held by many even before the thirteenth century that ice could under certain conditions produce heat and even burn.[42] Footnote 40: P. ix, note. Footnote 41: C. xix. Footnote 42: Thus Solinus (pp. xxxiv, xxxvii, 236) says “the sea-ice on this island ignites itself on collision, and when it is ignited it burns like wood.” See Nansen, _In Northern Mists_, I, 193. Adam von Bremen (_Gesta Hammaburgensis Ecclesiae Pontificum_, iv, 34) writes: “they report this remarkable thing about it that this ice appears so black and dry that, on account of its age, it burns when it is kindled.” _Ibid._ The same belief appears in a German poem _Meregarto_: “Thereby the ice there becomes so hard as crystal, that they make a fire above it till the crystal glows.” _Ibid._, I, 181. Among the author’s scientific notions very little that is really original can be found. It is Riant’s belief that he drew to some extent from Oriental sources, the lore of the East having come into the North as the spoil of crusaders or as the acquisitions of Norwegian pilgrims.[43] It may be doubted, however, whether the Saracenic contribution is a real one: almost everything that the author of the _Speculum Regale_ presents as his belief can be found in the Latin scientific manuals of the middle ages. He alludes to the writings of Isidore of Seville, and there can be little doubt that he was acquainted with the ideas of the great Spaniard, though he does not accept them all. His ideas as to the shape of the earth and the probable causes of earthquakes may have been derived from the writings of the Venerable Bede, or from one of his numerous followers. The divisions of time are discussed in many of the scientific treatises of the middle ages, but the division of the hour into sixtieths called _ostenta_ is probably not found in any manual written before the ninth century; so far as the writer has been able to determine, _ostenta_, meaning minutes, first appears in the works of Rabanus Maurus.[44] Footnote 43: Riant, _Expéditions et Pèlerinages des Scandinaves en Terre Sainte_, 440-441. Footnote 44: Rabanus Maurus died in 856.