The stone aqueduct, constructed by the Middlesex Canal Company in 1829 to replace an earlier wooden one, together with the lock at its western end were the means by which the canal crossed the Mystic River at the site of the present Boston Avenue bridge. The rebuilt aqueduct was 135 feet long with the stone abutments on each bank about a hundred feet apart. Supporting the aqueduct as it spanned the river were three massive stone piers. The aqueduct had an inside width of fourteen feet, with the surface of the water in it about ten feet above the water-level in the river at high tide; the trough was of timber and plank. The aqueduct remained in use until the canal was abandoned in 1852 after which it fell into decay until 1873 when the stonework served as the foundations for a highway bridge at Boston Avenue which was later superseded by the present bridge. (Christopher Roberts, The Middlesex Canal, 1793–1860, Cambridge, 1938, p. 195; Lewis M. Lawrence, The Middlesex Canal, Boston, 1942 [processed], p. 110.) The view illustrated is from a reproduction in The Medford Historical Register (volume 20, frontispiece [January] 1917) of an oil, unlocated, said to have been painted in 1865.