How Much were Spinoza’s Lenses and Microscopes?

In the interest of making Spinoza’s lens-grinding, polishing, and telescope and microscope building more vivid to those considering his metaphysics, this evidence is posted as to the kinds of prices for those services one would expect.

Lueken and Lueken (1694)

E. G. Ruestow writes:

At a date I read to be late 1670’s: “…Johan van Musschenbroek in Leiden [sold micro-beaded lenses] forty for a gilder – roughly a day’s wages for skilled manual labor in the Netherlands. Musschenbroek otherwise advertised his cheapest simple microscope for 7½ gilders and his most elaborate, with nine seperate and interchangeable lenses, for nearly ten times as much” (The Microscope and the Dutch Republic, 28).

And the footnote reads: “Johan van Musschenbroek advertised six beads – “Glaze dropjes, en bolletjes” – for three stuivers, which, there being twenty stuivers to the guilder, was the price equivalent to forty for a guilder…Earlier in the century, Constanijn Huygens, Sr., had paid forty guilders for one of Drebbel’s microscopes.”

If indeed Spinoza made simple bead lenses, provided a buyer was available – which for these type lenses would be likely be infrequently – he could make a laborer’s day’s wages in about an hour (Ruestow points out that Swammerdam said he could make them at this rapid rate, 40 and hour). The prices of any primary grinding of lenses to specific focal lengths or uses for other salesmen or instrument makers of course are not reflected here. But perhaps a week’s wages could be made for his simplest microscopes.

Lenses not Rare

One can see from the depiction of a spectacle makers’ storefront, strewn with glimmering lenses and spy glasses, that by the late 17th century such devices are quite common. In fact, when Descartes writes his Dioptrics in 1637, when Spinoza is five years old, he mentions how common “flea glasses” have become. It is good to remember both the commonality of Spinoza’s trade, its brute, craftsman standing, but also the elite circulation of ideas which came about in applying these somewhat widespread devices, both in terms of theories about the nature of what was seen, but also changing techniques and optical conceptions on how to see it. Spinoza stood in both worlds.