From Stockport the Mersey serves as the boundary line between the counties of Chester and Lancashire. At Northenden, where its surroundings are rural and pleasing, it takes a sudden turn to the north, and after several twists runs decidedly and sharply to the north-west, till it gets to Stretford. Here it is in touch with the southern suburbs of Manchester, and is at its nearest point to that city. For its natural junction with the stream which leads to Manchester, we must, however, follow the river over what is now a tortuous westerly course, past Flickstone to Irlam. At this point, some nine miles from Manchester, the Irwell and the Mersey used to meet in confluence. They do so still, but under other than the old conditions. In the course of last century Manchester found it advisable to meet the demands of its increasing trade by making the Irwell, and next the upper parts of the Mersey, navigable for small vessels; and in the closing years of the nineteenth century she has caught up the waters of her own considerable tributary, and those of the main stream, in a series of capacious locks along that great water-way which has now made what Mr. Gladstone has called "the commercial metropolis of England" a great inland seaport. The Irwell is fed by more rivers than any other of Mersey's tributaries of the same length, and all along its course it serves manufacturing purposes, as the appearance of its waters betokens only too clearly. Rising in the neighbourhood of Burnley, it passes through Rosenstall, Tottington, Bury, and Radcliffe. At the last-mentioned place it receives the Roch, and then goes westward to Farnworth, where it is joined by the Tong. Taking next a south-easterly direction, it passes through Prestwich, and after a bend to the north of Pendleton it runs into Manchester. At Manchester the Irwell is fed by three other streams darker even than itself, these being the Medlock, the Irk, and the Cornbrook. The Irwell divides Manchester from Salford, but it is only by the black boundary line thus afforded that it is possible to tell where the one borough ends and the other begins. Each is distinct so far as civic and Parliamentary affairs are concerned; but in all that concerns their material well-being, they are one. Both are mentioned in the Domesday Book, and there are glimpses of them back to the Roman occupation.