Mr Stevenson's Description of Bridges of Suspension. 241 
Menai Chain-Bridge,— The Straits of Menai, which sepa- 
rate the island of Anglesea from Caernarvonshire, have long 
formed a troublesome obstruction upon the great road from 
London to Dublin by Holyhead, by which the troublesome fer- 
ry of Bangor might be avoided. Many plans for the execution 
of this undertaking have also been agitated, chiefly in cast- 
iron, including a range of estimate from about L. 128,000 to 
L. 268,000 ; but that which is now acted upon, is a bridge of 
suspension upon the catenarian principle, the extent of which, be- 
tween the piers or points of suspension, is to be 560 feet, the esti- 
mate for which is only about L. 70,000. This, by many, has 
been considered a work of great uncertainty ; but the Union 
Bridge on this plan has already been executed on the Tweed, 
to the extent of 361 feet, as we shall afterwards more particu- 
larly notice. We shall now proceed to give some general account 
of the progress of malleable-iron bridges in Scotland, where this 
art, at least to any considerable extent, has been first put in 
practice in Great Britain. 
Galashiels Wire-Bridge.— We have already alluded to the 
great designs of chain-bridges for the river Mersey and the Straits 
of Menai. The first practical example, however, of this kind, was 
that over Tees, PI. VIII. Fig. 1 . The next malleable iron-bridges, 
which we know of in this country, were those executed on the 
river Tweed, and its tributary streams of Gala and Etterick. 
Mr Richard Lees, an extensive woollen-cloth manufacturer at 
Galashiels, whose works are situate on both sides of Gala-Water, 
conceived the idea of forming a foot-bridge, of slender iron-wires, 
for the conveniency of communicating readily with the different 
parts of his works. This gangway, or bridge, was erected in the 
month of November 1816; its extent is 111 feet, and it cost 
about L. 40. Though only of a very temporary, and even im- 
perfect construction, yet being the first wire-bridge erected in 
Great Britain, it deserves our particular notice, as affording a 
useful practical example of the tenacity of iron so applied, and 
of its utility in many situations, and particularly in an inland 
country such as the vale of the Tv^eed, where the carriage 
of bulky materials, of every description, is extremely expen- 
sive. 
Kings-meadow^s Wire-Bridge.— -The wire-bridge followed 
