How Agrippa distinguishes the elements in stones

Heinrich Cornelius Agrippa von Nettesheim (1486–1535), a German scholar and physician, poses a problem about the order of the elements in the first book of his Occult Philosophy. Stones would seem to belong to the earth simply by their place beneath our feet. How, then, might water, air and fire also be recognized within the same kingdom of nature? Agrippa answers with a series of properties that can be compared in individual specimens.

A difference the eye can follow

For amongst the Stones they especially are called earthy that are dark, and more heavy; and those waterish, which are transparent, and are compacted of water, as Crystall, Beryll, and Pearls in the Shels of Fishes […]

– Heinrich Cornelius Agrippa von Nettesheim, De occulta philosophia, 1651, p. 18–19.^[1]

Imagine putting two stones on a wooden table. One lies dark against the wood and has a noticeable heft when lifted. The other allows light to reach the surface beneath it. In Agrippa’s vocabulary the first suggests earth and the second recalls water. A single feature does not always suffice. Darkness and weight stand together in the description of what is earthy. In the watery kind of stone one thing that matters is whether an observer can see through it.

What the classification does

Agrippa extends the enquiry beyond stones to other bodies. Once readers have learned to attend to transparency, weight or warmth, they can ask similar questions of quite different objects. This explains why the names of the elements recur at more than one level, first as large divisions of nature and then as properties of particular things. A transparent stone remains a stone throughout the chapter. Its kinship with water lies in what it does to light and in what an observer can discover there. A term such as “watery” becomes an instruction about where to look when making the comparison.