[358] Asphalt, alum, salt, soda, etc.
[359] Striped jasper.
[360] Unknown.
[361] Twenty-one of these are named.
[362] The information on military matters contained here and in bk. ix was drawn ultimately from the succession of Roman writers on military science. The chief of these were Frontinus, Hyginus, Vegetius.
[363] The title, De Spectaculis, and much of the material are drawn from Tertullian’s De Spectaculis. See M. Klussman, Excerpta Tertullianea in Isidori Hispalensis Etymologiis (Hamburg, 1892).
[364] Compare Tertullian, De Spectaculis, chs. 6–9.
[365] At this point in his work Isidore turns from the ‘sciences’ to the useful arts.
[366] For a similar subject and treatment, compare De Genere Navigiorum, in Nonius Marcellus’s encyclopedia. See [p. 43].
[367] For passages illustrating Isidore’s cosmology, see Etym., 2, 24, 2; 3, 52, 1; 3, 47; 9, 2, 133; 11, 3, 24; 13, 1, 1. See also pp. [50]–[58] and notes.