Petrus Peregrinus de Maricourt

"You must realize, dearest friend," Peregrinus writes, "that while the investigator in this subject must understand nature and not be ignorant of the celestial motions, he must also be very diligent in the use of his own hands, so that through the operation of this stone he may show wonderful effects.

Indeed, the increasing perfection of magnetic compasses during the thirteenth century allowed navigators such as Vandino and Ugolino Vivaldi to strike out on voyages to unknown lands.

The Nova Compositio Astrolabii Particularis (found in only 4 manuscripts) describes the construction and use of a universal astrolabe which could be used at a variety of latitudes without changing the plates.

But the association of the praise with Peregrinus appears only in a marginal gloss to Bacon's Opus tertium and only in one of the five manuscripts used in the critical edition, which leads us to conclude that it was a later comment added by someone else.

[11] This is considered a piece of plagiarism, as Taisnier presents, as though his own, the Epistola de magnete of Peregrinus and a treatise on the fall of bodies by Gianbattista Benedetti.

[12] The Epistola de magnete was later issued by Guillaume Libri (Histoire des sciences mathématiques en Italie, vol 2 [Paris, 1838], pp.

487–505), but, based on only one manuscript, this edition was full of defects; corrected editions were published by Timoteo Bertelli (in Bulletino di bibliografia e di storia delle scienze matematiche e fisiche pubblicata da B. Boncampagni, 1 (1868), 70–80)[13] and G. Hellmann (Rara magnetica 1269-1599 [Neudrucke von Schriften und Karten über Meteorologie und Erdmagnetismus, 10], [Berlin, 1898]) .

[14] The modern critical edition was prepared by Loris Sturlese and appears in Petrus Peregrinus de Maricourt, Opera (Pisa, 1995), pp. 63–89.

The modern critical edition of the astrolabe text was prepared by Ron B. Thomson and appears in Petrus Peregrinus de Maricourt, Opera (Pisa, 1995), pp. 119–196.

The European Geosciences Union (EGU) established the Petrus Peregrinus Medal in recognition for outstanding scientific contributions in the field of magnetism.