[123] Page 48, line 23. Page 48, line 25. arsenicum.—This is orpiment. See the Dictionary of metallick words at the end of Pettus's Fleta Minor.
[124] Page 48, line 23. Page 48, line 26. in convenienti cœlo sicco.—The observation that only in a dry climate do rock-salt, mica, and rock-alum act as electrics is also of capital importance. Compare page [56].
[125] Page 48, line 27. Page 48, line 31. Alliciunt hæc omnia non festucas modo & paleas.—Gilbert himself marks the importance of this discovery by the large asterisk in the margin. The logical consequence was his invention of the first electroscope, the versorium non magneticum, made of any metal, figured on p. 49.
[126] Page 48, line 34. Page 48, line 36. quod tantum siccas attrahat paleas, nec folia ocimi.—This silly tale that basil leaves were not attracted by amber arose in the Quæstiones Convivales of Plutarch. It is repeated by Marbodeus and was quoted by Levinus Lemnius as true. Gilbert denounced it as nonsense. Cardan (De Subtilitate, Norimb., 1550, p. 132) had already contradicted the fable. "Trahit enim," he says, "omnia levia, paleas, festucas, ramenta
tenuia metallorum, & ocimi folia, perperam contradicente Theophrasto." Sir Thomas Browne specifically refuted it. "For if," he says, "the leaves thereof or dried stalks be stripped into small strawes, they arise unto Amber, Wax, and other Electricks, no otherwise then those of Wheat or Rye."
[127] Page 48, line 34. Page 48, line 38. Sed vt poteris manifestè experiri....
Gilbert's experimental discoveries in electricity may be summarized as follows:
1. The generalization of the class of Electrics.
2. The observation that damp weather hinders electrification.
3. The generalization that electrified bodies attract everything,