Suspension Bridge at Paris. 241 



masonry, 01 other immoveable fixture, were deflected perpen- 

 dicularly downward at A, through hollow masses of building, 

 at the bottoms of which they were made fast. In order to 

 prevent these masses from being pulled inward, their sides next 

 the bridge were supported by buttresses of masonry, which 

 in their turn were sustained by platforms (as at C) resting on 

 piles. 



If this construction had been executed in strict consonance 

 with the theory which indicated it, the platform C would have 

 been at right angles, and the piles parallel to a line bisecting 

 the angle DAB formed by the chain, but the difficulty of driv- 

 ing piles when they deviate much from the perpendicular, pro- 

 bably prevented this from being done, and the masses as exe- 

 cuted had a tendency to a movement of rotation round the 

 point C. It could hardly be expected, under such circum- 

 stances, that this point should have remained fixed, even in 

 dry weather ; and, accordingly, it appears to have been from 

 this part of the structure yielding inwards, that the whole gave 

 way ; fortunately the scaffolding on which the roadway had 

 been formed, was still standing a few inches below it, and im- 

 mediately relieved the chains of a great portion of their load, 

 so that little damage was done to any part of the materials. 



The indication of approaching failure which struck me dur- 

 ing my short visit to the works of the bridge, was a vertical 

 fissure which had taken place in the masses AJB, the sides on 

 which the chains pressed having receded about an inch from 

 the opposite ones. This showed, that though the bridge had not 

 been fully loaded, the pull of the chains had overcome both 

 the resistance of the mass AC, and the adhesion of the mason- 

 ry in AB. This had happened although the season had been 

 remarkably dry, and it occurred to me that wet weather, by 

 softening the ground, would cause a complete subversion. I 

 understood afterwards (from report) that the great water main 

 from Chaillot, which passed between the masses and the bridge 

 about F, (and had perhaps contributed materially to their sup- 

 port) had been broken across by their pressure, and that the 

 escape of its water hastened the work of destruction. 



I may add, that considerable inconvenience seemed to have 

 been experienced from the triple ranks of chains having been 



VOL. VI. NO. II. APRIL 1827. (4 



