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388 Intelligence and Miscellaneous Articles. 



have already mentioned, are fastened to large masses of masonry 

 beneath the surface of the ground, and this fastening is made, in 

 each case, by means of a large disk of cast-iron, to which the first 

 link of the chain is bolted. That link, instead of being composed 

 like the others of two round bars of iron, and joined to the next 

 link in the manner above described, is composed of a strap of iron, 

 about 3| inches broad, and is joined to the second link by a bolt 

 in the manner represented in the subjoined sketch. 



Now it must be very obvious to any person who has the slightest 

 acquaintance with matters of this kind, that the bolt in this link, 

 not being supported at the 



ends as in the one above 



mentioned, could not offer a 

 resistance nearly equal to the A 

 former, unless its dimensions j 

 were increased. But the bolt 

 used in each case was of the 



same dimensions, namely, two inches in diameter. The weakness of 

 the latter joint was also greatly increased by a circumstance, which 

 is not very well represented in the engraving, but which we can 

 probably explain to our readers. The bars forming the link A being 

 round, only a very small portion of their surface touched the bolt ; 

 and as they were two inches in diameter, the point of contact was 

 an inch distant from the side of the iron strap to which they were 

 joined by the bolt. The tension of the .chain therefore might be 

 considered as acting on the bolt with a leverage of an inch ; and, 

 under those circumstances it was not at all surprising that the bolt 

 should give way. Indeed it is probable that, even if it had been 

 iron of a fair average quality, the joint would not have borne more 

 than one-fourth, or perhaps one-fifth of the tension which the other 

 joints would bear. 



But the bolt, instead of being good metal, was composed of iron 

 which was either originally bacl, or had been rendered brittle by 

 mismanagement in the process of forging the bolt. It broke with 

 a granular and crystalline fracture, exactly like that of cast-iron, 

 and did not exhibit anything of the fibrous appearance of good 

 iron. Under these circumstances, the wonder is, not that the bridge 

 should have given way now, but that it should have stood a single 

 week after its erection. 



We understand it is intended to remedy the defect to which we 

 have alluded, not only in the chain which has given way, but in all 

 the other stay-chains, in which it equally exists ; and there can be 

 then no doubt that the bridge will be of abundant strength to bear 

 any load which is likely to pass over it. 



A defect occurred a long time ago in the disk or plate with which 

 the bolt was connected, and the necessary repairs were lately made 

 under the superintendence of Mr. Stephenson, a gentleman possess- 

 ing extensive knowledge in mechanics, and who resides on Mr. Fitz- 

 gerald's estate. It is due to him to state that the plate and bolt 

 have been minutely examined, and the fact has been clearly esta- 

 blished 



