At Iversnaid we embarked in a steamboat which took us to the northern extremity of the lake, where it narrows into a channel like a river. Here we stopped to wait the arrival of a coach, and, in the mean time, the passengers had an hour to wander in the grassy valley of Glenfalloch, closed in by high mountains. I heard the roar of mountain-streams, and passing northward, found myself in sight of two torrents, one from the east, and the other from the west side of the valley, throwing themselves, foaming and white, from precipice to precipice, till their waters, which were gathered in the summit of the mountains, reached the meadows, and stole through the grass to mingle with those of the lake. The coach at length arrived, and we were again taken on board the steamer, and conveyed the whole length of Loch Lomond to its southern extremity. We passed island after island, one of which showed among its thick trees the remains of a fortress, erected in the days of feudal warfare and robbery, and another was filled with deer. Towards the southern end of the lake, the towering mountains, peak beyond peak, which overlook the lake, subside into hills, between which the stream called Leven-water flows out through a rich and fertile valley. Coaches were waiting at Balloch, where we landed, to take us to Dumbarton. Near the lake we passed a magnificent park, in the midst of which stood a castle, a veritable castle, a spacious massive building of stone, with a tower and battlements, on which a flag was flying. "It belongs to a dry-goods merchant in Glasgow," said the captain of the steamboat, who was in the coach with us; "and the flag is put up by his boys. The merchants are getting finer seats than the nobility." I am sorry to say that I have forgotten both the name of the merchant and that of his castle. He was, as I was told, a liberal, as well as an opulent man; had built a school-house in the neighborhood, and being of the Free Church party, was then engaged in building a church. Near Renton, on the banks of the Leven, I saw a little neighborhood, embosomed in old trees. "There," said our captain, "Smollet was born." A column has been erected to his memory in the town of Renton, which we saw as we passed. The forked rock, on which stands Dumbarton Castle, was now in sight overlooking the Clyde; we were whirled into the town, and in a few minutes were on board a steamer which, as evening set in, landed us at Glasgow. I must reserve what I have to tell of Glasgow and Ayrshire for yet another letter. Letter XXIV. Glasgow.—Ayr.—Alloway. Dublin, _July_ 24, 1845. I promised another letter concerning Scotland, but I had not time to write it until the Irish Channel lay between me and the Scottish coast.