Between the western end of Loch Oich and the east ern end of Loch Lochy, a distance of about 2.-; miles, the surface of the ground is about 20 feet above the surface of Loch Oich, which, with the 20 feet depth of water, re quires a cutting of about -40 feet. Near the western ex tremity of this cutting, there are two locks, one lifting, and another a lifting and regulating lock. The fall from Loch Oich to Loch Lochy, after the latter has been (as intended) raised 12 feet, is about 9 feet 9 inches.
Loch Lochy is about 101 miles in length, and one in breadth ; its general direction is straight ; its depth from 5 to 76 fathoms, with various good anchoring 'places; there is one considerable bay on the north-west side, and at the north-east extremity, a singularly well protected roadstead. In order to avoid. rock-cutting at the south west extremity, the surface of the water in the lake is to be raised 12 feet above its former level ; and a new chan nel has been cut from it, by. which the river Lochy is carried into the river Spean, From Loch Lochy to the tideway at Loch Ell, a dis tance of about 8 miles, the canal is carried along the north-west side of the river Lochy, over ground of a rugged surface, intersected by one considerable river, and various small streams, all of which require aque ducts to pass the mountain torrents. A small distance from the.south-west end of Loch I.ochy, there is a regu lating lock, 170 feet in length, 40 in width, with a rise of two feet; but the ordinary sot face of the lake, after it is raised, will be continued to within one mile of Loch Eil, where there are eight connected locks or 180 feet in length each, and 40feet wide, and together descending 64 feet : from thence a level is continued to Corpach shore, where there are first two connected locks falling 15 feet, and one single sea-lock falling 7 feet 9 inches, which enters the tideway of Loch Eil. The chambee of this lock was excavated in rock, to afford 20 feet of water at high water of ordinary neap-tides. This con nection with the tideway, being to the westward of the general direction of the great valley, and there being good anchorage, an excellent roadstead is obtained.
From this haven, down Loch Eil, to the strait of Ard gower, a distance of about 9 miles, the inlet is about a mile in breadth, in a straight direction. This strait or
narrow of Ardgower, of half a inile in width, forms an entrance similar to that of Fort George, on the eastern side of the island. From this station onward south-west, to opposite the eastern extremity of the Sound of Mull, the arm of the sea is named the Linnhe Loch, it opens gradually to about nine miles in width, and is interspers ed with islands, the principal (Lisrnore) being about seven miles in length : they are composed chiefly of limestone, which, when calcined and mixed with clean sand, forms a mortar which hardens under water, and was, on that account, and its vicinity, a most valuable object to the canal works.
The inland navigation, when arrived at the Sound of Mull, falls into the present general track of shipping, which now passes by the Orkneys and Cape Wrath, and is therefore reckoned the western termination of this new line. of communication, which not only lessens the distance one half, but is free from the dangers and de lays to which the present circuitous one is subjected.
All the most difficult works upon this great inland navigation have been completed, and the whole is in such a state of forwardness as to afford a prospect of the communication between the two seas being opened by the latte.r end of 1821. The eastern part of it has been navigable for the last three years, with facility and safety. During 1820, upwards of 300 passages have been made. A steam boat has also plied upon it.
Having stated that the navigation by the Caledonian canal extended westward to opposite the island of Mull, and that the general track of shipping continued by the eastern side of Jura Isle, we then find a valuable ap pendage, named the Crinan canal. This forms a very direct communication with the southern extremity of the arm of the sea called Loch Fine, also the Firth of the Clyde, and opens the Greenock and Glasgow markets to the north-west parts of Scotland. By consulting. the map of that country, it will be seen that this canal saves the doubling the NIull of Cantyre, a slip of land about 60 miles in length; the passing round which, besides the great distance, requires two winds, ancl is also much exposed to the north-west gales, so frequent and violent in this quarter.