...ks, passing under the main street over an aqueduct across the brook-near which are some quaint old houses erected by the proprietors for the use of their employes —and through the long swamp to River Meadow brook , also crossed by aqueduct. Thence it was continued to Billerica, where it entered the Concord river by a stone guard lock, with a floating tow path, and passed out on the southern side through anot...