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A History of Early Spherical Microscope Lenses – Spinoza’s Place in Optics

Spinoza’s Microscope

In view of organizing the possible context for Spinoza’s lense-grinding and instrument making, here is a brief timetable of spherical lens use, such that surrounds Spinoza. Spherical lens making was the use of tiny spheres of melted glass, some of them ground and polished. The smaller the sphere, the greater the magnfication, surpassing all compound microscopes at the time, making at a times very minute magnifying glass to which one pressed one’s eye [see here for Van Leeuwenhoek’s example]. This history is quite approximent.

1628 Harvey sees the heart of a flea.
1629 painter de Gheyn II dies at age 64, before Constantijn Huygens, Sr. can convince him to illustrate microscopic views for the proposed “The New World”.
1644 Odierna uses a chickpea sized globule, Toricelli as well.
1646 Kircher sees flea’s leg and hair with spheres no bigger than the smallest of pearls; (Cardinal Medici’s gift).
1646+ Bettini uses a sphere smaller than a millet seed.
1654-1663 Hudde studies under van Schooten, working on Descartes’ Geometry, with J. de Witt, at Leiden.
1656 Borel sees the nerves, feet and eyes of a mite.
1657 Schott uses “transparent atoms”
1657 Hudde writes of plans to study generation microscopically, letter to Van Velthuysen
1658 Kircher sees worms in the blood of fever victims.
1659 Van Leeuwenhoek claims (40 years later) to have produced bead glass lenses, in Delft.
1659 Spinoza begins periodic studies at the University at Leiden.
1660 Blaes influential speech at the Athenaenum of Amsterdam, addresses the microscopes use in anatomy.
1661 Spinoza said to be a maker of telescopes and microscopes, Borch’s Diary
1661-1662 Enrolled at Leiden University studying medicine Swammerdam, Steno, Kerckring, de Graf, Ruysch
1661-1663 Spinoza lives in Rijnsburg grinding lenses and making instruments, a couple of miles from the University at Leiden and the young anatomists.
1663 Spinoza moves to Voorburg, five minute walk from Huygens’ estate, a few miles from The Hague.
1663 At The Hague Vossius shows the French diplomat Monconys his simple microscope of a little hemispherical lens mounted in woodframe behind black board (Journal).
1663 Hudde in Amsterdam shows to visiting Monconys his technique of forming lenses by melting beads of glass, and polishing them with salt (Journal).
1664-5 Hooke‘s influential Micrographia, wherein he describes his beads from threads of glass method. Likely seen by Spinoza in visits to the Huygens’ estate in the summer of 1665 when he also saw Huygens’ machine for grinding lenses.
1666 Vossius, Spinoza’s associate, writes that smaller sphericals of glass best. De Nihi et aliorum…
1666 Spinoza in correspondence with Hudde over the nature of God and technical questions of optics and lens grinding (Letters 34 to 36).
1667 Spinoza speaks to Vossius about an alchemical matter.
1667 Huygens twice writes his brother, complimenting the polish that Spinoza is able to achieve by “the instrument” in small lenses for his microscopes. (Parenthetically, also writes to his brother about Spinoza‘s collaboration with Hudde on calculations on a40ft lens which would have been among the largest in Europe.)
1668 Swammerdam declares sphericals best lenses.
1668 May 11, Christiaan Huygens admits to his brother in letter that he agrees that Spinoza was right, smaller objectives in microscopes represent objects much finer fashion.
1670 Spinoza moves to The Hague.
1670 Kerckring (Spinoza’s former classmate), declares he has seen vascular bundles with Spinoza’s microscope, and organs teeming with minute, possbily symbiotic animals [post-mortum microorganisms or “still active cilliated surfaces”?, Ruestow 265]: yet declares that things viewed solely by microscope should be held suspect. Spicilegium anatomicum.
1671 Kerckring claims to have seen, and draws a tiny, tiny human inside a 3-day old fertilized human egg [seen with Spinoza’s microscope?], Anthropogeniae ichnographia.
1674 Hartsoeker makes beads of glass lenses after his father visits Van Leeuwenhoek.
1677 Johan Ham, a student a Leiden, possibly with a bead-lens, first sees spermatozoa and brings them to Van Leeuwenhoek.
1677 Hartsoeker, a student at Leiden with a bead-lens, later claims to be the first to see spermatozoa.
November 1677 The Huygenses purchase Spinoza’s lens-grinding equipment at auction.
March 1678 Huygens makes his first bead-glass lens microscope aided by Hartsoeker.

 

The importance of this time table is that it builds a net of associations with the bead-like, small spherical lens techniques which made up some of the most powerful yet simply microscopes of the day, in part through the person of Hudde around Spinoza. Hudde taught at least two persons his technique of microscope lens-making, and possibly many more. It also places Spinoza in the context of the anatomist debates of the early 1660’s, as a microscope maker and a Cartesian living in Rijnsburg. The role of Kerckring in this debate (glands vs. vessels and preexistence) under the authority of Spinoza’s microscope also is suggestive of Spinoza’s connection to this group, and the possible powers of his instruments.

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