, 6(2):9–60.
15
E. Muller and K. Zandvliet, eds., Admissies als landmeter in Nederland voor 1811: Bronnen voor de geschiedenis van de landmeetkunde en haar toepassingen in de administratie, architectuur, kartografie en vestingen waterbouwkunde (Alphen aan de Rijn: Canaletto, 1987), p. 179 (no. 630). Gerrit de Haan, Ligtende Zeefakkel
off de geheele Oost Indisch Waterweerelt, manuscript atlas in two volumes, is preserved in the VOC Archives
(VELH 156), held in the Nationaal Archief in the Hague; it is mentioned in Schilder, “Het cartografisch bedrijf
van de VOC” (cit. n. 13), p. 40 n 61. The archival records of the VOC are described in M. A. P. Meilink-Roelofsz,
R. Raben, and H. Spijkerman, eds., The Archives of the Dutch East India Company (1602–1795) (The Hague,
1992); they will hereafter be cited as NA/VOC, with inventory number and date as available and necessary.
8
gether with an assistant, Pieter Jan Soele, a skipper who was also employed by the VOC,
he made all the necessary preparations. In the early morning of 6 June 1761 they took off
for the outskirts of Batavia, headed for “Kliphoff,” the estate of Johan Maurits Mohr,
parson of the local Portuguese church.16 But Mohr was not merely a reverend. He was also
a man of learning with a solid reputation as a translator; it seems likely, then, that GovernorGeneral Mossel had sought Mohr’s help in translating Delisle’s French instructions for
observing the transit. While translating Delisle’s mémoire Mohr must have offered his
seaside residence, with its unimpeded view of the horizon, as a suitable vantage point for
making the observations.
As planned, De Haan and Soele went to work. Both the ingress of Venus on the solar
disk and its egress were observed with the observer’s eye at about 10 feet above sea level
and without any cloud interference. The effort was a complete success. According to the
report of the observation, published in 1763, their instruments were modest but of good
quality. At their disposal was a universal octant made by the London instrument-maker
George Adams and a few accurate pocket watches, one of which showed seconds. The
rate of these watches was tested by Soele from several observations of the Sun’s altitude.
Mohr—who, with a friend, observed De Haan and Soele at work—had brought two of
his own Gregorian reflectors, also made by Adams, with focal lengths of 18 and 27 inches,
respectively. During the transit these telescopes were probably used to project an image
of the solar disk on a screen. Normally such telescopes were used in the colonies to observe
ships far out at sea.17
As one might expect, the designated observers De Haan and Soele prepared a report of
their observation, which they duly sent to the Netherlands with one of the first ships
returning there. Probably as a courtesy—in return for the opportunity to use “Kliphoff”—
they also delivered a copy of their report to Mohr. This led to unexpected results, however,
for now Mohr too prepared a report in which he retrospectively appointed himself as the
leader of the observation team. Why he acted in this way is at first glance mysterious; we
will try to reconstruct Mohr’s intentions later in this essay.
In his report of the observation, written in January 1762, more then half a year after the
event, Mohr claimed that the account of De Haan and Soele was far below the standards
required for a scientific report. He found their report not only “far too clumsy and inefficient, but in a way also defective and too inferior for an official account.”18 He therefore
distanced him from De Haan and Soele’s results, stating that their report was sent to the
Netherlands without his knowledge or consent.
As the German astronomer Johann Encke noted in the nineteenth century, the values
given by Mohr in his account were not reliable. This was confirmed by the astronomerhistorian Johan van der Bilt, who reported in his 1940 monograph on the Dutch transit
16
“Kliphoff” was located about an hour’s journey to the east of Batavia, near Fort Antjol at the mouth of the
Antjol River. On modern municipal maps of Jakarta this corresponds with the Ancol “Dreamland” Amusement
Park, situated halfway between the “Old Harbor” and the “New Harbor.” See the manuscript map of Batavia
drawn by D. M. Barbier in 1798, reproduced in Van Mil and Scharloo, eds., De VOC in de kaart gekeken
(cit. n. 13), Fig. 101.
17
For this terrestrial use of reflecting telescopes see Daniel Brand, Cape of Good Hope, to Jan Hendrik van
Swinden, Franeker, 6 Mar. 1777, University Library, Leiden, BPL 755.
18
Lulofs to Van der Aa, 6 Feb. 1763 (offering Mohr’s report), HMW Archives. A second draft of Mohr’s
report was delivered later that year by Mohr’s “worthiest master,” Nicolas Engelhardt (1696–1765), professor
of philosophy at Groningen. See J. M. Mohr to Nicolas Engelhardt, 5 May 1762, HMW Archives. See also
Engelhardt to Van der Aa, 10 May 1763, HMW Archives; and HMW Notulen (“minutes”), fol. 357, 10 May
1763, HMW Archives.
9
observations that “the solar heights given by Mohr do not fit with the corresponding
times.”19 Van der Bilt suspected that something had gone wrong with the clocks. Mohr
himself was aware that this had been a weak point in the observations. The clocks used
were ordinary pocket watches, and Mohr had expressed skepticism about the results they
produced. Besides, the micrometers and dark glasses recommended in Delisle’s instructions had not been available, and as a consequence the bright sunlight had prevented them
from observing the ingress and egress completely. Nevertheless, Mohr thought that their
reported results were a good approximation of the truth. He hoped that these Batavian
observations would help in the effort to find a better value for the solar parallax; he was
certain that they would contribute to glorifying the Lord who in his wisdom had created
this amazing universe.
As was the usual practice with important documents, Mohr sent two copies of his report
to the Netherlands on different ships: one was addressed to Leiden University and the
other to his alma mater, the University of Groningen. Mohr’s report was printed in 1763
in the Verhandelingen of the Hollandsche Maatschappij der Weetenschappen.20 The original report, by De Haan and Soele, was never made public. It seems to have been lost.
THE CAREER OF JOHAN MAURITS MOHR
From 1762 onward, then, Mohr presented himself as an astronomer. To find out why he
did so, we must consider his biography more carefully. Since his settlement in the Dutch
East Indies, Mohr had acquired quite a reputation as a scholar.21 In the strictly commercial
setting of Batavia, scholarly status was extremely rare; such an asset would certainly have
improved his standing in Batavian society.
Born in 1716 in Eppingen, Germany, the son of a minister of the Reformed Church,
Mohr enrolled at the University of Groningen as a student in theology in August 1733.
The matriculation rolls note that he was entered “free of fee,” suggesting that he came
from an impoverished family. In 1736 he completed his studies with a public disputation
on the role of biblical visions. Later that year he was appointed minister to the Dutch East
India Church with a modest monthly allowance of 90 Dutch guilders.22 The following year
Mohr set sail on the Dutch East Indiaman Oostrust and, after a call at the Dutch provisioning station at the Cape of Good Hope, arrived at Batavia on 24 October 1737. After
two years of service as a vicar in Batavia, Mohr was commissioned to lead the Portuguese
Van der Bilt, Venus tegen de Zonneschijf (cit. n. 13), p. 58.
Lulofs to Van der Aa, 6 Feb. 1763; and Mohr to Engelhardt, 5 May 1762. For the eventual publication see
J. M. Mohr, “Waarneminge over den schijnbaaren loop van Venus over de zonneschijf, in zijn begin, midden en
einde, den 6 Juni 1761,” Verhandel. Hollandsche Maatsch. Weetensch. Haarlem, 1763, 7(1):380–391.
21
The main biographies of Mohr are P. Melvill van Carnbée, “Iets over den Nederlandschen Sterrekundige
Johan Maurits Mohr, te Batavia,” Tijdschr. Neêrland’s Indië, 1st Ser., 1844, 6(4):172–179; J. S. van Coevorden,
“Nog iets over den Nederlandschen Sterrekundige Johan Maurits Mohr, te Batavia,” ibid., 1845, 7(3):270–272;
P. A. Leupe, “Berigten: Johan Maurits Mohr,” Tijdschrift voor Indische Taal-, Land- en Volkenkunde, 1859, 8
[⳱ 3rd Ser., 2]: 317–318; Leupe, “Iets over den Nederlandschen Sterrekundige Johan Maurits Mohr te Batavia,”
Bijdragen tot de Taal-, Land- en Volkenkunde van Nederlandsch Indië, 1864, 11 [⳱ 2nd Ser., 7]: 160–168; P. J.
Veth, “Johan Mauritz Mohr,” De Gids, 1885, 49(3) [⳱ 4th Ser., 3]: 55–87; S. Kalff, “Eene Indische Sterrewacht,”
De Indische Gids, 1921, 43:409–423; and J. van der Bilt, “De sterrewacht van J. M. Mohr: Een rechtzetting en
een aanvulling,” Hemel en Dampkring, 1942, 40:69–73.
22
Daniel Benedictus Mohr from Eppingen, who may have been J. M. Mohr’s younger brother, likewise enrolled “free of fee” as a student of philosophy at the same academy in September 1735. See J. A. Feith and
J. G. C. Joosting, Album Studiosorum Academiae Groninganae (Groningen: Historisch Genootschap, 1915),
pp. 182, 185. For the text pertaining to the disputation see J. M. Mohr, Dissertatio theologica de Abrahami
visione (Groningen, 1736). On his appointment as minister see NA/VOC, no. 256, 10 Dec. 1736.
19
20
10
community at the Dutch settlement at Galle in Ceylon. However, he requested permission
to stay in Batavia to perfect his knowledge of the Portuguese language. Shortly afterward
he got married. His Ceylonese appointment was cancelled in February 1739, when, having
given proof of his ability to preach in Portuguese, he was appointed to lead the Portuguese
community of Batavia instead. When G. W. Baron van Imhoff, then governor-general of
Batavia, founded a Naval Academy and a Theological Seminary in 1743, Mohr—as a
“man of learning and of good qualities who is dearly beloved in the Indies”—was appointed the first rector of the seminary.23 During his tenure as rector he produced several
books, which raised his status as a scholar. Mohr was especially known for his literary
work as a translator of the Bible into both the local Malayan and the Portuguese languages.
Thanks to this scholarly work, he was one of the few persons in Batavia with academic
contacts in the Netherlands.24
After ten years of service, Mohr resigned as rector in November 1753. His second
marriage, the year before, was perhaps one of the reasons for this resignation. Mohr’s first
wife, Johanna Cornelia van der Sluys, had died in September 1750. In April 1752 he
married Anna Elisabeth van ’t Hoff, the Asian-raised daughter and principal heiress of Jan
van ’t Hoff, a very wealthy official of the VOC.25 Mohr’s new bride also had money of
her own, being the widow of two wealthy men, Gabriel Hendrik van Gehren (d. ca. 1741)
and Willem Cornelis Visboom (d. ca. 1747). Each of her earlier marriages had produced
a son. In her marriage with Mohr she would give birth to a daughter: Johanna Mauritia
Mohr, christened on 22 November 1761.26
23
NA/VOC, no. 761, pp. 414–415; no. 763, pp. 270–272; no. 775, pp. 390–401. See also J. R. Bruijn, F. S.
Gaastra, and I. Schöffer, eds., Dutch-Asiatic Shipping in the Seventeenth and Eighteenth Centuries, 3 vols. (The
Hague: Nijhoff, 1979–1987), Vol. 2, no. 3052.7. The Oostrust, built in 1721, was one of the largest vessels in
this fleet of eighteen ships bound for Ceylon and Batavia. The history of the Theological Seminary of Batavia
is described in Van Hoëvell, “Geschiedkundig Overzigt van de beoefening van Kunsten en Wetenschappen in
Neêrlands Indie” (cit. n. 4), pp. 41–44; and J. A. van der Chijs, De Latijnsche Scholen van 1642 en 1666,
alsmede het Seminarium van 1745 te Batavia: Proeve eener geschiedenis van het onderwijs in Nederlandsch
Indië (Batavia: Lange, 1860). The Theological Seminary was erected along the Verburgsgracht, just outside the
city walls, near the Rotterdammer Poort (the Eastern Gate). This is the present-day Jalan Kampung Muka Timur,
between the old City Hall (Stadhuis) and the Railway Museum.
24
For more details about Mohr’s publications see John Landwehr, VOC: A Bibliography of Publications
Relating to the Dutch East India Company, 1602–1800 (Utrecht, 1992). They include J. M. Mohr and L. A.
Böhmer, Do Velho Testamento: O Primeiro Tomo (Batavia, 1748); Mohr, Breviario da doutrina da verdade
(Batavia, 1750) (this title is not listed in Landwehr’s volume); Mohr and Böhmer, Do Velho Testamento: O
Segundo Tomo (Batavia, 1753); Mohr and H. P. van de Werth, Al-Kawl al-’Atik iya-itu segala surat Perdjandjian
Lama, 4 vols. ([Batavia], 1758); Mohr and Van de Werth, Indjil al-kudus ’Tsa al Masih, lya Itu, segala surat
Perdjanddj ian Baharu ([Batavia], 1758); and Mohr, O Novo Testamento (Batavia, 1773). For examples of Mohr’s
academic contacts see Mohr to J. Schultens (the famous Leiden orientalist), 28 Apr. 1759, 1 Nov. 1759, Univ.
Library, Leiden, BPL 245a.
25
Veth, “Johan Mauritz Mohr” (cit. n. 21), p. 74; and Melvill van Carnbée, “Iets over den Nederlandschen
Sterrekundige Johan Maurits Mohr” (cit. n. 21), p. 176. The seminary was closed shortly after Mohr’s resignation,
having had little impact. Only two of its pupils went to the Netherlands to complete their education in theology,
and only one of them became a vicar. Jan van ’t Hoff was an officer of the Civilian Cavalry (Ritmeester der
burger Cavallerije) and a member of the Water Board of the Batavia Outskirts (Heemraad der Batviaasche
Ommelanden). In his will, drawn up in 1761, he named his daughter as his principal heir: NA/VOC, nos. 6895,
9931.
26
The elder son, Johannes Gabriel van Gehren (born in 1742), studied law at the University of Leiden (enrolled
10 Jan. 1760), where in 1763 he defended his thesis “De repetitione dotis.” He became a member of the Board
of Aldermen (Scheepen) of Batavia in 1767 and a member of the Justice Council (Raad van Justitie) in 1768.
The second son, Jan Cornelis Visboom (born in 1748), was employed at the General Secretariat of Batavia, first
as a clerk (in 1765) and then as a bookkeeper (in 1766). See. N. W. du Rieu, Album Studiosorum Academiae
Lugduno Batavae MDLXXV–MDCCCLXXV (The Hague, 1875), p. 1066. Johanna Mauritia Mohr was mentioned
as a beneficiary in the will drawn up by her half-brother Jan Cornelis Visboom on 6 Nov. 1775, shortly after
Mohr’s death. In 1782, at the age of twenty-one, she would become the fourth bride of David Johan Smith
11
SCIENTIFIC STATUS AS A SOCIAL MOTIVATION FOR PRACTICING ASTRONOMY
It was primarily his reputation as a scholar that had enabled Mohr to rise socially in the
status-conscious Batavian society. It was probably only because he was highly respected
that he had been able to make such an advantageous second marriage. His scholarly work
also made him a personal friend of Governor-General Mossel, who in 1758 provided the
funds that enabled Mohr to print the four volumes of his Malayan Bible translation. When
Mossel died suddenly, in May 1761, Mohr was asked to join the officials of the VOC in
the impressive, almost royal, funeral procession that walked behind the casket.27 So Mohr
knew about the value of status.
In 1763, his reputation bolstered as a result of his report on the 1761 Venus observations,
Mohr was named a member of the Hollandsche Maatschappij der Weetenschappen. The
appointment came shortly after his father-in-law had died and his wife had inherited a
large fortune.28 A few months later the couple decided to build a large country house, in
the style of Louis XIV, on the prestigious Molenvliet canal, and Mohr included an astronomical observatory in the plans for the luxurious building. In 1763, as well, he commissioned the Leiden professor of astronomy Johan Lulofs to purchase astronomical and
meteorological instruments up to the value of 3,000 Dutch guilders. Getting these instruments was evidently no simple matter: some two and a half years elapsed between the
time the equipment was ordered and its arrival in Batavia.
In the meantime, in September 1765, Mohr obtained official permission to build on his
newly erected country house an astronomical observatory 80 feet or more above ground
level. According to one of Mohr’s contemporaries, the construction of this six-story edifice
set the couple back some 80,000 “rijksdaalders”—the equivalent of about 200,000 guilders. This was roughly twice the cost of “Buitenzorg,” the nearby palace of the governorgeneral (the present “Bogor”). How overwhelming the construction was is illustrated by
two striking drawings of the observatory and its setting made in the early 1770s by the
Danish artist Johannes Rach (1720–1783).29 The first drawing (see Figure 1) presents a
view of Mohr’s observatory as seen from a distance along the stately entrance gate and
lane. The second drawing (see the cover illustration) depicts the observatory from a point
much closer and shows a small Chinese temple in the foreground.
In 1768, in a letter to the Hollandsche Maatschappij der Weetenschappen, Mohr acknowledged that the honor of being appointed a member had prompted him to build his
observatory. The three colored architectural drawings that accompanied this letter testify,
however, that the assertion of social status must have been a major motivation for building
(1740–1792), who was twice her age. Smith was a close relative of former governor-general Van de Parra. See
Jean Gelman Taylor, The Social World of Batavia: European and Eurasian in Dutch Asia (Madison: Univ.
Wisconsin Press, 1983), p. 206. See also NA/VOC, nos. 6847, 177, 219; and Kalff, “Eene Indische Sterrewacht”
(cit. n. 21), p. 419.
27
Nederlandsche Jaerboeken, 1762, 16(1):461–470, esp. p. 467. On the social structure of Batavian society
see Taylor, Social World of Batavia.
28
Mohr was elected to the Dutch society on 24 May 1763; see Verhandel. Hollandsche Maatsch. Weetensch.
Haarlem, 1763, 7:vii, xxvii. He was recommended for the appointment by the Leiden professor Johan Lulofs in
a letter written 6 Feb. 1763. Jan van ’t Hoff was buried on 22 Apr. 1763: CBG, Batavia, Hollandsche Kerk, B
1761–66, fiche 16.
29
The cost is noted in a letter of Friedrich Baron von Wurmb, dated 30 Oct. 1775, printed in Briefe des Herrn
von Wurmb und des Herrn Baron von Wollzogen auf ihren Reisen nach Afrika und Ostindien in den Jahren 1774
bis 1792 (Gotha, 1794), pp. 104–135, esp. pp. 123–124. Initially held privately, these drawings were at some
point acquired by the Batavian Society of Arts and Sciences. They are now preserved in the National Library of
Indonesia (Arsip Nasional Indonesia) in Jakarta. See Max de Bruijn and Bas Kist, Johannes Rach, 1720–1783:
Artist in Indonesia and Asia (Jakarta: National Library; Amsterdam: Rijksmuseum, 2001).
12
Figure 1. View of Mohr’s observatory from a distance, as seen along the stately entrance gate and
lane from the Molenvlietse dike. Drawing in ink by Johannes Rach. (National Library, Jakarta.)
such a luxurious edifice. The first view (see Figure 2), depicting the main entrance on the
eastern side of the building, shows a four-story structure—lavishly decorated with celestial
figures (stars, a half moon, and a radiant sun), classical gods (Mercury and Neptune), and
allegorical statues of the muses holding mathematical and astronomical instruments—on
which an octagonal tower seems to be precariously balanced. To the right of the main
entrance the name “J. Bittner” (the architect, presumably) and that of the draftsman, “J.
Clement,” can be distinguished. Another view, of the northern side of the building, shows
a much sturdier arrangement (see Figure 3). Finally, a third diagram depicts the layout of
the ground floor. From the scale in feet and rods given on this diagram, the observatory
can be inferred to have been 80 feet (221⁄2 meters) in width and 62 feet (171⁄2 meters) long,
with a total height of about 108 feet (301⁄2 meters).30 Both the design of the octagonal
tower and the astronomical imagery seem to have been inspired to a large extent by the
well-known frontispiece of Urania’s temple in Johannes Kepler’s Rudolphine Tables of
1627.
Though its magnificence could only have enhanced his social status, Mohr pointed to
other motives. In 1768, in a letter to Thomas Hope, one of the seventeen directors of the
30
The first two drawings, from the HMW Archives, are reproduced in Van der Bilt, “De sterrewacht van J. M.
Mohr” (cit. n. 21); and G. C. Molewijk, “Twee onbekende afbeeldingen van de achttiende-eeuwse sterrenwacht
te Batavia,” Jambatan: Tijdschrift voor de Geschiedenis van Indonesië, 1987, 5:132–136. During our investigations in Dec. 1998 these drawings and Mohr’s accompanying letter of 20 Jan. 1768 (excerpted by Van der
Bilt) were not found in the HMW Archives. See HMW Notulen, Vol. 2, fol. 534, 6 Sept. 1768, HMW Archives.
Neither Bittner nor Clement could be traced in the VOC Archives. “J. Clement” was perhaps the “J. F. Clement”
who engraved several plates for Carsten Niebuhr’s report of a Danish expedition to Arabia (1761–1769). The
dimensions are calculated on the assumption that the Amsterdam rod (⳱ 12 feet ⬇ 3.40 meter) was used.
13
Figure 2. Front view (eastern face) of Mohr’s observatory. Architectural drawing by J. Clement.
(Hollandsche Maatschappij der Wetenschappen, Haarlem.)
VOC, he offered the following fashionable physico-theological statement to explain why
he built an observatory:
For some years I have dedicated myself, along with other useful sciences, to physics and
astronomy, one of my oldest and most favorite passions, with the intention of raising its status
and promoting these sciences as most suited to fighting ignorance and superstition, so much
prevalent in this country. This with the purpose of filling the hearts of the people with reasonable
14
Figure 3. Side view (northern face) of Mohr’s observatory. Architectural drawing by J. Clement.
(Hollandsche Maatschappij der Wetenschappen, Haarlem.)
and lofty thoughts about the works of their Creator, worthy of making them susceptible to
religion.31
31
Mohr to Thomas Hope, 2 Nov. 1768, printed in Leupe, “Iets over den Nederlandschen Sterrekundige Johan
Maurits Mohr te Batavia” (cit. n. 21), pp. 164–167; and Veth, “Johan Mauritz Mohr” (cit. n. 21), pp. 67, 75–77.
15
MOHR’S ASTRONOMICAL INSTRUMENTS AND THEIR PROVENANCE
As already noted, in 1763—after his decision to promote himself as an astronomer—
Mohr had commissioned the Leiden professor Lulofs to buy astronomical and meteorological instruments for him. The records of the General Council of the VOC confirm that
Lulofs assisted Mohr in choosing, ordering, and shipping these specialized instruments.
In October 1765 four crates containing various mathematical and astronomical instruments
were sent to Batavia. Four more crates followed two years later. After Lulofs’s death in
1768, orders were placed with the Leiden instrument-maker Jan Paauw.32 This time the
archives reveal more particulars about the shipments. In October 1770 Paauw sent with
one of the ships of the Amsterdam chamber of the VOC “an astronomical clock 6 feet
high, 17 inches wide and 12 inches deep and a pair of Adams’ globes of two feet in
diameter.” Also shipped were “a 2-foot radius astronomical quadrant with its pedestal in
two crates, one measuring 21⁄2 feet wide, 2 feet deep and 1 foot high and the other measuring 3 feet on all sides; an ‘equal-altitude’ instrument 2 feet wide and deep, 6 to 8 inches
in height and a ‘parallactic machine’ whose size cannot be accurately stated and a sea
octant 21⁄2 feet long, 11⁄2 inch in width and 8 inches high.” In October 1773 this was
followed by the delivery of three little boxes containing instruments: “an 18-foot long
astronomical telescope, in three segments; a ‘heliometer’ to measure the quantity of rainwater fallen [obviously this was a rain gauge or ‘pluviometer’], mounted on a pedestal;
an anemometer [or wind-speed meter] and a compass with a direction finder.”33 Unfortunately, apart from the globes, no details are given with regard to the manufacturers of the
instruments. Some of them may have been made by Paauw himself, but others were probably of foreign origin.
MOHR’S OBSERVATIONS OF THE TRANSITS OF 1769
Further particulars about the instruments Mohr purchased are found in his memoirs on the
1769 transit of Venus. It is striking how much Mohr’s situation had changed in eight years.
In 1761 he had been more or less an outsider, watching the observational activities of De
Haan and Soele; they had few instruments at their disposal and lacked accurate knowledge
of the geographical coordinates of Batavia. In 1769, in contrast, Mohr was the owner of
a marvelous new observatory, equipped with some of the best observational instruments
the European market had to offer. He had been working with these instruments since 1767,
determining as accurately as possible the latitude and longitude of his observatory, inter
alia by observing the satellites of Jupiter.34 So all the conditions necessary for an accurate
32
NA/VOC, nos. 60 (draft), 132 (copy), 177 (fair copy), 19 Oct. 1765; and NA/VOC, nos. 61 (draft), 133
(copy), 178 (fair copy), 14 Oct. 1767. See also Van der Bilt, Venus tegen de Zonneschijf (cit. n. 13), p. 53. After
the death of Jan van Musschenbroek in 1748, Jan Paauw, Jr. (ca. 1723–1803), was one of the principal scientific
instrument-makers in the Netherlands. He supplied several scientific instruments for the physical cabinets of the
academies of Leiden, Utrecht, Franeker, and Harderwijk as well for private cabinets. See M. Rooseboom, Bijdrage tot de geschiedenis der instrumentmakerskunst in de Noordelijke Nederlanden tot omstreeks 1840 (Leiden:
Rijksmuseum voor de Geschiedenis der Natuurwetenschappen, 1950), pp. 110–112.
33
NA/VOC, nos. 63 (draft), 133 (copy), 180 (fair copy), 15 Oct. 1770; and NA/VOC, nos. 66 (draft), 134
(copy), 182 (fair copy), 19 Oct. 1773. At that time an azimuth compass ( peilkompas) was a piece of standard
meteorological equipment.
34
Mohr’s best instruments, like an astronomical clock, the astronomical quadrant, and an achromatic telescope
made after Dollond’s new invention of 1759, would not arrive until 1770–1773. In his letter of 20 Jan. 1768 to
the Hollandsche Maatschappij der Weetenschappen in Haarlem (cit. n. 30), Mohr referred (without giving much
detail) to several observations that he had collected while his observatory was still under construction. The
16
determination of the solar parallax seemed to be fulfilled. Nonetheless, the 1769 observation almost failed. It was very cloudy that day, and at sunrise the Sun was not visible at
all. But by eight o’clock the clouds had disappeared, and the disk of the Sun appeared
bright in the morning sky. As calculations had predicted that at sunrise Venus would already
be on the solar disk, Mohr had equipped his 31⁄2-foot focal length Dollond-made Gregorian
reflector with a frame of silk threads in order to establish the place of the planet on the
Sun’s surface. Although he knew that his heliometer objective glass would be more effective in locating the planet on the solar disk, because of the limited field of his telescope
he could use the heliometer (see Frontispiece) only when Venus was very close to the edge
of the disk. Nevertheless, in the end he could report: “Under this favourable condition of
the sky I could observe the egress of Venus with this telescope bright, sharp and precisely”
(see Figure 4). During the observations he was assisted by an unnamed friend who counted
out the seconds on the timekeeper, an astronomical pendulum clock with a Graham-type
escapement made by the London clockmaker John Shelton. Shelton regulators were also
used by the Venus expeditions set up by the Royal Society of London.35 Another instrument
Mohr used in 1769 was a 21⁄2-foot astronomical quadrant made in London, with an azimuthal scale, mounted on a pedestal.
Mohr waited to observe the transit of Mercury in November 1769 before sending his
reports to the Netherlands by VOC ship. Another account of his observations reached
Europe by way of the circumnavigator and explorer James Cook (1728–1779). In the fall
of 1770 Cook was forced to call at Batavia when his ship, the Endeavour, needed repairs,
and during this stay he paid a visit to Mohr and his observatory. Just a few hours before
the Endeavour weighed anchor, Mohr gave Cook a Latin version of his report on both
transits. On his arrival in England in July 1771 Cook sent these observations to the Royal
Society, where on 21 November they were read out to the members. Mohr’s report was
printed in the same year’s issue of the Philosophical Transactions.36
VISITORS TO A “PRINCELY” OBSERVATORY
There were others who were delighted with these new scientific developments in the Dutch
East Indies. The French naturalist and circumnavigator Louis-Antoine de Bougainville
latitude determinations would be based on meridian altitude measurements of Procyon (␣ CMi) and Sirius (␣
CMa), two bright stars passing near the zenith at Batavia and thus minimally susceptible to errors caused by
uncertainties as to the correction for refraction. The longitude would be obtained from timed eclipses of the two
innermost moons (Io and Europa) of Jupiter and an occultation of Antares (␣ Sco) by the Moon, after comparing
these with the times for the meridian of Paris as listed in the Connoissance des temps for 1767. In his memoirs
on the Venus transit of 1769 (Latin version only) and the Mercury transit of 1769, Mohr announced the preparation of a memoir on the longitude of Batavia to be sent to Dutch society. However, this memoir was either
never completed or failed to arrive in Haarlem.
35
J. M. Mohr, “Waarneeming van Venus, by haaren uitgang van de Zonne-schyf, gedaan den 4. Juny 1769.
te Batavia op het Observatorium (liggende op 6 gr. 12 min. Zuider br.),” Verhandel. Hollandsche Maatsch.
Weetensch. Haarlem, 1770, 12:123–130; see also Van der Bilt, Venus tegen de Zonneschijf (cit. n. 13), p. 67.
Regarding Shelton’s regulators see H. Alan Lloyd, “Description of a Clock by John Shelton, Owned by the Royal
Society and Used by Maskelyne on His Visit to St. Helena in 1761, and Probably by Mason and Dixon in
Pennsylvania,” Proceedings of the American Philosophical Society, 1950, 94:268–271; and Charles Green and
James Cook, “Observations Made, by Appointment of the Royal Society, [in 1769] at King George’s Island in
the South Sea,” Phil. Trans., 1772, 61:397–421.
36
J. M. Mohr, “Waarneeming van Mercurius by zynen uitgang van de Zonne-schyf, gedaan den 10. Nov. 1769.
te Batavia op het Observatorium,” Verhandel. Hollandsche Maatsch. Weetensch. Haarlem, 1770, 12:131–134;
and Mohr, “Transitus Veneris & Mercurii in eorum Exituè Disco Solis, 4to Mensis Junii & 10mo Novembris,
1769, observatus,” Phil. Trans., 1772, 61:433–436. See also J. C. Beaglehole, ed., The Journals of Captain
James Cook on His Voyages of Discovery, 4 vols. plus portfolio (Cambridge: Cambridge Univ. Press, 1968),
Vol. 1, pp. 694–695.
17
Figure 4. Manuscript drawing by Mohr of his observation of the Venus transit of 1769. (Hollandsche
Maatschappij der Wetenschappen, Haarlem.)
(1729–1811), for example, called at Batavia in October 1768, during a twenty-eight-month
journey around the world. Together with the astronomer Pierre Antoine Véron (1736–
1770), who was assigned to this French expedition with instructions to observe the 1769
transit of Venus, de Bougainville paid a visit to Mohr’s observatory. He wrote enthusiastically in his diary:
We could never be tired with walking in the environs of Batavia. Every European, though he
be used to live in the greatest capitals, must be struck with the magnificence of the country
around it. This is adorned with houses and elegant gardens, which are kept in order, in that
taste and with that neatness which is peculiarly observable in all the Dutch possessions. I can
venture to assert that these environs surpass those of the greatest cities in France, and approach
the magnificence of those of Paris. I ought not to omit mentioning a monument, which a private
person has there erected to the Muses. Mr. Mohr, the first clergyman at Batavia, a man of
immense riches, but more valuable on account of his knowledge and taste for the sciences, has
built an observatory, in a garden belonging to one of his country-houses, which would be an
ornament to any royal palace. This building, which is scarce completed, has cost prodigious
sums. Its owner now does something still better; he makes observations in it. He has got the
best instruments of all kinds from Europe, necessary for the nicest observations, and he is
capable of making use of them. This astronomer, who is doubtless the richest of all the children
of Urania, was charmed to see M. Verron. He desired he should pass the nights in his observatory; unluckily, not a single one has been favourable to their purposes. M. Mohr has observed
18
the last transit of Venus [of 1761] and has communicated his observations to the society of
Harlem; they will serve to determine the longitude of Batavia with precision.37
De Bougainville’s favorable description of Batavia is noteworthy, as this Dutch settlement
was generally thought of as an insalubrious place and was much feared by soldiers and
seamen, who knew it as the “graveyard of the Europeans.” The aforementioned James
Cook would not have disputed this bad reputation. His Batavia stop in Endeavour was to
prove fatal to several crew members, though up to that point all had enjoyed reasonably
good health. One of the men who caught a fever during his stay at Batavia and died after
a few weeks at sea was the expedition’s astronomer, Charles Green (1735–1771). He had
assisted Maskelyne at Greenwich in observations of the Venus transit of 1761 and had
observed the 1769 transit with Cook from King George’s Island (present-day Tahiti).
Green’s sudden death, just a few weeks after he left Batavia, is probably the reason why
we are deprived of his views on Mohr’s observatory. From Cook’s journal we know that
some members of his expedition visited the site, but unfortunately Cook (who was also
taken ill) gives no particulars. However, a glimpse of Green’s visit is unveiled by an
anonymous “letter from a gentleman on board the Endeavour,” printed in the London
Evening Post, which reports that “great respect was paid here to Mr. Green by the principal
people of Batavia, but no particular notice was taken of the rest of us by the Dutch.”38
According to Joseph Banks, the Endeavour’s botanist, the main reason for the somewhat
labored relations between the Dutch and the British during their stay in Batavia was the
fact that “we could have no business with them.” Thus it was only after a long period of
negotiation that he and his traveling companion, the Swedish scientist Dr. Solander, were
granted an audience with the governor-general, where they “had the honour of conversing
for a few minutes with his High Mightiness.” In his Endeavour journal Banks makes no
mention of a visit to Mohr’s observatory. However, some particulars of Banks’s meeting
with Mohr can be inferred from the correspondence of the Dutch-born former VOC governor of Ceylon, Joan Gideon Loten, who in 1771 lived in London. By coincidence, Loten
was a neighbor of Banks. In some letters to his younger brother in Utrecht, Loten vividly
described the enthusiasm with which Banks and Solander told him about their trip around
the world. These gentlemen also spoke about their meeting with Mohr in Batavia: “They
don’t stop talking about the magnificent and well equipped Observatory in Batavia, built
by the reverend Mohr. . . . This is such a noble undertaking, especially under the administration of a governor who is ignorant of all the sciences and hates everybody who tries
to practise them.”39
37
L.-A. de Bougainville, Voyage autour du monde, par la frégate du roi La Boudeuse, et la flûte L’Étoile: En
1766, 1767, 1768 et 1769 (Paris, 1771), quoted from the English translation by John Reinhold Forster, published
in 1772 (pp. 425–426). In the end, Le Véron was unable to observe the 1769 transit effectively because his ship
was at sea when it occurred; see Woolf, Transits of Venus (cit. n. 2), p. 156.
38
Regarding the insalubrious nature of Batavia see Peter H. van der Brug, Malaria en Malaise: De VOC in
Batavia in de Achttiende Eeuw (Amsterdam: Bataafsche Leeuw, 1994). On illness among the Endeavour crew
see Edward Smith, The Life of Sir Joseph Banks (New York: Arno, 1975), pp. 19–20. Green’s death is noted in
Beaglehole, ed., Journals of Captain James Cook (cit. n. 36), Vol. 1, p. 442, entry for 26 Dec. 1770. On the
anonymous letter see Margaret Morris, “Man without a Face: Charles Green,” Cook’s Log, 1980, 3(4):92–99;
the original date of publication in the London Evening Post is not given.
39
John C. Beaglehole, The Endeavour Journal of Joseph Banks, 1768–1771, 2 vols. (Sydney: Public Library
of New South Wales, 1962) (online edition: South Seas Project, State Library of New South Wales, 2002), entry
for 20 Oct. 1770; and J. G. Loten, London, to Arnout Loten, Utrecht, 18 July 1771 (quotation), 30 June 1775,
Archive of Utrecht, Collection Grothe, no. 1428. The reports on Mohr’s observatory made such an impression
on Arnout Loten that in 1771 he established his own astronomical observatory on the roof of his house in Utrecht.
19
THE SCIENTIFIC CLIMATE AT BATAVIA UNDER GOVERNOR-GENERAL VAN DE PARRA
The “governor” Loten referred to was Governor-General Paulus Albertus van de Parra
(1714–1775), who had succeeded Jacob Mossel in 1761. The Ceylon-born parvenu Van
de Parra never received a formal European education. Even his coat of arms was “borrowed” from the distinguished Dutch family Van de Perre, to which he was not related in
any way. In a letter of 1775 Loten again vents anger about Van de Parra’s attitude toward
the sciences: “The present lord Governor [of Batavia] used to be a major enemy of those
studies. I have no doubt at all that in his heart he still is.” From these and other remarks
it becomes clear that Mohr (to whom Loten referred as “this happy son of Urania”) received
little official support for his scientific undertakings. Indeed, the only support we know of
was that the governor-general funded the printing of the last volume of Mohr’s Portuguese
translation of the Bible. Jealousy may have been one of the reasons for this hostile climate
for the sciences. According to a letter from Friedrich Baron von Wurmb, a zoologist and
a close friend of Mohr’s, the fortune that Mohr had invested in his observatory aroused
envy indeed. To free himself from the “hate and disdain” of those in Batavia who “tried
to obstruct the undertakings of others which do not conform to their own taste and approval,” Mohr sought the support of one of the highest-ranking members of the Dutch
VOC hierarchy. In 1768 he pleaded with Thomas Hope, one of the directors of the Amsterdam chamber of the VOC, to be granted official status as astronomer of the VOC.
Mohr complained that the only science heard of in Batavia was the practice of making a
lot of money very fast. Now that, driven by “love for the sciences,” Mohr had voluntarily
appointed himself astronomer of Batavia, he sought to secure this position by an official
letter of recommendation from the Dutch East India Company. The fact that Hope was at
the time the official representative of the Dutch stadholder at the VOC suggests that Mohr
knew of the official appointment given to the Dutch astronomer Jan de Munck (1668–
1768) twenty years earlier: in 1748 this self-made Dutch astronomer had received the title
“Astronomus of the Stadholder” from Prince William IV of Orange.40 Mohr probably heard
about this gesture of princely protection from the Batavia official Jacob Cornelius Mattheus
Radermacher (1741–1783). It had been his father, Jacob Cornelis Radermacher (1700–
1748), then treasurer-general to the prince, who was responsible for creating De Munck’s
official title in 1748. Whether Mohr ever received an answer to his request is doubtful; we
know of no official appointment or any other pertinent document issued by VOC officials.
At about the same time, another local scientific enterprise failed. Sometime around 1770,
J. C. M. Radermacher came forward with a plan to establish a learned society in the European style in Batavia. Radermacher was a member of a very influential Dutch family.
Both his uncle and his nephew were members of the board of directors of the VOC. In
His London-based brother Johan Gideon was commissioned to buy instruments from several English instrumentmakers such as Adams, Bird, Nairne, and Dollond. See J. G. Loten to A. Loten, 13 Sept. 1771, 24 Nov. 1771,
17 Mar. 1772, 25 Aug. 1772, 20 Sept. 1773, 8 Oct. 1773, 11 Mar. 1774, 23 July 1774, 30 June 1775, Collection
Grothe, no. 1428.
40
J. G. Loten, London, to A. Loten, Utrecht, 30 June 1775, Collection Grothe, no. 1428. Regarding the funding
of Mohr’s translation see “Van de Parra,” in Nieuw Nederlandsch Biografisch Woordenboek, 10 vols. (1909–
1935), Vol. 7, pp. 940–941. For Von Wurmb’s letter see Friedrich von Wurmb et al., Briefe des Herrn von
Wurmb und des Herrn Baron von Wollzogen (cit. n. 29), pp. 104–135, esp. pp. 123–124. In 1778 Wurmb
(d. 1782) would become the first secretary of the Bataviaasch Genootschap. For Mohr’s request see Mohr to
Hope, 2 Nov. 1768 (cit. n. 31). On De Munck’s appointment see Huib J. Zuidervaart, “Astronomische waarnemingen en wetenschappelijke contacten van Jan de Munck (1687–1768), stadsarchitect van Middelburg,”
Archief: Mededelingen van het Koninklijk Zeeuwsch Genootschap der Wetenschappen, 1987, pp. 103–170.
20
1757, at the age of sixteen, he had traveled to the Dutch Indonesian settlements as a
merchant for the VOC. Following in the footsteps of his father, who in 1735 had been the
first Freemasonic grand master in the Netherlands, the young Radermacher created a Freemasonic circle in Batavia in 1762, the first of its kind in Asia. A year later Radermacher
returned to the Netherlands, where he enrolled at the University of Harderwijk. After
having completed his studies in law, he went back to Batavia in 1767. While in the Netherlands Radermacher had been inspired by the spirit of the Enlightenment. In those years
several learned societies were established in the Netherlands, and so Radermacher came
forward with the proposal to found in Batavia “a Society with several members, who in a
joint effort would promote fine arts and crafts in the Dutch East Indies and in the other
Dutch Asian settlements.”41 But Radermacher’s appeal (and similar proposals by others in
the Netherlands) was made in vain. He would have to wait until the death of both Van der
Parra and his successor Jeremias van Riemsdijk (governor-general of Batavia from 1775
to 1777) before such an initiative met with success.42
MOHR’S DEATH AND THE FOUNDING OF THE BATAVIAASCH GENOOTSCHAP VAN
KUNSTEN EN WETENSCHAPPEN
In 1778, at long last, the Bataviaasch Genootschap van Kunsten en Wetenschappen (Batavian Society of Arts and Sciences) was founded, this time with the official support of
the newly appointed governor-general Reinier de Klerk (who governed from 1777 to 1780).
The fact that De Klerk was the stepfather of Radermacher’s wife surely contributed to the
eventual launching of this first learned society in Asia. In the early days of the Bataviaasch
Genootschap some meetings “devoted to the Arts and Sciences” were held on the porch
of De Klerk’s house. Moreover, he encouraged all senior officials in Batavia to join the
newly founded society by sending out a circular announcing its formation and his acceptance of the post of chief director. In the first year 103 Batavians enrolled, along with 77
41
“Voorbericht,” Verhandelingen van het Bataviaasch Genootschap der Konsten en Wetenschappen, 1779,
1:3–4; on Radermacher’s role in Batavian Freemasonry see Paul W. van der Veur, Freemasonry in Indonesia
from Radermacher to Soekanto, 1762–1961 (Athens: Ohio Univ. Center for International Studies, 1976). After
the establishment of the Hollandsche Maatschappij der Wetenschappen in 1752 more scientific societies emerged:
in 1769 at Rotterdam (the Bataafsch Genootschap der Proefondervindelijke Wijsbegeerte), in 1769 at Flushing
(the Zeeuwsch Genootschap der Wetenschappen), and in 1772 at Utrecht (the Provinciaal Utrechtsch Genootschap voor Kunsten en Wetenschappen). In 1777 the Oeconomische Tak came into being, an offspring of the
Hollandsche Maatschappij der Weetenschappen devoted to the promotion of commerce and industry. In the
course of the founding of this society some suggested the establishment of a special branch in the East Indies.
However, the founding of the Bataviaasch Genootschap brought this initiative to a standstill. See H. A. M.
Snelders, “Het Bataviaasch Genootschap van Kunsten en Wetenschappen in de periode 1778 tot 1816,” Documentatieblad Werkgroep Achttiende Eeuw, 1979, 41–42:62–90, esp. p. 68, and Snelders, “Professors, Amateurs,
and Learned Societies: The Organisation of the Natural Sciences,” in The Dutch Republic in the Eighteenth
Century: Decline, Enlightenment, and Revolution, ed. Margaret Jacob and Wijnand W. Mijnhardt (Ithaca, N.Y.:
Cornell Univ. Press, 1992), pp. 308–323.
42
See Snelders, “Het Bataviaasch Genootschap van Kunsten en Wetenschappen”; and P. Bleeker, Overzigt der
Geschiedenis van het Bataviaasch Genootschap der Kunsten en Wetenschappen, van 1778–1853 (Batavia, 1853).
The fact that both Van de Parra and his successors Van Riemsdyk and De Klerk were appointed “director” of
the Hollandsche Maatschappij der Weetenschappen (in 1768, 1775, and 1777, respectively) should not be seen
as evidence of their scientific interests but points, rather, to the importance attached to these officials, who
represented the highest authority in the Dutch East Indies. This status is also reflected in the fact that both Van
de Parra and De Klerk were made “honorary members” of the Bataafsch Genootschap at Rotterdam (in 1770
and 1778, respectively) and the Zeeuwsch Genootschap at Flushing (in 1774 and 1778, respectively). In the
years 1777–1779 J. C. M. Radermacher also was appointed “foreign director” of the three most important Dutch
learned societies.
21
additional participants who were residents of the other Dutch dependencies in Asia. There
were a few “corresponding members” in the Netherlands as well.43
Mohr would not live to witness Radermacher’s success. As early as spring 1775 Mohr
had informed the Hollandsche Maatschappij der Weetenschappen in Haarlem that his
health was deteriorating. As a consequence, he explained, he could no longer continue his
astronomical and meteorological measurements. According to Johan Splinter Stavorinus,
a rear admiral for the VOC Chamber of Zeeland, Mohr had developed into an assiduous
observer over the years, especially in the field of meteorology. Although Mohr never
published any meteorological measurements, Stavorinus tells us that his daily barometer
readings showed little variation throughout the year.44
Mohr’s last scientific memoir, dating from 1773, gives a vivid description of the volcanic
eruption and the subsequent collapse of the nearly 3,000-meter mountain Gunung Papandajan, located some 165 kilometers southeast of Batavia. According to his detailed report,
based on dispatches sent to him by European and Javanese witnesses, on the night of 11–
12 August 1772 an area of some 240 square kilometers was completely swallowed by the
earth in the aftermath of the eruption, resulting in the destruction of forty villages and the
loss of nearly three thousand lives.45
In October 1775 Mohr’s life came to an end, the result—according to the statement of
his widow and stepson—of “a long loss of strength.” Strangely enough, the obituary
speech, delivered by one of Mohr’s colleagues, said very little about his scientific undertakings.46 If Mohr had lived, he surely would have had a prominent place in the newly
founded Bataviaasch Genootschap van Kunsten en Wetenschappen, for its mission statement echoed his own earlier recommendation. In 1764, in a letter to the Hollandsche
Maatschappij in Haarlem, Mohr had asked the society to appoint more members in the
East Indies, not only to promote astronomy but on behalf of the other sciences, such as
physics and natural history, as well. Although very few people in Batavia were working
in these fields, Mohr argued, it would be a huge step forward when useful observations
could be collected from the Indonesian islands.47
43
On De Klerk’s role see Jan Hooyman, De rechtvaerdige op zyn sterfbedde, . . . treur-rede, ter gedachtenisse
van . . . Reynier de Klerk (Batavia, 1780), p. 27. This obituary, delivered as a speech before being published,
was dedicated to De Klerk’s heirs, among them his son-in-law, J. C. M. Radermacher. On the society’s early
membership see Taylor, Social World of Batavia (cit. n. 26), p. 86.
44
HMW Notulen, 2 Jan. 1776, mentioning the contents of a letter from Mohr, no longer extant, dated 16 May
1775; and J. S. Stavorinus, Reize van Zeeland over de Kaap de Goede Hoop, naar Batavia, Bantam, Bengalen,
enz. Gedaan in de jaaren MDCCLXVIII tot MDCCLXXI, door den heer J. S. Stavorinus, Schout bij Nacht bij de
Admiraliteit van Zeeland, 2 vols. (Leiden, 1793). According to Stavorinus, Mohr noted that the level of mercury
never deviated significantly from the average of 29 inches and 10 lines.
45
J. M. Mohr, “Bericht nopens het springen en instorten van een brandenden Zwavel-Berg, met het droevig
gevolg van dien, op het eiland Java, in de Maand Augustus 1772 voorgevallen: Met bygevoegde aanmerkingen
nopens dit verschynsel,” Verhandel. Hollandsche Maatsch. Weetensch. Haarlem, 1773, 14(2):82–96. The manuscript and the accompanying letter have not been preserved in the HMW Archives; see HMW Notulen, 3 Aug.
1773. Mohr’s memoir was excerpted in a geological survey of Java by the American army surgeon–naturalist
Thomas Horsfield (1773–1859). On-site investigations in 1837 by the German-Dutch naturalist Franz Wilhelm
Junghuhn (1809–1864), the “Von Humboldt of Java,” revealed that Mohr’s description of the catastrophe had
been much exaggerated.
46
The loss of strength is mentioned in two printed obituary letters, signed by Mohr’s widow Anna Elisabeth
van ’t Hoff and his stepson Johannes Gabriel van Gehren, preserved with the correspondence for the year 1775
in the HMW Archives. For the speech see Theodorus Vermeer, Lyk-reede op het afstervan van . . . Johan Maurits
Mohr, in deszelfs leeven oudsten evangelie-bedienaar in de Portugeeschen Gemeente te Batavia, printed together
with another obituary (on the Rev. Hermanus Teeringh) in Albertus van der Parra, in leeven gouverneur generaal
van Nederlands Indië ([Batavia, 1776]). This obituary was dedicated to the widow and (step-)children of Mohr.
47
Mohr to HMW, 30 Oct. 1764, in Van der Bilt, “De sterrewacht van J. M. Mohr” (cit. n. 21), p. 73. In this
letter Mohr presented the physician Christaan Rose as a candidate for membership. But it would be sixteen years,
after his return to Utrecht, before Rose was elected a member of the society.
22
MOHR’S INSTRUMENTAL RESEARCH PROGRAM CONTINUED BY THE BATAVIAASCH
GENOOTSCHAP
From the very beginning, the Batavian society tried to put into effect the program outlined
by Mohr. Members even tried to extend some of the instrumental observations he had
started. Although Mohr’s observatory was no longer used after his death, his instruments
were bought in 1776 by Johannes Hooijman (d. 1789), one of the most active members
of the Bataviaasch Genootschap. In a way he was a second Mohr. Like his famous predecessor, Hooijman was a clergyman: he had been minister of the Lutheran Church of
Batavia since 1764. Also, like Mohr, Hooijman had married a very wealthy Eurasian
widow: the heiress Elisabeth Odilia Weijerman, the Indian-born daughter of a Dutch commander at Malabar.48 Even more essential, Hooijman had a scholarly attitude and was
curious as to what his investigations would find. On his plantation “Pondok-Gedeh,” near
Buitenzorg, he conducted several agricultural studies and performed botanical experiments.
At the request of the Bataviaasch Genootschap he investigated the growth of wheat imported from the African VOC colony at the Cape of Good Hope. In the first three volumes
of the transactions of the society Hooijman published extensively on the state of agriculture
in the Batavia region. It seems that initially he hoped to continue Mohr’s observations,
especially—probably because of his agricultural interests—the daily meteorological measurements. However, the instruments recovered from Mohr’s observatory were in such bad
condition that restorations were urgently needed. There was no instrument-maker in Batavia capable of fixing these devices, so Hooijman decided to ship most of them to the
Netherlands for repairs.49 The defects were not specified, but probably one of the complaints concerned the state of the telescopic mirrors. In general, oxidation of the reflecting
metal occurred much more readily in the tropics than in milder climatic regions. So in
1776 the Amsterdam merchant Hendrik van Akker was commissioned to see that the
instruments were repaired. In the meantime, it was probably Hooijman who urged the
members of the Batavian society to continue and even extend Mohr’s meteorological
observations. And with success: in October 1778 the society decided to order four thermometers, four barometers, two hygrometers, two anemometers, and two rain gauges from
Amsterdam. Indeed, starting in 1779—and under the supervision of the Bataviaasch Gen48
See the laudatory remarks in remembrance of Mohr made in 1779 by Josua van Iperen, secretary of the
Bataviaasch Genootschap, in the opening speech of his philosophical lessons for fellow “lovers of the arts”
(kunstgenoten) in the society and others interested in the sciences: Josua van Iperen, Inleidingsredenvoering tot
zyne openbare lessen, over de wysbegeerte en fraaije letteren (1779; 2nd ed., Amsterdam: Allart, 1780), pp. 82–
83. The fact that Mohr’s observatory was not used after his death was noted by the Swedish doctor, later professor
of medicine and botany at Uppsala, Karl Peter Thunberg (1743–1822) during his stay in Batavia from 1775 to
1777 as master surgeon (opper-chirurgijn) of the VOC: K. P. Thunberg, Resa uti Europa, Africa, Asia förrättad
åren 1770–1779, 4 vols. (Uppsala, 1788–1793); we have used the German edition (Berlin, 1792–1793), Vol. 1,
p. 197. On Hooijman’s marriage see Taylor, Social World of Batavia (cit. n. 26), p. 87.
49
The 31⁄2-foot Dollond refractor that Mohr used for the observation of the Venus transit of 1769 appears to
have remained in Batavia. In 1843 Mohr’s first biographer, the naval officer Pieter Baron Melvill van Carnbée
(1816–1856), found the telescope in the museum of the Bataviaasch Genootschap. It was reported to be in
excellent condition. He and his assistant F. A. A. Gregorij used the instrument for longitude observations. Ten
years later the geographical engineer Sjoerd Hendrik de Lange (1816–1855) used the telescope for the same
purpose. Around 1910 this instrument was removed from the museum; it has been missing ever since. See
F. A. A. Gregorij, “Lengte-bepaling van den tijdbal te Batavia, geplaatst op den Uitkijk, door middel der waargenome eclipsen van den 1ste en 2de satteliet van Jupiter in 1843,” Tijdschr. Neêrland’s Indië, 1845, 1st Ser.
7(1):397–401; S. H. de Lange, “Reis van de geografische ingenieurs S. H. de Lange en G. A. de Lange van
Batavia naar de residentie Manado en terug, van 23 January 1852 tot 20 Maart 1853,” Natuurkundig Tijdschrift
voor Nederlandsch Indië, 1853, 5 (⳱2nd Ser., 2): 1–66, esp. p. 27; and Van der Bilt, Venus tegen de Zonneschijf
(cit. n. 13), p. 64.
23
ootschap—instrumental meteorological observations were carried out on a daily basis at
Batavia, at the Cape of Good Hope, and at the Decima factory of the VOC in Japan.50
Furthermore, by funding some essay contests—organized in the name of the Bataviaasch
Genootschap by major scientific societies in the Netherlands, such as the Rotterdam-based
Bataafsch Genootschap der Proefondervindelijke Wijsbegeerte (Batavian Society of Experimental Philosophy)—the society tried to contribute to scientific, and sometimes even
instrumental, research (see Figure 5). One of these competitions addressed the interpretation of meteorological observations.51
To place the society on a firm footing, Radermacher, its first president, arranged for a
building to house its growing assets. Radermacher himself presented the society with eight
“well filled” cases with books, manuscripts, instruments, and some specimens for the
“Cabinet of Natural Curiosities.” He soon became even more ambitious. In order to guarantee the ongoing investigations of the Bataviaasch Genootschap, Radermacher (who
planned to return to Holland in 1783) sought to employ an educated scientist who would
be capable of making botanical, meteorological, and other observations on a regular basis.
In September 1781 and again in December 1781, he wrote to the Swedish professor Karl
Peter Thunberg (who had been in Batavia in 1775 and 1777), asking if he could send one
of his students to Java to be employed in the service of the society. Radermacher himself
would guarantee the salary of this employee.52
At the end of 1782, then, one of Thunberg’s students, Klas Fredrik Hornstedt (1758–
1809) from Finland, set out for Java. In August 1783 Radermacher could inform Thunberg
that Hornstedt had arrived, after a short delay in the African Cape colony. However, the
arrangement did not last very long. In 1785 Hornstedt left Batavia, traveling back through
France to Sweden. But by 1786 there was a successor. Hooijman, who had continued the
correspondence with Thunberg after Radermacher’s departure, informed the Swedish professor that Francisco Noroña, a capable botanist from Manila, had taken over the supervision of the society’s museum. In 1786 and 1787 Noroña collected all kinds of natural
specimens on Java and published reports on them in the transactions of the Bataviaasch
50
The new meteorological instruments were shipped to Batavia in 1780 after being inspected by members of
the recently founded Dutch Meteorological Society, the Natuur- en Geneeskundige Correspondentie Societeit.
See I. J. van den Bosch to Van Swinden, 30 Sept. 1780, University Library, Leiden, BPL 755. See also Huib J.
Zuidervaart, “An Eighteenth-Century Meteorological Society in the Netherlands: An Investigation on Early
Instrumentation, Organisation, and Quantification of the Science of Weather” (forthcoming). Regarding the daily
measurements see “Bericht wegens de hoogte der barometer en thermometer: De gesteldheid van weêr, wind,
en hoogte van het water aan het zeehoofd, en in de rivieren in 1779, op Batavia en van weêr en wind tot Caap
de Goede hoop, en Nangazaki,” Verhandel. Bataviaasch Genootsch. Konst. Wetensch., 1784, 2:65–87.
51
The contest was organized in August 1785 by the Rotterdam-based Bataafsch Genootschap der Proefondervindelijke Wijsbegeerte. The question was, “First: what use can be made of the meteorological observations
that are so eagerly taken nowadays? Second: what use can they be to Medicine and to Human Society as a
whole?” In the end, no answers were published. See Verhandelingen van het Bataafsch Genootschap der Proefondervindelijke Wijsbegeerte, 1787, 8:xii; and M. J. van Lieburg, Het Bataafsch Genootschap der Proefondervindelijke Wijsbegeerte te Rotterdam 1769–1984: Een bibliografisch en documenterend overzicht (Amsterdam:
Rodopi, 1985), p. 105 (prize essay 38).
52
Radermacher’s stakeholder in the Netherlands, Frans de Wilde, an accountant of the VOC at Amsterdam,
was commissioned to pay any botanist that Thunberg would send. See J. C. M. Radermacher to K. P. Thunberg,
1 Sept. 1781, 10 Dec. 1781, University Library, Uppsala), cited in D. O. Wijnands, “De relaties van de Zweedse
botanicus/naturalist Carl Petter Thunberg (1743–1828) met de Nederlandse genootschappen,” Teylers Museum
Magazijn, 1990, 8(3):11–16; see also Wijnands, “The Letters of Maarten Houttuyn to Carl Peter Thunberg
(1780–1790),” Proceedings of the Koninklijke Nederlandse Akademie voor Wetenschappen, 93:77–95. Thunberg
himself had made meteorological measurements during his stay in Japan in 1775 and 1776: C. P. Thunberg, “Thermometrische waarnemingen in Japan gedaan in den jaaren 1775 en 1776,” Verhandel. Hollandsche
Maatsch. Weetensch. Haarlem, 1780, 19(3):123–137.
Figure 5. Gold prize medal (front and back) of the Bataviaasch Genootschap van Kunsten en
Wetenschappen, enlarged size. (Courtesy Teylers Museum, Haarlem.)
25
Genootschap. But in 1787, after serious arguments with his superiors at the society, he,
too, left Java, setting off to the island of Mauritius, where he died shortly afterward.53
For a time the survival of the Bataviaasch Genootschap was in doubt. Hendrik Nicolaas
Laclé, who had become the secretary in 1783 after the collective departure for the Netherlands of Radermacher, the society’s president, and the Reverend Metzlar, the secretary,
initially failed to win sufficient support for the organization. The absence of an inspiring
president with the zeal and stature of a Radermacher was sorely felt. Moreover, the mighty
patron of the society, Governor-General De Klerk, had died, as had several other original
members. The continuous deaths and departures of “capable Europeans” led to severe
problems for the Bataviaasch Genootschap. In 1783 even the printing of the Verhandelingen, the transactions of the society, seemed to pose an insurmountable problem because
the remaining compositors in the region (most of them of Portuguese descent) could
scarcely read Dutch. The manuscript of the fourth volume had to be sent to the Netherlands
for publication. In 1789, on his departure as secretary of the Bataviaasch Genootschap,
Laclé summed up the difficulties. In addition to the problems already mentioned, he noted
that the hot and harsh climate, “the enemy of a concentrated mind,” did not encourage
intellectual activity of the kind a flourishing scientific society needed. The isolation of the
East Indies was also perceived as a problem. It took years for news of some of the intellectual accomplishments of the Western world to reach Asia. Most of the work done by
foreign scholars remained unknown there. Contacts with other scientific societies were
scarce. Intellectually, Batavia was indeed positioned on the outskirts of the literary and
scientific world. A last factor that—according to Laclé—had hampered the flourishing of
the society was the business obligations of most of its members. Spare time for science
was a luxury that only a handful could afford. Still, Laclé concluded, the Bataviaasch
Genootschap had not been founded to be a “shining exhibit of scholarship” but, rather, to
make itself useful by informing the inquiring world about these foreign territories.54
Despite these setbacks and difficulties, Hooijman wanted to maintain the original instrumental research program of the Batavian Society. Over the years he had continued his
own investigations and meteorological measurements. In the spring of 1789 he wrote to
the Amsterdam professor Jan Hendrik van Swinden, noting that he had asked the Bataviaasch Genootschap to order some additional meteorological instruments, including newly
invented hair-hygrometers after the design of De la Saussure and two barometers after the
design of De Luc. In the same letter Hooijman asked whether Van Swinden knew any
53
Hornstedt’s travel diary was published in P. J. Bladh, ed., Anteckningar under en resa till Ostindien åren
1782–1786: Anteckningar under en ekonomisk resa till Tyskland, Nederländerna och Paris åren 1799–1800
(Hfors, 1888). See also L. C. Rookmaaker, “The Descriptiones animalium (1784) Prepared by C. F. Hornstedt
on a Journey to the East Indies,” Archives of Natural History, 1988, 15:289–309. One of Hornstedt’s last
commissions for the Bataviaasch Genootschap was the arrangement of transport to the Netherlands of a live
“Oerang Oetang,” caught in the woods of Borneo. However, the animal was lost at sea. See Zeeuws Archive,
Middelburg, Arch. KZGW, no. 5, fol. 239, 30 Aug. 1785. On Noroña see Susana Pinar, “The Scientific Voyages
of Francisco Noroña (1748–1788) in Southeast Asia and the Indian Ocean,” Itinerario: European Journal of
Overseas History, 1995, 1:161–164; and Pinar, “Little-Known Travellers and Natural Systems: Francisco Noroña’s Exploratory Voyage through the Islands of the Indian Ocean (1784–1788),” Arch. Nat. Hist., 1997,
24:127–144.
54
Regarding the printing of the Verhandelingen see Metzlar to Justus Tjeenk, secretary of the Zeeuwsch
Genootschap, 20 Oct. 1780, 31 Aug. 1783, Zeeuws Archive, Middelburg, Arch. KZGW, no. 62, fols. 266–267,
376. For the difficulties faced by the society see H. N. Laclé to the Secretary of the Zeeuwsch Genootschap, 7
Sept. 1789, Zeeuws Archive, Middelburg, Arch. KZGW, no. 59, fols. 370–371. The society survived these
problems. It flourished in the nineteenth and early twentieth centuries, only to be dissolved when the Dutch
colonial rule came to an end.
26
Dutch scholar capable of taking over the scientific investigations on Java. As Adriaan
Moens, the newly appointed president and temporary secretary of the Batavian society,
was withholding the finances necessary to employ such a person, Hooijman himself was
prepared to pay the expenses. He was looking for “an able person, middle aged, knowing
the botanical system of Linnaeus very well.” The man in question could live on his estate,
free of charge, and would receive a yearly income of 1,200 Dutch guilders. In return, he
had to be prepared to record the state of the atmosphere three times a day and, in “the
empty hours” between recordings, go out into the field in search of unknown plants. A
contract for at least two years would be guaranteed to any person willing to come to Batavia
on these conditions.55
Hooijman further asked Van Swinden if he was willing to make inquiries as to the fate
of Mohr’s astronomical instruments, sent to Amsterdam for repairs in 1776. Although the
merchant Van Akker had promised to get them repaired, Hooijman had never received an
adequate response from him. It was still the case that no one in Batavia was up to the job:
recently Hooijman had again been forced to send astronomical instruments to Holland to
be fixed. They had been used by a naval officer named Wille who had tried to determine
the longitude of several places in the Indonesian archipelago.56
THE DEMISE OF INSTRUMENTAL SCIENCE AT BATAVIA
Hooijman would not live long enough to see his dreams fulfilled. Two months later, in
June 1789, he was gruesomely murdered on his estate. The new meteorological instruments
he had just received, made by the English-born Amsterdam craftsman John Cuthbertson,
were returned to the Bataviaasch Genootschap. They never worked properly. One of the
barometers was broken in transit and lost all its mercury. The other barometer, after De
Luc’s design, also failed to perform properly, despite Hooijman’s many attempts to get it
running. The same thing had happened with the hygrometers: the human hair in the instrument prepared in Holland appeared to be completely useless. Moens, as acting secretary
of the society, wrote to Van Swinden informing him of Hooijman’s death. He also complained that a hot, wet tropical climate was not suited to instrumental science. The fact
that only a very few people in the East Indies knew how to use these kinds of instruments
only made matters worse. According to Moens, Hooijman had come to the same conclusion
just before his death, a verdict corroborated by the fact that all the scientific instruments
recovered from his estate appeared to be defective. At this point instrumental science in
the Dutch East Indies came to a standstill, not to be revived for several decades.57
THE FATE OF MOHR’S ASTRONOMICAL INSTRUMENTS
In the meantime, Van Swinden had located Mohr’s astronomical instruments, which had
been stored in the attic of the merchant Van Akker since their arrival in Amsterdam in
1776. This rediscovery had been an easy job, for Van Akker and his business partner
Heineken had just started negotiations with the Amsterdam society Felix Meritis for the
loan of these instruments. Oddly, they were behaving as though they owned the instruJohannes Hooijman to Van Swinden, 2 May 1789, University Library, Leiden, BPL 755.
Ibid. The Dutch naval officer Wille had taken a “common astrolabium,” a small reflecting telescope of which
the mirror had became dull, and a large naval telescope to Holland for repairs.
57
Adriaan Moens to Van Swinden, 7 Apr. 1789, 4 Nov. 1789, Univ. Library, Leiden, BPL 755. On the second
period of instrumental research on Indonesian soil see Pyenson, Empire of Reason (cit. n. 1).
55
56
27
ments, even though the rightful owner—Hooijman—was still alive. The Maatschappij
Felix Meritis was founded in 1777 as an institute for promoting the arts and sciences. To
accommodate its four departments (Commerce, Physics, Arts, and Literature) the society
was constructing a large, specially designed edifice on the Amsterdam Keizersgracht. An
astronomical observatory was planned for the roof, and during the years of its construction
(1786–1788) the society was on the lookout for proper instruments. Having heard of these
ambitious plans, the merchants Van Akker and Heineken came forward. Although Mohr’s
instruments were in bad shape, they were of an excellent design, and once repaired they
would be perfectly suited for use in the new observatory. In December 1786 the merchants
offered the instruments for a period of twenty years, on the condition that Felix Meritis
would pay for the repairs. And so it was agreed. In 1787 the instrument-maker Frans
Pasteur was commissioned by Felix Meritis to perform the work.58
Although Van Akker and Heineken had not revealed the provenance of the instruments,
this soon became known. On 31 October 1789 Van Swinden, who was invited to give a
lecture at the official opening of the new building, praised both Mohr and the second life
now granted his instruments:
I know that [Felix Meritis] has a wonderful collection of artefacts, made by the most famous
English artisans, first shipped at great costs to the East Indies, where they were used in Batavia
by the late Mr Mohr. They were returned to the Fatherland after his death and were relegated
to an attic as dead weight, being subjected to rust and decay . . . , but you have been able to
retrieve them, and had them restored . . . with the intent of installing them in your observatory.59
Apparently Van Swinden, who had just received Hooijman’s letter asking him about
Mohr’s instruments, accepted their presence at Felix Meritis since 1786 as a fait accompli.
In 1791, however, having learned the year before of the sad fate of the legitimate owner
of the instruments, Van Swinden pleaded with the board of Felix Meritis to buy the instruments from Van Akker and Heineken (who evidently were still acting as the legal
owners). The inventory handed over on this occasion summarizes eleven astronomical
instruments: (1) a large standing quadrant, made by John Bird [at London]; (2) a smaller
one [2 feet in radius, also by Bird]; (3) a [wooden] sextant [with brass inlay], made by
Bird; (4) a sextant, made by [Samuel?] Gregory [at Dublin]; (5) an octant by [Daniel]
Voster [at Cork?]; (6) a large [41⁄2 foot] Gregorian telescope [with a heliometer], made by
Dollond, [London]; (7) a smaller one [of 3 feet, by the same]; (8) an astronomical telescope
[with accessories in a long wooden box] by Dollond; (9) a [41⁄2 foot] meridian [⳱ transit]
telescope [with a level and a lantern for illuminating the cross-wires at night] by Sisson;
(10) a [3 foot achromatic] transit telescope by Dollond; and (11) a parallel telescope [with
its stand, in a triangular box] by Paauw.60 These eleven instruments were offered for sale
58
On the loan agreement see Municipal Archive, Amsterdam, Archive of the Society “Felix Meritis” (AFM),
no. 234 (meeting of 29 Dec. 1786). See also M. R. Hermans, E. Lievense-Pelser, and O. Vlessing, Inventaris
van de archieven van de Maatschappij Felix Meritis 1777–1889 (Amsterdam: Gemeentearchief, 1994). The
Geneva-born instrument-maker Bernard François Pasteur (1741–1801) worked in Amsterdam from 1767. In
1791 he was appointed a member of Felix Meritis. In 1793 he left for Leiden, where he got a job as scientific
instrument-maker at the university.
59
J. H. van Swinden, Redevoering en aanspraak, ter inwijding van het gebouw der Maatschappij Felix Meritis
(Amsterdam, 1789), p. 97. In 1788, in one of the first descriptions of Felix Meritis, the provenance of the
instruments was made public: Amsterdam in zyne opkomst, aanwas . . . beschreeven, ten vervolge op het werk
van Jan Wagenaar (Amsterdam, 1788), p. 506.
60
AFM, no. 235 (meeting of 8 Apr. 1791). Some details of the instruments are added from inventory lists in
AFM, no. 235 (9 July 1794); AFM, no. 260 (1794–1795); AFM, no. 274 (short inventory ca. 1820), and AFM,
no. 275 (inventory in 1835). See also [C. S. Roos], Historische Beschrijving van het Gebouw der Maatschappije
van Verdiensten, ten spreuke voerende: Felix Meritis (Amsterdam, 1800), pp. 94–95, 123.
28
for the total of 4,500 Dutch guilders. The board of Felix Meritis refused the offer, intending
to prolong the lending arrangement as before. But in 1794 Adriaan Gilles Heineken (1763–
1824), representing the firm of Van Akker and Heineken, granted permission for lending
only the instruments of minor importance. The most important instruments were taken
back; as a result, the instruments numbered 1, 4, 5, 7, 8, and 10 disappeared from the Felix
Meritis building, never to be heard of again. After the dissolution of Felix Meritis in 1889,
all remaining scientific instruments were handed over to the physics laboratory of Amsterdam University; most of them have since disappeared. The whereabouts of only two
parts of Mohr’s costly instruments can now be traced.61
THE DEMISE OF THE BATAVIA OBSERVATORY
Nor had fate smiled on Mohr’s observatory in Batavia. In 1780, only five years after its
founder’s death, the building was severely damaged by a heavy earthquake. Two years
after that, in May 1782, Mohr’s widow, Anna Elizabeth van ’t Hoff, passed away. Just a
month later, in June 1782, the future owner was granted permission “to modify, lower or
demolish” the building, but no such plan was immediately carried out. In 1784 the site
was purchased by Willem Vincent Helvetius van Riemsdijk (ca. 1752–1818), one of the
many children of former Governor-General Jeremias van Riemsdijk. Apparently little was
done to repair or maintain the observatory, and in August 1788 Van Riemsdijk gave permission to convert the deserted facility and the adjoining buildings into lodgings for the
poorly housed company clerks of Batavia’s Castle. From that time on the building was
known as the “Scribbler’s Asylum” (Pennistengesticht).62
Evidence of the speed with which the observatory was falling to ruin is found in the
correspondence of the young Francis Beaufort (1774–1857), who would later become
famous as an admiral and hydrographer. Enrolled as a fifteen-year-old captain’s servant,
he visited Batavia in the summer of 1789 and described the abandoned observatory built
by a certain “M. de More” in a letter to his parents:
Such an Observatory I never saw. There is but one room in the house calculated to observe in,
which is at the top of the house, near one hundred feet from the ground, affording only the
most awkward viewing and so built that if you just stamp in any one part of the house it shakes
the Observation room. Indeed we find that a person walking about on the stairs or in any . . .
room of the house shakes the Horizon and makes the objects turn about in the Equatorial
Telescopes. . . . In short, I never saw or heard of such a place in my life.
Nonetheless, Beaufort and his captain carried their instruments to the old observatory every
day during the three weeks of their stop in Batavia to check and improve on Mohr’s
longitude and latitude determinations. Four years later George Staunton (1781–1859), a
61
On the transfer of the instruments to Amsterdam University see AFM, no. 59 (last meeting: 5 June 1889).
The Bird sextant (listed under no. 3) is now in the Nederlands Scheepvaart Museum, Amsterdam (no. B 21 [1]/
H.12). A heliometer objective, originally an accessory to Mohr’s 41⁄2-foot reflecting telescope made by Dollond
(listed under no. 6), is now at the Museum Boerhaave, Leiden (no. 6130). The 3-foot achromatic telescope by
Dollond (listed as no. 10) is the only instrument claimed back in 1794 whose fate can be traced. Through the
Amsterdam astronomer J. F. Keyser and his pupil, the Utrecht professor Gerrit Moll, it went to the Utrecht
Observatory in 1838. It was handed over to the Utrecht University laboratory in 1892; it has since disappeared.
62
NA/VOC, no. 812, 18 June 1782; and NA/VOC, no. 820/821, printed in J. A. van der Chijs, ed., NederlandschIndisch Plakaatboek, 1602–1811 (Batavia/The Hague, 1885–1900), Vol. 11, pp. 29–34.
29
member of a British mission to the Chinese court, noticed during his stopover in Batavia
in March 1793 that “there was an observatory, but we found it to be in a ruinous state.”63
In August 1809 the Pennistengesticht was closed down by Herman Willem Daendels,
governor-general from 1807 to 1811, and for some years the buildings served as army
barracks. According to J. M. van Beusechem, director of the “Scribbler’s Asylum” from
1808 to 1810, the observatory was still standing in 1812, but in 1844 nothing remained
except its foundation. The memory of the imposing structure, however, would be kept
alive locally for another century. Up until the last years of Dutch rule in Batavia, the
parallel streets in the district of Klĕntong (Glodok), running westward from the Molenvlietse dike (Jalan Gajah Mada) through the former entrance and the garden to the site,
were marked on the city’s municipal maps as the “Gang Torong” (i.e., Tower Alley) and
the “Gang Kebon Totong” (Tower Garden Alley).64
CONCLUSIONS
Stimulated by a prediction made by Halley in 1716, the French astronomer Delisle pleaded
in 1760 with the Dutch East India Company to ensure that observations of the 1761 transit
of Venus were made at Batavia. This simple request triggered a long chain of events. The
local reverend Mohr, until then a man devoted only to the humanities, attended the 1761
observations performed at Batavia by VOC officials. This event prompted Mohr to appoint
himself the astronomer of Batavia. Between 1765 and 1768, using the funds of his wealthy
Eurasian wife, he built himself an astronomical observatory equipped with instruments of
a quality theretofore unheard of in the region. Though Mohr himself emphasized the
physico-theological incentive, enhancement of his social status appears to have been the
major motivation for him to build this luxurious observatory.65
Very different attitudes toward the sciences characterized Dutch colonial authorities and
the officials of other colonizing nations—such as France and Britain—in the eighteenth
century. The government of the Dutch Republic failed to support pure scientific research.
The few achievements made in the sciences in the Dutch colonies were the result of private
63
Beaufort is quoted in Alfred Friendly, Beaufort of the Admiralty: The Life of Sir Francis Beaufort (London:
Hutchinson, 1977), p. 31. See also W. F. J. Mörzer Bruyns, “Prime Meridians Used by Dutch Navigators: A
Survey of the Prime Meridians Used by the Dutch for Navigation and Hydrography, Prior to 1884,” Vistas in
Astronomy, 1985, 28:33–39, esp. pp. 37–38. For the latitude, Beaufort worked out a value between 6⬚ 8⬘ and
6⬚ 8⬘ 40⬙ South—somewhat lower than Mohr’s estimates, which ranged between 6⬚ 10⬘ and 6⬚ 12⬘. Beaufort
probably made some observations for the determination of the longitude of Batavia, as well but these measurements appear to have been lost in the shipwreck of his vessel near the southeastern coast of Sumatra a couple
of weeks later. For Staunton’s remark see George Staunton, Travels of Lord Macartney to China (London, 1799),
pp. 2, 75–76.
64
On the closing of the Pennistengesticht see Van der Chijs, ed., Nederlandsch-Indisch Plakaatboek (cit. n. 62),
Vol. 15, pp. 848–849. Van Beusechem is cited in Melvill van Carnbée, “lets over den Nederlandschen Sterrekundige Johan Maurits Mohr” (cit. n. 21), p. 177. For “reminders” of Mohr’s observatory see the “Stadskaart
van de Gemeente Batavia” (revised in 1918, published in 1921), reproduced in B. Brommer and D. de Vries,
Historische Plattegronden van Nederlandse Steden, Vol. 4: Batavia (Alphen aan de Rijn: Canaletto, 1992), no. 14.
The two streets are marked on present-day municipal maps of Jakarta as the Jalan Kemurnian 8 and Jalan
Kemurnian 9, behind a hotel and a shopping center.
65
In this respect, it is noteworthy that in the 1920s similar social reasons played a major role in the founding
of Indonesia’s second astronomical observatory: the Bosscha Observatory at Lembang. “Providing funds for
pure research allowed [Karel] Bosscha, a failure at the Delft Institute of Technology, privileged access to the
drawing rooms of polite society and the antechambers of political power”: Pyenson, Empire of Reason (cit. n. 1),
p. 183. Like Mohr before him, the plantation owner Bosscha was a colonial overlord who used pure science as
a vehicle to raise his own status. Nevertheless, in spite of this more or less hidden social agenda, in both cases
well-equipped observatories were built and some relevant scientific results were obtained.
30
initiative and funding. One reason why the state was reluctant to support pure science may
be the fact that eighteenth-century Dutch society was completely dominated by the concept
of usefulness. We met this idea in the remark of the Dutch astronomer Klinkenberg that
“the usefulness of astronomy to mankind was not sufficiently appreciated in Dutch society.” He was right, indeed! The concept of usefulness was a key factor in Dutch intellectual
ideology; all scholarly and scientific efforts were at the mercy of this utilitarian bias. And
while in the Netherlands the promotion of theology was also considered a useful goal, in
the colonies “commerce” trumped every other interest. Adriaan Moens, governor of Malabar, remarked on the founding of the Bataviaasch Genootschap in 1779 that he surely
hoped that “this scientific society would help to serve the sciences and the promotion of
the Christan faith”; but he feared that this would be a difficult mission, for “it is a pity
that in the East Indies the aim of making money is the principle object of study.”66
The situation elsewhere in Europe was very different. In the 1950s, in his influential
study on the eighteenth-century transits of Venus, Harry Woolf outlined the massive efforts
in support of scientific expeditions made in name of the crowned heads of Great Britain,
France, Sweden, Russia, and other countries. More recently, in analyzing the French “colonial machine” of the ancien régime, James McClellan and François Regourd concluded
that the central government systematically engaged its elaborate scientific infrastructure in
its colonizing efforts. They suggest that the chief motivation for such an effort appeared
to be “the sheer glory and magnificence of a great empire,” which “was enough of a raison
d’être for the French state to underwrite costly colonial investments.”67 In short, the majesty
of the great kings of Europe was not to be taken lightly.
Evidently the decentralized Dutch Republic, in which all the provinces were sovereign
and which by nature lacked a royal court, was not similarly sensitive to imperial arguments
of glory and royal luster—with perhaps one small exception. In 1761 the Dutch Province
of Friesland subsidized a local mathematician in making observations of the transit of
Venus. The provincial authorities of Friesland wanted to support the “royal art” of astronomy. Unlike most other Dutch provinces, Friesland had not had a period without a stadholder. While the other provinces had abandoned this function between 1702 and 1747,
in Friesland and Groningen members of the House of Orange had stayed in office. Thus
the provincial capital of Leeuwarden could boast a continuous tradition of court culture
up to the death of the last Frisian Princess of Orange in 1765. Perhaps more than other
Dutch authorities, then, the Frisian officials were aware that funding scientific projects
might serve to reinforce their own “royal” status.68 However, Friesland did not have any
66
Moens to Tjeenk, secretary of the Zeeuws Genootschap der Wetenschappen, Flushing, 15 Dec. 1779, Zeeuws
Archive, Middelburg, Arch. KZGW, no. 62, fols. 68–69. On the hegemony of usefulness see Wijnand W.
Mijnhardt, “The Dutch Enlightenment: Humanism, Nationalism, and Decline,” in Dutch Republic in the Eighteenth Century, ed. Jacob and Mijnhardt (cit. n. 41), pp. 197–223, esp. p. 217. See also H. F. Cohen, “Open and
Wide, Yet without Height or Depth,” Tractrix: Yearbook for the History of Science, Medicine, Technology, and
Mathematics, 1990, 2:159–165; Klaas van Berkel, “Over nationale stijl en wetenschappelijke cultuur in Nederland,” in Citaten uit het boek der natuur: Opstellen over Nederlandse wetenschapsgeschiedenis (Amsterdam:
Bakker, 1998), pp. 11–23; and Bert Theunissen, Nut en nog eens nut: Wetenschapsbeelden van Nederlandse
natuuronderzoekers 1800–1900 (Hilversum: Verloren, 2000).
67
Woolf, Transits of Venus (cit. n. 2); and James E. McClellan III and François Regourd, “The Colonial
Machine: French Science and Colonization in the Ancien Régime,” in Nature and Empire, ed. MacLeod (cit. n. 2),
pp. 31–50, esp. pp. 31, 49.
68
Huib J. Zuidervaart, Speculatie, Wetenschap en Vernuft: Fysica en Astronomie volgens Wytze Foppes Dongjuma (1707–1778), instrumentmaker te Leeuwarden (Ljouwert/Leeuwarden: Fryske Akademy, 1995), pp. 59–
76; and H. J. Zuidervaart, “Reflecting Popular Culture: The Introduction, Diffusion, and Construction of the
Reflecting Telescope in the Netherlands,” Ann. Sci. 2004, 60, pp. 1–41.
31
say in the board of the Dutch East India or West India Companies, and so the echo of
“royal” state funding of pure science was not heard in the Dutch colonies. Nonetheless,
as we saw with Mohr in Batavia, there were some wealthy Dutch individuals who came
close to copying the royal behavior of the foreign sovereigns. So why did their work not
have the same effect, especially when these scientific efforts were institutionalized—as
was the case with the Bataviaasch Genootschap, one of the earliest scientific societies in
Asia?
It was long believed that Mohr’s initiative was an isolated effort, the work of a single
person that was not followed up. We have shown that this idea, first put forward by Frederik
de Haan and repeated by many others, is wrong. Mohr’s initiative did contribute, around
1770, to thoughts of starting a scientific movement among some Europeans living on Java.
But even if the Dutch governments did not provide any money to advance the cause of
science, their approval was a factor of major importance. Mohr himself sought to secure
his position through an official letter of recommendation from the VOC. Science could
perhaps do without money from the state but surely required its authority and protection.
Because support from the colonial authorities was not forthcoming sooner, the founding
of a scientific society in Batavia had to wait until 1778. Mohr did not live to see this
particular fruit of his labors; nonetheless, the Bataviaasch Genootschap tried from its inception to put into effect the program he had outlined. Moreover, Mohr’s family contributed wholeheartedly to the assets of the society. Over the years his son-in-law would
become one of its most dedicated patrons, donating money and a costly collection of
manuscripts, maps, and paintings.69 Originally the Bataviaasch Genootschap even wanted
to continue the kind of instrumental measurements Mohr had started a decade before and
bought his instruments from his widow for that purpose. However, furthering this instrumental program proved to be more than the society could manage. The reasons for its
failure can be summarized briefly. First, all scientific instruments had to be imported from
Europe, causing long delays. Once they arrived, only a few members of the Bataviaasch
Genootschap had the expertise needed to use and, especially, maintain them. Even a small
defect meant the end of the useful life of an instrument. The tropical climate speeded up
the deterioration of almost every scientific instrument brought to Batavia—and there was
not a single philosophical instrument-maker in the East Indies capable of making the
necessary repairs. As a consequence, most of Mohr’s astronomical instruments had to be
returned to the Netherlands for repair. Once sent, it was almost a decade before they
resurfaced—and in the end they were never sent back to the East Indies.
Frequent repatriation and the deaths of many important members of the Bataviaasch
Genootschap were likewise difficulties this small society had to cope with, bearing heavily
on the continuity of its scientific programs.70 Another setback was the short stay of the
two botanists recruited to serve the society and maintain its work on a regular basis. The
escalating shortage of funds in the decade before the financial breakdown of the VOC in
1799 eventually brought to an end this first period of instrumental and institutional science
in the Indonesian Archipelago.
69
For the idea that Mohr’s initiative was an isolated effort see [Frederik de Haan], Oud-Batavia: Gedenkboek
uitgegeven door het Bataviaasch Genootschap van Kunsten en Wetenschappen naar aanleiding van het driehonderdjarig bestaan der stad in 1919, 3 vols. (Batavia: Kolff, 1922–1923), Vol. 2, p. 280; Klaas van Berkel, Albert
van Helden, and L. C. Palm, eds., A History of Science in The Netherlands: Survey, Themes, and Reference
(Leiden: Brill, 1999), p. 215; and Taylor, Social World of Batavia (cit. n. 26), p. 88. On Mohr’s son-in-law’s
support see ibid., p. 87 and App. 3.9.
70
Moens to Van Swinden, 4 Nov. 1789, University Library, Leiden, BPL 755: “ . . . because the continuous
dying and repatriation of competent men sets us back here more than one in Holland would believe.”
32
On the whole, this eighteenth-century episode confirms Lewis Pyenson’s observations,
made with regard to nineteenth-century Indonesia, that the scientific effort in this colonial
setting was an initiative taken by Europeans, modeled after European examples, and leaning on European-made instruments. Apart from the localized subjects of study, especially
in natural history, the colonial setting had little influence on the science undertaken. For
the scientists themselves, however, that setting was very influential indeed. Jean Gelman
Taylor has pointed out that almost all the men active in the eighteenth-century Bataviaasch
Genootschap were European immigrants married to local “Mestizas,” women raised in
Asia and often many years their juniors, who had no connection at all to European culture.
The wives of Mohr, Radermacher, De Klerk, and Hooijman were all of Eurasian descent.
Thus this small group of men, who tried to create Dutch or European institutions in a
somewhat alien world, was firmly linked with the Indonesian homeland of their wives.
Taylor even goes so far to attribute some of the relative lack of success of the Bataviaasch
Genootschap to such factors, suggesting that “in taking young Eurasian wives with whom
they shared no cultural affinity, nor language for weighty discourse, these men of the
Enlightenment defeated their own purpose of promoting Dutch culture in Asia.” For whatever reason, we must admit that, despite great efforts and costly investments in equipment,
very little was achieved as far as the instrumental sciences are concerned. From that perspective we agree indeed with James McClellan that the Bataviaasch Genootschap can be
seen as a “bare outpost of learned [European] culture on the edge of the jungles of Java.”71
EPILOGUE
Some final remarks, then, can be made about the nature of scientific interest in Holland
and the Dutch colonies. First, it must be noted that in Batavia almost all scientific efforts
went to the observational sciences: astronomy, meteorology, and natural history. Whereas
in Holland local physical societies flourished from the middle of the eighteenth century,
and often members had their own cabinets of scientific instruments, in the colonies very
few of these konstgenoten (“fellows of the arts”)—as they called themselves—could be
found. Physical instruments other than those necessary for observational purposes were
extremely rare. As far as we know, an air-pump was used only once at the Bataviaasch
Genootschap, when one of its medical members lectured on the properties of air. How
different things were at the Cape colony, where in 1776 several “distinguished amateurs
of the sciences” could be found and even the local governor possessed “an air-pump,
electrical instruments and other magnificent machines.”72 An instrument-maker could easily make a living there; even so, however, his repeated orders for dozens of glass barometer
and thermometer tubes from the Netherlands illustrates the fact that here too observational
71
Pyenson, Empire of Reason (cit. n. 1), pp. 176–178; Taylor, Social World of Batavia (cit. n. 26), p. 92
(Taylor uses the word “Mestizas” in this unusual sense); and James E. McClellan III, Science Reorganized:
Scientific Societies in the Eighteenth Century (New York: Columbia Univ. Press, 1985), p. 125. A short review
of discussions on the subject of the European basis of Indonesian science is given in Roy MacLeod, “Introduction,” in Nature and Empire, ed. MacLeod (cit. n. 2), pp. 1–13, esp. p. 4.
72
Regarding the lecture on the properties of air see “Voorbericht,” Verhandel. Bataviaasch Genootsch. Konst.
Wetensch., 1792, 6:17; and Snelders, “Het Bataviaasch Genootschap” (cit. n. 41), pp. 77, 88. On the situation at
the Cape colony see Brand, Cape colony, to Van Swinden, 28 Feb. 1776, 28 Feb. 1777, 6 Mar. 1777, 7 Apr.
1777, 1 Apr. 1778, University Library, Leiden, BPL 755. Daniel Brand, who originated from the Frisian town
of Sneek, had been one of Van Swinden’s students. In 1768 he enrolled at the Franeker University to study
medicine and philosophy. In 1774 he left Franeker for the Cape, where in addition to his work as a physician
he constructed and repaired scientific instruments.
33
science was most common. It was the same in the Dutch West Indies. Regular observational
science started in Surinam in 1743 with daily meteorological observations, the readings
of which were noted on preprinted tabular sheets. These sheets were prepared, distributed,
and collected again by Nicolaas Duyn from Haarlem, a member of a very active local
physical and astronomical society. Why the other Dutch colonies did not participate in this
meteorological project is not known. The question of whether this might be attributed to
different attitudes toward instrumental science in the Dutch West India Company and the
VOC requires further investigation. At any rate, in the Dutch West Indies the “critical
mass” for science was also too small. An attempt, made in 1784, to found a “learned
society” in Surinam (a Société pour l’Avancement de la Physique et l’Histoire Naturelle
de Paramaribo) never went beyond preliminary inquiries. And the few meteorological
observations that were carried out in those areas were organized from the Netherlands.73
In short, direct factors such as the availability of manpower, expertise, means, and money,
together with indirect factors such as governmental support, high status, and spare time,
appeared to be key in the success or failure of scientific practice in this Dutch colonial
context as well.
73
The sheets are preserved in the Koninklijke Bibliotheek, The Hague, Van Swinden Collection, no. CCCIIB. See also Bert C. Sliggers, “Honderd jaar natuurkundige amateurs in Haarlem,” in Een Elektriserend Geleerde:
Martinus van Marum, 1750–1837, ed. A. Wiechmann (Haarlem: Enschedé, 1987), pp. 67–102, esp. pp. 71–75.
Regarding the proposed Surinam society see J. Voegen van Engelen to Van Swinden, 7 Feb. 1784, University
Library, Leiden, BPL 755; on meteorological observations organized in the Netherlands see Van Swinden to
Jean Deutz, 5 Jan. 1784, University Library, Leiden, BPL 755.

A Bare Outpost of Learned European Culture on the

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