from the Museum of the Royal Irish Academy. 337 



leable iron in the first instance, but were ignorant of the methods of giving it 

 the properties of steel by any after-process, though it is plain from passages of 

 Greek and Roman authors* that the latter substance was known to them. The 

 subject, however, demands further investigation. 



Having concluded the account of the metallic antiquities, I proceed now to 

 the examination of some other objects, principally used for ornament. And 

 first of — 



PRECIOUS STONES. 



Of these I found seven varieties, at least according to the classification of 

 the jeweller, though not all distinct mineralogical species, viz. sapphire, beryl, 

 turquoise, garnet, amethyst, clear rock-crystal, and chalcedony. The deter- 

 mination of the periods when these were used as ornaments is of course 

 altogether an antiquarian question, and I do not know to what dates these 

 individual specimens are referred; but with the exception, perhaps, of some of 

 the articles of crystal, none of them seem to belong to the period of the Celtic 

 makers and users of the gold and bronze objects above examined. Some of 

 the amethysts found in crosses and other ecclesiastical relics are merely the 

 uncut terminations of quartz crystals of the common form, no part of the prism, 

 but only the hexagonal pyramid, being visible. Some of the sapphu'es, which 

 are small and uncut, have been most probably found in the county of Wicklow, 

 with rolled pebbles of the mineral occurring in which county they agree per- 

 fectly in external characters.^ 



Four beads of amber which I examined, of different degrees of transparency 

 and colour, were quite unchanged in chemical properties, and, except one, 

 presented nothing remarkable in appearance ; this, on being split, was found to 

 be white and nearly opaque (wax amber) in the interior, while the exterior, 

 including the surface of the hole, piercing the bead, was orange-yellow and trans- 

 parent, like the more ordinary variety of this substance, to a depth of about the 

 twentieth of an inch. This change of molecular condition must, I imagine, have 



* See Aristotle, De Mirab. Pliny, lib. sxxiv. c. 14. Dr. Pearson (Phil. Trans. 1796) found 

 all the supposed iron weapons, from Lincolnshire, which he examined, to consist of steel. 



t See the author's Examination of Gold Sand of Wicklow. Proceedings of Geological Society 

 of Dublin for 1851-52. 



