At the Waterfalls of Hofverud, the most interesting point of this canal, the rock on one side is almost perpendicular for 150 feet, while the other side of the stream is occupied by the ironworks of Hofverud. For this reason Ericson constructed an iron aqueduct over the fall of 110 feet span. This aqueduct has the form of an open box. The two sides for carrying the weight are wrought-iron bow girders, 10 feet deep at the middle and 6½ feet at the ends, of English iron plate ¼ inch. The bottom and top flanges are ½ inch and ⅛ inch thick respectively, formed of three layers of plates bolted together. The top flange serves as a pathway as well. The Dalsland canal rises 192 feet 6 inches by twenty-five locks, the summit level being 338 feet above the sea. The length of the navigation is 155 miles; but the actual length of the works that were needed to complete the system is only 4·8 miles. The locks on this canal are each about 98 feet 6 inches long, with a breadth of 13 feet 8 inches, and a depth over the sill of 5 feet 4 inches. The breadth of the bottom is 14 feet 6 inches and 15 feet 7 inches, in soil and rock, respectively. The canal is navigated by vessels of 70 tons, and steamers of 45 tons and 25 H.P. The traffic amounts to about 4000 vessels per annum. It was completed in 1868 at a cost of 81,500_l._ _The Kinda Canal_ rises 171 feet by fifteen locks to a level of 277 feet above the sea. The length of the navigation is 49½ miles, of which 22¾ is either artificial canal or trained river. The length of the locks is 90 feet 6 inches, breadth 18 feet 4 inches, and depth over sill 4 feet 10½ inches. The traffic is from 3000 to 4000 vessels per annum. It was completed in 1871 at a cost of 72,500_l_.