desire to effect a
compromise between the tried and the untried in bridge-construction.
But the use of iron to so limited an extent, and in such a part of the
structure, was of more than questionable utility; and if Mr.
Pritchard's plan had been adopted, the problem of the iron bridge would
still have remained unsolved.

The plan, however, after having been duly considered, was eventually
set aside, and another, with the entire arch of cast-iron, was prepared
under the superintendence of Abraham Darby, by Mr. Thomas Gregory, his
foreman of pattern-makers. This plan was adopted, and arrangements
were forthwith made for carrying it into effect. The abutments of the
bridge were built in 1777-8, during which the castings were made at the
foundry, and the ironwork was successfully erected in the course of
three months. The bridge was opened for traffic in 1779, and proved a
most serviceable structure. In 1788 the Society of Arts recognised Mr.
Darby's merit as its designer and erector by presenting him with their
gold medal; and the model of the bridge is still to be seen in the
collection of the Society. Mr. Robert Stephenson has said of the
structure: "If we consider that the manipulation of cast-iron was then
completely in its infancy, a bridge of such dimensions was doubtless a
bold as well as an original undertaking, and the efficiency of the
details is worthy of the boldness of the conception." [10] Mr.
Stephenson adds that from a defect in the construction the abutments
were thrust inwards at the approaches and the ribs partially fractured.
We are, however, informed that this is a mistake, though it does appear
that the apprehension at one time existed that such an accident might
possibly occur.

To remedy the supposed defect, two small land arches were, in the year
1800, substituted for the stone approach on the Broseley side of the
bridge. While the work was in progress, Mr. Telford, the well-known
engineer, carefully examined the bridge, and thus spoke of its
condition at the time:--"The great improvement of erecting upon a
navigable river a bridge of cast-iron of one arch only was first put in
practice near Coalbrookdale. The bridge was executed in 1777 by Mr.
Abraham Darby, and the ironwork is now quite as perfect as when it was
first put up. Drawings of this bridge have long been before the
public, and have been much and justly admired." [11] A Coalbrookdale
correspondent, writing in May, 1862, inf