At a period beyond the reach of history they obtained a knowledge of the use of both iron[872] and steel, the invention of which they attributed to Hephaistos.[873] Homer, who speaks of axes and other implements of steel, or, rather, of iron steeled at the edge, describes the process of forming it by immersion in cold water.[874] In the manufacture of the Homeric swords steel only would appear to have been, in most cases, employed, since they were extremely brittle, and often shivered to pieces by a mere blow upon shield or helmet. To guard against this effect the superior and more delicate articles were, in later times, cooled not in water but in oil.[875] The Spartans, we are told, quenched their iron money in vinegar which rendered it, they supposed, brittle and unmalleable, consequently of no value but as a token.[876] ----- Footnote 872: Palæphat. Fragm. ap. Gal. Opusc. Mythol. &c. p. 64, sqq. Footnote 873: Il. δ. 487. Footnote 874: Odyss. ι. 391. Footnote 875: Tenuiora ferramenta oleo restingui mos est, ne aqua in fragilitatem durentur. Plin. xxxiv. 41. Footnote 876: Plut. Lycurgus, § 9. Among the earliest nations who excelled in the smelting of iron and the manufacture of steel were the Chalybes,[877] who are said to have collected the ore from the beds of their rivers, and to have mingled therewith a certain quantity of the mineral pyrimachos. Aristotle, in describing the process of smelting, observes, that steel, in passing through the furnace, not only diminishes in quantity but in specific gravity also, that is to say, becomes less valuable. It was one merit of the Chalybean steel that it was not liable to rust. The method of preparing this metal which prevailed among the Celtiberians was this:[878] they buried a number of iron plates in the earth, where they suffered them to remain until the greater portion was converted into rust.[879] They then drew them forth and wrought them into various kinds of weapons, particularly swordblades, which were so keen that neither shields, nor helmets, nor sculls, were able to resist their edge. To this the complimentary Plutarch likens the language of the Spartans.[880] Footnote 877: Justin. xliv. 4. Plin. vi. 4. 34. vii. 57. viii. 82. Footnote 878: Diodor. Sicul. v. 33. Suid. v. μάχαιρα. t. ii. p. 108. c. Footnote 879: Aristot. de Mirab. t. xvi. p. 187. Meteorol. iv. 6. p. 119, seq. Footnote 880: Καθάπερ γὰρ οἱ Κελτίβηρες ἐκ τοῦ σιδήρου τὸ στόμωμα ποιοῦσιν, ὅταν κατορύξαντες εἰς τὴν γὴν τὸ πολὺ καὶ τὸ γεῶδες ἀποκαθᾴρωσιν, οὕτως ὁ Λακωνικὸς λόγος οὐκ ἔχει φλοιὸν, ἀλλ’ εἰς αὐτὸ τὸ δραστήριον ἀφαιρέσει τοῦ περιττοῦ διωκόμενος στομοῦται. De Garrulitat. § 17. -----