Chapter IV: Van der Willigen
Precision and the Discipline of
Physics
I. An Unexpected Guessing Game (Intro)
One year after Elisa van der Ven had been appointed the new curator of Teylers Museum’s
scientific instrument collection, he sent his first detailed report on his activities and future
plans for the collection to the trustees of the Teyler Foundation. It was April 1880, and van
der Ven reported that he had spent a great deal of time trying to gain an overview of what
instruments he had inherited from his predecessors, and trying to figure out what exactly they
had acquired them for. This, he stated, had been far more difficult than he had expected for a
number of reasons: his predecessors appeared not to have been particularly eager to record
their thoughts and plans in writing, for instance, and the instruments did not appear to have
been stored in a particularly orderly fashion. As van der Ven complained:
“In the museum the strangest objects were then to be found together, so that often from a
cupboard that seemingly served for the storage of similar instruments, different ones emerged,
that had nothing to do with the others scientifically.” 1
But while this delayed his compiling a catalogue of the collection, what completely stumped
van der Ven was a small building in the garden behind the museum that had been constructed
by his immediate predecessor, Volkert Simon Maarten van der Willigen, sometime between
March 1866 and February 1867.2 The report to the trustees contains a remarkably frank
admission that he didn’t have a clue why this building - which was roughly the size of a large
hut, was built in stone, had a large slit in its roof and was referred to as the “observatory” —
had been erected. Van der Ven literally wrote about this building in the garden: “For what
purpose it has been put there is difficult to guess.”3
“In het museum toen stonden vrij wel de meest vreemdsoortige zaken bij elkander, zoodat dikwijls uit een kast,
die schijnbaar geheel ter berging van gelijkwaardige instrumenten diende, andere te voorschijn kwamen, die
wetenschappelijk daarmede niets hadden te maken.” E. van der Ven: “Verslag, betreffende den toestand van en
de werkzaamheden van Teylers Physisch Kabinet, voor het jaar 1879/80”, 02.04.1880, Harlem, ATS, vol. 191.
Gerard L’E. Turner, The Practice o f Science in the Nineteenth Century: Teaching and Research Apparatus in
the Teyler Museum (Haarlem: Teylers Museum, 1996), 16. The approximate construction date can be deduced
from the costs incurred by the building activities. The relevant bills are to be found in: “Kasbewijzen”, 1866-
1867, Haarlem, ATS, vol. 6 9 8 .1 am gratefiil to Marijn van Hoorn for drawing my attention to these sources.
“Voor welk doel het daar is neergezet is moeilijk te gissen.” E. van der Ven: “Verslag, betreffende den toestand
van en de werkzaamheden van Teylers Physisch Kabinet, voor het jaar 1879/80”, 02.04.1880, Harlem ATS vol.
191.
The only thing that was clear was that the building had been used for measurements of some
sort. One promising clue seemed to be that no iron had been used in the building, which
suggested that any sort of electromagnetic induction was to be avoided. However, van der
Ven pointed out that this, too, failed to explain why he had found a Universal Instrument
“with thick iron axles” in the building.
To this day the mystery of the “observatory’s” exact purpose has never been solved
completely. Van der Willigen’s publications, together with other sources from the archives of
the Teyler Foundation - e.g. on their bookkeeping or the trustees’ meetings - do not provide
any conclusive evidence. Nevertheless there are a few good clues (such as the lack of iron in
the building): the positioning of the slit in the building’s roof for instance indicates that the
passage of stars through the meridian might have been determined from this building - which
would also help explain why it was labelled the “observatory”. At one point during his career
van der Willigen was trying to establish a standard length, and Gerard Turner for one has
argued that this aim “establishes the link between the small building in the Museum grounds
and many of the instruments acquired by Teyler’s from 1865”.5 This is certainly not at odds
with van der Ven’s own summary in his report to the trustees:
“It is most likely that in the course of the years the intention has changed and that the
instruments brought together there [in the observatory] were given the destination of keeping
track through them of the true time.”
But what is of course most striking about all this confusion is that the trustees themselves
were literally not aware of what was going on in their backyard, i.e. in the backyard of one of
the institutions they were financing. Yet, as strange or even ignorant as this may sound at first,
it is in fact indicative of something far more fundamental, and ultimately highly crucial to the
overall status of the instrument collection: by the second half of 19 century science in
general - and physics in particular - had become so specialised and complicated that it had
become both incomprehensible and inaccessible to laypeople. Science was becoming
something of a “black box”: on the one hand technology and, by extension, science were
affecting people’s everyday lives on an unprecedented scale (think of the steam engine and
photography); but on the other hand science itself, or, to phrase this more precisely, the
research process through which the body of knowledge that was then deemed scientific was
obtained, was becoming ever more incomprehensible and thereby also ever more puzzling to
the general populace. Just as importantly, because all sciences - and, again, physics in
particular — were increasingly relying on precise, quantitative measurement as the sole
legitimate basis of all knowledge claims, the places where scientific research was being
performed were becoming increasingly inaccessible to those not involved in the
measurements themselves.
“met dikke ijzeren assen” ; Ibid.
5 Turner, The Practice o f Science in the Nineteenth Century: Teaching and Research Apparatus in the Teyler
Museum, 17.
6 “Allenwaarschijnlijkst is men in den loop der jaren van denkbeeld veranderd en heeft men aan de daar
bijeengebrachte instrumenten de bestemming willen geven door hunne bemiddeling zieh steeds rekenschap te
kunnen geven van den waren tijd.” E. van der Ven: “Verslag, betreffende den toestand van en de
werkzaamheden van Teylers Physisch Kabinet, voor het jaar 1879/80”, 02.04.1880, Harlem, ATS, vol. 191.