Narratives of two excursions to the ports of England, Scotland, and Ireland, in 1816, 1817, and 1818 : together with a description of the Breakwater at Plymouth, and also of the Caledonian Canal / translated from the French of Charles Dupin ... and illustrated by notes, critical and explanatory, by the translator.

  • Dupin, Charles, baron, 1784-1873.
Date:
Between 1800 and 1899
Catalogue details

Licence: Public Domain Mark

Credit: Narratives of two excursions to the ports of England, Scotland, and Ireland, in 1816, 1817, and 1818 : together with a description of the Breakwater at Plymouth, and also of the Caledonian Canal / translated from the French of Charles Dupin ... and illustrated by notes, critical and explanatory, by the translator. Source: Wellcome Collection.

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    way will be driven right before the wind. It was also considered as extremely dangerous for a large ship to ply or turn to wind¬ ward, or merely even to navigate with a free or leading wind on a sort of canal, the bottom of which is, near the shore, strewed with trunks of trees and rocks, and, more in the offing, of an extreme depth *, while the collateral valleys which open into the great valley of the lochs or lakes, bring down sudden squalls, which tend forcibly to throw vessels on the opposite shore. These objections seem to have great weight, it is true, but they are exaggerated. In the first place, it is not correct to say, as has been asserted, that from one end to the other of Loch Ness, no safe anchorage can be found. It is sufficient for us to mention that of Urquhart, which is situated at one third of the route on the eastern side ; and there are other anchorages to the westward. With a view to ascertain whether, as has also been asserted, the winds always blow^ on the loch in the division of its length, a register of the winds, and state of the weather, by the barometer and thermometer, has been kept, since the year 1804 to the present day, at the two extremities and at the centre of the Caledonian Canal, that is, at Clachnaharry, Fort Augustus, and Fort William. These meteorological observations have proved, that the winds are nearly as subject to change in the great vale between Inverness and Fort William, as in other parts of the country.* But if, in certain times of the year, ships could not or durst not proceed against the wind, or rather in calms, the progress of the maritime arts furnish at the present day the means of ob¬ viating that inconvenience, by the means of steam-boats em¬ ployed for tracking. To conceive all the advantage of this new method of towing, let us suppose that we have a vessel which displaces as much water as the steam-boat, and which, in making the same progress or head-way, experiences the same resistance on the part of the fluid. In this hypothesis, the progress of the steam-boat, as well as the propelling power, being represented by a unit, that power applied to the two vessels will not produce merely a progress or rate of going equal to one and a half, or five-tenths, but a progress sensibly equal to seven-tenths. Therefore, from the effect of towing, not more than three-tenths of the progress of the steam-boat will have been lost. As to the possibility of towing vessels in this way on an extensive sheet of water, the experiments made towards the end of the year lSl7j in the Firth of Forth, between Leith and the entrance of the • From the 7th of April to the 24th of November, 1818, above one hundred and ^fty voyages were made upon Loch Ness, without accident or inconvenience. Translator.