Royal Irish Academy. 233 



Boyne, near Clonard, in the county of Meath, in raising gravel ; 

 and a fourth was discovered many years ago at a short distance from 

 Dublin. 



From the extreme degree of heat to which they appear to have 

 been subjected, and the consequent vitrification which has in some 

 measure taken place, they are quite as capable of resisting the 

 attacks of time as the glass and porcelain deities and ornaments 

 found in the mummy cases of Egypt, and may have lain for an in- 

 definite period beneath the surface of the earth. It is therefore, at 

 least, possible that they may have arrived hither from the East, 

 along with the weapons, ornaments, and other articles of commerce, 

 which were brought to these islands by the ships of the great mer- 

 chant-princes of antiquity, the Phoenicians, to whom our ports and 

 harbours were well known. 



Mr. Smith then called the attention of the Academy to the re- 

 markable discovery, by Rosellini, Lord Prudhoe, and other recent 

 travellers, of unquestionable Chinese vases in the tombs of Egypt. 

 He read a passage from Davis's China, in Avhich some of them were 

 described ; and also an extract from Wilkinson's Ancient Egyp- 

 tians, from which it appeared that the number of Chinese vases 

 found at Coptos, Thebes, and elsewhere, amounted to seven or 

 eight, and that the inscriptions on them had been translated by 

 Chinese scholars to mean, " The flower opens, and, lo ! another 

 year," being a line from an ancient Chinese poem. 



From this the trade of China with distant countries, at a period 

 of the remotest antiquity, being clearly proved, Mr. Smith sub- 

 mitted to the Academy that a case of strong probability had been 

 made out, that the porcelain seals found their way into Ireland 

 at some ver}^ distant period. In fact, if they be not of modern in- 

 troduction into this country — a supposition which the situations in 

 which several of them have been found seems utterly to preclude — 

 their arrival here must of necessity have been most ancient. 



January 13, 1840.— Sir Wm. R. Hamilton, LL.D., President, in 

 the chair. Professor Mac Cullagh made a communication respecting 

 the optical Laws of Rock-crystal (Quartz). 



In a paper read to the Academy in February 1836, and published 

 in the Transactions, (vol. xvii. p. 461), he had shown how the 

 peculiar properties of that crystal might be explained, by adding, to 

 the usual equations of vibratory motion, certain terms depending on 

 difi'erentlal coefficients of the third order, and containing only one 

 new constant c. This hypothesis, which was very simple in itself, 

 not only involved as consequences all the laws that were previously 

 known, but led to the discovery of a new one — the law, namely, by 

 which the ellipticity of the vibrations depends on the direction of 

 the ray within the crystal. He was not able, however, to account 

 for his hypothesis, nor has it since been accounted for by anyone. 



But the theory developed in the paper which he read at the last 

 meeting of the Academy, now enables him to assign, with a high 

 degree of probability, the origin of the additional terms above-men- 



