369 



planation of the meaning of the term " cross-keele groats;" 

 and stated his opinion that it was the Irish word cpoc caol, 

 (cross-keale, or slender cross,) and that it was applied by 

 the native Irish to distinguish the groats of this period from 

 the other kinds with a broader cross, which were in circula- 

 tion. There are many instances of coins being denominated 

 from some peculiarity of their type, e.g. Angel, Salute, 

 Harpers, &c. 



Many other points of interest to numismatists were fully 

 considered in this communication, and accurate drawings of 

 the coins described were exhibited. 



Dr. Apjohn read a note by George J. Knox, Esq., "on 

 the oxidating Power of Glass for Metals, and on the want 

 of Transparency in ancient Glass." 



"In a late work, which treats of the manufacture of glass, 

 an experiment of Guyton Morveau is mentioned, in which 

 six per cent, of copper filings having been mixed with 

 pounded glass, and the compound completely melted, it was 

 found to have assumed a red colour uniformly diffused 

 throughout the mass, so deep as to render the glass nearly 

 opaque. The experiment originated from a workman in the 

 glasshouse having dipped a heated copper ladle into a pot 

 of fused glass. The copper ladle was melted; the casting 

 and annealing of the plates were proceeded with as usual; 

 and on their completion the workmen were surprised to find, 

 that not only were grains of metallic copper embedded in 

 the substance of the glass, but bands uniformly coloured of 

 a fine bright red, were distributed throughout the mass. 



" The experiment of Guyton Morveau, being but a repe- 

 tition of the accidental one made by the workman, seems to 

 have but little engaged his attention, the colour being con- 

 ceived to be due to an imperfect state of oxidation, as oxide 

 of copper imparts to glass a greenish colour. 



" It appeared to me, at first sight, that the red colour was 



