The Board of Commissioners for the Caledonian Canal, appointed by this • act, accordingly met, and made certain arrangements for the immediate com mencement of the work ; having, in the iirst•placei appointed Mr Thomas Telford to be their Engineer. He had formerly been employed by the Lords of the Treasury in making various surveys of the Highlands. But in so important an undertaking, the Commissioners judged it necessary to call to his assistance Mr William Jessop, another emi nent and experienced Engineer. Mr Telford, in structed by the Commissioners, proceeded immedi ately for Scotland, and again made an entire sur vey of the whole line of •the canal from Inverness to Fort-William. To ascertain the soil, trial-pits borings were made from shore to shore, at distances not exceeding half a mile. Mr Murdoch' Downie, an experienced Marine and Nautical Surveyor, was employed to make a survey of the chain of lochs upon the line, in order to sound and determine their respec tive depths and anchorages. The line of the canal, where cutting was necessary, was now carefully laid out. Stone and lime quarries, timber and other ne cessary materials were looked after, and some idea was formed•as to the probable value of the land to be passed through. Places were also fixed upon for the entrance-basins or sea-locks, at both extremities, and every possible information prepared for Mr Jar sop's survey, which took place in the month of Oc tober. He was met by Mr Telford. at Edinburgh, and these gentlemen proceeded together to a full ex amination of the whole ; and, upon this survey, Mr' Jessop reported his opinion to the Commissioners, and furnished an estimate of the expence. The chief difficulties alluded to in his Report, as inci dent to this great work, refer to the cattingnew:chan nels or courses for the rivers Ness, Oich, and Lochy, the deepening Lochs Doughfonr and Oich by excava tion,—the damming up and raising the surface of Loa Lochy, which is about ten miles and a half in length, to an additional depth of twelve feet,—the spilling or run ning off its floodwaters by a new cut into the River Speen ; and some extra cutting at the summit level between Lochs Oich and Lochy. But one of the most difficult parts of the navigation, is stated to consist in the deepening and management of Loch Doughfour. Mr Jessop seems to have been prepared to meet with rather an unfavourable soil for canal operations ; he was of opinion, that the whole valley between Loch Ness and ForteWilliam, has been one entire sheet of water ; and that the portions of land intervening between the lochs are the debris of the adjoining mountains. The first trial-pits dug in the neighbourhood. of Inver mess, did not fail to give some alarm upon this sub• ject, as the ground consisted of sand and gravel so open and porous, that the tidal waters of Loch Beauly flowed and ebbed through it. But on other • parts of the line of the canal, the gravel was found to have such a mixture of earthy particles as would be sufficient to render it impervious to water.
The extent of canal to be formed and cut, is stat ed to be about 24 miles, and the loch or lake navi gation at 87k, making a total distance of inland na vigation from sea to sea of about. 59 miles ; the bot tom width of the cutting 50 feet, withsdopes of 18 inches to a foot, with benchings at the water-line making the width at the surface to be about 110 feet.. general • dimensionsof the canal, though afterwards enlarged, were now estimated at 20 feet for the depth; the width of the locks is taken at 88 feet, and their length at 162 feet. The number of locks is estimat ed to be 28. They are to be built of masonry, with gates and platforms of American pitch-pme. After critically examining the whole intended line of the Caledonian Canal, its proposed dimensions, soil, materials and workmanship, Mr Jessop estimated the expence at the sum of L.474,581, including 8 per cent. for contingencies; but exclusively of the price of land, and the necessary moorings for the anchor at the respective lochs. Upon, a joint Report
ages afterwards by Messrs Jessop and Telford, this sum is proposed to be expended, and the works com pleted, in the course of seven years from the period of their commencement.
might " enable ships and vessels of considerable bur den, trading between the eastern and western coasts of Great Britain and Ireland, and the German Ocean to avoid a long and dangerous navigation round the northern coasts of Scotland ;" the Commissioners, considering also that the proposed dimensions of the works of excavation, viz. 20 feet of depth, 50 feet of width at bottom, and 110 feet at the surface wa ter-line of the canal, would admit and be sufficient to float a 32 gun frigate ; and as only a very small • addition to the original and annual expense would be incurred by enlarging the locks for that purpose ;— it was finally ordered, that the length of the locks should be increased from 162 to 172 feet, and that the breadth should be from 88 to 40 feet, the depth to remain at 20 feet as before intended. The Com missioners thought it •their duty to prefer this large scale of construction, as, although it would increase the expence, the canal would thereby be capable of affording an occasional passage to that class of His Majesty's ships, of which there was, at that pe riod, upwards of forty in the service, which must otherwise have been excluded from it. In this re solution, the Board of Commissioners had also in view the inereasing tonnage of merchant ships, as some of the vessels trading between Liverpool and the Baltic, approach to the dimensions even of these enlarged locks.
With a view to give greater facility to the passage of small vessels, and to avoid the consequent wear of the large locks, the Engineers had - been di rected to consider the propriety of constructing small side-locks for vessels of about 200 tons, which draw about twelve feet water, or of such dimensions as to correspond with the depth of the Crinan Canal. This appendage of small locks, it appeared, would have added to the original expence about L. 75,200; and considering that two, or even three small vessels might pass together through the large locks, the ad. vantages attending the side-locks appeared to be very uncertain, and the idea was therefore laid aside for the present. • • It appears from the first Report of the Commis sioners for making the Caledonian Canal, that the sum of L. 6052, 10s. 101d. had been expended in the preparatory measures for this great undertaking. In the Session of Parliament 1804, another act was passed, entitled, " An Act for making further Pro vision for making and maintaining an Inland Navi gation, commonly called The Caledonian Canal, from the eastern to the western Sea, by Inverness and Fort-William in Scotland." By this additional act, a further provision of L. 50,000 was made for this undertaking.