37 



bodies, which retain an electric charge on their surfaces, or 

 which, by a change of form from mechanical pressure or dif- 

 ference of temperature, exhibit differences of electric state. 

 In speaking of a charged electric, we may consider it a pile 

 of an infinite number of plates, each of which, except the 

 extreme surfaces, is composed of a surface of atoms, which 

 are acted on by two sets of induced electric forces, whose 

 differences, arising from their distances from the extremes, 

 we discover when we split the plate, or if it be a pile, when 

 we separate the plates from each other." 



January 11, 1841. 



His Grace the ARCHBISHOP OF DUBLIN, V. P., 



in the Chair. 



Rev. Henry Barry Knox, Rev. John West, Thomas 

 Fortescue, Esq., M. P., Chichester Bolton, Esq., and Henry 

 Coulson Beauchamp, M. D., were elected Members of the 

 Academy. 



The Rev. Thomas H. Porter, D.D., read a paper " On the 

 Deposits of Gravel in the Neighbourhood of Dublin." 



After detailing the facts commonly known as to the stra- 

 tified beds and ridges of limestone gravel, lying over the 

 great central limestone region of Ireland, and the continu- 

 ance of deposits containing a large proportion of rounded 

 pebbles and stones of the same material, over the granite 

 and other primitive rocks to the eastward of the limestone 

 country ; it was argued that there were clear indications of 

 a great diluvial action from west to east, by which the sur- 

 face of the limestone was reduced to its present level, and 

 the remains of its upper portions spread over the limestone 



