82 Conciſe Account of Inland Navigation.[Aug. f-ven tons each, are caſily drawn out of the paſſage, where tw90s three or more are linked together, and drawn by horſes or mules to the place of their deſtination.

Fhe canal is in ſome places carried over the roads on arches, and in places where the arch is not high enough for carriages to paſs, the road has been ſunk, at a‘great expence, for the con- venience of the paſſage. But the moſt ſtupendous work on this canal is the bridge and aquedu& over the river Irwell. At Barton-bridge, three miles from the baſon, is an aquedu& which conveys thé canal over a valley for two hundred yards, and over the navigable river Irwellabove 40 feet higher than the level of the river. The canal is carried over the meadows on each fide of the river Merſey, and over a place called Saltmoor, at an incre- dible expence. Mr. Brindly proceeded thus: he cauſed trenches to be made, and then placed deal balks upright, ſo as to back and ſupport each other, ſupporting them by other balks, laid horizontally in rows, and ſecured together; thóuſands of oak piles were driven in between them; he then threw in the proper quantity of earth and clay, and cauſed it to be well rammed in. Having thus completed about forty yards, he removed his balks and pro=- ceeded again./ The bridge over the Irwell is of ſtone, and has three arches all of hewn ſtone; the center arch is ſixty-three feet wide, and will admit barges to paſs through with their ſails ſtanding. The river Medlock is raiſed, and ſupplies the canal with water by means of a fine wear, conſtructed in a curious manner.

The ingenuity diſplayed by Mr. Brindly through the whole of this work is ſurprifing. His ſmiths forges, his carpenters, and his maſons workſhops, were covered barges, which floated on the canal, and: followed the work as it advanced. The Duke had one great ádvantage, having all the neceſlary materials, timber. fone, lime, and coals, táken from his own eſtate.

In the ſeſſion of parliament, 1758-9, the Duke obtained an act to make a navigable canal from Worſley to Salford, near Man- cheſter, and to carry the ſame to Holien?s Ferry; but after he tad cornpleted the canal from Worſley to the highway between Warrington and Mancheſter, it was diſcovered that it would be hore beneficial to carry it over the Irwell, and to extend it to Longford-bridge. An a vras obtained for that purpoſe.

On a further ſurvey it was diſcovered that it was praticable to extend thé cañal from Longford-bridge to a place on the river Merſey, called the Hempftonesz a third ad was obtained for that purpoſe. The whole navigation was then proceeded on and completed, being more than twenty-nine miles in length, and having, at its fall into the Merſey, locks which let boats down ninety-five feet, for it is ſo contrived as to be on a leve! the whole length to that place. It may be proper to remark