This is the first edition of the first work in which electrical repulsion is recognized and described. It is the second Latin book published on electricity, being preceded only by Gilbert's De Magnete. Wolf calls the discovery of electrical repulsion "the most significant of the century following Gilbert"¹³

The author, a learned Jesuit and professor of mathematics at Parma, investigated the magnetization of iron, now attributed to the inductive action of the Earth's field. He noticed that filings attracted by excited amber sometimes recoiled to a distance of several inches after making contact. He writes "Magnetic attractions and repulsions are physical actions which take place through the instrumentality of a certain quality of the intermediate space, said quality extending from the influencing to the influenced body... Bodies are not moved by sympathy or antipathy, unless it be by certain forces which are uniformly diffused. When these forces reach a body that is suitable they produce changes in it, but they do not sensibly affect the intermediate space nor the non-kindred bodies close by it..."
 

Cabeo follows Gilbert closely, although he opposed the views of his predecessor on terrestrial magnetism. He disproves sympathetic telegraphy, and gives diagrams of the magnetic (lover's) telegraph. In one chapter he institutes a comparison between electrical and magnetic attraction.


Rare, especially with the Ferrara imprint (copies were also published with a Cologne, 1629, imprint). "Copies of this first edition... are much sought after⁴ "

*Poggendorff I, 355; Mottelay, Bibl. Hist. of Electricity, pp. 109-10.