572 Proceedings of the Royal Irish Academy. 



ance, to withstand tlie force and action of tlie water circulating 

 tkrough all the leakages that may be expected. I would, therefore, 

 urge, as absolutely necessary, should the tunnel be undertaken, that 

 it be lined throughout with masonry consisting of squared blocks of 

 the most resisting, impervious, and endurable stone. Obviously, how- 

 ever, this cannot be done except at an enormous expense — a matter 

 which may be safely left to be considered by capitalists. 



