Twenty years later, in 1793, Mr. Rennie was consulted as to the canal, and he also prepared a scheme: but nothing was done. The project was, however, revived in 1801 during the war with Napoleon, when various inland ship canals--such as those from London to Portsmouth, and from Bristol to the English Channel--were under consideration with the view of enabling British shipping to pass from one part of the kingdom to another without being exposed to the attacks of French privateers. But there was another reason for urging the formation of the canal through the Great Glen of Scotland, which was regarded as of considerable importance before the introduction of steam enabled vessels to set the winds and tides at comparative defiance. It was this: vessels sailing from the eastern ports to America had to beat up the Pentland Frith, often against adverse winds and stormy seas, which rendered the navigation both tedious and dangerous. Thus it was cited by Sir Edward Parry, in his evidence before Parliament in favour of completing the Caledonian Canal, that of two vessels despatched from Newcastle on the same day--one bound for Liverpool by the north of Scotland, and the other for Bombay by the English Channel and the Cape of Good Hope --the latter reached its destination first! Another case may be mentioned, that of an Inverness vessel, which sailed for Liverpool on a Christmas Day, reached Stromness Harbour, in Orkney, on the 1st of January, and lay there windbound, with a fleet of other traders, until the middle of April following! In fact, the Pentland Frith, which is the throat connecting the Atlantic and German Oceans, through which the former rolls its, long majestic waves with tremendous force, was long the dread of mariners, and it was considered an object of national importance to mitigate the dangers of the passage towards the western Seas. As the lochs occupying the chief part of the bottom of the Great Glen were of sufficient depth to be navigable by large vessels, it was thought that if they could be connected by a ship canal, so as to render the line of navigation continuous, it would be used by shipping to a large extent, and prove of great public service. Five hundred miles of dangerous navigation by the Orkneys and Cape Wrath would thereby be saved, while ships of war, were this track open to them, might reach the north of Ireland in two days from Fort George near Inverness.