[91] There was then a ford at Dumbuck, a few miles below Glasgow, which prevented boats of more than ten tons burden ascending to the Broomielaw. This was shortly after removed by the Clyde Trust, who have expended 3,564,397_l._ in improvement of the navigation between 1770 and 1863, the revenue collected during the same time in dues having been 2,288,000_l._ Vessels drawing 21 feet can now ascend to the Broomielaw; and when the present improvements are completed the depth at high water is expected to be upwards of 24 feet. Among Watt’s other labours about the same period may be mentioned his survey of a canal between Perth and Cupar Angus, through Strathmore; of the Crinan Canal, afterwards carried out by Rennie; and other projects in the western highlands. The Strathmore Canal survey was conducted at the instance of the Commissioners of Forfeited Estates. It was forty miles long, through a very rough country. Watt set out to make it in September, 1770, and was accompanied by snowstorms through almost the entire survey. He suffered severely from the cold: the winds swept down from the Grampians with fury and chilled him to the bone. The making of this survey occupied him forty-three days, and the remuneration he received for it was only eighty pounds, which included expenses. The small pay of engineers at that time may be further illustrated by the fee paid him in the same year for supplying the magistrates of Hamilton with a design for the proposed new bridge over the Clyde at that town. It was originally intended to employ Mr. Smeaton; but as his charge was ten pounds, which was thought too high, Watt was employed in his stead. The Burgh minutes record that, after the Act had been obtained in 1770, Baillie Naismith was appointed to proceed to Glasgow to see Mr. Watt on the subject of a design, and his charge being only 7_l._ 7_s._, he was requested to supply it accordingly. “I have lately,” wrote Watt to Small, “made a plan and estimate of a bridge over our river Clyde, eight miles above this: it is to be of five arches and 220 feet waterway, founded upon piles on a muddy bottom.”[92] The bridge, after Watt’s plan, was begun in 1771, but it was not finished until 1780.[93] [92] Watt to Small, 21st Dec. 1770. Boulton MSS. [93] The bridge was partially destroyed by a flood in 1806, when one of the central piers was thrown down. Two of the arches fell, and were rebuilt, but the others stand as originally constructed. [Illustration: HAMILTON BRIDGE.]