Nicolaas Hartsoeker was a Dutch mathematician and physicist who invented the screw-barrel simple microscope circa 1694.
Biography
He was the son of Anna van der Meij and Christiaan Hartsoeker 1626–1683, a Remonstrant minister in Moordrecht near Gouda. His father took the family to Alkmaar in 1661 and finally to Rotterdam in 1669. Nicolaas started to make a living as a lens maker in Rotterdam, and was instructed in optics by Antonie van Leeuwenhoek. In 1674, he and a fellow student, assisted by Van Leeuwenhoek, were the first to observe semen, a situation that would later lead to a priority dispute between Hartsoeker and Leeuwenhoek over the discovery of spermatozoids.
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Hartsoeker returned to Rotterdam, where his parents still lived and where he married Elisabeth Vettekeucken in October 1680. His business as an instrument maker and wine merchant failed and, after the death of his father in August 1683, he moved his family in 1684 to Paris, where he made instruments for the Paris observatory and the academy. Hartsoeker also came up with contrivances for aiming very large aerial telescopes originally popularized by Huygens. He remained there until 1698.
It is often said that in 1694, while observing human sperm through a microscope, Hartsoeker believed that he saw tiny men inside the sperm, which he called homunculi or animalcules. However, he only postulated their existence as part of his Spermist theory of conception and never claimed to have seen them. The 1694 "Essay on dioptrics", in which this hypothesis appears, was a highly lauded book, in fact tackling several misconceptions of the time. For example, Hartsoeker disavows the contemporary position e.g. of Robert Hooke that with refractor telescopes one soon would be able to see man-sized creatures on the moon, if any in fact existed.
At the end of the century, Hartsoeker had become quite famous. In 1699 he was elected member of the French Academy of Sciences and in 1704 of the Prussian Academy of Sciences, in both cases as one of the first foreign members. Czar Peter met him in Amsterdam and offered him the chair of mathematics in St Petersburg. Hartsoeker did not accept, but the czar did finance an observatory for him in Amsterdam. Later, in 1704, Hartsoeker accepted the offer of Johann Wilhelm, Elector Palatine to become "first mathematician and honorary professor of philosophy" at the University of Heidelberg. The last years of his life were spent in Utrecht.
Major works
- Essai de dioptrique, Paris, 1694.
- Principes de la physique, Paris, 1696.
- Conjectures physiques, Amsterdam, 1706.
- Suite des conjectures physiques, Amsterdam, 1708.
- Eclaircissements sur les conjectures physiques, Amsterdam, 1710.
Top questions
Who was Nicolaas Hartsoeker?
Nicolaas Hartsoeker was a Dutch mathematician and physicist, born in Gouda in 1656. He worked as a lens and instrument maker, studied optics with Antonie van Leeuwenhoek and invented the screw-barrel simple microscope around 1694. He became one of the first foreign members of the French Academy of Sciences.
What did Nicolaas Hartsoeker invent?
Hartsoeker invented the screw-barrel simple microscope around 1694. He also came up with contrivances for aiming the very large aerial telescopes that Christiaan Huygens had popularized, and he made instruments for the Paris observatory and academy while living in Paris.
What was Hartsoeker's theory about homunculi?
It is often said that in 1694 Hartsoeker believed he saw tiny men inside human sperm, which he called homunculi. In fact he only postulated their existence as part of his Spermist theory of conception and never claimed to have seen them. The idea appeared in his 1694 Essay on dioptrics.
How did Nicolaas Hartsoeker learn optics?
Hartsoeker started out as a lens maker in Rotterdam and was instructed in optics by Antonie van Leeuwenhoek. In 1677 he met Christiaan Huygens and showed him how to make lenses, and in 1678 he went with Huygens to Paris as an assistant. A fall-out followed when Huygens failed to mention him in a publication.
What was Hartsoeker's Essay on dioptrics?
The Essay on dioptrics, published in Paris in 1694, was a highly lauded book that tackled several misconceptions of the time. For example, Hartsoeker rejected the view of Robert Hooke that refractor telescopes would soon let people see man-sized creatures on the moon, if any existed.
What honors and positions did Nicolaas Hartsoeker receive?
Hartsoeker was elected to the French Academy of Sciences in 1699 and the Prussian Academy of Sciences in 1704, in both cases as one of the first foreign members. Czar Peter offered him a mathematics chair in St Petersburg, which he declined, but the czar financed an observatory for him in Amsterdam.
Where did Nicolaas Hartsoeker live and work?
Hartsoeker was born in Gouda, and his family moved to Alkmaar in 1661 and Rotterdam in 1669. After his business in Rotterdam failed, he moved to Paris in 1684 and stayed until 1698. In 1704 he became first mathematician and honorary professor of philosophy at Heidelberg, and he spent his last years in Utrecht.
