206 



and the pressure of this mixture on a unit of surface will be, as 

 before, k x number of molecules in the unit of volume. Hence, 

 denoting this pressure by P, we shall have 



vn + v'ri + v"?i" 



P=k _ ; 



and therefore 



VP = vp + vp' + v"p", 



the same expression as that deduced under the supposition of 

 non-mutual action. 



Mr. Haughton mentioned that Mr. Patton, the author of 

 the last paper, had forwarded to him a sum of money to pro- 

 vide a European collection of rocks and fossils, for the purpose 

 of promoting the advancement of science among the Hindoos. 



The Secretary exhibited an ancient circular piece of bronze, 

 containing figures on both sides, the property of Mr. Quinn, 

 of Belfast. 



The Rev. J. H.Todd, D.D., Secretary, exhibited an ancient 

 ecclesiastical bell, and read a letter from John Bell, Esq., of 

 Dungannon, relative to it. The bell is the property of Mr. 

 M'Clelland, of Dungannon, who has kindly permitted it to 

 be exhibited to the Academy. It is said to have been found 

 in the cabin of a poor fisherman, at Fahan, six miles north-west 

 of Deny, on Lough Swilly, in Innishowen, and was recently 

 purchased by Mr. M'Clelland. Fahan, or Fahan-mura, was 

 a monastery, dedicated to St. Murus or Muranus, and founded 

 by St. Columba (Colgan, Trias Thaum., p. 495 and 510). St. 

 Murus, second Abbot of this house, flourished in the begin- 

 ning of the seventh century, and from the fame of his sanctity 

 has since been reputed its patron. Of the relics preserved in 

 this monastery, Colgan mentions a MS. life of St. Columba, 

 in Irish metre, written by St. Murus himself ; a chronicle, also 



