De toetreding van Nederland tot de Middeneuropese
Graadmeting
5e jaargang no. 5, mei 1975
1 Inleiding
Omstreeks 1860 lag tussen de grote Frans-Engelse
en Russiseh-Skandinavisehe graadmetingen in Eu
ropa een gebied waar nog slechts op kleinere schaal
graadmetingen waren verricht. Voor topografische
doeleinden waren in de meeste staten weliswaar
driehoeksmetingen uitgevoerd doch een onderling
verband ontbrak. De Pruisische luitenant-generaal
Baeyer kwam op de gedachte deze afzonderlijke
driehoeksmetingen met elkaar te verbinden en met
ongeveer dertig in dit gebied gelegen astronomisch
bepaalde punten dienstbaar te maken aan de graad
meting in Europa. Dit zou dan mogelijk resulteren
in een betere bepaling van de vorm en de grootte
van de aarde.
Johann Jacob Baeyer (1794-1885), leerling van Bessel
en later diens medewerker bij de Oostpruisische
graadmeting (1831-1836), was door zijn werk maar
al te zeer bekend met de moeilijkheden die de geo
deet ondervindt indien de dimensies van de aarde,
N. VAN DER SCHRAAF
SUMMARY
The entry of The Netherlands into the Central European Degree-measurement
In 1861 The Netherlands received an invitation to join the "Mitteleuropaische Grad-
messung" (Central European Degree-measurement), a project proposed by the Prussian
general J. J. Baeyer. His idea was to unite the triangulations and astronomical points in
this area and obtain in this way a better determination of the figure of the earth. Older
triangulations were allowed provided they satisfied the accuracy requirements adopted
at the first conference on this project (Berlin, 1862). In The Netherlands the triangulation
in use was the one carried out by general C. R. T. Krayenhoff in the years 1802-1811.
Prof. F. Kaiser, the director of the Leiden Observatory was asked by the government to
give advice in this matter.
From correspondence with Baeyer he learned that a recomputation applying the method
of least squares should be considered. Kaiser approached L. Cohen Stuart, lecturer in
geodesy at the Royal Academy, Delft, (the forerunner of the Delft University of Techno
logy) and asked him to investigate whether the quality of Krayenhoff's results warranted
such a recomputation.
Cohen Stuart made a thorough study of all available data (1862-1864) and arrived at the
conclusion that Krayenhoff's triangulation did not meet the standards set for the Mittel
europaische Gradmessung. In a report to the government by Kaiser and Cohen Stuart[l8]
a new triangulation between Leiden and the Belgium and German borders, consisting of
double chains of triangulation, and determination of the longitude differences between
Leiden and the observatories of Greenwich, Brussels, Bonn and Gottingen were proposed.
These proposals were accepted by the government and in 1865 The Netherlands joined
officially the Mitteleuropaische Gradmessung.
Kaiser took charge of the astronomical part of the new measurement while Dr. F. J. Stam-
kart was finally willing to carry out the geodetic part after Cohen Stuart and Dr. M. Hoek
for various reasons had declined this task.
Cohen Stuart's judgement about Krayenhoff's work was critized by J. D. van der Plaats in
an article published in the professional journal "Tijdschrift voor Kadaster en Landmeet
kunde [29]". This criticism was disproved by the Netherlands Commission for Triangu
lation and Levelling published in the same journal in 1892 [30],
175
ngt 75
81
