MENAI BRIDGE. 399 



principal pillar on the Anglesea side; when, 

 with a board and a string and plummet, I 

 managed to take, probably without much error, 

 the angle of inclination to the horizon of the 

 top link or bar in the chain, on each side of 

 the pillar : the angle of the internal link was 

 16**. 10', that of the external, or link of the 

 side chain, l8^ 3'. 



Having these data*, and the area of a section 

 of the catenarian chain (which I believe is 

 uniform), we will seek for the strength of the 

 structure and the strains upon it; and then 

 make a few observations on chain bridges 

 generally. 



• As there may be some who would wish to know the 

 dimensions of the bridge in other respects, I will gl?e them 

 from the lar<(e plan, published by Mr. William Provis, the 

 resident engineer. 



Distance from center to center of the main pillars . . 579 feet. 



Span of the catenary 670 feet, versed line 43 „ 



Height from low water of Spring tides to the road-way. . 121 „ 

 Height from high water of ditto to ditto .... 100 „ 

 Height of main supporting pillars above ditto .... 50 „ 

 Span of each of the Stone Arches 62^ „ 



Total breadth of the road-way 28 feet, divided into a foot- 

 way of 4 feet wide in the center, and a carriage-way of 12 feet 

 wide on each side. 



Number of suspending cables 16, each composed of 5 bars, 

 and each bar having a section of 3^ inches of iron. 



Number of sets or lines of suspending chains 4. 



