...rected 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 another stone guard lock. The canal is still used by the Talbot mills at North Billerica for the supply ...