The second bridge or Upper Arch (120 feet above the river) was constructed 34 feet above it in 1816 and "gave it an easier gradient" by removing the steep slope down to the old bridge. 1816 was a dramatic year as ... 1816. "On 18th March, happened the greatest flood ever heard of or seen in Kinross; all the burns were brimfull;" and later "On 13th August a smart shock of earthquake was felt throughout Kinross at 11 o'clock at night." Plates rattled on shelves; chairs moved about and were thrown over; beds shook, &c." There was also a "wet and late harvest" during which there was snow on four different occasions from five to six inches deep.'
The lower gorge is not easily accessible although Caldron Linn (one mile below Rumbling Bridge), accessed through fields by Powmill, is worth the effort and the 150ft slippery descent to reach it. The height of its fall was lessened in 1886 by rock fall. Here are two cataracts, 28 yards apart from each other. The upper fall, thirty-four feet in height, declines a little from the perpendicular; the rocks rise out of the channel, and there is one like a pillar, horizontal at the top, by which many persons have passed from one side to the other. Between these falls, the river has formed three round cavities, having the appearance of large caldrons or boilers. In the first, the water is perpetually agitated as if it were boiling; in the second, it is covered with a constant foam ; in the third, which is the largest, being 22 feet in diameter, it appears as if spread out in a large cooler.
These cavities are separated from each other by ledges of rock; they communicate, not by the water running over their brim, but by apertures about middle depth in their ledges, wrought out in the course of ages by the action of the water. The lower caldron discharges the water into the last fall through a similar aperture, having the appearance of a door or large window hewn out of the rock. Through this opening, the river rushes in one vast and rapid torrent over a stupendous pile of perpendicular rocks, into a deep and romantic glen.
The noise of its fall is tremendous, and the rocks seem to tremble to their centre, while the mind of the spectator is deeply affected by emotions of wonder and admiration. The height of the rock is 88 feet, and the fall 44 feet.
The most complete view of this magnificent scene, and of the deep and finely-wooded dell, is from the bottom of the great fall, where it has the appearance of a prodigious fountain gushing from the solid rock. It is beheld to most advantage between one and two o'clock in the afternoon, when the sun shines directly in front of it. A vapour constantly ascends from the pool; in sunshine this vapour exhibits all the colours of the rainbow, which, by the constant agitation of the air, disperse, and again appear in the most beautiful combinations.
The Caldron Linn, in short, is perhaps the greatest natural curiosity, and certainly one of the most sublime objects in Scotland. More than twenty years ago [c.1818] the following extraordinary occurrence happened at this place: a fox, which was hard pursued by a pack of hounds, led them along the banks of the river, till he reached the boiling caldron, which he crossed; the dogs attempted to follow, but being unacquainted with the path, they fell, one after another, into the caldron, and were drowned. Several years ago, a gentleman fell into the same caldron, and was extricated with the greatest difficulty."
The gorge is fairly dangerous. In May 1849, "James Anderson, a boy while bird nestling on the high rocks to the west of the Rumbling Bridge, lost his hold and fell [downwards] of a hundred feet, into the Devon. When taken up [his] life was quite extinct." And on 7 August 2002, after heavy rains and flash flooding, 16-year Alix-Ann Aisin MacKay fell into the gorge and died while swimming across it with a friend.
It was a very popular tourist destination even before the railway was built. The clear winding Devon," was celebrated by Robert Burns in his beautiful lyric, "The Banks of the Devon." Miss Charlotte Hamilton (afterwards Mrs. Adair), was the "Loveliest flower on the banks of the Devon" whom Burns met during a visit to the Cauldron Linn on Thursday 30 August 1787. She was at that time residing at Harvieston, near Dollar.