NEWBRIDGE, a village (extensive and populous), in the parishes Of LLANWONNO, EGLWYSILAN, and LANTWIT-VAIRDRE, unions of CARDIFF and MERTHYR-TYDVIL, partly in the hundred of CAERPHILLY, but principally in the hundred of MISKIN, county of GLAMORGAN, SOUTH WALES, on the turnpikeioad from Cardiff to Merthyr-Tydvil, 12 miles (S. by E.) from Merthyr-Tydvil: the population is returned with the respective parishes. It is situated On both banks of the river 'I &f, which here receives the Rhondda, and derives its name from the celebrated bridge called Pont-y-Pridd, over the Tif: there are also three other bridges connecting the different parishes. Its sudden rise, and progressive increase and importance, are entirety owing to the mineral treasures of the neighbourhood, and to its favourable situation en the line of the Glamorgan-shire canal, midway between Merthyr-Tydvil and the sea at Cardiff. It has for some time been distinguished for a chain-cable manufactory, usually affording employment to about one hundred persons, and where, among many other large works, the suspension bridges across the Thames at Hammersmith, and across the Usk and the Tweed, together with the Brighton chain pier, were made. In that part of the village which is within the parish of Lantwit-Vairdre works have been erected for the manufacture of patent wrought iron railway plates; and, a little lower down the river, Mr. Crawshay, of Merthyr, a few years since erected numerous cottages for workmen, prior to the establishment of tin-mills, which are now completed and in full operation, and they are said to be the largest tin-mills in the world. The entire length of the village is not less than a mile; and a church has been recently erected in that portion situated in the parish of Eglwysilan, with the aid of a grant from the Church Commissioners. Pont-y-Pridd, otherwise called the New bridge, over the river Tif, forms a beautiful and picturesque object from the various points at which it is visible; but, owing to the steepness of its ascent, it is somewhat inconvenient to travellers on horseback, and is almost impassable for vehicles heavily laden, which ford the stream when practicable. It consists of one arch, a hundred and forty feet in the chord, and thirty-five feet in height above the level of the river at low water, forming the section of a circle of one hundred and seventy-five feet in diameter, which, at the time of its erection, was considered the largest stone arch in the world. At each extremity are three cylindrical holes, gradually diminishing in size as they approach the summits introduced to relieve the arch from the extreme pressure arising from its abutments; the diameter of the lowest is nine feet, that of the middle six, and that of the uppermost four. The architect was Mr. William Edwards, a native of the parish of Eglwysilan, and a self-taught genius, whose talents procured for him great distinction as a bridge-builder:- he first began the work, in 1746, by constructing a light and elegant bridge of three arches, which, in the course of about two years and a half after the period of its completion, was swept away by a flood of extraordinary magnitude, the mountain torrents having torn up by the roots several large trees, which, forming a dam as they floated along by the middle piers of the new bridge, caused a vast accumulation of the waters; and these, ultimately bursting through their barrier with irresistible force, carried. away the entire structure. Bound by the terms of the contract to maintain the stability of the bridge for seven years, Edwards conceived the design of earmouilting the difficulty by a structure of one arch, of the then unexampled width of a hundred and forty feet, from pier to pier, which he completed in 1751, having only to add the parapets; but, owing to the keystone of the arch being unable to resist the pressure of the abutments, the whole gave way and fell into the river. The luckless architect was thus driven a second time to the resources of his own fertile genius, to prevent the recurrence of so unpropitious an event; and adhering to his latter plan of a single arch, he contrived an ingenious method for diminishing the enormous weight that had previously forced the keystone out of its place, by constructing the cylindrical holes in the present bridge, already described, which enabled him to complete this curious and much admired edifice. There are several places of worship for dissenters, noticed in the parishes where they are respectively situated; and a branch of Mrs. Aldworth's school for female children, natives of Eglwysilan, has been established at Newbridge. Near the turnpike-road is a curious rocking-stone, which, however, has been much injured of late.