instruments up to a certain price on his own, he corresponded with the trustees frequently,
securing their backing for his purchases. It is interesting to note that when van Marum had the
possibility of acquiring a small camera obscura, van Zeebergh was so taken with the
description of this device that he immediately granted van Marum permission to buy it.54 This
turned out to be the only time that he didn’t check with his fellow trustees first. The camera
obscura was removed from the museum’s collection sometime in 1817.55
In London, van Marum visited a number of instrument makers’ workshops such as those of
Adams and Dollond, he met Joseph Banks, various members of the Royal Society, attended a
meeting of that illustrious gathering of men, visited the Royal Observatory in Greenwich, and
made a pilgrimage Newton’s grave.56 He then moved on to Slough, where William Herschel
resided and had just had the world’s largest telescope constructed, with a 40 foot focal range.
This was out of order when van Marum visited, but the Dutchman was already blown away by
what he saw when he gazed through one of Herschel’s smaller, but still comparatively large,
20 foot telescopes: it was so powerful that nebulae became discernible. Van Marum must
have felt he had found a kindred spirit in Herschel, whose philosophy of having ever larger
telescopes constructed and thereby successfully pushing the boundaries of astronomy must
have chimed well with van Marum’s conviction that he would be able to settle various issues
with the Cuthbertson electrostatic generator because of the machine’s sheer force. Van
Marum ordered a seven foot telescope for Teylers Museum. Finally, he travelled on to
Birmingham, where he visited the factory of Watt and Boulton, and was hoping to obtain a
model of their steam engine. Fearing patent infringements, the inventors however pursued a
very strict policy of not distributing any such models, and did not make an exception for van
Marum, who began to suffer from a hacking cough caused by the polluted air of this industrial
city.
As planned, van Marum had also struck a deal with an instrument maker in London. Frederik
Willem Fries, of Swiss origin, had agreed to come to Haarlem if he was provided with at least
an equal salary to the one he was earning in London, and if he was provided with the funds to
purchase new tools, because trade laws prohibited him from bringing his own to the
Netherlands from London. Both demands were considered perfectly reasonable, and in
November 1790 van Marum was able to introduce Fries to the members of the Second Society
in Haarlem.
Fries immediately went to work, and together with van Marum constructed two devices - in
all likelihood in the new laboratory that must have been completed precisely during this
period — over the course of the next months that received a lot of praise for many years to
come. The first of these was an improved, smaller electrostatic generator. Its most striking
54 Levere, “Teyler’s Museum,” 60.
551.Q. van Regteren Altena, J.H. van Borssum Buisman, and C.J. de Bruyn Kops, Wybrand Hendriks 1744-1831
(Haarlem: Teylers Museum, 1972), 11.
56 For more detail on his activities in London see: Martinus van Marum, “Notes on a Voyage to London in
1790,” vol. 2, Martinus van Marum: Life & Work (Haarlem: Tjeenk Willink & Zoon, 1970), 266-272; Levere,
‘Teyler’s Museum,” 53-65.
57 “Notulen Tweede Genootschap”, 19.11.1790, Haarlem, ATS, vol. 1382. The minutes erroneously state that
Fries was originally from Strasbourg.
feature was that it only used one disc, rather than two, as was the case with all of van
Marum’s previous disc machines. More importantly however, it was the first disc machine
that could generate either a positive or a negative charge. Up until that point, this had been the
main advantage of the rival cylinder machines that to van Marum’s chagrin were more
popular than disc machines in England.58
The second device was a gasometer, which enabled a far cheaper demonstration of the
decomposition of water that was so crucial to Lavoisier’s analytic chemistry than was possible
with Lavoisier’s own devices, which had proved unaffordable for all but a few chemists.
Alongside the 1784 electrostatic generator, this gasometer proved to be van Marum’s most
sensational device. Upon its completion he received many requests for copies to be made
from academies across the world.
But even though Fries was clearly excelling at his job, by April 1791 the poor man was
feeling so homesick that, as van Marum phrased it three decades later, he had become
“melancholy and peevish” and “incapable of continuing his work”.60 Perhaps this dismissive
judgement - even if it was made years later w is indicative of a more general change of
atmosphere at Teylers. A general pattern seems to emerge if one takes into account van
Marum’s relationship with his research associates from the 1780s: by the time van Marum
returned from London Cuthbertson, Paets van Troostwijk and Deiman all had broken - or
were about to break - their ties with van Marum. Was van Marum’s hobnobbing with the elite
of his generation going to his head? Cuthbertson became involved in a nasty public dispute on
a series of improvements to the electrostatic generator. Having worked together so closely for
almost a decade, the two men now flung accusations at each other of withholding information
that was vital to the other’s work, sullying each others’ reputation. This altercation was
carried out through the medium of articles in local scholarly journals. Some years later,
Cuthbertson left the Netherlands and returned to his native Britain, after which he left too few
traces to say what fate had in store for him. Even the circumstances surrounding his departure
are hazy. It is likely that losing his best and by far most lucrative client - Teylers Museum -
broke his business.61 Paets van Troostwijk and Deiman were affected in a less profound
manner. Together with other chemists predominantly from the Amsterdam region they set up
the Gezelschap der Hollandsche Scheikundigen, after they had already shown that water could
not only be decomposed, but could also be synthesised from its components, oxygen and
hydrogen. They had drawn international attention with their demonstration, but van Marum
had been little more than a bystander.62
5 Levere, ‘Teyler’s Museum,” 65.
59 Ibid., 66.
60 “droefgeestig en gemelig”; “tot het voortzetten van zijn werk geheel ongeschikt”; Martinus van Marum: “De
Geschiedenis van de oprigting van Teyler’s Museum”, 1823-1833, Haarlem, NHA, Archief van Marum, vol.
529, nr. 9, fol. 38.
61 On the available archival material on Cuthbertson see: Hackmann, John and Jonathan Cuthbertson: The
Invention and Development o f the Eighteenth Century Plate Electrical Machine.
62 On the Scheikundig Gezelschap see: H.A.M. Snelders, Het Gezelschap der Hollandsche Scheikundigen:
Amsterdamse chemici uit het einde van de achttiende eeuw (Amsterdam: Rodopi, 1980).