Note 17 — Part I
Reading edition
To Peregrinus is due the first inception of the terrella. He makes the magnet round, and says, “You must know that this stone bears in itself a likeness of the heavens and contains two points, one North and the other South, thus resembling the poles of the sky....” In his Memoria Prima, “Sopra P. P. de Maricourt,” 1868, P. D. Timoteo Bertelli Barnabita states (Chap. VI. p. 22) that, besides the terrella, Gilbert appropriated other observations and experiments of Peregrinus, and, farther on (Chap. VII. p. 28), he gives us the following extract from Thévenot: “L’on voit encore que la pluspart des choses que l’on attribue à Gilbert et qui luy ont donné la réputation de Père de la Philosophie de l’Ayman estaient scües dès le treizième siècle.” This, says he (in a note, pp. 28–29), is doubtless an exaggeration. That Gilbert took from P. Peregrinus his terrella and many excellent scientific plans on magnetism, the ideas of others also, is probable, but it is indubitable that much was his own, and that, for his time, his work is a veritable chef-d’œuvre of inductive and experimental method and the most finished treatise on magnetism which had up to that time appeared.
In this connection, Bertelli adds (Part III. p. 92): “We must conclude that historical truth was undoubtedly distorted when, for so long a period, it was asserted and repeated, without any sufficient mature investigation, that the famous William Gilbert of Colchester was the real and sole founder of magnetism and of the inductive method in experimental science. We certainly must not deny him the no small merit which is his due, nor the share he had in the discoveries at the commencement of the seventeenth century, but we must, likewise, confess that the copious collection of facts which he gives us, and the experimental and discursive method with which he presents them is neither altogether his own nor is it new” (see W. Wenkebach, “Sur Petrus Adsigerius,” Rome, 1865, p. 8; “Universal Lexicon,” Leipzig, 1741; N. Cabæus, “Phil. Magn.,” Ferrara, 1629, p. 23).