[49] PAGE 9, LINE 22. Page 9, line 30. _Differentiæ priscis ex colore_.--Pliny's account of the loadstones of different colours which came from different regions is mainly taken from Sotacus. The white magnet, which was friable, like pumice, and which did not draw iron, was probably simply magnesia. The blue loadstones were the best. See p. 587 of Holland's translation of Pliny, London, 1601. St. Isidore (_Originum seu Etymologiarum_, lib. xvi., cap. 4) says: "Omnis autem magnes tanta melior est, quanto [magis] cæruleus est." [50] PAGE 10, LINE 29. Page 10, line 42. _Suarcebergo ... Snebergum & Annæbergum_.--In the Stettin editions of 1628 and 1633 these are spelled _Swarcebergs ... Schnebergum & Annebergum_. The Cordus given as authority for these localities is Valerius Cordus, the commentator on Dioscorides. [51] PAGE 11, LINE 3. Page 11, line 12. _Adriani Gilberti viri nobilis_.--"Adrian Gylbert of Sandridge in the Countie of Devon, Gentleman" is the description of the person to whom Queen Elizabeth granted a patent for the discovery of a North-West passage to China. See Hakluyt's _Voyages_, vol. iii., p. 96. [52] PAGE 11, LINE 17. Page 11, line 28. _Dicitur a Græcis_ [Greek: êraklios].--The discussion of the names of the magnet in different languages by Gilbert in this place is far from complete. He gives little more than is to be found in Pliny. For more complete discussions the reader is referred to Buttmann, _Bemerkungen über die Benennungen einiger Mineralien bei den Alten, vorzüglich des Magnetes und des Basaltes_ (Musæum der Alterthumswissenschaft, Bd. II., pp. 5-52, and 102-104, 1808); G. Fournier, _Hydrographie_ (livre xi., chap. I, 1643); Ulisse Aldrovandi, _Musæum Metallicum_ (Bononiæ, 1648, lib. iv., cap. 2, p. 554); Klaproth, _Lettre à M. le Baron A. de Humboldt, sur l'invention de la Boussole_, Paris, 1834; T. S. Davies, _The History of Magnetical Discovery_ (Thomson's _British Annual_, 1837, pp. 250-257); Th. Henri Martin, _De l'Aimant, de ses noms divers et de ses variétés suivant les Anciens_ (Mémoires présentés par divers savants a l'Academie des Inscriptions et Belles-lettres, I^{re} série, t. vi., I^{re} partie, 1861); G. A. Palm, _Der Magnet in Alterthum_ (Programm des k. württembergischen Seminars Maulbronn, Stuttgart, {21} 1867). Of these works, those of Klaproth and of Martin are by far the most important. Klaproth states that in modern Greek, in addition to the name [Greek: magnêtis], the magnet also has the names [Greek: adamas] and [Greek: kalamita]. The former of these, in various forms, _adamas_, _adamant_, _aimant_, _yman_, and _piedramon_, has gone into many languages. Originally the word [Greek: adamas] (the unconquered) was applied by the Greeks to the hardest of the metals with which they were acquainted, that is to say, to hard-tempered iron or steel, and it was subsequently because of its root-signification also given by them to the diamond for the same