Page:Archaeological Journal, Volume 8.djvu/454

 35;J AIsTlENT BRITISH AND ROMAN BEADS. tion of my friend, Professor Voelcker, ^A'ho readily imdertook to render every aid his chemical skill and good laboratory offered. As the results are somewhat interesting in a chemical point of view, and I think such inquiries might, if not in a single case, yet by multiplied examinations, be made of great value to the scientific antiquary, J am inclined to lay a few notes upon the subject before the members of the Institute. The bead, (only a single specimen could be spared.) was of a Prussian-blue coloured glass, having three circular grooves at equal distances around its surface, which had been filled with a white paste or enamel. (See woodcut, No. 1.) 1. Brit'sli : Mue. with rings 2. l^ritisli : blue, with circlets 3. IJoman: light of wliits paste. of opaque glass. green. The analysis was performed in the usual mode ; the alkalis — Potash and Soda — were determined separately, by fusing the finely powdered glass with an excess of Carbonate of Bar^^tes. It fused with great diflSculty when exposed to a very strong heat, in this respect resembling the hard Bohemian glass, which is manufoctured into combustion-tubes for chemical purposes. A qualitative analysis showed that the glass of Avhich the bead was formed contained the following substances : — Silica, Alumina, in small quantity, Potash, Lime, "l o 1 -xf • r some traces, ooda, Magnesia, J ' Oxide of Iron, Oxide of Copper. In this analysis, two circumstances are especially worthy of attention, — Istly. The absence of Lead : and 2ndly. The presence of Oxide of Copper. The absence of Lead best explains the diflSculty with which the glass was fused; on this account, and the almost impossi-