LARY BRIDGE. 213 



have already had, fully justifies the opinion,) that the 

 whole will be as compact and hard as many of our in- 

 durated rocks. The sectional form given to this 

 bottoming will be clearly understood, on reference to 

 the accompanying drawing of the bridge. 



All the masonry, with the exception of such parts of 

 the piers and abutments as are in contact with the iron 

 work, which is in granite, is built with lime-stone from 

 the neighbouring quarries, belonging to the noble pro- 

 prietor of the bridge. The piers and abutments are 

 built with wrought blocks, in sizes varying from two to 

 five tons each. 



As the strength of masonry depends much on the 

 goodness of the cement or mortar, particular care was 

 observed in preparing the mortar for the work under 

 water. One part of Puzzolana, to two parts of ground 

 blue Lias lime, were mixed under a mortar-mill, with 

 three parts of sharp clean sand, until the whole formed 

 a tough paste. Mortar of this description acquires the 

 hardness of Portland stone, in the course of a month, 

 though constantly immersed in water; but common 

 lime and sand mortar, prepared in the most careful 

 manner, will never acquire hardness under water, and 

 should therefore be avoided in such situations. 



The works were begun on the 4th of August, 1824 

 the first stone was laid on the 16th of March, 1825, and 

 the bridge was opened on the 14th of July, 1827 

 on which day her Royal Highness the .Dutchess of 

 of Clarence and suite first passed over it. * 



* The following inscription which was furnished by Mr. Waller, 

 and approved and amended by the late Right Honourable George 

 Canning, Mr. William Bankes, the Earl of Carlisle, the Rev. 

 Charles Young, and other scholars of eminence, is affixed to a block 

 ef granite, at the northern extremity of the bridge : 



HUNC PONTEM 



SENATUS AUCTORITATE SUSCEPTUM 



NOVAS ET COMMODAS VIAS 



RECLUDENTEM 



JOHANNES COMES DE MORLEY, 



SUIS SUMPTIBUS 

 STRUENDEM CURAVIT. 



