_The Foyle River_ is navigable for 10 miles from its mouth, in the estuary of Lough Foyle, below Londonderry, up to Strabane. _The Lagan Navigation_ commences in the tideway at Belfast, and proceeds mostly by the course of the rivers as far as Lisburn, from which it is continued by a canal by Hillsborough and Moira to Lough Neagh. The total length is 28 miles. _The Lee River_ is navigable in the tideway up to the city of Cork, and for small craft somewhat farther. Below Cork, however, the navigation is principally an arm of the sea called Cork Harbour. _The Liffey River_ is navigable from its mouth in Dublin Bay for about 3 miles up to Carlisle Bridge, at the farther end of the city of Dublin. From the south side of this navigable part proceeds the Grand Canal, and from the north side the Royal Canal, of which we shall presently speak. _The Limerick Navigation_ commences at that city, and proceeds in a north-easterly direction, partly in the Shannon and partly by canals, for 15 miles, to Killaloe, at the south end of Lough Derg. _The Moig River_, county Limerick, is navigable from its mouth in the Shannon to near Adare. _The Moy River_, county Mayo, is navigable for about 5 miles, from Killala Bay up to Ballina. _The Neagh Lough_, or Lake, being about 20 miles long and 10 broad, is generally of sufficient depth to be navigable to a considerable extent in every direction. It communicates with Belfast by the Lagan Navigation, with the Tyrone Collieries by the Blackwater, with Antrim by the Antrim river, and southward with the sea by the Newry Navigation. _The Newry Navigation_ commences in the tideway of Lough Fathom, 3 miles below Newry, which it passes, and proceeds 16 miles by a canal to the Upper Bann River, in which it continues to Lough Neagh. The entire length is about 30 miles, generally in a northerly direction. This, which has always been a very imperfect navigation, was the first executed in Ireland. _The Slane, or Slaney River_, is navigable from its mouth in Wexford Haven, for 14 miles, to Enniscorthy. _The Suir, or Sure River_, unites with the Barrow in the estuary called Waterford Harbour, about 5 miles below the town, and is navigable from that up to Carrick for sloops, and to Clonmel for barges. At the town of Waterford the largest ships lie afloat in 40 feet water. _The Tyrone Colliery Canal_ commences at the south-west extremity of Lough Neagh, proceeding by a short cut across the isthmus of Maghery to the Blackwater River, and, following it a short way, passes by another cut of 3 miles to the Colliery Basin, from which a railway extends to the mines. THE GRAND CANAL.