This river is navigable for vessels of considerable burden so far as the mouth of the Irwell,--a distance of thirty-five miles from Liverpool. It derives its source from the confluence of several small streams on the Cheshire and Derbyshire frontier, and pursues a serpentine course, gradually inclining to the south-west. Its largest tributary is the Irwell, which falls into it near the village of Flixton, seven miles from Manchester. A little below Warrington, the Mersey expands into a broad arm of the sea, and turning abruptly to the south-west, contracts its channel as it passes Liverpool to about three quarters of a mile in breadth; but in proceeding farther inland, it again increases its width to more than three miles. This peculiarity is very advantageous to the port, as the great body of water, passing and repassing at every tide, keeps the navigation of the Mersey always open. A range of sand banks run parallel with the coast for many miles, but several channels intervene, giving sufficient depth for vessels of the heaviest draught at high water, at which time the Mersey presents the most interesting and striking scene,--particularly when a westerly wind favours the arrival of the numerous fleets destined to this port, bearing the flags and freighted with the produce of all nations that have found a place in the chart of commercial enterprise. [Illustration: CANNING DOCK AND CUSTOM HOUSE, LIVERPOOL. Dedicated to the Right Hon. Viscount Sandon, M. P.] CANNING DOCK AND CUSTOM-HOUSE, LIVERPOOL. Liverpool presents one of the most remarkable instances on record of the vast influence of commercial speculation, when pursued with steady vigour, prudence, and resolution. Commerce is the first step to empire, and, successfully prosecuted, never fails to consolidate the strength and independence of the state. To this important end no city in the kingdom has so amply contributed as Liverpool; none of our rivers, the Thames excepted, has wafted to our shores so many precious cargoes as the Mersey, nor exported so much of the produce of our native manufactures to all parts of the world. This great commercial city, rapid as its progress has been, is still advancing in the career of prosperity; hardly a month passes without some local improvement,--some substantial proof that her trade is on the increase, stimulating domestic industry, and affording the means of unlimited intercourse with every shore of the commercial world.