century. The first time was after Volta had discovered the eponymous Voltaic pile which,
upon being perfected and in modem terms, was capable of creating a steady current.70
Through his network of correspondents, particularly through Joseph Banks and Volta himself,
van Marum was one of the first to be privy to the Italian’s milestone discovery. Upon Volta’s
request, van Marum then soon set out to establish whether the electricity - or, to use the
contemporary term, the electric fluid - generated by the pile was the same as that generated
by a disc machine. What better disc machine to use than the huge one built by Cuthbertson in
Haarlem? Together with an associate of Volta’s, the professor from Kiel Christoph Heinrich
Pfaff, van Marum spent ten days in late 1801 conducting a series of experiments in Haarlem.
They came to the conclusion that the machine and the pile did indeed generate the same kind
of electricity.
The second time was almost twenty years later, after Hans Christian Oersted had discovered
the phenomenon of electromagnetism. Van Marum lost little time in recreating the
groundbreaking experiments that had led to this discovery.72 But by this time, he was a
septuagenarian, and although in good health, he must have started feeling the physical strain
of working the electrostatic generator — together with assistants that were not getting any
younger either.
So these two instances were exceptions. In his Second Sequel published in 1795 van Marum
had in fact already stated that he felt electrical science was in a “stationary period”, and that
he did “not see for the present that there is any train of promising investigations which offer
the prospect of interesting results”.73 And even though, at that point, he was still busily
working on chemistry experiments, he recalled later how by 1798 he wanted to devote more
time to the earth sciences and the museum’s geological collection, “having completed the
collection of physical and chemical instruments, as far as it seemed possible to me at the
time”. As he summarised in 1810: “Geology was then my favourite study.”74 It was to remain
so until a huge row erupted between him and van Zeebergh in 1802. Before the turn of the
century, however, apparently all was still well.
11. Down to Earth
Although Teylers Museum’s instrument collection has been chosen as the vantage point from
which to approach the history of the entire museum and this specific collection’s history is
70 Heilbron, Electricity in the 17th and 18th Centuries: a Study o f Early Modern Physics, 494.
Hackmann, “Electrical Researches,” 362; Christoph Heinrich Pfaff, Carl Friedrich Kielmeyer, and Gregor
Wilhelm Nitzsch, Lebenserinnerungen (Kiel: Schwers’che Buchhandlung, 1854), 134.
7 Hackmann, “Electrical Researches,” 369.
73 Marum, “Second Sequel to the Experiments with Teyler’s Electrical Machine,” 147.
74 “ayant achevé alors la collection des appareils physiques et chymiques, autant quil me parût possibl dans ce
tems là” ; “La Geologie fut alors mon étude cherie.” Martinus van Marum, Catalogue des plantes, cultivées au
printems 1810; dans le Jardin de M. van Marum à Harlem (Haarlem, 1810), v.
therefore disproportionately emphasised throughout this study, for a full appreciation of
Teylers Museum’s history and the changes it underwent over the course of the 19‘ century it
is also of pivotal importance to gain a sense of the importance and the general status of the
museum’s other collections - such as its geological collection. As far as the geological
collection is concerned this is all the more so during van Marum s tenure, because all of the
museum’s scientific collections were still intimately linked in that they all fell under van
Marum’s purview - by the time Volkert Simon Maarten van der Willigen was put in charge of
the instrument collection in the second half of the 19th century the geological collection and
the instrument collection were no longer conjoined, but formed entirely distinct entities, albeit
not yet spatially.
Moreover, as with the instrument collection, it was van Marum who essentially laid the
groundwork for the subsequent curators’ work in that he determined the focal points of the
collection through his early acquisitions. Subsequent curators’ own interests are clearly
reflected in the collection’s later development, but it is no exaggeration to say that if van
Marum had not been in charge, the museum might never have established a fossil collection
in the first place. His acquisitions for the geological collection therefore need to be seen in
relation to his other activities, and, vice versa, in any assessment of the instrument collection’s
overall status within the context of Teylers Museum one needs to take the geological
collection into account as well.
There are two crucial points one needs to be aware of when trying to understand the genesis
of the fossil collection during van Marum’s tenure. The first of these is that the earth sciences
were undergoing fundamental changes around the turn of the century. The second point is van
Marum’s physico-theological approach to the study of nature.
As far as the first point is concerned, perhaps the most striking development was that the
study of fossil bones was emerging as an area of research in its own right.75 This in turn led to
an increasingly narrow definition of “fossils”: whereas at the end of the 18 century they were
still defined as pretty much any solid material the earth divulged — van Marum stated that he
wanted to build a collection of “Fossilia”B- they were increasingly associated with the
fossilized remains of living creatures by the early 19th century.
This in turn reflected the way, over the course of van Marum’s lifetime, various branches of
the earth sciences started to emerge in their current form. In fact the term geology itself
only began to be used during this period. This had everything to do with a far more
fundamental shift in the general thought pattern of earth scientists. More specifically, they
began to historicise the earth. The Earth itself began to be seen as a product of nature, i.e.
subject to nature’s laws, and subject to the fluctuations of nature. This showed in two different
ways. Firstly, the timeframe within which practitioners of the earth sciences considered the
object of their study changed. The Earth itself need neither be eternal, nor the product of some
fairly recent catastrophe or process of creation. Rather, there was now room for an
intermediate timescale. That period of time might have included numerous catastrophic events
7S The following paragraphs in this section are based on: Martin J.S. Rudwick, Bursting the Limits o f Time: The
Reconstruction o f Geohistory in the Age o f Revolution (Chicago: University o f Chicago Press, 2005).