René Descartes  (1596-1650), Principia Philosophia (Amsterdam: Ludovicus Elzevirius, 1650), Zentralbibliothek Zürich, Alte Drucke und Rara, FF 91, p. 266

(more…)

Judith Albert

[ZB Magnet 3] Athanasius Kircher (1601-1680), Magnes sive De arte magnetica tripartium ( Köln: Iodocus Kalcoven, 1643), Zentralbibliothek Zürich, Alte Drucke und Rara, Z 113, p. 51.

Nicolaus Cabeus (1585-1650), Philosophia magnetica (Coloniae, 1629), Zentralbibliothek Zürich, Alte Drucke und Rara, TZ 117: 1, p. 9.

Nicolaus Cabeus (1585-1650), Philosophia magnetica (Coloniae, 1629), Zentralbibliothek Zürich, Alte Drucke und Rara, TZ 117: 1, p. 11.

These channels follow the length of the stone. Magnetic force (like water) passes through this channels.

Nicolaus Cabeus (1585-1650), Philosophia magnetica (Coloniae, 1629), Zentralbibliothek Zürich, Alte Drucke und Rara, TZ 117: 1, p. 6-7.

After a split, these channels continue to function.

Nicolaus Cabeus (1585-1650), Philosophia magnetica (Coloniae, 1629), Zentralbibliothek Zürich, Alte Drucke und Rara, TZ 117: 1, p. 110.

Does the position of the stone change the movement of the vessel in which the stone is placed?

Nicolaus Cabeus (1585-1650), Philosophia magnetica (Coloniae, 1629), Zentralbibliothek Zürich, Alte Drucke und Rara, TZ 117: 1, p. 111-112.

Cabaeus’ instruments are similar to Gilbert’s. But Cabaeus follows (in his emphasis on channels) another line of investigation. It leads him towards an understanding of magnetic forces as flux through channels.

Nicolaus Cabeus (1585-1650), Philosophia magnetica (Coloniae, 1629), Zentralbibliothek Zürich, Alte Drucke und Rara, TZ 117: 1, p. 49.

Nicolaus Cabeus (1585-1650), Philosophia magnetica (Coloniae, 1629), Zentralbibliothek Zürich, Alte Drucke und Rara,  TZ 117: 1, p. 79.

* [ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p.162.

(more…)

Long loadstone with versoria. Versoria deviate according to the distance from the middle or equator of the loadstone (CD). The deviations are greater the greater the distance of the versoria is from the equator. [ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 164.

[ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 155.
AB is a terrella imperfect in parts and of unequal power on the circumference. The needles H and L vary, because they are placed in a decayed part and incline towards the sound parts (where the needles C, D, E, F are placed). Needle O does not deviate because it is placed in the middle of the decayed part.

(more…)

Iron will obtain north-south direction when it is hammered and heated properly: “Let the smith stand facing north, with back to the south, so that as he hammers the red-hot iron it may have a motion of extension northward.” (Gilbert, De Magnete (translated by Mottelay) p. 211ff) [ZB Magnet 2] William Gilbert, De Magnete (London: Petrus Short, 1600), Zentralbibliothek Zürich, Alte Drucke und Rara, XVI.28, p. 139.

(more…)