on site), from the Viaduct Works to the valley floor. The cast iron tubes and other castings came from Kennard's works at Falkirk, presumably by sea to Newport, and then by canal or railway to Crumlin. The canal basin was situated to the north of the viaduct site and so a length was drained and stopped off to provide a base for the first pier. The canal bed was excavated to a depth of fourteen feet on which a foundation was laid consisting of one foot of concrete, a course of four inch Memel timbers and finally a twelve foot course of masonry to which the baseplates were bolted. This procedure was followed for the other piers except where rock was encountered, in which case the rock was levelled and bolts sunk directly in to it. It should be explained that consideration was given to the building of a masonry bridge with iron superstructure, there being ample stone available in the vicinity, but the nature of the ground called for a lighter structure and the following comparisons ensured that the viaduct was entirely built of iron. Weight of stone pier 3300 tons Cost £ 4,116 Weight of iron pier 600 tons Cost £ 2,881 Two other factors in favour of the metal bridge were its ease of construction and shorter building time (one quarter that for a masonry bridge). The piers are constructed as follows. Each con- sists of fourteen hollow C.I. columns of one inch metal, twelve inches in diameter and seventeen feet long, connected by horizontal bracing and springing from three foot square baseplates secured to the foundations by twelve inch long ragbolts. The baseplates are set in an irregular hexagon, and all but two of the lines of columns leaned inwards to make a common form at the apex to accom- modate the horizontal girders, the maximum inclination being 1 in 12. The horizontal girders presented different problems being 150 feet in length, each being one-tenth of the total length of the bridge, ten to the main span and three in the span crossing the Kendon valley. They were fabricated on the floor of the valley and lifted into position by a steam winch, there being four girders to each span. A gang of twenty men, paid in total £ 5 per day, spent two days making and preparing each girder for lifting, then the third day was spent in lifting and securing each girder. The first was lifted successfully on 3rd December 1854, but the second collapsed and a man riding on it was killed. Subsequent girders were braced with timber until they were secured to the apex of their respective piers and no more accidents occurred. The last girder was lifted on 17th December 1855.