From Merthyr downwards Taff flows fast, as if anxious to reach the sea from the uncomely rows of colliers' cottages which rise so thickly above it. It is still hedged about by mountains, but the mountains are not now "things of beauty." Quaker's Yard, Aberdare Junction, and Pontypridd are names of industrial value. At each of these places, "coal" railways from lateral valleys join the Taff Vale line. With these tributary railways descend tributaries for the Taff itself, the river Rhondda (which itself bifurcates higher up into the Rhondda Fawr and Fechan) being the most noteworthy for the volume of its water. The scenery of these affluents is, like that of the Taff itself, imposing, with deep glens and wooded dingles, but mercilessly cut about by capitalists. Pontypridd deserves particular mention for the famous bridge which gives it its name. In the words of a specialist, this bridge "is a perfect segment of a circle, and stretches its magnificent chord of 140 feet across the bed of the Taff, rising like a rainbow from the steep bank on the eastern side of the river, and gracefully resting on the western--the _beau idéal_ of architectural elegance." It is the supreme achievement of a local stonemason named Edwards, who, a hundred and fifty years ago, devoted himself to the construction of bridges much as a mediæval artist devoted himself to the Madonnas of his canvases or to his crucifixes. South Wales owes much to Edwards the bridge-builder: we shall meet with his work on the Towy and the Teifi as well as here. In 1755 this "_beau idéal_ of architectural elegance" showed to better advantage than now, when it is surrounded by the common buildings of a mining town; but it was never more useful than at present. [Illustration: THE PALACE GATEWAY, LLANDAFF (_p. 166_).] Hence, now wide in a shallow bed, and now narrow and rushing deeply between high banks, gaily wooded in places and mere refuse-heaps in others, Taff speeds towards Llandaff. Three or four miles ere it comes to this tranquil spot, a striking crag is seen on its left bank, with glorious beech woods clothing the steep red slopes of the rock. This is an historic spot: Castell Coch, or the Red Castle. It is such a site as in Rhineland would at one time have given a robber-baron a superb base for his depredations. As such, in fact, it was utilised. We read how, in 1158, Ivor Bach of Castell Coch descended upon Cardiff Castle and carried off the Earl and Countess of Gloucester as prisoners: the event is set forth on canvas in the Cardiff Town Hall. Nowadays the turret that rises above the topmost trees of the crag tells of other exploits. Castell Coch belongs to the Marquess of Bute, and it is here that the wine is grown which, in the opinion of some, is convincing proof that England might, if she would, become a viniferous country. In the Cardiff Exhibition of 1896 a stall was devoted to the sale of Castell Coch wines.