233 
Royal Irish Academy. 
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 which 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 very 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 Academ,y 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 
differential 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 any one. 
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- 
