226 Proceedings of the Royal Irish Academy. 



prevailed in former times. This task was undertaken and carried out 

 to a definite conclusion by IS'ewton, as regards the Egyptian cubit or 

 cubits used in the construction of the great monuments of that 

 country, arid by other eminent savants as regards the units of Persia, 

 Babylonia, Greece, and Italy. It presents, therefore, a field of study 

 which has been cultivated by men of the greatest learning, and as 

 necessary for the proper understanding of the histories of the countries 

 mentioned as displayed in their monuments, works, and utensils. 

 The study of the ancient cills or oratories of Ireland, from this point 

 of view, would, I beg leave to submit, furnish data of the very 

 highest historical interest, and merits, therefore, the encouragement of 

 the Royal Irish Academy. 



EXPLANATION OF PLATES. 



Plate XIII. 



Fig. 1. — "Western elevation of Dalkey Island Church. 

 Fig. 2. — E. to W. vertical section of same. 



Plate XIV. 



Fig. 1. — Plan of old Church on Dalkey Island. 



Fig. 2. — Plan of St. Begnet's Church, Dalkey Town: showing orientation. 



Plate XV. 



Fig. 1. — Interior elevation of western gable wall of Dalkey Island Church. 

 Fig. 2. — Interior elevation of eastern gable wall of Dalkey Island Church. 



Plate XVI. 



Fig. 1. — Interior elevation of S.-E. window of Dalkey Island Church. 

 Fig. 2. — Interior elevation of S.-E. end window of Dalkey Town Church. 

 Fig. 3. — Vertical cross-section of this, N.-S. 

 Fig. 4. — Elevation of same, facing south. 

 Fig. 5. — Plan of same. 



Fig. 6. — E.-W. vertical cross-section of Dalkey Island, to show lie of ground, and 

 visual from Belfrey of Old Church towards eastern horizon. 



Plate XVII. 



Fig. 1. — Plan of Dalkey Island Church, to show relation of orientation ^dth Greek 



cross on rock to the "W. 

 Fig. 2. — Elevation of rock bearing Greek cross, Dalkey Island. 

 Fig. 3. — S.-E. opening in western end of St. Begnet's Church, Dalkey Town : 



N.-S. section, showing the angles of extinction of rays of sunlight. 



