G.—ENGINEERING 123 
the ignorance in the mechanics of design of some engineers of those days. 
The wrong ideas of these men led to the suspension-bridge being regarded 
with suspicion for many years. 
A supposed improvement was introduced by a Mr. James Dredge, with 
the object of reducing the amount of iron required, and it was claimed 
also that his bridge was stronger and less flexible. Claims for the im- 
provement were demonstrated with models (which could not have been 
exactly representative) and the soundness of the construction was vouched 
for by those who were supposed to have expert knowledge, while the 
excellence of the scheme for building bridges according to the new prin- 
ciple was pressed by several eminent persons. After a large number of 
bridges had been built in this country and in India, all confidence in the 
type, and indeed in suspension-bridges generally, was severely shaken when 
a large bridge of Dredge’s improved type collapsed under its own weight 
when on the point of completion, and a second one failed to carry its test 
load and collapsed later. 
A patent for the above ‘ improvement ’ was granted to James Dredge 
in 1836 for a ‘ Taper Chain Bridge.’ Dredge conceived the notion that 
instead of carrying all the component links of the chain the whole length 
between the supporting towers and hanging the platform on vertical sus- 
pension rods, the links or components of the chain could be deflected 
down in a diagonal direction at successive intervals, and made to terminate 
at their connections to the platform and so displace the suspension rods. 
Thus in a bridge with eleven bays and ten cross girders, starting at the 
tower with six links in the chain at each side, the two outer links would 
be carried down diagonally from the tower to the first cross girder, 
leaving ten links (five on each side). Then from a point over the first 
cross girder the outer two links would pass diagonally to the second 
cross girder, and so on for the five bays, leaving only two links at the 
centre of the bridge. The scheme converted the bridge virtually into 
two cantilevers or brackets projecting from the towers towards the centre. 
The saving of iron was enormous, and appealed so strongly to those who 
advocated the new principle that exaggerated statements, in perfectly 
good faith, were made, as the following extracts from the journals of 
the day show. ‘Though fundamentally wrong, any criticism that may 
have been made was rendered ineffectual by the weight of the approving 
authority and by the difficulty experienced at the time with the Menai 
bridge. 
Lord Western wrote to the Editor of The Times as follows : 
‘ Sir, If you will notice, in any way, in your widely circulating paper the 
improvement in Bridge Architecture detailed in this letter of mine to 
Lord Melbourne, you will materially assist in bringing forward genius and 
the promulgation of an improvement in the department of science of 
considerable national importance, which is my only motive. 
‘On Saturday last I introduced Mr. Dredge, the Inventor of this 
improvement in bridge building, to the Marquis of Northampton, at his 
evening assembly. He brought his models and drawings with him, and 
they attracted great attention and admiration. On the Monday morning 
