From the book
A Chymical Dictionary
Gerhard Dorn and John French · Diotimos Editions · 2026
Browse this book’s lexicon →Orientation
At a Glance
- The wordOne name with a common mineral use and a distinct artificial preparation.
- In the bookMarcasita gives the broader account of unripe metallic matter.
- A place to readThe historical definition below, 1650 dictionary, unnumbered definition page 31; facsimile PDF page 359.
Historical definition
Magnesia is commonly used for a marcasite; artificial magnesia is tin melted with quicksilver, the two being mixed into a brittle, white mass.
Meaning
The definition expressly separates what is commonly meant from what is made artificially. In the first use Magnesia leads to marcasite. In the second, the compiler describes the union of tin and quicksilver, with brittleness and whiteness as properties of the resulting mass. Those two accounts should not be blended into a single unspecified mineral.
The product’s name therefore depends partly on the context in which it occurs. A passage about a mine may require a different reading from a passage describing a prepared mass, even though both use Magnesia.
Use in the book
Marcasita gives the broader account of unripe metallic matter. Iupiter names tin and Luna compacta names quicksilver. These equivalents provide a route through alternative names for the materials mentioned in the artificial branch of the definition.
Places to read
- MagnesiaRead the complete historical definition and its commentary.
- MarcasitaA varied category of metallic matter understood as unripe.
- IupiterThe planetary name Jupiter denotes tin here.
- Luna compactaA lunar compound assigned to quicksilver.
In this edition
The modernised wording keeps the two uses separate and does not substitute the modern material suggested by a familiar-looking name.
Source note
Historical source. 1650 dictionary, unnumbered definition page 31; facsimile PDF page 359 — Facsimile
Sources. A Chymical Dictionary 1650, 1650 dictionary, facsimile PDF page 359, Magnesia