AT BROUGHTON. 391 



the corners of the pier, on which the pillars 

 stood, would be acted on by a vertical force of 

 307 tons, and a horizontal one of 32 tons ; the 

 tendency therefore to separate the pier slanting 

 in the form of a wedge must be very great. 

 The deflected link is only at one corner of the 

 bridge, and therefore that corner would be 

 exposed to half the above effect. 



6. To find the strength of the piers to resist 

 the forces in Art. 4. 



Should failure in the piers take place, it may 

 be in one of the following ways : — 



1st. They may slide in a mass toward each 

 other in consequence of the horizontal force, 

 which we have shown would in the extreme 

 case above be 332 tons. 



2nd. The fastening of the chain being by 

 means of a large disk of iron at a, the pier 

 might separate in some line ka; the part, 

 whereof k a H n k is a plane, turning round 

 a point K in the foundation. 



3rd. The pier might fail by the wedge whose 

 end is B A H being drawn upwards, all the rest 

 remaining undisturbed. 



