Volkert Simon Maarten van der Willigen, sometimes referred to as Volcardus Simon Martinus van der Willigen, was a Dutch mathematician, physicist and professor.
Life
Volkert was son of the ministerJohannes van der Willigen and his wife Gerarde Maria Elsabé Bodde. He was the nephew of the Dutch patriot and writer Adriaan van der Willigen. He studied at the Hoogeschool Leiden and promoted in 1847 with his dissertation De aberratione lucis. After graduating he became teacher at the Latin school in Amsterdam. In 1848 he was appointed to professor in the mathematics and physics and philosophy at Athenaeum Illustre in Deventer. He accepted his appointment with the lauratio Over natuur- en sterrekundig onderzoek. In 1857 he became a member of the Koninklijke Nederlandse Akademie van Wetenschappen. When the Athenaeum Illustre of Deventer was abolished in 1864, he was appointed conservator of the Physical Cabinet of the Teylers Museum in Haarlem where Jacob Gijsbertus Samuël van Breda had resigned his post nine months earlier. Contrary to Van Breda however, Van der Willigen refused to accept the responsibility for the Paleontological-Mineralogical cabinet alongside his duties for the Physical cabinet, and that position was later filled by Tiberius Cornelis Winkler. Thus free to devote himself to the instrument collection and physics experiments, in the years that he spent at Teylers, Van der Willigen published 51 papers. As a scientist, Van der Willigen did significant work inthe research on physical units – where he tried to use the wavelength of light to set a new and trustworthy standard for a unit of distance. In those days there was insufficient data on the reliability of measurement units because errors had been made in the standards based on the circumference of the earth. The DutchMinister of the Interior had requested the Koninklijke Nederlandse Akademie van Wetenschappen in 1851 to come up with a new standard for both length and weight. Inspired by this discussion and a publication by the Swedish scientist Anders Ångström in 1855, Van der Willigen decided to dedicate himself first to the determination of the refractive index and the wavelength of light, in order to be able to more accurately define the unit of length. In the inner garden of the Museum, he had a small observatory built in 1866/1867, where he set up several precision instruments to determine the latitude and time. There he also kept an astronomical regulator, heliostat, spectroscope, diffraction gratings, microscope with micrometer, balance, thermometers and barometers. He also ordered the standards of length and weight. Combining these instruments he tried to determine a standard of length by use of a seconds pendulum. Besides his work on measurements, he also purchased acoustics instruments, on which he gave a series of lectures in the museum. Van der Willigen became active in Haarlem society and was a member of the Haarlem city council from 1864 to the year of his death.
Works
Iets over meteorologische waarnemingen
Slingerproeven te Deventer ; 1852
Verzameling kleine geschriften ; 1852
Bepaling der poolshoogte voor Deventer ; 1852
Proeve betreffende den galvanschen lichtboog ; 1854
Nog iets over electrische ringen ; 1863
De coefficienten van breking van mengsels van zwavelzuur en water ; 1864
Over de verschijnselen van gekleurde polarisatie voor eenassige kristallen convergent licht ; 1873
Over de onhoudbaarheid der stelling dat de betrekking der lichtstralen wordt gewijzigd door de beweging van licht-bron en prisma ; 1873
Mémoire sur la détermination des longueurs d'onde du spectre solaire ; 1875
Over het electrisch spectrum ; unknown year
Over eene optische illusie, waarbij het relief van het beschouwde voorwerp wordt omgekeerd ; unknown year