Unique alchemical emblem

[Adam McLean]

I recently found this rather puzzling alchemical emblem. I can't recall seeing anything quite like it
It is a folded parchment sheet in

University of Kassel, 2° Ms. chem. 24

It is entitled, Spherae sive Compassi mineralis Nova inventio  (A New Discovery of the Mineral Sphere or Compass)

It was created by Justus de Buschia, probably in 1552.


Six rays stream down from heaven and are being collected in a hemispherical vessel. It has a number of holes in its base, and beneath this, on the platform supporting the hemisphere, there are six circular discs. The rays from above shine through the holes onto these discs, which are labelled, Iovis, Solis, Lunae, Martis, Saturni, and Veneris. These discs each bear a symbol that I cannot quite make out.



   

[Adam McLean]

I have just had the thought that the little forms inside the oval discs may be intended as compass needles (they do appear somewhat like pointers).
The Latin text below, does refer to the compass.

specie sive compass si mineralis, per quem omnia metalla in crescentus ac venis suis...

I'm not sure of some of the letters but it suggests these are compasses through which one may find the individual metals growing in their veins.

It is interesting that Mercury is not included with the other six metals.

[Paul Ferguson]

38 Henry VIII 32 names Justus de Buschia as a servant to King Henry VIII with an annuity of 62 pounds 10 shillings, which would have bought him 7 horses or 33 cows according to the National Archives Currency Converter.

https://www.nationalarchives.gov.uk/currency-converter/

Also spelt De Bushia. His patron seems to have been Sir Philip Hoby:
https://www.british-history.ac.uk/letter.../pp546-582
https://en.wikipedia.org/wiki/Philip_Hoby

[Paul Ferguson]

Or fragments of the mineral perhaps, as discussed here:

The idea that the Vikings navigated across the Atlantic using birefringent Iceland spar (calcite) to locate the Sun's position on cloudy days is surely one of the most ingenious and captivating recent hypotheses about ancient materials use. The suggestion itself is an old one, but has been given strong support in new experiments by Ropars and colleagues.

A narrow beam of polarized light passing into the mineral is split into two by the optical anisotropy that causes birefringence. The 'ordinary' beam behaves as it would in glass; the 'extraordinary' beam is parallel but displaced from it, defying Snell's law. Light passing through a hole in a screen over a calcite crystal therefore forms two images on the far side. When the crystal is oriented to equalize their brightness, it completely depolarizes the light.

https://www.nature.com/articles/nmat3188

[Adam McLean]

I found this in  Carl Herrmann Gravel. Fontina Bernhardi revelata, 1750.

1. It is a mineral magnet, which attracts all metals to itself, as the common magnet does iron, and with which all mines can also be found, if one only makes a little rod of it, as in another common compass, and sets it on a point, then places it on the ground and in the place where one believes that there might be metals. Then one observes where the pointer is directed, and there, on the opposite line, one holds out to it a piece of fine gold; and if the mine is of gold, the pointer will stand still; but if it is a worse metal, it will push the opposed gold around and away from itself, since one can then put the gold away, and in the same way make an experiment with silver and all the other metals until one discovers what metal the mine has in it.

It may throw some light on the strange apparatus.